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Pindell, J.L., and Kennan, L., 2007, Cenozoic Kinematics and Dynamics of Oblique Collision Between two
Convergent Plate Margins: The Caribbean-South America Collision in Eastern Venezuela, Trinidad and
Barbados, Transactions of GCSSEPM 27th Annual Bob F. Perkins Research Conference, 458-553.
Cenozoic Kinematics and Dynamics of Oblique Collision Between two Convergent
Plate Margins: The Caribbean-South America Collision in Eastern Venezuela,
Trinidad and Barbados
James Pindell and Lorcan Kennan
Tectonic Analysis, Ltd., Chestnut House, Duncton
West Sussex, GU28 0LH, UK
Email: [email protected]
Abstract
Numerous structural, tectonic, and geometric aspects of the Eastern South Caribbean Plate Boundary
Zone are assessed or reassessed in the light of seismic reflection data, field studies from 2000-2007, heavy
mineral analysis, updated interpretation of seismic tomography, seismicity, GPS data, and refined plate
kinematic constraints for the Cenozoic. We show that the Cretaceous passive margin of northern South America
was transformed to a north-facing, slowly convergent margin in the Late Maastrichtian, and that the collision
between the Caribbean and South America was a collision of two convergent margins above an intervening,
“doubly subducting” Proto-Caribbean oceanic lithosphere. The new assessments are iteratively integrated to
create semi-quantitative palinspastic reconstructions for 5, 10, 25, 31 and 42 Ma, on which paleogeographies are
developed. The origin of key sandstone units are considered, due to their importance as major reservoirs, as well
as the implications of the kinematic and dynamic modeling for structural timing. The primary collision between
the two plates was completed by 10 Ma, with subsequent motion being essentially E-W strike slip, the
deformations of which are driven mainly in a bow-wave model of transcurrent simple shear.
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Introduction
We present an updated synthesis of the tectonic processes and stages of history that have shaped Eastern
Venezuela and Trinidad during Cenozoic time. Throughout our analysis we seek to emphasise three primary
points. The first is that regional syntheses such as this one must be conducted in, as far as possible, a quantitative
palinspastic reference frame that retrogressively retracts deformations backwards through time. This requirement
is in addition to the definition of a rigorous but more regional plate kinematic framework. Second, in contrast to
the common perception of an ongoing transpressive collision between the Caribbean and South America in the
eastern South Caribbean Plate Boundary Zone (ESCPBZ), the last 10 million years of evolution at this boundary
have occurred under a regime of E-W dextral shear. It was only prior to 10 Ma (end Middle Miocene) that these
two plates underwent dextral oblique collision. Third, the collision prior to 10 Ma took place between two active
margins rather than an arc and a passive margin, because northern South America had already been converted to
an actively convergent margin before the Caribbean Plate began to collide with it.
We start with a summary of new perspectives on various aspects of the ESCPBZ. The new perspectives
are afforded largely on the basis of large volumes of (1) seismic data courtesy of Petrotrin, BPTT, Venture, the
Trinidad and Tobago Ministry of Energy and Energy Industries; (2) copious amounts of field work in parallel
with the seismic interpretation; (3) heavy mineral analyses of over 150 field and core samples from Eastern
Venezuela, Trinidad, and Barbados; (4) extensive thin section analysis of field and core samples; and (5) gravity
modeling of various key cross sections. The new perspectives allow us to identify the important tectonic
processes and elements of tectonic history within the plate boundary zone. It is seen that a “bow-wave” model
built around E-W shear is a highly satisfactory way in which to view regional development since 10 Ma. The
analysis also lets us develop a reconstruction for the end of the oblique Caribbean-South America collision at
about 12 Ma from which the transcurrent phase subsequently took over.
We then review and expand upon the arguments in favour of the development of a “Proto-Caribbean”
subduction zone along northern South America prior to, and unrelated to, the arrival of the Caribbean Plate from
the west. An important part of this is a comprehensive examination and interpretation of the mantle seismic
tomography of Van der Hilst (1990). This analysis in turn helps to establish a refined definition of regional plate
kinematics, in which we abandon the Cayman Trough as the primary yardstick for assessing CaribbeanAmerican relative motion rate, although it remains critical for understanding the general azimuth of motion. For
rate, we employ instead the kinematic requirements of the migrating Caribbean foredeep basin along northern
South America, which give a fairly steady South America-Caribbean displacement rate of 18 to 24 mm/yr back
to the Late Paleocene. This plate kinematic section establishes that both the Caribbean and South American
plates were convergently active margins at the time of their mutual collision, such that the collision was a
“prism-prism” or “trench-trench” collision. General concepts of such a collision are noted, and aspects of
regional geology are identified which support the concepts.
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Next, we employ the 12 Ma palinspastic reconstruction derived earlier in order to assess the structural
geometries and processes of the Early and Middle Miocene orogeny associated with the Caribbean-South
America collision in the ESCPBZ. Assessment of this orogeny simply cannot be achieved with any
paleogeographic rigour without first removing some 240 km of subsequent E-W strike slip offset from the
orogen. Identification and understanding of the primary structural elements of the orogen in palinspastic
coordinates in turn allows us to propose a Late Oligocene reconstruction for the margin which retracts the bulk
of deformations from the Serranía Oriental and Trinidad.
The Late Oligocene palinspastic reconstruction in conjunction with the regional plate kinematics allows
us to construct paleogeographic maps showing sandstone distributions and to identify tectonic processes for
northern South America at times prior to the “orogenic” phases of the ESBPBZ. In particular, various sandstone
units, which are important due to their hydrocarbon reservoir capacity, are related to those processes and
highlighted by the reconstructions. The provenance and causes of deposition of these sandstones could not have
been so rigorously identified had we not first completed the iterative procedures of all the above.
Perspectives on today’s Eastern South Caribbean Plate Boundary Zone
The eastern South Caribbean Plate Boundary Zone (ESCPBZ; Figs. 1A,B) is commonly perceived as a
site of ongoing dextral oblique collision or transpression involving a component of N-S contraction (e.g., Speed,
1985). This misperception is caused by the recognition of widespread SE-directed folding and thrusting across
the region (e.g., Case and Holcombe, 1980; Hung, 2005), as well as by the ongoing rapid subsidence in the large,
asymmetric Maturín-Southern Basin foredeep (e.g., Di Croce et al., 1999). However, the perception is not
strictly valid, because the relative motion between the Caribbean and South American plates in the ESCPBZ has
an azimuth of 085° (N85E), meaning dextral slip, and is occurring at 20 mm/yr. The 085° azimuth derives from
the style of young structural development (Robertson and Burke, 1989; Algar and Pindell, 1993), analysis of
seismicity (Deng and Sykes, 1995), and GPS motion studies (Perez et al., 2001; Saleh et al., 2004).
One way to explain this misperception is to invoke a dextral simple shear model on the entire region
(e.g., Robertson and Burke, 1989). Such a model predicts that the axis of maximum horizontal compression is
NW-SE, thereby explaining SE-directed convergent structures. This model certainly holds merit for much of the
regional structure, but it appears not to explain three important observations:
The first is the magnitude of the development of the Maturín-Southern Basin foredeep, because dextral
shear, on its own, does not provide a progressive increase in tectonic load large enough to drive the observed
subsidence (Fig. 2; Jacomé et al., 2003a,b).
The second is the drastic change in structural style at about 10 to 12 Ma noted by Algar and Pindell
(1993) and Pindell et al. (1998). The simple shear model, on its own, does not explain why the predominant
deformation style should change from SE-ward compression to E-ward extension at 10 Ma in various areas such
as the Gulf of Paria or the Maturín Basin. These authors showed that the 085° azimuth satisfies structural
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-67°
-66°
-65°
-64°
-63°
-62°
-60°
Lesser
Antilles
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)
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Guyana Shield
-67°
-66°
-65°
-64°
-63°
-62°
-61°
-60°
-59°
-58°
-57°
-56°
-55°
-67°
-66°
-65°
-64°
-63°
-62°
-61°
-60°
-59°
-58°
-57°
-56°
-55°
-54°
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ibbe
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-54°
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Venezuelan Basin
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FZ
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Bonaire Basin
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leo
ta
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Columbus Basin
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Maturin Ba
Escalera FZ
sin
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9°
edge tomographically defined
Carib lithosphere beneath
SoAm cont crust, dashed
where estimated
-68°
-67°
-66°
Barcelona Volcanic Wedge
(edge Carib crust) beneath
Serrania section
-65°
-64°
-63°
-62°
-61°
-60°
-59°
-58°
-57°
-56°
-55°
8°
-54°
Figure 1. A) Generalised structure map of the Southern Caribbean, including deep features such as the Proto-Caribbean Subduction Zone and the subducted Caribbean slab beneath Central Venezuela; B) Features relating to Caribbean-South America interaction, and the southern Caribbean Plate Boundary Zone, developed within the Caribbean “orogenic float”. The
background is Sandwell and Smith free-air gravity.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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0
NW
Mud diapir
2 Ma
4.5 km accom. space
2
4
Note orientation reversed to Trinidad-standard N. on left
Piggy-back basin
Pirital
5 Ma
2
10 Ma
4
El Furrial
25 km
Monagas Foothills and Foreland Thrust Belt
8
0
Maturin Basin
“Regional”
6
S
6
Modified from Jacomé 2003b, Line 1, El Furrial area
8
Figure 2. Cross-section of the Maturín foreland basin, through El Furrial, modified from Jacomé et al., 2003b. Note that
Middle Miocene thrust structures are buried by Late Miocene and younger sediments. Only very minor post-10 Ma shortening can be seen in the section, and yet there is over 4.5 km of accommodation space developed since that time, more than
during the Middle Miocene imbrication of Serranía Cretaceous strata.
A
10 Ma
Lines from Ysaccis, 1997
A
10 Ma
B
B
From Ysaccis, 1997
C
D
10 Ma
C
10 Ma
D
Lengthening in associated basins is used to estimate NCFZ offset
Figure 3. Selected seismic lines modified slightly from Ysaccis (1997). A) N-S line extending from Araya to La Blanquilla
Basin showing compressional structures within upper layer of Caribbean Plate developed in the Caribbean “orogenic float”
prior to ca. 10 Ma. B) Similar pre-10 Ma structures immediately north of Margarita and the western end of the La Blanquilla
Basin. C) Close to the Bocas High, Northern Range metasediment is present on the south end of this line. Original seismic
in this area locally shows pronounced south-dipping reflectors within the Patao (Tobago Terrane) metavolcanics and close to
the contact with the Northern Range, suggesting that many thrusts in this area are north-vergent, not south-vergent as suggested here, and that Caribbean basement beneath the basal detachment to these thrusts may wedge underneath the Northern
Range. This event is dated by the pre-10 Ma thrusts and appears to post-date the south-vergent high-level emplacement of
the leading edge of the Caribbean Nappes over Araya-Paria. D) Apparent cumulative west to east extension on rightstepping pull-aparts along the NCFZ, off the north coast of Araya-Paria, can be used to estimate the maximum slip on the
NCFZ. Including young basins as far east as Tobago, we conclude that probably not more than ca. 25 km dextral slip
occurred on the NCFZ since 10 Ma, and larger measured offsets on older structures are probably older than 10 Ma. There
are no through-going lineaments along this fault zone, in contrast to the very sharply defined El Pilar-Caroni-GuaicoScorpion Fault trend.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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development back to about 10 Ma only, prior to which the Caribbean and South America were undergoing a
much more compressional collision (see Fig. 18A, developed below).
The third is the emplacement of allochthonous Caribbean rocks, such as the Villa de Cura Complex of
the Caribbean Mountains and the basalts drilled in the Gulf of Barcelona (Ysaccis, 1997), up to 100 km south of
what is commonly perceived as the main Caribbean-South American shear zone (i.e., the Morón-El Pilar fault
system). It is difficult to imagine the emplacement of these bodies, involving up to 100 km of lateral
displacement from the fault zone, as petals of a positive flower structure.
From the above, a two stage evolution apears to be required, and 10 Ma seems to mark the transition
from a more convergent phase of evolution to a more transcurrent one. In the following sections, we will
characterise the present ESCPBZ and construct the bow wave model for tectonic development over the last 10
m.y., and restore the post-10 Ma deformations to reconstruct the orogen at the end of the convergent phase.
Aspects of the tectonics of the Eastern South Caribbean Plate Boundary Zone
Aspect 1
The trace of the southeastern edge of crystalline Caribbean crust is curvilinear, trending E-W along the
El Pilar Fault but curving around to N-S at Barbados (Fig. 1). As we shall see, this is critical for understanding
the regional deformation history since 10 Ma.
Aspect 2
Seismic data north of Trinidad and Araya-Paria Peninsulas suggest that structures originally formed
during early to Middle Miocene oblique compression have been subject only to relatively minor transpressional
or transtensional reactivation since 10 Ma (Fig. 3; Ysaccis, 1997; Robertson and Burke, 1989). Seismic lines
show thrusts with northward structural vergence within what is usually mapped as Patao-Tobago Terrane
volcanic arc. Some lines also show what appear to be south-dipping thrusts very close to the edge of the
Northern Range, and limited well data suggest that some of the highest level rocks drilled off the north coast
have affinity with Northern Range rocks or the Sans Souci and Toco Formations than with true Tobago Terrane
(primitive island arc) and may be remnants of the proposed “Proto-Caribbean Accretionary Prism”. These thrusts
must merge at a detachment several kilometres deep and thus Caribbean crust below this detachment probably
underthrust the Northern Range during the Middle Miocene (Fig. 4). This is no longer a simple thrust
relationship except in relatively small areas, but has been modified by low magnitude dextral shear north of
Trinidad since 10 Ma. There does not seem to be any significant through-going, large offset, shear zone that
could act as the principal plate boundary. A summation of the apparent offsets on transtensional and
transpressional structures along the North Coast Fault Zone leads us to propose no more than about 25 km
dextral offset between Tobago and the Northern Range, increasing west to perhaps 50 km north of Araya (GPS
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A) Location map
-65°
14°
-64°
-63°
-62°
B) Serrania (Cumana) cross-section
-61°
-60°
-59°
-58°
PILAR SERRANIA
SSE
0
CARIBBEAN
PLATE
13°
MARG
NNW
-57°
14°
South American Crust
13°
Base of “orogenic float”
12°
12°
100
11°
South American Lr. lithosphere
Carib. Lr. lithosphere
Caribbean wedged
beneath Serrania
11°
EL PILAR
DGE
SE
AN
NR
MAFIC WE
10°
SE
T IO
SE C
N IA
400
500
9°
0 km
N
-64°
300
N
IO
CT
8°
-65°
200
GE
A
RA
9°
100
10°
Basement sliver, above
ca. 20 km detachment
-63°
-62°
-61°
-60°
C) Port of Spain cross-section
NNW
ARC
0
50
100
-59°
150
200
-58°
Distributed
dextral shear
250
8°
-57°
Post-rift passive
margin section Foreland basin fill
NCFZ ELP CRF
SSE
South American Crust
Base of “orogenic float”
100
South American Lr. lithosphere
Carib. Lr. lithosphere
Caribbean wedged beneath
backthrust and Northern Range
100
200
Basement sliver, above ca. 20
km detachment
300
400
500
600
Figure 4. A) Location map, and lithospheric-scale cross-sections through B) Cumaná (Serranía Oriental, Venezuela) and C)
Port of Spain (Northern Range, Trinidad), showing the interpreted wedging of Caribbean forearc lithosphere under the
Araya-Paria-Northern Range Terrane at a depth of ca. 10-20 km. This is accommodated in part by backthrusting of the
upper most Caribbean crust and associated sediments and in part by south-vergent thrusting of the Cretaceous and possibly
Jurassic strata of the former passive margin, with slices of basement also possibly present within the northern part of this
thrust belt. The key feature of these sections is that there is not a steep lithospheric scale strike-slip fault zone separating
Caribbean lithosphere in the north from South American lithosphere in the south. We show Caribbean crust overthrusting
South American basement beneath the underthrust wedge and extending 100-150 km north of the surface trace of the El
Pilar Fault, consistent with tomographic data. This deep “flap” of South America is limited in the north by the former ProtoCaribbean Subduction Zone, and continues up dip to the east to emerge at the trench east of Tobago. The strike-slip faults,
such as the North Coast Fault Zone (NCFZ), the El Pilar (ELP) and Central Range Fault (CRF), which cut the thrust belt
that had developed by 10 Ma, are inferred to root into the north-deepening basal detachment of the thrust belt at depths of ca.
20 km under the Central Range, 25-30 km under the Gulf of Paria, and perhaps 40 km under the El Pilar Fault near Cumaná.
During Middle Miocene orogeny, the bivergent “orogenic float” structural style developed, but since 10 Ma, CaribbeanSouth America motion has largely been accommodated by strike-slip on the El Pilar Fault and Point Radix-Darien Ridge
Fault, and by reactivation of compressional features only on the south side of this strike-slip belt. Middle Miocene compressional structures within the Caribbean have largely been dormant since 10 Ma (see seismic line examples in Fig. 3).
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data from Perez et al., 2001 and seismic lines from Ysaccis, 1997). Furthermore, offsets on Late Pleistocene to
Recent sediments along the NCFZ are small to non-existent, indicating that the structure has not been active for
perhaps 1 Ma or more, as also indicated by the GPS data. East of El Pilar Village near the El Pilar Fault in the
Serranía Oriental, the Carupano and Tobago platform crust likely continues beneath the Northern Range to about
the trace of the El Pilar Fault. West of El Pilar Village it does as well, but there it also is present on the south
side of the El Pilar Fault, and probably at two different structural levels (see Aspects 13 and 14). In summary,
the Northern offshore area does not seem to have been a strongly transcurrent part of the plate boundary zone
since 10 Ma, implying that most relative motion since that time has passed farther south, through onshore
Trinidad.
Aspect 3
The active El Pilar Fault, which appears to accommodate most Caribbean-South America motion in
Venezuela is commonly shown as continuing along the line of the “Arima Fault” at the southern foot of the
Northern Range. Both transtensional and transpressional models have been proposed for this fault , but neither is
supported by seismic lines. Marine seismic data east of the Northern Range (“North Basin” area) in the area
where the Arima Fault is commonly presumed to exist show that no such fault exists there. Instead, the Northern
Range rocks continue SE-ward beneath a Late Miocene SE-dipping unconformity onlapped NW-wards by latest
Miocene-Pleistocene strata. Thus, the strike-slip displacement on the El Pilar Fault cannot track along the foot of
the Northern Range. However, Caroni Basin onshore seismic data do show a continuous approximately E-W
zone of stratal disruption along the line of the Caroni and Guaico Rivers (Figs. 5 and 6), rather than on the
northern edge of the Northern Basin. This zone shows transtensional graben structures were it trends slightly SE
and pop-up structures where it trends slightly NE. Faults along this line break all reflectors to the surface, and
separate slightly incised Pleistocene and older strata to the south, from still subsiding, swampy river valleys to
the north. We propose that this disrupted zone overlies the eastward continuation of the El Pilar Fault across
northern Trinidad , and we call this the Caroni Fault Zone. Offshore to the east, its continuation is seen in a
narrow graben which swings SSE from the El Pilar Fault near the Dragon’s Mouth and intersects the coast about
5 km south of the Caroni River delta. In the eastern offshore, the Caroni Fault passes south of the “North Basin”
homocline and merges with active fault traces trending 065° along the north side of the Central Range. Overall,
the proposed Caroni Fault is more laterally continuous, narrow, through-going and younger a lineament than the
North Coast Fault Zone.
Aspect 4
GPS data (Saleh et al., 2004) show that effectively all Caribbean-South America relative motion (20
mm/yr) is occurring south of the Northern Range today, through central Trinidad (Fig. 7). About 75% of it (15
mm/yr) appears to be distributed along the Central Range and probably the Point Radix Fault Zone, while a
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-63°
-62°
20 mm/yr
-61°
Newly defined “Caroni Fault”
Fig. 6
El Pilar
S
Gu
Ju
an
Darie
Fig. 9
an
oc
Gr
ab
e
S. Fran. Ft n
o
Hi
gh
Pt. Radix F
Los B
ajos
ge
n Ri d
CO
t
TPS?
To
p
K
25 km
Caribbean
lithosphere
10.5°
B
sh
elf
faults since 10 Ma
faults since ~3 Ma
thin-skinned thrust, SoAm basement, continental in Gulf of Paria, oceanic to east
Figure 5. Map showing main displacement loci during post-10 Ma transcurrent phase, and position of Caroni seismic line
(Fig. 6). The trace of the newly-defined Caroni Fault Zone across northern Trinidad, from Piarco to Guaico is shown. In
Mid-Miocene time, Caribbean crust (green) had abutted against SoAm crust, an outer wedge of which (red) was caught up
between the plates during thrusting. Late Miocene shear on the blue faults stretched this wedge in the northern Gulf of Paria,
forming that basin, and controlling Manzanilla deposition. These faults are still active, but were joined in Pliocene (yellow
faults) by deep deformation jumping south and west into San Juan Graben and Southern Range. Los Bajos Fault was active
in both phases, but it is unclear where Late Miocene strain on it was accommodated eastward. Central Range activity now
steals most displacement formerly on Point Radix-Darien Ridge. San Francisco Fault may be involved in this later phase.
Also shown is the location of a semi-balanced strike-line (Fig. 9) through the Gulf of Paria from which east-west extension
can be estimated.
Caroni FZ
N
0
1
TWTT
0
Talparo
Springvale
Springvale?
Manzanilla
2
S
CARONI BASIN
Guaico?
1
Manzanilla
Guaico
Brasso
3
Guaico
2
Cretaceous?
NW-SE normal
faults sole into
top Couva?
4
3
4
2500 m
5
5
Figure 6. Example seismic line across the Caroni Basin near Piarco Airport, showing still active structures along the proposed “Caroni Fault”. Similar transtensional graben or transpressional pop-ups are found in a continuous through-going
fault zone from the Caroni Swamp to the Guaico River and Oropuche Swamp. The structures define the northern boundary
of the mapped, incised Talparo and older strata on the geological map of Trinidad, and is narrower and more continuous
than the North Coast Fault Zone. Furthermore, the fault zone merges offshore with the very young “Scorpion” Fault which
runs just north of Angostura. Off the east coast there is no sign of the trace of the Arima Fault along the line most commonly
drawn (e.g. Robertson and Burke, 1989; Saunders et al., 1997) and thus we infer that this lineament, with the Central Range
Fault and Darien Ridge Fault farther south, is in fact the locus of much of the strike-slip between the Caribbean Plate and
South America, and that the North Coast Fault Zone has been less significant, at least since 10 Ma.
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-82
16
-80
-78
-76
-74
-72
-70
-68
-66
-64
-62
-60
16
20 mm/yr
14
14
12
12
10
10
Anaco F.
El Baúl
CANOA (Stable SoAm)
8
-82
8
-80
-78
-76
-74
-72
-70
-68
-66
-64
-62
-60
Figure 7. GPS vectors for Caribbean motion relative to South America. Red vectors come from Perez et al. (2001) and black
vectors from Weber et al. (2001) and Saleh et al. (2004). Note that in the Trinidad region CA-SA motion is uniformly
towards ca. 085° at 20-21 mm/yr. In Trinidad, these magnitudes of eastward motion continue as far south as the Central
Range Fault, indicating that the Northern Range is effectively riding passively with (and probably on) the Caribbean Plate.
North of Carupano Village perhaps as much as 25% of the relative plate motion is occurring on the North Coast Fault Zone.
Thus, there must be a southward step in plate motion between here and the Northern Range, possibly through the area of the
Dragon‘s Mouth, which appears to be undergoing east-west extension, leading to subsidence and drowning of coastal valleys in northwesternmost Trinidad (e.g. Diego Margin and Tucker Valley).
S
N
10 Ma u/c
10 Ma u/c
pre-10 Ma thrust stack, eg Brighton, with Nariva Fm on backside
“pseudo-10 Ma
unconformity”
(footwall of low angle
detachment fault)
section
line
North Marine
footwall
South Boundary
Fault (mud ridge)
post-10 Ma hanging wall,
continental crust with KMid-Miocene cover
fault merges with El
Pilar/Caroni Fault
Manzanilla (pink) in “half graben”, cut
in Plio-Pleistocene by South Boundary
Fault after significant transtensional
opening, growth recorded by
Springvale and younger (yellow).
From Flinch et al., 1999.
Figure 8. Schematic cross-section of the Gulf of Paria low angle detachment basin, showing the South Boundary Fault Zone
reactivating a formerly slightly extensional (ca. 5 km) strike-slip (up to 50 km) fault. Also shown is a location map of the
major through-going strike-slip zones in the Gulf of Paria.
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minor amount occurs along the Southern Range or even farther south in submarine extensional faults of the
Columbus Channel. However, seismic data as well as the general paucity of basement-depth seismicity in central
Trinidad suggest that the active fault zones dip north and pass beneath the Northern Range, and are not high
angle faults into deep central Trinidadian basement (Fig. 4). The actual “basement-level, or petrologic, plate
boundary” lies beneath the Northern Range.
Aspect 5
The E-W trending strike slip fault zones of the ESCPBZ were initiated at about 10 Ma within a preexisting Middle Miocene compressional orogen with SW-NE-trending structures which formed primarily during
oblique Caribbean-South American collision. These include the Morón, El Pilar, Caroni (see below), South
Boundary, Point Radix (see below), and Los Bajos (SE-trending but motion was eastward; see below) faults.
Sedimentation (e.g., La Pica, Morichito, Cruse, Manzanilla Formations)in the transtensional basins controlled by
these faults (Cariaco and Gulf of Paria basins) and overlying the earlier compressional orogeny began at about
10 Ma close to the Middle to Late Miocene boundary (Erlich and Barrett, 1990; Algar and Pindell, 1993; Babb
and Mann, 1999). In addition, after widespread Middle Miocene uplift and erosion across the Tobago and
Carupano platforms, subsidence and sedimentation were renewed there in the Late Miocene as well (Bellizzia,
1985; Yssacis, 1997).
Aspect 6
The Gulf of Paria is an extensional basin which formed at the site of a right step splaying off the dextral
El Pilar Fault. Seismic data in the Gulf of Paria Basin (northern part of the geographic Gulf of Paria) show a Late
Miocene to Recent N-ward collapsing, rotational half-graben geometry that is bisected by an E-W high-angle
transcurrent fault zone (Fig. 8), the South Boundary Fault (referred to erroneously by some authors as the Warm
Springs Fault), which runs close to the southern edge of Blocks 1ab. The basin on the whole is a low-angle
extensional detachment basin within the pre-existing Serranía-Nariva thrust belt, the unroofed footwall of which
is the northern flank of the E-W trending North Marine Ridge. The “hanging “wall” is now a series of NW-SE
trending ridges (e.g., Avocado, Domoil, Gulf Highs) in the northern half of the basin that are buried by Late
Miocene and younger basin fill strata, and that have been extended E-W during basin extension to form the
intervening troughs between the ridges. Thus, the basin has undergone three-dimensional strain, extending
eastward while collapsing northward. Eastward extension is far larger (up to 70 km; Fig. 9) than northward
detachment (~5 km), such that actual fault plane motion directions were toward azimuth 080°-085°. The
detachment surfaces formed entirely within the pre-existing Middle Miocene thrust pile, the lowest thrust-sheet
of which appears to be a slice of South American basement (see Fig. 4) overlain by 2-3 km of Neocomian
evaporite (post-rift Yucatán Platform type, not rift-related) and younger Cretaceous strata. There may be a preevaporite marine (Upper Jurassic) section as well (Pindell and Erikson, 1994), but this has not been reached by
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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Restored Cuche and El Cantil to original thickness.
Apparent extension ca. 50 km
E
0
Talparo
TWTT
1
2
3
Cret.
10 km
0
1
2
Couva
4
TWTT
W Rescaled to near 1:1
3
4
Figure 9. Strike-line in the Gulf of Paria (modified from Flinch et al., 1999, location shown on Fig. 5) shows strong west to
east extension of Cretaceous carbonates with low angle normal faults cutting through the Couva evaporates and ultimately
rooting into the basal detachment of the older Middle Miocene Fold-Thrust Belt. We have taken a number of approaches to
estimating the extension, using offsets of seismic markers across faults (line-length balancing) and the approach shown here
(area balancing). If we outline the area on the section occupied by Cretaceous carbonates we can restore these to a reasonable estimate of their pre-extension thickness. This in turn yields an extension estimate for this line of about 50 km. Using
all these approaches, we have estimated a total extension between the San Juan Graben, in the eastern Serranía, and the
Caroni Basin, in Trinidad, of about 70 km.
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wells drilled to date. The basement slice in interpreted to have been involved in the Middle Miocene thrusting,
and is displaced SE-ward by about 40-50 km (i.e., we infer that it drove the shortening of Cretaceous strata from
the Brighton area to the south coast), such that it is not a classic “thick-skinned” style of deformation; rather, it is
a thin-skinned basement-involved thrust deformation. This parautochthonous slice sits above the northwarddipping autochthonous South American footwall and subjacent to the allochthonous migrating Caribbean crust,
which is situated in turn beneath the Northern Range metasediments. Thus, the basement slice has been sheared
between the two stronger, more intact plates since 10 Ma, which is probably why it has been extended E-W so
much in the Gulf of Paria Basin. The slice probably continues eastward (although broken) into the western part
of the Caroni Basin, and westward back towards the Urica Fault. Beneath the Serranía, it is probably the same
basement slice as has been proposed to be present in the hanging wall of the Pirital Thrust (Roure et al., 2003).
Extensional detachment faults controlling Late Miocene strata within the Gulf of Paria low angle
detachment basin reach westward to the NW-trending coastline along the northwestern Gulf of Paria. However,
the westernmost “head” of extensional detachment faulting jumped westward in the middle Pliocene (~2-3 Ma)
to at least the San Juan Graben of the Serranía Oriental as shown by seismic, and probably (i.e., no proof from
seismic) to the San Francisco Fault. This younger system of faults cuts through the entire Serranía Oriental thrust
pile southward to the Middle Miocene deformation toe. This is farther south than the Late Miocene-Early
Pliocene boundary of the basin; both these fault zones tie directly into the diapir trend of the eastern Maturín
Basin, which is the western part of the transfer zone that continues into the Pedernales-Southern Range trend.
Eastward extension on this younger system is on the order of 5 km, and this strain has been carried eastward
along the Pedernales-Southern Range trend all the way to Galeota (or the western Columbus Channel normal
faults). The effect of the shift was to incorporate more of the Middle Miocene thrust pile (i.e., all of it) into the
zone of eastward collapse; the former (Late Miocene-Early Pliocene) footwall of the detachment basin now
(since 2 or 3 Ma) lies in the hanging wall. In contrast, transtensional dismemberment of the previously
mentioned basement slice appears to have controlled the position of Late Miocene-Early Pliocene basin
development.
Aspect 7
The Los Bajos Fault Zone has a deep expression and history that has not been fully appreciated in the
past (Fig. 10). The Los Bajos Fault sensu-stricto is a high angle, dextral transcurrent fault zone with up to 11 km
offset (Wilson, 1968). However, the anastomosing faults in the fault zone project downwards to the trailing tip of
a hanging wall above a NW-SE trending, NE-dipping low angle detachment fault between the Brighton (hanging
wall keel) and Soldado Highs (top of footwall). The shallow, relatively steep, faults do not pass through this
detachment surface. This detachment occurs within the Middle Miocene thrust pile only and may have originated
as a dextral, east-dipping, lateral ramp. Judging by offset of the 10 Ma unconformity on the hanging wall relative
to that on the footwall, the hanging wall has undergone a net normal throw of about 5 km since 10 Ma. The
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Middle Miocene (15 – 10 Ma)
Herrera fairway?
local splays
“Soldado” Footwall
top Nariva/Brasso
“Nariva” Hanging Wall
?
Los Bajos F
ault (dee
p)
Sole of thrustbelt
Late Mio-Early Plio. (10-3.5 Ma)
10 Ma u/c
Soldado Footwall
Late Plio.-Pleistocene (< 3.5Ma)
10 Ma u/c
Cruse
Cruse Fm is thicker, was closer to
original footwall, than was the Manzanilla Fm.
Cruse
Manzanilla
Los Bajos Fault (shallow)
Manzanilla
10 Ma u/c
Lateral ramp appears
to be transtensional.
Top Nariva may be
offset by more than
the 10 Ma unconformity (above BrassoHerrera) is.
Post-10 Ma fault
displacement is about
5.1 km in E-W direction, or about 2.6 km
when measured normal to fault strike.
Upper level structural
style of Los Bajos
Fault (LBF) requires
strike slip: shear stress
is not tranferred to
footwall, so half graben does not invert in
typical fashion.
Figure 10. Synthesis of the geometry and history of the Los Bajos Fault Zone. This “typical section” derives from seismic
lines offshore Point Fortin. The fault as commonly mapped is at the upper level only, an anastomosing set of dextral, mainly
transpressive faults cutting to surface with a collective offset of 10 to 11 km (Wilson, 1968). But a more significant, deeper
control underlies this upper level within, and probably cutting through, the Cretaceous-involved Middle Miocene thrustbelt.
The precursor to the fault is an east-dipping lateral ramp separating the Soldado and Brighton Thrust stacks, and SW Peninsula from the structurally higher imbricate stack in the Moruga-Guayaguayare area. During the Late Miocene this lateral
ramp was reactivated as a down to the east extensional fault (“Soldado Breakaway”), which bounded a Manzanilla (possibly
even Lengua?) depocenter on the NE side of the Soldado Main Field and which reached the surface close to the crest of the
Main Field (clearly delineated by drilling, with almost all Main Field wells drilled in the footwall of the fault). Subsequent
SE-directed thrusting on the east side of the breakaway (forming the Rock Dome thrust culmination) reactivated this detachment, but faulting splayed vertically off the detachment at the edge of the more competent Cretaceous units in its hanging
wall (which can be traced on seismic up-dip towards Brighton) rather than cutting at a shallow angle through the incompetent Cruse and Springvale. As a result, the “neotectonic” Los Bajos Fault is seen as a more or less vertical fault zone, with
positive flower structures indicating an overall slight transpressive inversion, that can only be traced to base of the Late
Miocene section. What has not previously be recognised is that the undulations in the “10 Ma unconformity surface” into
which the Los Bajos Fault appears to root are in fact the trace of a Manzanilla-aged half-graben and associated breakaway
fault, and not the result of compressional deformation. Thus, there is no deeper vertical expression of the Los Bajos Fault
and the strike-slip roots east into the base of the Rock Dome thrust sheet. Seismic data in the Soldado area also indicate that
Los Bajos offset predates the base Talparo unconformity in the North Field area, placing important constraints on the age of
the Rock Dome Thrust, and also explaining why the Los Bajos Fault cannot be traced through the area of thick Talparo NW
of North Field to link with the South Boundary Fault; it does link, but only at a sub-Talparo level.
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azimuth of motion since 2 or 3 Ma is parallel to the surface trace of the fault, and the strike-slip displacement
runs along the low-angle detachment at depth and then cuts upward at a high angle toward the surface. From 10
Ma to about 3 Ma, however, the only provable displacement was the above-noted extension, whose azimuth we
estimate was toward about 080° in order to cohere with regional structural development of that period. The SEward directed component of motion along the fault since 3 Ma has been fed into the shortening accumulated at
the Rock Dome fold/thrust and, to a lesser degree, the tightening of the Moruga fold/thrust to the south of Rock
Dome. This model can help explain the termination towards the northwest of the shallow Los Bajos Fault; SWNE trending folds appear to link to a similar trending fault to the SW, very close to the surface trace of the Late
Miocene low-angle detachment fault. Furthermore, the apparent disappearance of the Los Bajos Fault towards
the NW is also in part explained by its being overlapped by the basal Talparo (Pleistocene) of the Gulf of Paria,
indicating that it may be largely inactive since ?Middle Pleistocene time; thus is does not cut through the thicker
Talparo section in the that area.
Aspect 8
Between San Fernando and Point Radix, the geological map of Trinidad (Kugler, 1996) shows an
apparent dextral, en-echelon, displacement of structures. De Verteuil and Eggertson (2000) called this zone the
Point Radix Fault, and pointed out that the trend continues eastward offshore to define the southern edge of the
Darien Ridge. The supposed Rio Claro “Boulder Beds” (Saunders, 1974, stratigraphic chart, in Kugler, 1996)
occur directly along this trend, but Liska (1988) studied these in a 30 m trench cut for a gas pipeline and
determined that the “bouldery appearance” was in fact a tectonic melange (fault breccia) with numerous vertical
faults running E-W. Since then, Saunders et al. (1997) accordingly have removed the “Rio Claro Boulder Beds”
from the stratigraphic lexicon included with their map, acknowledging that the bouldery texture was produced
tectonically. Smaller apparently dextral offsets are seen in the alignment of slivers of Lizard Springs on the north
side of Dunmore Hill and in the abrupt E-W strike changes in Cipero Formation strata between Debe and St.
Croix. The tectonic rupturing of the section is testament to the existence of the Point Radix fault zone. In
addition, our seismic mapping in the Southern Basin seismic data set has shown this entire belt to be completely
disrupted, no coherent reflectors being correlatable from N to S across it. The zone does, however, dip to the
north, and presumably ties into the detachments beneath the Central Range and eventually into those beneath the
Northern Range. To the east in the offshore, this trend marks a primary structural boundary defining the Darien
Ridge, and recently one or more mud volcanoes leading to intermittent island formation have erupted along it
(see http://www.gstt.org/Geology/radix/Radix%20event%202007.htm). To the west, the Point Radix Fault ties
into the South Boundary Fault of the Gulf of Paria Basin, which cuts upward through young section from the
primary trace of E-W displacement through that basin. Balancing of E-W seismic sections across the Gulf of
Paria (see Fig. 9) suggests that total post-10 Ma extension is as large as 70 km. Realignment of the two known
sandy portions of the Nariva Formation (i.e., those at Brighton and Nariva Hill) requires a similarly large
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displacement (De Verteuil and Eggertson, 2000). The South Boundary Fault is the primary transfer zone for
carrying this motion eastward as the basin opened (southerly step from El Pilar Fault), but the Central Range and
the eastward component on the Los Bajos Fault have carried some of this as well. We roughly estimate that the
post-10 Ma offsets on these 3 systems are: Los Bajos, 10 km; Central Range, 10-20 km; Point Radix Fault, 4050 km. Bear in mind, however, that due to the transfer nature of these three faults, displacement along them will
vary with location as extensional and compressional faults splay off of them.
Aspect 9
If we accept that the Caribbean-South American displacement rate has been 20 mm/yr since 10 Ma, and
that all of the E-W transcurrent shear zones (El Pilar, Caroni, Point Radix, Southern Range, Los Bajos, and
Central Range) are 10 Ma or less in age, then the total offset on the various fault zones should sum to 200 km.
Therefore, in addition to the respective ca. 10, 20, and 50 km proposed for the Los Bajos Fault Zone, Central
Range, and Point Radix Fault Zone (see above), we need to identify the positions of another ca. 120 km of
displacement. The available options are the Southern Range, the Caroni Fault, faults in the northern offshore
(NCFZ, or perhaps through the northern parts of the Northern Range as no E-W faults younger than 10 Ma occur
in the offshore between Galera Point and the Caroni Fault). Seismic lines across the Southern Range west of the
Los Bajos Fault show a simple fault propagation fold with limited (<5 km) shortening, and the paucity of surface
breaks along the trend by strike slip faults suggests that such strike slip displacement is also less than 5 km.
These deformations are very young (<3 Ma). We estimate no more than ca. 25 km on the North Coast Fault
Zone, and that perhaps as much as 30 km can be accounted for as distributed simple shear (manifested in, for
example, the young shortening within the Central Range and Southern Basin). This places the bulk of excess
motion since 10 Ma on the Caroni Fault, approximately 70 km. If the internal parts of the Northern Range have
been dormant and riding passively on the Caribbean fringe since 10 Ma, we may need to reduce our estimate for
the NCFZ and increase our estimate for the Caroni Fault and/or the Central Range Fault. The proposed offset on
the Caroni Fault is sufficient to bring the end Middle Miocene unconformity in the “North Basin” of the eastern
offshore, back to the north side of the same unconformity across the Caroni Basin onshore, and also to pull the
toe of what appears to be a “basement wedge” (in our view, a fragment of the Proto-Caribbean hanging wall
ridge) back to align with the leading edge of the inferred basement wedge under the Gulf of Paria, before it was
stretched west to east (locations of basement wedges shown in Fig. 5).
If one prefers to increase the general simple shear value, then motion on the Caroni can be reduced
accordingly. We note that the Arima Fault is primarily a down to the south normal fault, accommodating the
vertical component of motion of the blocks stretching west to east in the Gulf of Paria, and strike slip does not
reach into the offshore at the eastern end of the Northern Range. However, a small component of strike slip
motion on the Arima could step southward at unidentified places in the Caroni (Northern) Basin to the Caroni
Fault, in particular through the swampy, low ground where the Toco Main Road crosses the Oropuche River.
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Finally, it must be greatly emphasised that all the motions mentioned here are with respect to section beneath the
10 Ma unconformity. This is because the unconformity also serves as a detachment horizon on which the post-10
Ma section commonly slumps eastward, especially south of Point Radix Fault. In places, such as along the
Darien Ridge, the section above the 10 Ma unconformity in the growth fault province to the south, driven largely
by gravity and delta progradation, is moving east at about the same rate as the section north of the Point Radix
Fault, thereby masking the fact that the northern flank is moving east relative to the sub-10 Ma section of the
southern side of the fault.
Aspect 10
In the eastern offshore, the continent-ocean crustal boundary or transition, at the foot of the continental
slope, is easier to recognise on seismic than those at most margins. It is also relatively clear on Bouguer gravity
anomaly maps (but not quite so clear on free-air anomaly maps, which are dominated by the effects of
bathymetric gradient. The location is shown on Fig. 1A) as a pronounced gradient stepping up to the northeast. It
trends NW and passes under the Darien Ridge at about 10.7°N/-60.2°W. This margin is a former transform fault
where the Bahamas basement pulled away from the Demerara High, and migrated sinistrally relative to South
America during the Jurassic and Early Cretaceous; the plate motions for this event are very well constrained by
Central Atlantic magnetic anomalies. It is kinematically unlikely for the COB trend to step substantially to the
right at the Darien Ridge, because such a step would be require compression during Bahamas migration. Thus,
the COB most likely projects and continues beneath the Darien Ridge on the same trend, passing between Galera
Point and Tobago. The Late Cretaceous shelf edge on the Guyana-Suriname margin sits updip and about 75 km
to the west of the COB and can be traced NW towards Galeota. This raises an issue with the occurrence of the
Cretaceous (Naparima Hill Formation source rocks) outer neritic and/or upper bathyal facies in the offshore
Angostura-Emerald area (Emerald-1 well files, courtesy of Petrotrin), which lies immediately above the COB
trend. Here, it is at least 50 km to the east of where we would expect it based on projections of the Late
Cretaceous shelf edge from data on the Suriname-Guyana margin, keeping it approximately parallel to the
continent-ocean transition. If the shelf edge and slope swings towards the NW as shown by Erlich et al. (2003),
then the shear required to bring the Cretaceous in the Angostura area to its present position may be as high as 75
km or more. How did that stratigraphic package get there if the area is floored ultimately by transitional crust
(highly attenuated continent, with strong oceanic crust influence)? We submit that the entire offshore Central
Range trend, which lies north of the Point Radix Fault and Darien Ridge, has migrated laterally from farther west
of the COB, where normal-thickness continental crust away from the COB once supported outer shelf-upper
bathyal paleo-water depths, to its position close to the COB as a function of the post-10 Ma strike slip history.
The top Cretaceous structure map of Boettcher et al. (2003) shows this very nicely. However, because the Point
Radix Fault dips north, roots into the basal detachment of an essentially thin-skinned orogen, and ties into the
true plate boundary beneath the Northern Range, the offshore platform section (1) has been detached from its
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original continental foundation, and (2) is allochthonous (detached) with respect to the transitional crust it now
sits on while continuing to transpress eastwards. This serves to reactivate Middle Miocene thrusts in the pile, and
also to inflate the Darien Ridge by structural shortening of previously undeformed section. This low angle
detached transpressional foldbelt has overridden and accreted fresh source rocks at depth since 10 Ma,
suggesting the possibility of two phases of hydrocarbon maturation within the thrust pile, one of Middle
Miocene age and the second of Late Miocene and younger age.
Aspect 11
To the southeast of Trinidad, the southern limit of the supra-Middle Miocene growth fault province is
defined by a scallop shaped set of transtensional gravitational collapse structures (location shown on Fig. 1B),
informally called the “Escalera fault zone” by British Petroleum Trinidad and Tobago and not strictly related to
the Caribbean plate boundary zone. Instead, it is much more due more to gravity-driven tectonics within the
prograding Orinoco Delta. The more E-W fault segments in the “Escalera fault zone” are dextral lateral ramps or
transfer zones between the collapsing hanging walls and the southern, more stable portion of the shelf and slope.
The total extension across E-W stratigraphic dip is significant, on the order of 40 km (Gibson et al., 2004). This
motion must carry eastward along a lateral ramp connecting the Escalera transtensional growth fault limit to the
transpressional southern end of the Barbados prism. Very few seismic lines exist with which to map the details
of this process, but limited data do show that it occurs, as it must, and that the two features are in fact connected
along a diffuse E-W line. The trend of folds and thrusts at the southern end of the prism curves into E-W
parallelism with the transfer zone by processes beyond the scope of this paper, but which probably involve fault
drag (along the transfer zone) and the imposition of the near north to south tectonic strain on the extending
hanging walls of the gravity-driven normal faults.
We suspect that dextral motion on the Point Radix-Darien Ridge shear zone certainly facilitates the
gravitational collapse in the Columbus Channel, by dextral drag rotating and opening growth faults further, or by
pulling hanging wall stratigraphic section which continues up and over the Darien Ridge from the south towards
the east with the ongoing dextral shear, thereby tectonically enhancing gravity-driven growth fault offsets.
Locally, gravity-driven growth faulting is able to extend eastwards slightly faster than the dextral motion to the
north of the Darien Ridge, and this is manifested in the E-trending or ENE-trending normal faults seen east of
Diamond and Emerald, close to the very abrupt transition between shelf and extremely steep slope (built
structurally, not by a prograding delta slope).
Overall, the Columbus Channel can best be described as a thin-skinned pull-apart basin with a complex
mix of tectonic and gravity (delta progradation) stresses driving the deformation, as suggested by Pindell and
Kennan (2001) and by Gibson et al. (2004).
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Aspect 12
Seismic tomography (Van der Hilst, 1990) allows us to define where and how far the Caribbean Plate
projects southward beneath northern South America. Briefly, Caribbean lithosphere now projects at a low dip
angle to underlie all of the Maracaibo region, the Barinas Basin, the Caribbean Mountains, and the northern
fringe of the Guarico Basin (shown on Fig. 1A). Beneath the Gulf of Barcelona, the Caribbean lithosphere rises
toward Margarita where it emerges at the surface along the Orchila-Margarita fault zone, a dextral lateral ramp
allowing the Aruba-Orchila islands to thrust NW-ward onto the Caribbean Plate interior (Dewey and Pindell,
1985; 1986). The subducted portion of the Caribbean Plate is continuous with the plate at the surface (the
subduction trace is the South Caribbean Foldbelt/Orchila-Margarita fault zone) and, being unbroken, must have
the same kinematics relative to South America. Therefore, the present position of the leading edge of the
subducted Caribbean crust was achieved by motion toward 085° since 10 to 12 Ma. This west to east motion is,
in fact, responsible for the intensification of the northern Andean orogeny; the entire Santa Marta-MaracaiboFalcón region is riding eastward at a significant portion of the full Caribbean-South America displacement rate
(Trenkamp et al., 2002) due to basal traction of this region’s lithosphere on the underlying Caribbean Plate.
Hence, the Mérida Andes are a strong zone of dextral transpression where most Caribbean-South America
seismicity now occurs. In addition, the high relief of the Caribbean Mountains is also caused by the motion of
the Caribbean Plate beneath them. However, this uplift appears to have more to do with volume increase beneath
the mountains by the progressive eastward emplacement of the Caribbean slab than to basal traction: only the
portion of the mountains north of La Victoria Fault is moving eastward at any appreciable rate, suggesting that
the crustal sliver between the Morón and La Victoria faults does in fact feel some basal shear stress.
Aspect 13
In the Gulf of Barcelona, at least 4 wells have penetrated Pliocene-?Late Miocene section and entered
Cretaceous basaltic volcanic basement south of the Cariaco Basin/El Pilar Fault shear system (Ysaccis, 1997).
These rocks are likely the eastward continuation of the Villa de Cura allochthon, although they appear to
comprise less metamorphosed rocks similar to the Tiara volcanics, a cover section upon the Villa de Cura highpressure, low temperature (HPLT) rocks (location shown on Figs. 1A,B).
Aspect 14
A dense wedge of resumably mafic (oceanic), rock likely occurs deep beneath the northern Serranía del
Interior Oriental, south of El Pilar Fault, as shown by gravity modeling (Passalacqua et al., 1995). The
stratigraphy of the Cretaceous passive margin in this area is not what we would expect were it underlain by
oceanic crust, and regional geology does not support the existence of South American ophiolites of preCretaceous age. Therefore, we propose the wedge is a piece of Caribbean forearc, emplaced during the Middle
Miocene orogeny involving the collision of the Caribbean Plate with the Serranía Oriental. The wedge helps to
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
19 of 76
resolve the space problem identified by Hung (2005). The location of the deep wedge is shown on Figure 1A,
and a cross-section view is shown on Figure 4B.
Tectonic history since 10 Ma
The above aspects of the ESCPBZ may now be used to outline the history of development since the end
of the Middle Miocene. We set the development within the kinematic history of Figure 18 (see later section,
below), which shows the change from SE-ward Middle Miocene oblique convergence to more or less E-W
(085°) transcurrence at about 10 Ma. If the present-day plate motion rate of 20 mm/yr can be extended back to
10 Ma, total displacement should be 200 km since that time. This fits well with the rate of advance of Caribbean
foredeep basins (Pindell et al, 1991; see also Fig. 17, below), and it also realigns the following four features
which we believe have been offset by the Morón-El Pilar Fault since 10 Ma: (1) Cretaceous basaltic “primitive
island arc” volcanic rocks of the Gulf of Barcelona and those of the Bocas High and the Patao High (Ysaccis,
1997); (2) the Orchila-Margarita and the Urica lateral ramp transfer zones; (3) the juxtaposition of Araya
Peninsula with the eastern end of the Cordillera de la Costa of the Caribbean Mountains (i.e., 200 km neatly
closes the Cariaco Basin); and (4) the SE edge of Caribbean crust (Tobago Terrane) and the deep, dense wedge
beneath the Serranía Oriental. In addition, we note that the 085° azimuth cannot be employed for distances
greater than about 200-240 km, because larger values begin to overlap the basement of the Carupano Platform
and Margarita with that in the Caribbean Mountains, the latter of which are thought to be essentially in place
since 10 Ma (i.e., La Victoria Fault has only small, probably <<30 km, offset, and has slipped during Quaternary
time at <3 mm/yr; Schubert, 1981; Audemard, 2000; Perez et al., 2001).
Using the fault offsets and movement directions discussed above, with 200 km of total motion between
the Caribbean and South America since 10 Ma, we can draw the 10 Ma palinspastic reconstruction of Figure 11.
Because we believe the Caribbean crust has reached southward to the El Pilar Fault since the Middle Miocene
(Fig. 1A), the Araya-Paria and Northern Range restore westward along with the Caribbean Plate and realign with
the Cordillera de la Costa. These ranges east of the Cariaco Basin ride essentially passively on the edge of
Caribbean crust, which is why GPS studies show they move at or nearly at the full Caribbean velocity. The 10
Ma reconstruction is supported by the realignment of the blind toe of the Tobago Terrane with the deep, dense
wedge beneath the Serranía Oriental, which together defined the leading edge of the Caribbean crystalline crust
until the 10 Ma onset of faulting on the El Pilar Fault. Thus, in Venezuela, the majority of relative plate motion
since 10 Ma has occurred on the El Pilar Fault, with only minor motions on fault splays and bulk shear strain
occurring to the north or south of that fault.
Where the El Pilar Fault enters the northern Gulf of Paria, some (about 70 km) of the total El Pilar
displacement has stepped southward across the basin to the northern flank of the North Marine Ridge and South
Boundary Fault, producing the Gulf of Paria Basin (dextral pull-apart soling into a low-angle detachment at the
base of the thrust wedge). From there, about 10 km (eastward component) of this 70 km has splayed southward
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
20 of 76
-70°
16°
-68°
-67°
-66°
-65°
-64°
-63°
-62°
-61°
-60°
-59°
-58°
-57°
16°
10 Ma crustal configuration:
Onset of E-W azimuth of
Carib/SoAm relative motion
South C
aribbea
. Front
Grenada intraarc Basin
Margarita
backthrust
n Foldb
elt
sl u
mp
s?
12°
Morón
Manicuare/
t o-
ean
n
Tre
14°
ch
Proto
Barbados
today
-Ca
an
ribbe
Ridg
e
13°
Note: Barbados has
ramped onto ProtoCaribbean ridge since
10 Ma, which is why it is
positive today
White: Atlantic crust
not yet subducted
beneath Caribbean
12°
Tobago today
CA/SA relative
motion history
N Range
e
Coche napp
Pro
ibb
Car
200 km
Tobago @ 10Ma
Margarita
@ 10Ma
Bonaire Basin
11°
Barbados
@ 10 Ma
Inner Defm
Venezuela Basin
To
b
f or ago T
ea
rc roug
Ba
sin h
14°
13°
15°
Av
(pre es Ridg
-Eoc
e
ene
arc)
15°
-69°
11°
El Pilar
10°
Maracaibo Slab at 10
Ma, showing azimuths
pre- (blue) and post(red) 10 Ma
9°
e
Villa d
-69°
Urica
lat. ra
S. Fran
mp
Man
Late Miocene window to Barcelona Volcanic Wedge NW
of Barranquín backthrust
n
it io
pos ab
ent ibo sl
s
e
Pr raca
Ma
8°
-70°
Cura
resa
F
ial
urr
dia
pir/P
ap
er
edn
s
nale
Gu
pr
ox
im
at
e
Cr
et
ac
eo
us
sh
Blue lines: Middle Miocene structures associated with oblique collision, with some younger activation.
Black line: post-10 Ma structure, associated with E-W transcurrent phase (Morón, El Pilar-Caroni faults).
Green line: active at both time periods: like at Serranía, is wedging beneath Barbados backthrusts today.
Maracaibo Slab (red), attached to Caribbean, moved with Caribbean before (blue) and after (red) 10 Ma.
-68°
-67°
-66°
-65°
-64°
-63°
-62°
-61°
-60°
ya
na
elf
10°
M
ed
ar
gin
Co
nt
-O
ce
an
Bo
ge
-59°
9°
un
da
ry
8°
-57°
-58°
Figure 11. Simple palinspastic reconstruction of the SE Caribbean PBZ for 10 Ma, assuming 20 mm/yr displacement rate at
today’s azimuth of motion back to 10 Ma, at the time of transition from oblique collision to E-W trancurrence. Note the
realignment of the blind toes of Caribbean forearc crust at Tobago and the Barcelona Volcanic Wedge. Faults primarily
active before and after 10 Ma are shown in blue and black, respectively.
-62° 18'
-62° 12'
-62° 06'
-62° 00'
-61° 54'
-61° 48'
-61° 42'
-61° 36'
-61° 30'
-61° 24'
-61° 18'
-61° 12'
5 Ma Palinspastic Reconstruction, shallow horizons
10° 42'
61.5
61.6
61.3
ntr
Ce
61.0
10° 42'
10° 36'
61.1
61.2
61.4
Sh
elf
10.5
- Gua
ult Zone
lt
-60° 54'
Tectonic
Analysis
Ed
aroni
El Pilar - C
g Pond Fa
ico - Fishin
Fa u
-61° 00'
ge
?
10° 36'
e
ang
al R
-61° 06'
ne
Zo
10° 30'
lt
adix Fau
Point R
10.4
Marabella FZ
10° 24'
Zone
10° 24'
10.3
South Boundary Fault Zone
L os
10° 18'
10° 30'
Bajo
s
Faul
SALT
SPRING
SANTA
FLORA
10° 18'
ACTIVE
NORMAL
FAULTS
t
10.2
NO ACTIVE MAJOR THRUSTS
10° 12'
FIELDS
10° 12'
10.1
10° 06'
10° 00'
-62° 24'
10° 06'
25 km
-62° 18'
-62° 12'
-62° 06'
62.0
61.9
61.8
61.7
61.6
61.5
-62° 00'
-61° 54'
-61° 48'
-61° 42'
-61° 36'
-61° 30'
61.4
61.3
-61° 24'
61.2
-61° 18'
61.1
61.0
-61° 12'
-61° 06'
10° 00'
-61° 00'
Figure 12. 5 Ma Palinspastic Reconstruction suitable for plotting shallow horizons, above the base Late Miocene unconformity. Thus, this map restores the 5 Ma and younger extension in the Orinoco Delta sediments of the Southern Basin.
Because this extension detaches above the unconformity over the Middle Miocene orogen, the underlying rocks (Karamat
and older formations, including Cretaceous) would be positioned somewhat farther to the east for any given present-day latitude and longitude. Therefore, the apparent offset on the Point Radix Fault would appear to be larger for Cretaceous rocks
than for early Late Miocene rocks. The effect of extension in the Southern Basin and offshore Columbus Basin thus acts to
reduce the apparent offset we can see today on the Point Radix-Darien Ridge Faults, because the hanging walls of extensional faults (rooted below Cruse) to the south may be moving to the east almost as fast as the north side of the Darien
Ridge, rooted at the base of the fold-thrust belt.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
21 of 76
again along the Los Bajos Fault, while some 60 km has headed east toward San Fernando. Between 10 Ma and
mid-Pliocene, motion continued eastward along the Point Radix-Darien Ridge fault zone, passing around both
the northern and southern flanks of the San Fernando mega-fault sliver, of which San Fernando Hill is a part. But
since mid-Pliocene, a component of this eastward motion (~10-20 km) has splayed northwards along the Central
Range, leaving a total of some 40-50 km along the eastward continuation of the Point Radix Fault. The 5 Ma
reconstruction of Figure 12 accounts for the fault offsets noted above, and also restores the extension in the Gros
Morne and Mayaro Formations (developed within the Orinoco Delta) and therefore the grid in the Southern
Basin is appropriate for plotting paleofacies for late in the deposition of the Cruse Formation. The reconstruction
pre-dates the Central Range uplift and displacement, as well as the renewed shortening on the Southern Range
and the Pliocene-Pleistocene offset on the Los Bajos Fault.
Finally, also in the mid-Pliocene, along with the onset of the Central Range, the locus of low-angle
extensional detachment jumped westwards to the San Juan Graben, where about 5 km of eastward collapse has
occurred, with perhaps a smaller amount of additional extension reaching the San Francisco Fault (Fig. 5). The
E-W transfer zone for this expanded zone of detachment (now comprising the entire Middle Miocene thrust pile
down to its sole thrust and as far south as its toe) is the Late Pliocene-Recent Eastern Maturín diapir
belt/Pedernales-Southern Range trend, which is a growing fold above a thrust telescoping from beneath the
Middle Miocene deformation toe (Fig. 2).
The bow-wave orogenic model since 10 Ma in the ESCPBZ
The Gulf of Paria Basin, and to a lesser extent the San Juan Graben, are places where the original
Middle Miocene thrust belt has been broken by a combination of dextral tectonic shear and gravitational collapse
of the thrust belt toward the Atlantic since 10 Ma. These developments have produced very little N-S contraction
(<5 km west of Los Bajos Fault). The post-10 Ma phase of history is distinctly different from the Early and
Middle Miocene compressional orogeny. In contrast, however, structural development in eastern Trinidad and in
the eastern offshore has remained more compressional. Even though extensional detachment faults have
developed there, the detachments have themselves been folded quite strongly since their Pliocene formation.
There appears to be an increase in post-10 Ma N-S contraction in the eastward direction.
To explain this observation, we apply a “bow-wave” model to the post-10 Ma transcurrent phase in the
ESCPBZ. Because the southeastern limit of Caribbean crystalline crust is curvilinear (Aspect 1, above), veering
from N-S beneath Barbados to E-W in the Caroni Basin and westward, this analogy is highly applicable. Along
the “bow of the boat”, which is presently everywhere east of Port-of Spain, transpression occurs, like the waves
generated by a boat. Along the flank of the boat, which is presently west of Port of Spain, N-S convergence is
minimal or non-existent. This principle can be extended back in time, the migration of the boundary point
between transpression and near-perfect strike slip will match the migration rate of the Caribbean relative to
South America (Fig. 13). This point was situated 200 km west from Port of Spain at 10 Ma, placing it directly at
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
22 of 76
M
0
a
4M
a
a
8M
10
M
Caribbean motion at 085°
relative to SoAm
0
a
200 160km 80km
A. Eastward advance of Caribbean Plate
N. Range @ 10 Ma
0
4
8
10
first Paria Basin fault to form?
Los Bajos
line of section
in B, below
denotes migrating point between transcurrent
shear zone to W and transpressive zone to SE.
1:1
B. Effective S-ward advance of Carib forearc, and progressive
increase in accommodation space for Trinidad foredeep.
section in A
onshore Trinidad
20 km
20 km
Orinoco
River today
Nodal Point between foredeep
and bulge migrates
40 km
Carib @ 10 Ma
Carib @ 8 Ma
Carib @ 4 Ma
Carib @ 0 Ma
60 km
80 km
Slab continues
another 200 km
40 km
Caribbean
Forebulge in
Shield
SoAm profile at 10 Ma
SoAm profiles at 8 Ma
SoAm profiles at 4 Ma.
SoAm profile at Present
Figure 13. “Bow-Wave” model of orogenic shortening. A) Map of the displacement history of the curvilinear leading edge
of the Caribbean Plate, as well as its trailing flank, since 10 Ma, showing the apparent S-ward advance of the position of the
Caribbean crust along the profile, but not of its material particles (which move west to east), relative to Trinidad. B) The
progressive increase in tectonic accommodation space (i.e., foredeep basin) above South America (employing a flexural
profile) that is required to accommodate the eastward motion, and the effective southward motion of the Caribbean Plate,
which of course thickens towards the west, towards the axis of the volcanic arc. Coloured wedges track the position of the
leading edge of the Caribbean Plate along the profile, which apparently moves south. This model shows that southward
shortening can be driven along the “bow” of the “Caribbean boat” (i.e., SE Trinidad and the eastern offshore at present) in
the absence of actual N-S convergence. It also shows that shortening will not occur along the “sides” of the boat. It is
instructive to keep in mind that the effective southward shortening can only occur if strike slip is active. The strike slip component, as shown earlier, has occurred since the Late Miocene through Trinidad largely at the Point Radix and Caroni faults,
and since the Pliocene on the Central Range fault zone and “Southern Anticline” en-echelon culminations as well.
-80
-75
-70
-65
-60
300 km
25
360 km
total
15
10
-80
Anom = Age
5 = 10 Ma
6 =19 Ma
13 = 33 Ma
21 = 46
25 = 56 Ma
32 = 72 Ma
34 = 84 Ma
32
21 34
13
6
5
0
21 25
32
210 km
total
Muller et al.
1999 data
34
13
6
5
25
13
0
Pindell et al.
1988 data
32
21 25 32
21
34
6 34 13
6 5
5
0
0
10
Venezuela
-75
-70
15
-65
-60
Figure 14. Motion history of North America relative to
two points on South America since magnetic anomaly
34 (Early Campanian). Results of two data sets for
each point are shown, those of Pindell et al. (1988) to
the right and the updated results of Müller et al. (1999)
to the left in order to show how well constrained and
reproducible this relative motion history is. Actual path
of the points might be best represented by the pink
smoothed lines. Heavy black dots on the two pink
curves show the amount of convergence which had
accumulated between the Americas at the time when
the Caribbean Plate began to collide with the South
American margin at each point, which was about 100
km for both. The remaining convergence accumulated
after Caribbean-South America collision was underway,
below the developing suture zone of those two plates.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
23 of 76
the NW corner of the Gulf of Paria Basin. Thus, the transpressional bow always lay ahead of the Gulf of Paria,
and the growing Gulf of Paria Basin was always protected from N-S compression because it la to the west of the
boundary point.
Another observation that is explained by this model is the progressive development (loading) of the
Maturín-Southern Basin foredeep basin. The Caribbean Plate, which has not converged with South America
since 10 Ma, nevertheless has moved eastward into a position where it increasingly loads the foreland basin,
albeit laterally. The lateral loading has steadily increased in both the Maturín and the Southern foredeep subbasins because the thickness of the Caribbean forearc lithosphere increases from about 20 km below Tobago,
near the edge of the Caribbean plate, to about 100 below Margarita. This effective thickening of the plate in
north-south cross section must be accommodated by an associated increase in downward flexure of South
American basement and, hence, foredeep accommodation space.
The small amount of N-S shortening that is observed since the ?middle Pliocene west of the Los Bajos
Fault (i.e., western Southern Range, Maturín diapir trend/Pedernales, Pirital Fault) is likely the result of 5 to 10
km of eastward reactivation of the deepest Middle Miocene thrust plane. Such a thrust likely dips toward about
330°-340°; thus, eastward reactivation would be transpressional with the potential to drive up to 5 km of young
N-S transpressive shortening on certain structures such as Pirital Thrust and the diapir trends/Southern Range.
The Pliocene activation of the Central Range Fault Zone, trending at 070°, may also relate to this process, or
relate to the Trinidadian allochthons north of Point Radix Fault ramping up over the NW dipping basement
surface of the Jurassic Trinidad re-entrant (Pindell et al., 1998).
This minor, late transpressional reactivation might have involved the Añaco Thrust which lies outside
the Serranía Oriental re-entrant, west of the Urica Fault, and which is an inverted normal fault along the southern
flank of the Espino Graben, itself a low-angle detachment basin with a N-dipping detachment plane. Inversion of
the Añaco Fault is commonly thought to have occurred during Late Miocene deposition of the Freites Formation
as marked by Freites onlap (Banks and Driver, 1957). However, GPS results (Perez et al., 2001) show that the El
Baúl Massif may presently be moving east (Fig. 7) by perhaps 3 mm/yr relative to the South American base
station, which lies near the Orinoco River at Canoa, to the southeast of the Añaco Thrust. Because we are aware
of no other structure in the interior plains that could accommodate the eastward motion of the El Baúl High to
the east, we speculate that the eastward motion of El Baúl is driving the Añaco inversion, such that it may still be
active. And because El Baúl resides on the hanging wall of the 070°-trending Jurassic Espino Graben
(geometrically, a half-graben), we consider that the half graben may be inverting as a whole. Inversion on this
huge scale likely relates to the crust reaching all the way west to the basement-involved Mérida Andes and/or
basal traction of the underthrust Caribbean Plate against the South American lithosphere south of Caracas. A
dextral transfer zone extending from near the Colombian border to Añaco is suspected. We wonder if the
intersection of such a trend with the southern end of the Urica Fault Zone might account for the apparent
complexity in that area.
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24 of 76
Whether or not this late reactivation represents the onset of a third phase, acknowledging and
understanding the details of the oblique collision and subsequent transcurrence in the SE Caribbean is paramount
for hydrocarbon exploration, affecting interpretations of structural timing and style, maturation mechanisms and
timing, and the relationship between sedimentation (provenance) and tectonics (driving causes). Further,
individual components of various petroleum systems in the region have been amalgamated by the juxtaposition
of terranes of quite different origin. Trinidad is not a place that can be neatly summarised by only local models
of evolution; the bigger picture involving Venezuela and Barbados as well as a detailed understanding of
Caribbean kinematics is absolutely required.
Perspectives on the nature of the South American margin prior to 10 Ma
Enormous effort by the collective geological community has been devoted to the description and
characterisation of the Caribbean-South American plate boundary zone (Figs. 1A,B). Less but still considerable
effort has gone into understanding the history of the Caribbean-South American plate collision, and still less
effort has gone into trying to understand the nature of the South American margin prior to Caribbean collision.
Was it a passive margin as the Caribbean progressively collided with it from the west, as many have come to
believe, or was it already active during the Caribbean’s collision? If active, how so? Understanding the answer to
this question is important for understanding the history of the collision itself and the structure of today’s plate
boundary zone, as well as for better understanding the paleo-environments and distribution of source and
reservoir rocks in various petroleum systems along the margin.
Prior to the advent of plate tectonic theory, workers envisioned an end-Cretaceous-Eocene northern
marginal high that provided detritus with an orogenic signature to various clastic depocenters such as the
Scotland Formation in Barbados (e.g., Senn, 1940). With the advent of plate tectonics, but prior to accurate plate
kinematic control, came the idea that arc-continent collision caused tectonism and metamorphism in the
Caribbean Mountains and Margarita of Late Cretaceous age, followed by some thin-skinned thrusting or gravity
sliding in the Guarico foreland basin in the Paleogene (e.g., Maresch, 1974). With (1) the definition of accurate
circum-Caribbean plate kinematics as allowed by early SEASAT and GEOSAT data, and (2) the realisation that
northern South America’s foreland basin subsidence history is Tertiary, not Cretaceous, and youngs
diachronously eastward (Pindell, 1985), came the realisation that the predominantly Cretaceous metamorphic
and igneous rocks must be Pacific-derived allochthons that were not emplaced onto the margin until the
Paleogene, and that the northern South American shelf was passive at least until the Maastrichtian and possibly
to the time of Caribbean collision, facing onto the Proto-Caribbean Seaway, an arm of the Atlantic (Pindell,
1985; Dewey and Pindell, 1986; Pindell et al. 1988). But the arc-passive margin collision model was always
hostage to one major problem: N-S convergence between North and South America since the Maastrichtian was
significant (i.e., hundreds of km; Pindell et al., 1988) and this convergence began before the arrival of the
Caribbean allochthons in Venezuela and Trinidad.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
25 of 76
Thus, suspicion of a “pre-Caribbean-arrival” convergent boundary between the North and South
American plates, somewhere in the Proto-Caribbean Seaway, clouded our confidence in the margin remaining
passive until the time of Caribbean collision (i.e., during the Paleogene). It was not until the first seismic
tomographic work in the Caribbean (Van der Hilst, 1990) that the geological community gained good evidence
that the South American continental lithosphere has been severed from the Proto-Caribbean or Atlantic
lithosphere. Driven by the suspicion of convergence since the Maastrichtian, Pindell et al. (1991) honoured the
Cenozoic inter-American convergence by proposing that the northern South American Cretaceous passive
margin was converted in the Late Maastrichtian-Paleocene to a south-dipping “Proto-Caribbean” subduction
zone along the toe of the continental margin. This development had nothing to do with the Caribbean Plate,
which lay to the northwest of the Guajira Peninsula in the Maastrichtian. Further, it was suggested that this
Proto-Caribbean structure drove N-vergent accretion of South American continental slope and rise strata to
South America’s northern edge (e.g., Caracas Group, Paria, and Northern Range strata), prior to the eastwardly
diachronous collision of the Caribbean Plate, and associated emplacement of the Cretaceous allochthons, with
Venezuela and Trinidad. In such a model, the term “trench-trench collision” is a more accurate description of
Caribbean-South American interaction during Cenozoic time than is “arc-passive margin collision”, although
convergence at the Proto-Caribbean thrustbelt or subduction zone has been too small for a magmatic arc to
develop on South America.
Evidence for the Proto-Caribbean subduction zone
Evidence for the Proto-Caribbean subduction zone is geologically subtle in the onshore, but defining the
Paleogene existence of the plate boundary (Pindell et al., 2006) is critical for understanding the origin and
distribution of Paleogene reservoir clastics and burial/unroofing histories of Cretaceous source rocks, and thus
deserves our full attention. Evidence for the Proto-Caribbean subduction zone/thrustbelt includes the following
items.
•
Atlantic plate kinematic history (Fig. 14) requires about 100 km of North America-South America
convergence to have already occurred at the longitude of western Venezuela in the Middle Eocene when the
Caribbean Plate collided with South America there, as well as at the longitude of Eastern Venezuela in the
Middle Miocene when the Caribbean Plate collided there (Pindell et al., 1988; Müller et al., 1999). This
shortening presumably had a pre-Caribbean-arrival geological expression, either within or at the margins of
the Proto-Caribbean Seaway. We will see that the expression is greatest along the South American margin.
•
Mantle seismic tomography in the Caribbean and northern South America area (Van der Hilst, 1990) shows
a westward dipping subducted Proto-Caribbean (Atlantic) slab beneath the Caribbean Plate (Fig. 15, E-W
sections), but this same slab also dips south and is overthrust by and severed from the northern edge of South
American continental lithosphere (Fig. 15, N-S sections). This suggests subduction of Proto-Caribbean
lithosphere beneath northern South America. Further, because N-S contraction between the Americas began
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
26 of 76
A
Cuba
Bahamas suture
A
B
C
lt
Oriente Fau
D
E
F
Puerto Rico Trench
20
NORTH AMERICAN PLATE
Caribbean Trench
1
Hispaniola
Puerto Rico
G
Crystalline edge
Caribbean Plate
2
Muertos Trough
3
CARIBBEAN PLATE
4
South Caribbe
Oc a Fa
5
an Foldbelt
RC
FZ
ult
ove
Morón Fault
7
profile 7 continues 200 km
off map
M
id
er
n
re
aT
ru
rth
ro
st P
ch
ren
T
r
a
tod
ay
C
t o-
6
Barcelona
Wedge
Gu
SOAM coast in Maastrichtian, relative to NoAm
Maastrichtian trace of
Proto-Caribbean trench
~Proto-Carib COB
in Maastrichtian
15
SOUTH AMERICAN
PLATE
10
d
70
nch
r Tre
a
C
Proto
65
yan
a
CO
B
60
5
Figure 15. Our working interpretation of the Caribbean mantle seismic tomography as compiled by Van der Hilst (1990).
Figure 15A) Location map of: main Caribbean region plate/block boundaries and features (black lines); reconstructed
Maastrichtian paleoposition of South America and its continent-ocean boundary (COB) and the initial position, relative to
North America, of the Proto-Caribbean subduction zone (blue; after Pindell et al., 1988; 1991; 1998); and transect positions
A-G and 1-7 of the seismic tomographic profiles of Van der Hilst (1990). Ticks on profiles are at 100 km spacing. The
Proto-Caribbean Trench extends into the Atlantic from under the Barbados Prism out to about the location of magnetic
anomaly 30 (Maastrichtian). The obducted Caribbean terranes along northern South America are shown in grey, comprising:
the Ruma (in Guajira), the Lara (in Falcón), the Villa de Cura (in central Venezuela), the “Barcelona Volcanics” (in Gulf of
Barcelona), the Manicuare (western Araya), and the Copey/Toco/Sans Souci of Araya-Northern Range), which collectively
represent the leading subduction complex of the Caribbean Plate. The Oca, Mérida, El Pilar, and Urica faults now offset this
west-to-east diachronously emplaced belt whose basal thrust is the location of most Caribbean-South American displacement. RCMFZ is the Roques Canyon-Margarita Fault Zone, which was a dextral lateral ramp in the Middle Miocene allowing NW-ward backthrusting of the ABC island terrane above Caribbean Plate (Dewey and Pindell, 1985).
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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B
S
250
0
500
750
1000
1500
1250
N
Caribbean
SoAm
S
0
250
500
750
1000
1250
1500
N
Caribbean
SoAm
200
200
slab drop off
aribbean
Proto-C
400
slab gap
?
-Ca
Proto
400
ribbe
an
600
Proto-Caribbean
800
800
D
A
250
0
500
750
1000
1250
1500
Caribbean
SoAm
250
0
500
750
1000
1250
Caribbean
SoAm
be
arib
C
o
t
200
200
400
to
Pro
slab gap
?
-C
bea
arib
n
400
600
appears abnormally thick due
to data gather from in and out
of section from steep, westdipping flexure in slab?
800
800
E
B
0
500
750
1000
1250
200
400
P
600
1500
Caribbean
SoAm
Proto-Caribbean
ea
ibb
r
a
-C
roto
C
500
SoAm
750
i
-Car
Proto
0
ABC’s
400
1250
bbea
1500
n
South America
Caribbean
200
+3%
1000
Caribbean
F
400
slab gap
Velocity Perturbation
250
0
200
n
–3%
800
an
Pro
Proto-Caribbean
250
1500
G
0
250
500
750
1000
1250
Figure 15B) Our interpretations of the raw N-S seismic tomographic profiles in Van der Hilst (1990), profiles A-G shown on
Part A. South Caribbean Foldbelt is at km 800 on profile C; Morón Fault is km 550 on profile C; Villa de Cura Klippe is at
km 500 on profile C; Cariaco Trough is at km 550 on profile D; Barcelona Wedge is at km 500 on profile D; Paraguaná
Block is at km 600 on profile B; Lara Nappes are at km 500 on profile B; Guajira Block is at km 700 on profile A; Lara
Nappes are at km 500 on profile A; Bahamas overthrust crust is at km 1550 on profiles A, B, C and D, and Proto-Caribbean
slab is seen to be increasingly detached from Bahamas westward; Caribbean crust underthrusts SoAm on profiles A, B and
C, abutts it on profile D, and SoAm underthrusts Caribbean on profiles E, and F (i.e., polarity change); Proto-Caribbean lithosphere is seen fingering by N-S extension in the downdip direction on profiles A, B and C (gaps shown by double headed
arrows), but the total line length matches the Maastrichtian trace at the Earth‘s surface (Part E); in profile E, two interpretations of slab dip are permissible due to poor data resolution. The temptation to interpret SoAm as dipping northwards down
to 600 km in profile E is shown to be incorrect by the apparent gap in the slab on profile D. Seismicity is shown in dots, and
supports the seismic tomographically imaged slabs. Oca Fault seismicity lies at about km 600 on profile G.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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C
W
250
0
500
750
1000
E
1250
Caribbean
200
Prot
400
250
0
500
750
1000
1250
Caribbean
200
250
500
ean
200
Pro
800
n
bea
rib
a
C
t o-
?
5
250
0
500
750
1000
Caribbean
1250
SoAm
200
2
250
500
750
1000
1250
Caribbean
400
?
6
200
ibbe
Car
o
t
Pro
600
an
0
South America
200
600
+3%
–3%
3
1250
Caribbean
600
600
800
750
400
bb
-Cari
o
t
o
r
P
400
1000
E
4
0
1
0
1250
Pr
800
400
1000
bean
arib
C
oto
600
0
750
Caribbean
400
600
250
500
200
an
ibbe
ar
o-C
W
Velocity Perturbation
Caribbean
Atlantic (P-Carib)
7
400
0
500
1000
?
1500
Figure 15C) Our interpretations of E-W seismic tomographic profiles from Van der Hilst (1990), profiles 1-7 shown on Part
A. Caribbean overthrusts Proto-Caribbean (Atlantic) in profiles A-E; total subducted lithosphere is greater than 1500 km,
recording a minimum Caribbean-Atlantic convergence (larger than the Eocene-Recent 1000 km offset recorded by Cayman
Trough); in profile F, Caribbean overthrusts SoAm, and SoAm in turn has overthrust the upper reaches of the ProtoCaribbean slab. On 7, the Maracaibo slab of Caribbean lithosphere is seen dipping southwards from the South Caribbean
Foldbelt, although no magmatic arc has formed due to this very slow subduction and offscraping of hydrous upper crust at
the trench. Seismicity is shown in dots, and supports the seismic tomographically imaged slabs. Seismicity between km 800950 on profile 7 is related to Mérida Andes transpression.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
29 of 76
D
A
Cuba
B
C
lt
Oriente Fau
D
E
F
20
subducted ProtoCaribbean crust
tear in subducted ProtoCaribbean crust (that
under northern Dom
Republic not shown)
Puerto Rico Trench
P100
?
1
NoAm dislocatio
n
?
P30
G
P40
0
2
P20
0
0
X
3
4
Gap in subducted
Proto-Caribbean slab
5
P400
C10
00
0
S100
Y
location, Fig 3f
Crystalline edge of
the Caribbean Plate
S50
7
profile 7 continues 200 km
off map
6
Y
~50 km shortening
X
ll
g wa
ngin
a
h
m
SoA
B’dos
P3
trench
10
C200
P 450
“leading edge” of
subducted Caribbean
lithosphere
(Maracaibo slab)
P
70
500
“leading edge” of subducted
Proto-Caribbean lithosphere
65
C100 100 km contour to top
of Caribbean slab
P200 200 km contour to top
of Proto-Caribbean slab
S50 50 km contour to top
of South American slab
60
5
Figure 15D) Interpretation of the subsurface structure of the Proto-Caribbean or Atlantic, Caribbean, and South American
subducted slabs. The Caribbean or “Maracaibo” slab is attached to and descends from the Caribbean Plate at the South
Caribbean Foldbelt and Roques Canyon-Margarita fault zone (Van der Hilst, 1990). The Proto-Caribbean slab descends
from the Puerto Rico-Lesser Antilles trench, but is torn from South American lithosphere such that it has underthrust South
America. Further, the Proto-Caribbean lithosphere has a large slab gap beneath the western Venezuelan and Bonaire basins
(tips out near 12N/65W), such that the portion beneath South America and beneath the Maracaibo Slab projects and dips
southwestward from the SE Caribbean area. Relative to the mantle, the Caribbean (Maracaibo) slab is nearly stationary, but
the Proto-Caribbean slab is attached to the Americas and thus is migrating west. This westward movement is likely associated with development of the large tear, as well as with the broad “S-shaped fold” that has developed in ENE-WSW cross section of the dangling finger beneath South America. Beneath Hispaniola and western Puerto Rico, the Proto-Caribbean slab is
seen detaching from the Bahamas, perhaps due to slab drop off after the arc terranes collided with the Bahamas.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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E
South
0
Distance in km from southern ends of cross Section B in Part B
400
800
1200
North
1600
depth, km
0
200
Maastrictian initiation of Proto400 Caribbean Trench
600
0
Distance in km from southern ends of cross Section C in Part B.
400
depth, km
0
800
1200
1600
200
400
Maastrictian initiation of ProtoCaribbean Trench
600
Figure 15E) Cross-sectional reconstructions of Proto-Caribbean Seaway for the Maastrichtian, using N-S cross sections B
and C from Figures 15A and 15B. Heavy black uncoloured shapes are present day geometries and positions of: the Bahamas
slab, two foundered pieces of Proto-Caribbean slab, and South America, as interpreted in Figure 15B. Red shapes are the
Proto-Caribbean slab reconstructed to establish the slab’s line length prior to slab tearing and fingering. The blue shapes are
equivalent to the red shapes, but have been rotated back to the earth‘s surface about the subduction zone’s pivot point at the
Greater Antilles-Bahamas suture (heavy black spot). The green shape is where the northern edge of South American continental crust was located in the Maastrichtian. The heavy dashed blue line is the proposed position and geometry of the
Proto-Caribbean subduction zone when it first formed in the Late Maastrichtian, prior to the entry from the Pacific of the
Caribbean Plate. Note the nearly perfect match between the extents of Proto-Caribbean lithosphere when returned to the
earth‘s surface, and the former positions of the South American continental crust, prior to Cenozoic northward convergence
with North America. This greatly strengthens the interpretation that the tomographically imaged structures at 450 to 600 km
beneath present day northern South America is in fact Proto-Caribbean crust, because if it were not, then a 500 wide
lithospheric gap would have existed at the earth’s surface in N-S cross section in Late Cretaceous and Paleogene time. In
addition, the foundered finger of Proto-Caribbean crust beneath South America in these two sections does merge with the
main Proto-Caribbean slab eastwards (Figure 15D).
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F
Cross-section from Villa de Cura Belt, Central Venezuela to SE of Barbados, through Margarita.
Villa de Cura (upper Caribbean)
thin due to erosion
Urica
Fault
Cariaco
Trough
Margarita platform
km
ARC
South America
100
SoAm
200
Maracaibo Slab
300
400
1500
CARIACO TROUGH
Paria knot
Urica Fault, at SoAm
basement level, is a
down to east tear fault
ane
on pl
ducti
b
u
s
b
-Cari issoring)
Proto
(s c
Paria [seismic] knot
is plate interface
seismicity as deep
Caribbean abuts the
SoAm slab. It exists
Sl a b
n
a
e
b
arib
only to the east due
roto-C
ern P
h
t
to SoAm rolling
u
o
S
back at Urica Fault
Plate boundary near Cariaco Trough traces under
SoAm, shown in heavy pink highlighted line
dashed bases of Villa de Cura and Margarita Platform
denote Middle Miocene tectonic float detachments
within Caribbean lithosphere, now largely inactive
500
600
Proto-Carib
Barbados
Ridge (obducted) Prism
1200
NORTHERN TUYCARIACO SUB-BASIN
900
600
TIME
LA BLANQUILLA BASIN
Original interpretation in box
after Ysaccis (1997), Profile B7.
0
300
10 KM
0.0
1.0
2.0
3.0
4.0
5.0
6.0
This seismic line interpretation (from Ysaccis (1997)
lies in the red box in the section above, showing the
actual extension in the
Cariaco Basin as Margarita
Platform moves east with
respect to South America.
Figure 15F) Oblique section (see Figure 15D for line location) from Central Venezuela (10N/67W) to near Barbados
(13N/58W), situated on the hanging wall of the Proto-Caribbean subduction zone. Intra-plate deformations within the Caribbean Plate, including obduction of Villa de Cura, occur within tectonic float above a detachment at perhaps 10 km depth.
Deep Caribbean lithosphere is continuous from Lesser Antilles Arc to the Maracaibo Slab along this profile. Caribbean lithosphere dips westward from the surface at Margarita to beneath Central Venezuela, passing through a lithospheric, southward scissoring tear fault beneath the surface Urica fault zone, and beneath a zone of upper level orogenic float between the
Urica zone and the Orchila Canyon-Margarita lateral ramp that was associated with mainly Middle Miocene NW-ward
backthrusting toward the South Caribbean foldbelt. This passage through the Urica tear is how the polarity of CaribbeanSouth America collision changes to the west and east of the Gulf of Barcelona (see Figure 15B). The NW-ward
backthrusting became largely inactive after 10 Ma, after which Caribbean motion became eastward and the Morón-El Pilar
fault zone has allowed nearly E-W relative plate motion along the heavy pink highlighted fault.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
32 of 76
before the arrival of the Caribbean Plate along northern South America, it is likely that this subduction of
Proto-Caribbean lithosphere occurred ahead of the leading edge of the Caribbean Plate at a north-facing
“Proto-Caribbean subduction zone” along northern South America. A closer look at the N-S tomographic
cross sections reveals that the Proto-Caribbean slab: (1) has a westward widening wedge-shaped tear within
it which helps to account for the Proto-Caribbean slab projecting several km underneath South American
continental crust, and (2) has been severed from the lithopshere beneath the Bahamas (North America) by a
small amount relative to the severing from South America. Due to the regional southward dip component of
the Proto-Caribbean lithosphere and the rapid Middle Eocene uplift and erosion of the Greater Antilles Arc
and the Bahamas foreland, we judge that the dislocaton from the North American lithosphere is likely due to
Eocene and younger gravitational slab drop off with attendant isostatic rebound of the orogen. Thus, southdipping subduction of Proto-Caribbean lithosphere was probably established beneath northern South
America earlier, and it was there that inter-American convergence was first established.
•
ENE of Barbados on the Atlantic floor, a paired basement ridge/trough (south side/north side, respectively)
with an attendant free-air gravity signature projects ENE into the Atlantic from beneath the Barbados
accretionary ridge (Fig. 16). We interpret this feature as the eastward continuation of the N-facing ProtoCaribbean subduction zone’s hanging wall (ridge) and trench (trough), not yet overthrust in this area by
Caribbean lithosphere or Barbados Prism (Pindell et al., 2006). This ridge/trough pair extends eastward to at
least the position of western Atlantic magnetic anomaly 30 (Late Maastrichtian), which is the age when
convergence between the Americas began. Therefore, the Proto-Caribbean subduction zone may have
initiated simply as a third arm extending from a triple junction where it adjoined the Maastrichtian midAtlantic spreading center.
•
Paleogene uplift and erosion of section along the northern South American shelf (Hedberg, 1950) was
interpreted as being due to the eastward migration and passage of the Caribbean forebulge by Dewey and
Pindell (1986) and Pindell et al. (1988; 1991). It is certainly true that the drowning of this forebulge
unconformity is diachronous, mapped by the onlap of the unconformity (basal foredeep unconformity).
However, this does not mean that the onset of erosion was eastwardly diachronous. It may in fact be that
uplift occurred along the entire margin due to the onset of Proto-Caribbean subduction (i.e., hanging wall
uplift), and that the unconformity persisted until the erosional surface was loaded by the advancing
Caribbean Plate. Furthermore, the presence of well-rounded Turonian and Albian blocks in the Late Eoceneearliest Oligocene Plaisance Conglomerate in the Central Trinidad suggests that erosion of section may have
been deeper than expected by peripheral bulge uplift alone (i.e., 200 m), again pointing to the possibility of
hanging wall uplift. Further, seismic records in Central Venezuela (e.g., PDVSA 1995 bid round pamphlets)
show normal fault offsets at the basal foredeep unconformity that are often larger (up to 500 m) than those
predicted by lithospheric forebulge flexure. This erosion and faulting may better be related to the conversion
of the Cretaceous passive margin to the “Proto-Caribbean” subduction zone (Pindell and Kennan, 2001).
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
33 of 76
-67°
18°
-66°
-65°
-64°
15
P
-61°
-60°
-59°
-58°
-57°
-55°
-54°
-53°
Barr
acud
a Ris
on
-
rench
-Car T
e
250
Ridge
n Ris 33
e
34
thrust toe
Barbados
31
32
34 Ti
buró
7km
b Ridg
P-Cari
e
50
11°
Barcelona
-66°
-50
-65°
-64°
-63°
-62°
-61°
-60°
-59°
-58°
-57°
13°
-100
D
se r e m
ve era
s a ra
s o Fra
cea ctu
nic re
“ri Zon
fte e (
d” Ap
ma tia
Gu
rgi n-A
ya
n a lb
na
t ~ ian
10 )
CO
0M
B
a
12°
14°
0
33 magnetic anomalies
from Speed and
34 Westbrook (1984)
33
34 “Atlantic”
fra
zones
(post-1 cture
00 Ma
)
limit of Caribbean crystalline plate,
overthrusting
the ProtoCaribbean
subduction
zone
13°
15°
100
33
34
16°
200
150
rench
P-Carib T
14°
17°
300
33
P-Car
-52°
18°
350
16
Tibu
r
15°
10°
-67°
-56°
mGal
da
10km
14
-62°
57
racu
t
16°
16
. crus
Carib
17°
-63°
58
Ba r
Basement Structure
-150
12°
-200
-250
11°
-300
-56°
-55°
-54°
-53°
10°
-52°
Figure 16. Free air gravity image of the eastern Caribbean region, showing the projection (negative gravity trough) of the
Proto-Caribbean Trench eastward from beneath the Barbados Ridge out to about western Atlantic magnetic anomaly 30
(Maastrichtian), and the corresponding parallel gravity high immediately to the south. This trough exceeds (is more
negative) than the signature of the southward crustal boundary of the Caribbean-Atlantic interface, suggesting it is at least as
important as a tectonic crustal feature. Magnetic anomalies in the Trough are dashed due to uncertainty during the original
identification, possibly due to crustal deformations in the area. The main gravity trough lies at a 30° angle to regional fracture zones, and is thus not related to seafloor spreading. Difference in trend in the magnetic anomalies north and south of the
trough could suggest either a slightly different kinematic origin of the two sets of anomalies, or relative motion (rotation)
between the two sets since their formation, or both. The Cenozoic rotation between the Americas shown in Figure 14
accounts for some of the difference. Inset: structure contours to basement, after Speed et al. (1984), highlighting the ProtoCaribbean Trench and Ridge pair of structures. Note that basement relief is up to 4 km across the pair.
km
400
200
0
600
800
Tr
-Car
Proto
1000
CARIBBEAN PLATE
South Caribbean Foldbelt
RC
M
Oc a Fa
Ca
FZ
ove
ult
Morón Fault
rt h
tP
rus
orot
re n
rT
ey
70
Urica Ft
o
34
40
gu
M
i
Pa soa/
uj i
M
arc
eli
oli
M
75
49
na
no
65
19
cit
56
Pa
M
e of
trac
h
tian n trenc
h
c
i
st r
bea
Maa -Carib
26
o
Prot
Ro
ble
r
aT
id
er
C
ar
ta
api
r
pe
Ci
0
pe
15
orot
fP h
o
e
c
trac tren
oic bean
z
o
n
Ce Carib
da y
h to
10
El Pilar Ft
d
en
c
ench
ro
SOUTH
AMERICAN
PLATE
10
Gu
Up
Maastrichtian position of
SoAm (blue) relative to
Present, as calculated from
65 Atlantic kinematics (Muller 60
et al., 1999)
yan
aC
OB
5
Figure 17. West-to-east progression of initial collision between the Caribbean Plate (subduction complex) and the South
American craton. See text for details and abbreviations.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
34 of 76
Local occurrences of extensional faulting in the basement and/or the passive margin section may owe their
origin to gravitational relaxation of hanging wall elements toward the free face of the new trench.
•
Fission track cooling ages in apatite grains from the Barranquín Formation of the Serranía Oriental are
mostly Miocene, but some are as old as Eocene (Perez et al., 2001; Locke and Garver, 2005). These authors
speculate an Eocene onset of uplift in the Serranía Oriental, which pre-dates the Oligocene encroachment of
the Caribbean foredeep in that area, and may relate, if not due to partial annealing, to the hanging wall uplift
noted above.
•
Post-orogenic cooling of the “Caribbean Series” metasediments through 350°C, as shown by Ar-Ar dating of
first foliation micas, was underway in the Caracas Group by 42 Ma (Middle Eocene), and in the Paria
Peninsula and Northern Range by about 26 Ma (Oligocene) (Sisson et al., 2005; Foland et al., 1992). A
zircon fission track age of 29 Ma from Paria Peninsula (Cruz et al., 2004; in press) suggests that uplift and
cooling locally may have begun even earlier there. These ages predate the time of Caribbean collision at
these places as judged from initial foredeep development across strike (Oligocene in Guarico Basin; mainly
Miocene in Maturín Basin), suggesting that metamorphism in these ranges was underway prior to the arrival
of the Caribbean Plate. We suggest that an actively thickening orogenic pile of former continental slope and
rise strata existed along the Proto-Caribbean trench as the Caribbean prism and forearc collided
diachronously with it. Thus, the thermal conditions for metamorphism may have been largely established in
this thickening pile by the onset of the prism-prism collision, but the younger collision may ultimately be
responsible for many of the structural features preserved today, including the onset of progressive cooling at
the times noted above.
•
Speed (2002, and many earlier papers) built a comprehensive model for the depositional and deformational
history of the Scotland District, Barbados, employing a single SE-migrating Caribbean trench in which
Eocene-earliest Miocene pelagic strata of the forearc basin overthrust, in the Miocene, Eocene-?Oligocene
fine to coarse grained clastic accretionary prism strata that originally lay on the Proto-Caribbean (Atlantic)
seafloor. However, there are several apparent inadequacies in this model, some of which are: 1) fold and
thrusts trend 070°±20°, not 010°±20° as Caribbean migration models predict; 2) much of the Scotland
District deformation is NW-vergent, as opposed to ESE-vergent, as expected, thereby requiring special
structural dynamics or backthrusting during initial accretion to explain; and 3) there is no gradation in
lithology or composition between the Oceanics (pelagic forearc) and Basal Complex (clastic prism) strata,
except for some radiolarites in the lower Basal Complex that could, but do not appear to, relate to the
Oceanics; this raises doubt over whether the two units were ever adjacent enough to form parts of the same
forearc-subduction complex. In contrast, a prism-prism collision model appears to explain the geology of the
Barbados Ridge better; such a model is the subject of ongoing work by us. Much of the Basal Complex may
pertain to the Proto-Caribbean Prism, rather than the Caribbean Prism, whereas the Oceanics very probably
correspond to the Caribbean forearc/upper prism. If so, the observed N-vergence with fold-thrust trend 070°
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
35 of 76
in the Basal Complex is precisely that predicted for the Proto-Caribbean prism along northern South
America, prior to Caribbean arrival. In addition, this model allows us to predict where and when where the
two prisms collided; by backtracking the migration path of Barbados Island as part of the Caribbean Plate
(ignoring relatively minor deformations around the island), it is seen that the flow line for Barbados crosses
the trace of the Proto-Caribbean trench at about latitude 13.5° and longitude 62°, in the Middle Miocene.
This is exactly the time argued by Speed for the backwedging of the Basal Complex beneath the Oceanic
Complex, as constrained by the ages of involved and overlapping strata. Speed also concluded that the
juxtaposition of the Oceanic and the Basal complexes was E-directed, in keeping with collision of two preexisting prisms being driven by Caribbean migration. Finally, the backwedging of Basal Complex material
into the Tobago Trough forearc strata (Torrini and Speed, 1989) would be seen in this model as the
Caribbean crystalline forearc wedging beneath or into the pre-existing Proto-Caribbean Prism. Since this
Middle Miocene tectonic juxtaposition and accretion of Proto-Caribbean Prism to the leading edge of the
Caribbean Plate, the two prisms have moved eastwards by some 200-300 km relative to South America as a
composite accretionary prism terrane.
The above seven lines of evidence provide a broad basis supporting the existence of a Proto-Caribbean
subduction zone or convergent boundary situated ahead of the Caribbean Plate during its diachronous collision
along northern South America. In the next section, we will examine Caribbean-South American kinematics so
that comprehensive paleogeographic maps can be presented thereafter.
Caribbean-American Cenozoic plate kinematics: Cayman Trough magnetic anomalies compared to
diachronous Caribbean foredeep history in South America
Constraining the rate and azimuth of Caribbean relative motion with the Americas as the latter drift west
in the mantle reference frame is prerequisite to understanding the Cenozoic history of plate interactions between
the respective plate margins. In this section, we show that models for the Cayman Trough’s opening history vary
drastically in rate through time and thus are less firmly known than the history of Caribbean foredeep advance in
northern South America. Thus, we suggest that the latter be used as a more accurate yardstick for assessing the
rate of Cenozoic Caribbean-American displacement.
Opening of the Cayman Trough
Marine seismic, dredging, and heat flow data (Rosencrantz et al., 1988) indicate a Tertiary, probably
Eocene to Present (opening is ongoing) age for the Cayman Trough. Mann and Burke (1984) suggested 1,200
km as the total offset along the trough, whereas Pindell and Barrett (1990) pointed out that some of the trough’s
morphology was produced by stretching of arc crust at the trough ends such that the lateral offset was somewhat
less than the trough’s total length; they suggested 900 km of seafloor spreading plus another 150 km of syn-rift
extension. Rosencrantz (1995) inferred that 1,040 km of the Trough’s length is oceanic, Leroy et al. (2000)
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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suggested at least 900 km of oceanic crust, while Ten Brink et al. (2002) interpreted a length of about 812 km of
oceanic crust. These workers presume the existence of mappable magnetic anomalies. Finally, Sykes et al.
(1982) showed that a significant amount of slip is occurring along the SE margin of the trough (Jamaican flank),
such that the actual strike slip offset along the Cayman Trough is larger than the E-W extension required to
produce the trough itself. This point was amplified by Rosencrantz in 1993 while pointing out that Cayman
Trough opening does not perfectly record North America-Caribbean relative motion, because the latter is larger.
Several authors have attempted to establish the Caribbean-North America Cenozoic displacement rate by
mapping the N-S trending magnetic anomalies in the Cayman Trough as geomagnetic polarity reversals
(MacDonald and Holcombe, 1978; Rosencrantz, et al. 1988; Rosencrantz, 1995; Leroy et al., 2000). Table 1
shows three of the more recent efforts, each presumably using the best data available but with little agreement.
Reasons for the disagreement are probably four-fold: 1, to a lack of trustworthy data; 2, tectonic deformations
such as transform drag and block faulting may have disrupted the original magnetic signal from the trough’s
basement; 3, plate accretion (spreading) may have fed off-axis faults as well as the central spreading axis,
thereby disrupting the original magnetic pattern; and 4, ridge jumps have probably occurred (Rosencrantz et al.,
1988), thereby introducing model dependence in the interpretation of spreading.
Given the inconsistencies in Table 1 and the four very plausible possible causes for those inconsistencies
noted above, Caribbean-American kinematic history might be constrained better by mapping the migration of
Caribbean foredeep development along northern South America, which records the advance of the Caribbean
tectonic load during the oblique collision of those two plates (Pindell, 1985; Dewey and Pindell, 1986; Pindell et
al., 1988; 1991). In this paper, we review the foredeep migration analysis with more rigour than previously done,
and propose a Caribbean-South America migration history that can then be compared to Caribbean-North
America migration histories derived from the Cayman Trough.
Migration of the Caribbean foredeep in northern South America
Figure 17 shows the history of impingement (initial collision as a function of position as indicated by
foreland subsidence history) of the Caribbean forearc/subduction complex relative to South America, shown as
numbers (Ma) in the green squares. South America is shown in its Present position (gray) and also in its
Maastrichtian configuration relative to North America (blue; after Pindell et al., 1998) to highlight its former
NE-SW orientation during most of this collision, which was more head-on than is often thought. Formations
identified by Pindell et al. (1988; 1991) denoting onset of foreland subsidence and that define the long-term
Caribbean-South America migration are:
Molino Formation in Cesar Basin, Late Maastrichtian-Early
Paleocene; Marcelina Formation in western Maracaibo Basin, Late Paleocene to Early Eocene; Misoa-Pauji
Formations in central and eastern Maracaibo Basin, Early to early Late Eocene; Paguey Formation in northern
Barinas Basin, Late Eocene to Early Oligocene; Roblecito Formation in the Guarico Basin, Middle Oligocene to
earliest Miocene; Areo and Carapita Formations in the Serranía Oriental/Maturín Basin, Early to Middle
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
37 of 76
Miocene; Upper Cipero Formation in the Southern Trinidad Basin, Middle Miocene. Foredeep development
clearly migrates east through time and is controlled by Caribbean advance until 10 Ma, when Caribbean azimuth
changed to E-W (Algar and Pindell, 1993). Note also that WNW-ESE diachroneity within a given formation,
such as the Roblecito Formation, has long been recognised (e.g., Gonzalez de Juana et al., 1980). Heavy black
line marks the southern reach of Caribbean forearc obductions on this reconstruction (prior to Neogene Andean
offsetting), and green heavy lines mark the position of the Caribbean forearc associated with the initial
obductions at the indicated times, in Ma. The actual displacement distances between successive paleopositions of
the forearc must be measured parallel to the ESE Caribbean relative displacement azimuth, due to the collision’s
obliquity. RCMFZ is Roques Canyon-Margarita fault zone. Note that today’s high-angle strike slip faults (grey
lines) of the margin (e.g., El Pilar, Oca, Boconó, Morón Faults etc) formed late in the Caribbean-South America
collision, after obduction of the allochthons and onset of underthrusting (backthrusting) at the South Caribbean
Foldbelt; thus, they only record a minor amount of the overall relative motion (<200 km) and cut across the
obducted thrustbelts (e.g., Lara Nappes). The bulk of plate displacement occurs at the base of the allochthons
and thus is not directly measurable by fault piercing points (Pindell, 1985; Dewey and Pindell, 1986; Pindell and
Barrett, 1990).
Using Figure 17 as a template for assessing Caribbean-South America displacement rate, we now assess
Caribbean-South America kinematics more fully. In Figure 18A, Tertiary motion of the Caribbean forearc
(Tobago, red line) and Caribbean Plate (La Blanquilla Island, purple) are shown relative to South America. The
Tobago path dashed where dependent on the model for opening of the Grenada Basin; here, we employ a N-S
opening model, e.g., Pindell and Barrett (1990) or Pindell and Kennan (2001). The change in Caribbean-South
America (or Carib-SoAm) azimuth (purple line) at about 46 Ma relates to Caribbean motion becoming more EW after the Middle Eocene Antilles-Bahamas collision. Because the northern Caribbean boundary (with North
America) is essentially transcurrent, the S-ward component of Carib-SoAm motion (purple) from 46 Ma onward
is largely due to the convergence between North America (NoAm) and SoAm (Müller et al., 1999; Fig. 14). The
inset in Figure 18A directly compares the two flowlines (Blanquilla and Tobago), highlighting the effect of
Grenada Basin opening and also of Middle Miocene intra-arc backthrusting in the Cariaco-Margarita-Carupano
platform areas (about 50 km toward WNW, which brought the forearc/Tobago closer again to the plate
interior/La Blanquilla) (Ysaccis, 1997; Clark, 2004). Figure 18B shows vector triangles loosely describing the
poorly known kinematics of the intra-arc Grenada Basin opening (N-S opening model is employed here):
Caribbean (C) and Tobago (T) move independently relative to SoAm (S), the difference being that the Grenada
Basin opened in the N-S direction due to rollback of Proto-Caribbean lithosphere ahead of the arc (Pindell et al.,
2005). For Grenada Basin opening models with more NW-SE extension (e.g., Bird et al., 1999), the azimuthal
variation from the Carib-SoAm curve would be less drastic, but Tobago would still migrate faster (restore farther
to the NW back in time) in the Paleogene to account for the basin opening. Figure 18C then plots Tertiary
motion rate as derived from Figure 18A. Tobago of course moved faster than the Caribbean during intra-arc
spreading, but slower during intra-arc backthrusting. Carib-SoAm rate has averaged about 18-24 mm/yr since
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
38 of 76
??
A
Tobago Path
(Tobago/SoAm)
La Blanquilla Path
(Carib/SoAm)
46 42 40
55
65
leading edge Caribbean crystalline terrane through time
55
46
42
34
31
25
40
34
18
15
12 10
La Blanquilla
31
18
25
0 Ma
12
SOUTH
AMERICAN
PLATE
10
10
i
er
e
Tr
da
nd
difference
in flowlines is
oblique Eocene
opening of
Grenada Bsn
M
blue: Pre-Miocene palinspastic
shape of continental crust in the
northern Andes
To
b
ag
oP
ath
La Blanquilla Path
km 0
75
5
B
400
200
600
Gu
ya
na
C
34
31
25
18 12
10
Comparison of La Blanquilla and
Tobago flowlines when superposed
70
OB
Vector triangles (to scale)
55-46 Ma
46-42 Ma
42-40 Ma
40-34 Ma
for the three plate system
S = South America
C
S
S
C
S
C
South America-Caribbean S
C = Caribbean Plate
C
Plate-Tobago Terrane durT
T = Tobago Terrane
T
ing the opening of the
T
T
Grenada Basin
Carib-SoAm rate: 55-46 Ma, 24mm/yr; 46-42 Ma, 20 mm/yr; 42-40 Ma, 22 mm/yr; 40-34 Ma, 22 mm/yr; 34-31 Ma, 23
mm/yr; 31-25 Ma, 22 mm/yr; 25-18 Ma, 18 mm/yr; 18-12 Ma, 18 mm/yr; 12-10 Ma, 20 mm/yr; 10-0 Ma, 20mm/yr.
Tobago-SoAm rate: 55-46 Ma, 29mm/yr; 46-42 Ma, 28 mm/yr; 42-40 Ma, 28 mm/yr; 40-34 Ma, 28 mm/yr; 34-31 Ma, 23
mm/yr; 31-25 Ma, 22 mm/yr; 25-18 Ma, 15 mm/yr; 18-12 Ma, 15 mm/yr; 12-10 Ma, 20 mm/yr; 10-0 Ma, 20mm/yr.
C
Interval rates, Caribbean plate/SoAm.
Interval rates, Tobago forearc/SoAm.
Smoothed forearc motion history, constrained by interval rates.
Caribbean Plate relative to South America during opening
of Grenada-Bonaire Intra-arc Basin
40
30
20
intra-arc rifting,
forearc advance
mm/yr
10
Ma
60
50
40
backthrusting,
80 km/14 Ma
30
20
10
0
Figure 18. A, Tertiary motion of the Caribbean forearc (Tobago, red line) and Caribbean Plate (La Blanquilla Island, purple),
relative to South America. B, vector triangles showing the kinematics of the Grenada Basin opening employed here: Caribbean (C) and Tobago (T) move independently relative to SoAm, the difference being Grenada Basin opening N-S. C, Tertiary motion rates for the Caribbean Plate and Tobago relative to South America. See text for discussion.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
39 of 76
Eocene. This rate is similar to that of coeval Atlantic seafloor spreading (20-30 mm/yr; Klitgord and Schouten,
1986), indicating that Africa and the Caribbean lie in a similar reference frame (which is close to that of the
mantle; Müller et al., 1999; Dewey and Pindell, 2006) while the Americas drift westward.
Comparison of Table 1 with Figure 18C reveals significant discrepancies between the two approaches
to assessing Caribbean-American relative motion, although this is not a strict comparison because Table 1
portrays Carib-NoAm motion while Figure 18C portrays Caribbean-South America (Carib-SoAm) motion.
However, NoAm/SoAm motion is essentially N-S for Cenozoic time, so the rough comparison roughly holds. In
our opinion, the analysis deriving from the migrating Caribbean foredeep is more rigorous, as Table 1
demonstrates a degree of non-reproducibility in the analysis of Cayman Trough spreading. It would be
interesting to explore if a viable interpretation of Cayman Trough magnetics could be made that closely matches
the foredeep analysis as a hypothetical guide. Such a step may be wishful thinking, however, given that we do
not know how much, and when or how often, northern Caribbean slip might have bypassed the mid-Cayman
spreading center to pass along the Jamaican flank of the trough. We reiterate that the Cayman Trough only
records a minimum of the total Carib-NoAm relative motion.
Implications of regional kinematics: the generic prism-prism collision model
From the above, the Caribbean-South America diachronous collision took place at a trench-trench-trench
(actually, trench-trench-thrustbelt) triple junction where the Proto-Caribbean slab was concurrently subducted
beneath both the Caribbean and South American hanging walls (Figs. 19A-C). Prior to the arrival of the
Caribbean at any given point along South America, the Paleogene development of the Proto-Caribbean
subduction zone/thrustbelt caused progressive shallowing and significant regional erosion of the South American
hanging wall margin as it was thrust northwards over the Proto-Caribbean lithosphere (Figs. 19B). This thrusting
may have imparted a minor (<3°) southward tilt upon the Serranía del Interior depositional surface. Judging from
the surface geological map pattern, few thrusts could have been active within the Serranía hanging wall during
this phase, but the Zorro Thrust near El Pilar village (northern Serranía) is one possibility, with an ?Eocene
breccia/conglomerate under Aptian-Albian El Cantil limestone (Vierbuchen, 1984). Uplift of the South
American hanging wall was then reversed as the Caribbean Plate arrived and drove foredeep subsidence from the
WNW diachronously, due to the loading effect of the Caribbean lithosphere on first the Proto-Caribbean
lithosphere at the Proto-Caribbean trench and then on the South American lithosphere itself, once the ProtoCaribbean trench had been crossed by Caribbean lithosphere (Figs. 19C). Thus, although Proto-Caribbean
hanging wall uplift may have started synchronously along northern South America, the culmination of uplift and
the onset of Caribbean load-induced subsidence on South America was predicted to young eastward with the
migration of the Caribbean Plate (Pindell et al., 1991). In the eastern Serranía Oriental, the hanging wall uplift
culminated in the latest Eocene to earliest Oligocene, producing such redeposited detritus (transported to slope
facies) as the Plaisance Conglomerate of Trinidad. But the uplift was likely epeirogenic over the whole of the
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
40 of 76
Table 1. Comparison of postulated Eocene-Recent Cayman Trough opening rates by
Rosencrantz et al. (1988), Rosencrantz (1995), and Leroy et al. (2000).
Mag. Anom./Ma interval
timespan
distance opened
km/my
Rosencrantz et al. (1988)
0-5, 0-10 Ma
10 my
133 km
13.3
5-6, 10-19 Ma
9 my
141 km
15.7
6-13, 19-34 Ma
15 my
321 km
21.4
13-20, 34-42 Ma
8 my
266 km
33.3
total oceanic opening: 860 km since 42 Ma
Rosencrantz (1995)
0-5, 0-10 Ma
10 my
312 km
31.2
5-6, 10-19 Ma
9 my
100 km
11.1
6-13, 19-34 Ma
15 my
263 km
17.5
13-20, 34-42 Ma
8 my
375 km
46.9
total oceanic opening: 1040 km since 42 Ma
Leroy et al. (2000)
0-5, 0-10 Ma
10 my
162 km
16.2
5-6, 10-19 Ma
9 my
175 km
19.4
6-13, 19-34 Ma
15 my
275 km
18.3
13-20, 34-42 Ma
8 my
188 km
23.4
20-22, 42-49 Ma
7 my
100 km
14.0
total oceanic opening: 900 km since 49 Ma
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
41 of 76
A
an
n
ibbe
bea
Car bulge
a ri b e
C
fore
o
t
g
Pro orebul
f
h
renc
ge
an T
e
Ri d
b
n
b
i
a
r
e
a
b
to-C
arib rifted, deep water
Pro
to-C
o
r
P
continental edge
Bo
hor
CO
dal
B
Serrania
Trinidad
Ur
s
ica Oriental
hel
fe
B
dge
Ca
ri
Tre bbean
nc h
Merged forebulges, buttressing further rollback
A
C
Caribbean
Plate
Caracas
D
B
B Merging of SoAm & Caribbean forebulges
A
Proto-
Caribbean
C
Proto-Caribbean sinks vertically beneath the
advancing, uplifted forearc hanging walls.
C
Caribbe
an
SoAm
Proto-Caribbean vertically buried into the mantle
Foredeep
(Guarico Basin*)
D
SoAm
Caribbean
Proto-
prevents further rollback ahead of either
trench, thereby buttressing both forearcs,
with resultant hanging wall uplift and
loading of the Proto-Caribean during final
plate closure.
Caribbe
an
* foredeep will be
Maturín Basin in
Middle Miocene
Proto-Caribbean sinks into the mantle
Figure 19. Generic model for the collision of two convergent margins above an intervening oceanic lithosphere. A) Map of
the present case. Note that only the Caribbean hanging wall was volcanically active because convergence beneath the South
American hanging wall was so slow. Concerning the Proto-Caribbean Trench, the Alaskan subduction zone is an analogue
although directions (N and S) are reversed. From Guajira to either the Bohordal transfer zone or the Guyana paleo-transform,
the trench hanging wall was continental, as in the southern Alaskan segment, but eastward the hanging wall was oceanic, as
in the Aleutians. It is not clear whether the crust between the Bohordal and Guyana transfer zones was oceanic or thinned
continental. Peripheral bulges will lie outboard of both trenches and migrate through the Proto-Caribbean (Atlantic) lithosphere until they merge due to plate convergence. B) Once merged, the forebulges will no longer migrate, and then they
must be overridden by the advancing forearcs. This has the effect of driving the intervening lithosphere downwards into the
mantle, but this in turn can only be achieved as a result being loaded by the forearcs. Thus, both forearcs will actively be
uplifted, on a scale of 1 to 2 km depending on rates and other factors which we will not go into here, prior to actual contact
between the two forearcs. If the forearcs were shallower than the amount of forearc uplift, subaerial unconformity will result.
This was certainly the case for the South American margin, as shown by the Late Eocene-earliest Oligocene unconformity
(zig-zag line) and production of sandstone and shale sequences east of Urica Fault with only a clean, continental mineral
signature and no sign of detritus from the Caribbean Plate (applies to Vidoño, Caratas, Los Jabillos, Chaudière, Lizard
Springs, Pointe-a-Pierre, Navet, Plaisance “unit” (latter of which is no longer seen as part of San Fernando Formation), and
the San Fernando Formations of eastern Venezuela and Trinidad (Tectonic Analysis Ltd, 2005; 2007). C) Once the two
forearcs began to collide, the Caribbean remained on top and overthrust the South American crust. This is the stage that
drove much of the Guarico-Maturín-Southern Basin syn-collisional foredeep subsidence (La Pascua/Roblecito,
Carapita/Chapopotal, and Upper Cipero/Herrera Formations). Concerning the Tobago portion of the Caribbean side of the
collision, Pliocene rests on Albian and zircons in Albian rocks cooled through 220°C by 103 Ma and apatites cooled through
~100°C at about 45 Ma (Snoke et al., 2001). The Early to Middle Eocene cooling relates to the low-angle detachment opening of the Grenada Basin (Margarita and Tobago were parts of the footwall according to Pindell et al., 2005), thereby
explaining the lack of Upper Cretaceous rocks on Tobago, but the end Eocene forearc uplift by the mechanism of Figure
19B, followed by collisional uplift as in the mechanism of Figure 19B, kept any sediment from accumulating on the surface
of the Tobago High until the Late Miocene (Pliocene on the island itself).
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
42 of 76
Serranía, and the resulting angular discordances of only 2 or 3 degrees are not readily observable in today’s
deformed field sections.
In addition, South American hanging wall uplift is predicted to have produced a Cenozoic
paleobathymetric ridge projecting and plunging ENE from the northern flank of the Serranía del Interior out to
about 15°N/53°W in the Atlantic, passing under the present position of Barbados (shown schematically in (Fig.
19A). We believe that today’s expression of this is shown in Figure 16, inset. The seafloor expression of this
submarine ridge and its adjacent trough was buried by sedimentation only in the Middle or Late Miocene, and
thus the ridge separated the Paleogene clastic dispersal pattern from South America into 2 realms. The first is a
deep water “Proto-Caribbean” realm, which included the Tiburón Rise, whose complex heavy mineral signature
reflects Eocene-Oligocene orogenesis between the Caribbean and South America in western and Central
Venezuela (eg., Barbados field samples, Tiburón ODP cores). The second is a “Guyana-Trinidad-Eastern
Venezuela” realm on the backside (south) of this Proto-Caribbean ridge, which remained entirely cratonic and
mineralogically mature until the Upper Oligocene onset of the Naricual and Nariva formations, marking the
closure of the Proto-Caribbean Trough at the longitude of the East Venezuelan Basin, such that orogenic
minerals finally breached the barrier and reached into Trinidad (Tectonic Analysis, 2005; 2007). East of
Barbados, this buried Atlantic basement ridge, with about 3 km of relief at the basement level, is also at least
partly responsible for Barbados’ present, uniquely subaerial exposure on the E-wardly migrating Barbados
Ridge; the island is presently passing over the Proto-Caribbean basement ridge.
Late Oligocene-Middle Miocene orogeny in the ESCPBZ
Having unraveled the palinspastic effects of the last 10 m.y. of tectonic evolution, defined the regional
plate kinematics, and established the case for the existence of the Proto-Caribbean subduction zone, we now
focus our attention on the Late Oligocene to end Middle Miocene orogeny in Trinidad and, to a lesser extent, in
Eastern Venezuela and Barbados Ridge. The orogeny, culminating at about 10-12 Ma in Eastern Venezuela and
Trinidad, was dominated by ESE-directed folding and thrusting driven by the approach of the Caribbean Plate
from the northwest. This orogeny reached the Columbus Channel, and was detached at or near to the base of the
post-rift stratigraphic section in Central Trinidad; it appears to involve older rock toward the north. Restoring the
gross deformations produced in the orogeny will provide a Late Oligocene, pre-orogenic palinspastic
reconsruction which may be used to assess earlier Paleogene development of the Caribbean-South America plate
boundary.
Figure 20 shows an outline tectonic elements map of the Trinidad region based on our own mapping of
an extensive seismic database (Gulf of Paria, onshore and eastern offshore areas) supplemented where necessary
by published maps (e.g. Robertson and Burke, 1989; Babb and Mann, 1999; Flinch et al., 1999; Boettcher et al.,
2003). Trinidad is clearly a complex geological collage with a polyphase geological history and structural
elements that are continuously inherited and reused. Present-day structure is typical of strike-slip-dominated
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
43 of 76
-62
KEY:
-61
Cruse-Forest-aged
normal faults (folded)
11
CARIBBEAN
PLATE
Structure ages:
Cret-involved structures in SBC area
Southern limit of
Cretaceous involvement at 10-12 Ma
-60
Pleistocene
Late Mioc.E.-Pleist
Mid. Mioc.
Tectonic
Analysis
TOBAGO
Gu
ya
Not dated
Mud volcs.
na
Tr
an
N. Coast F. Zone
Limit of Caribbean Plate
(undethrusts N. Range, Paria)
Continent-Ocean Boundary at
base of Guyana Transform-slope
Sc o
Northern Range
PARIA
El Pilar Fault
n
r pi o
Fau
=
CO
B
lt
ANGOSTURA
Caroni
Basin
t
Ce n
r al
R
e
ang
D
nR
arie
i d ge
Ea
Point Radix Fault
?
jos
L
rl y
Cr
et.
Touchdown
Basin
sh
elf
Southern Basin
Los
Ba
Fau
Mi
lt
10
Upr. Cret. shelf edge
-62
sfo
rm
Caroni Fault
Gulf of Paria
Pull-apart
50 km
11
Columbus
Channel
d. C
ret
. sh
elf
ed
ge
?
10
e dg
e?
SOUTH AMERICAN PLATE
-61
-60
Figure 20. Map of principal present day structural elements of Trinidad, based upon extensive seismic mapping.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
44 of 76
deformation, and comprises several discrete through-going linear fault zones which bound overlapping and
anastomosing zones of extensional (releasing bend or pull-apart) and compressional (restraining bend) structures
(see earlier discussion of various aspects of the ESCPBZ). However, much of the terrane through which these
fault zones pass comprises deformed orogen from the Late Oligocene-Middle Miocene stage of development.
Figure 4B shows a cross-section across the map of Figure 20 through Port of Spain at full lithosphere
scale, based on seismic data (approximately depth-converted), patterns of earthquake activity, and seismic
tomography (Van der Hilst, 1990). We are confident this is a substantial improvement over most cross-sections
published to date, and that it coherently illustrates relationships between distinct elements of Trinidadian
structure. The most important point is that South American continental lithosphere, although dipping NW, can be
traced at least 150 km north of Trinidad (as proposed by Speed, 1985), reaching the Grenada Arc, and is
overridden by the Caribbean Plate. There is no indication of a lithospheric-scale vertical strike-slip tear below
about 30-50 km. Thus, South America does not end at the El Pilar or North Coast Faults (as implied by the maps
of, eg., Robertson and Burke, 1989). The deep seismicity of the “Paria Cluster” is part of a continuous Benioff
Zone which can be traced updip to the east where it emerges at the toe of the Barbados Prism. Thus, we show the
Caribbean Plate apparently over-thrusting the South American Plate above a detachment which shallows from
about 50 km beneath the North Coast Fault Zone, and is continuous with the basal detachments at about 30 km
beneath the Gulf of Paria, and about 15 km beneath the Southern Basin (see below). The Caribbean is now
moving approximately normal to this cross-section but because the Caribbean Plate thickens from east to west, it
is continually depressing the northern feather edge of South American lithosphere, and this continues to drive
subsidence in the absence of strong north to south compression (see “bow-wave model”, above). It is also
apparent that the East Venezuela-Trinidadian orogen is essentially a bivergent orogenic float developed above
this Benioff Zone, involving north-directed thrusting of the upper level of the southern edge of the Caribbean
Plate, as a response to its impinging on South America, and south-directed thrusting of the sedimentary cover of
South America. Oblique strain within this float prior to about 10 Ma is partitioned between dextral strike-slip
and apparently compressional deformations and the degree and type of partitioning varies through time
controlled by factors such as changing relative plate motions and variations in pre-existing structure and
stratigraphy of the South American margin.
Figure 21 shows a closer view of this cross-section. Note that all the major strike-slip lineaments in
Trinidad root into the detachment above South American lithosphere. None are associated with seismicity deeper
than ca. 30 km (Sobiesiak et al., 2002), and all earthquakes with dextral focal plane solutions are relatively
shallow. This rooting enables the strike-slip faults to move across the detachment surface towards the north or
south, and thus none are fixed with respect to South America, in contrast to the more traditional view of, for
example, Robertson and Burke (1989). The structure of the Southern Basin (see below) clearly roots to the base
of a more or less layer-cake post-rift stratigraphic section. Towards the north, beneath the Gulf of Paria, we
speculate that a sliver of basement (note that “thin-skinned” but “basement-involved” are not mutually
exclusive) may play a role in elevating the Early Cretaceous stratigraphy drilled in the Couva Marine area. This
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
45 of 76
NNW
Caribbean wedge beneath
Coast
backthrust and Northern Range
NCFZ
Distributed
dextral shear
ELP
Coast
CRF PRF
SRA
SSE
EXT
Post-rift passive
margin section
Orogen detached
at ca. 20-25 km
oat”
Moho
Deep basement sliver, above
ca. 20 km detachment
Flexural extension
100 km
Figure 21. Close-up cross-section (see Fig. 4C) showing “oblique-thin-skinned” character of the Trinidadian Orogen.
Kink zone
NNW
0
2 Ma u/c
MT. HARRIS
THRUST?
“Scorpion Fault Zone”
TRAD. CRF
NORTH BASIN
Deep Angostura?
(shallows to NE)
SSE
Mokatika
0
Late Plio.
Plio.
Brasso?
2
NORTHERN RANGE
NO CONTINUATION
OF ARIMA FAULT
Top Mio.
4
200
8
TWTT
10 km
qui
ra n
Co
u
DOES CARIBBEAN PLATE
UNDERTHRUST N. RANGE?
CENT. RANGE
CRETACEOUS
Angostura?
TYPICAL
CRETACEOUS
THICKNESS
n?
4
Nap. Hill?
t?
Ga u
va?
r
Ba
6
10 Ma u/c
2
Nariva FTB?
NORTH.
CRET.
rr
Ba
?
uin
a nq
a?
uv
Co
?
Cuche
quin?
Barran
Typical thickness of Cretaceous
thrust slices suggest unseen
Barranquin section is involved
SOUTHERN BASIN
CRETACEOUS
6
a?
v
Cou
Filtered from original seismic
provided by BPTT
400
8
Figure 22. Example seismic line-drawing through the Mokatika area (location on Figure 25). Note 1) Upper deck structure
is initially pre-Late Miocene; 2) Evidence of “relaxation” before and during Manzanilla; 3) Likely location of Central Range
Dextral Fault is “clear”; 4) Plio-Pleistocene folding near Central Range Fault; 5) Deeper structure shows stacked horses
detaching near base Cretaceous, truncated by Darien Ridge so age relative to young strata not so clear.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
46 of 76
sliver may either represent southward ramping of the detachment from a mid-crustal level (brittle ductile
transition) to more or less the base of the post-rift section, or may be a former low angle extensional horse
formed during Jurassic separation of Yucatán and South America.
Note that we show the leading edge of Caribbean forearc crust wedged between the metasediments of
the Northern Range and the proposed basement sliver to the south. This is based on observations to the west
(Serranía Oriental and Central) and east (Tobago area) but can only be inferred for onshore Trinidad. We infer
the wedging to be of Middle Miocene age and believe that it played a significant role in the Middle Miocene
unroofing and cooling of the Northern Range.
Seismic mapping of dismembered Middle Miocene structures in Trinidad
Figure 22 is an interpretation of a seismic line in the Mokatika area in the eastern Central Range
offshore, showing the major structural elements of the Middle Miocene and younger deformations. Cretaceous
strata are elevated at least 12 km (or about 10s TWTT) above the regional level of Cretaceous to the south. This
elevation is achieved through imbrication of horses of passive margin strata approximately 2s thick. The horses
shown in this figure were clearly in place prior to the erosion of the base Late Miocene (ca. 10 Ma)
unconformity. The uppermost horse (above bold black thrust) corresponds to the rocks of the Central Range and
Angostura areas, and appears to tip up to the south into intense imbrication of Nariva shales. Deeper horses
correspond to rocks found in the Southern Basin and beneath the Nariva Fold-Thrust Belt onshore. Note that the
projection of the Central Range Fault from Manzanilla Point is clear on this line, but it does not appear to be
neotectonically active; it does not break the seafloor or cut very young reflectors. The youngest surface breaks
are along the “Scorpion Fault” indicating that the active shearing (Prentice et al., 2001) we see along the onshore
Central Range Fault (CRF) steps north through Block 2ab (where there are young synclines comprising sediment
of Plio-Pleistocene age) or (less likely) steps south towards the Darien Ridge Fault on one of several E-Wtrending transtensional faults (see below). We do not explore this issue further in this paper, but it appears that
the magnitude of oblique shortening in the Central Range between Pointe-a-Pierre and Angostura thus places a
constraint on the magnitude of strike-slip on the Central Range onshore (perhaps 10-15 km, matching the
apparent offset on E-W-trending pre-Central Range faults north and south of today’s Central Range Fault).
Timing of structuring is constrained by the relationships of imbricated strata to major unconformities
(Figs. 22 & 23). In the immediate Angostura area, high-quality seismic appears to show initial imbrication
before ca. 30 Ma, and the entire width of the section was deformed prior to erosion of the ca. 10 Ma base Late
Miocene unconformity. Syn-depositional folding of Late Miocene and Pliocene strata is evident indicating
further tightening of folds related to the Cretaceous horses beneath.
Both figures also show the presence of numerous minor normal faults within the growth sections of Late
Miocene and Pliocene strata which hint at three-dimensional strain. These young compression and extensional
features overlap in time and cannot be neatly separated into discrete phases.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
47 of 76
Cross-section A-A’
Topaz interpreted as backthrust wedge driven
by reactivation of underlying Emerald Thrust..
NW Central Range
NFTB leading edge
(v. similar to Brighton)
Topaz
NFTB
0
SE dipping late
normal faults
Emerald
NFTB
SE
0
Upper NFTB?
10.5
1
Mt Harris Allochthon?
2
2
ANGO.
Angostura
Anticline
(Thick lowstand 3
wedge sands)
CRET.
3
Upper Cretaceous ?upper-slope stratigraphy beneath Emerald thrust sheets
4
5 km
1
10.5
5
Speculative interpretation of
clinoform type wedge suggests
approaching outer shelf - now in
Emerald area? - to north, but south of
paleoposition of Angostura sands.
Lateral ramps of Mid-Miocene
age were reactivated from 10-5
Ma as transtensional normal
faults before being refolded
after 5 Ma.
Deepest apparently normal
fault underlies Emerald and
its footwall and appears to
trend W-E, surfacing south of
Kitchener (“N. Darien Fault?”
4
Below here, there are further Southern Basin-like
repeats of Cret. stratigraphy, detached on ?Couva
5
Figure 23. Semi-schematic cross-section, based on seismic data, through Topaz-Emerald area (location on Figure 25). In this
view, it is very hard to tell whether north-dipping faults which cut the deep undrilled stratigraphy are true thrust faults or
oblique views through NE-dipping normal faults or lateral ramps.
Cross-section B-B’
WSW
Manzanilla in triangular
depocentres above
transtensional ramps
Major E-W fault truncates Angostura Trend
Emerald-Amber fold-thrust structure
Emerald
ESE faults truncated by
SE-dipping normal faults
after 3-5 Ma
ENE
Amber
0
0
Minor post 5 Ma normal faulting
1000
1000
10.5
Thick Manzanilla
2000
Thinned tail of E-A FTB
3000
4000
2000
10.5
Footwall of E-A FTB?
10.5
3000
“Parautochthonous”
Cretaceous Platform
4000
Apparent offset?
Thick Manzanilla related
to ESE-trending fault
5000
6000
Southern Basin type imbricates of Cretaceous, detached
on ?Couva. Basal detachment at. ca. 10s TWTT
Major lateral ramp reactived as
later normal fault. Appears to trend
E-W and pass south of KitcherSpitfire.
5000
6000
10 km
7000
7000
Figure 24. Strike-line through Emerald area (location on Figure 25) showing apparent W-E extension of the Miocene thrust
belt. Emerald and other structures terminate against a middle Miocene ESE-trending lateral ramp (heavy blue line). Ramps
have apparent dextral offset of up to 15-25 km, and significant apparent extension. Some ramps were reactivated since 10
Ma as extensional faults, bounding Manzanilla basins - smaller extension, almost no strike-slip. Distinctive structural and
stratigraphic features that allow us to restore middle Miocene dextral offsets.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
48 of 76
A further significant problem can only be resolved when strike-lines are also interpreted, and when
structures are mapped more fully in three-dimensions. In general, the quality of seismic imaging within the
imbricated Cretaceous is poor. Although the generally imbricated structural character is clear, it is not always
obvious whether we are seeing more or less across-strike views of thrust faults or oblique views of lateral ramps.
Mapping of the faults shown in black on Figure 23 in particular suggest that these may be significant lateral
ramps on which dextral strike-slip displacement oblique to the line may exceed the apparent thrust shortening.
There are also locations where the top of Cretaceous in some of the syncline cores appears to have dropped
lower than its expected level, indicating the possibility of cryptic extensional faulting.
Figure 24 is a line-drawing of a 2D seismic strike-line through the Emerald and Amber areas showing
apparent E-W extension of the Middle Miocene imbricate stack. Several of the faults identified on Figures 4
and 5 are clearly seen to be east-dipping apparent normal faults. As with dip-lines, a simple interpretation may
mislead. For instance, although the normal faults may appear to sole out at the same level as some of the thrusts,
in three-dimensions they are found to dip moderately to steeply to the northeast, while the thrust dip generally
steeply to the northwest. The complex three-dimensional structure also suggests that some, if not many, of the
reflectors in these lines are side-swipes coming from out of the plane of the section and should not be overinterpreted.
The apparently normal faults clearly bound Late Miocene (Manzanilla-equivalent) depocenters.
However, a map view (Fig. 25) shows that these apparently normal faults also appear to coincide with lateral
ramps which trend more or less E-W in the Mokatika-Angostura-Emerald area. Offsets on these ramps can be
estimated from terminations and offsets of distinctive architectural elements of the Middle Miocene orogen such
as the Topaz Anticline and the Emerald Imbricate Antiformal Stack. These offsets are generally about 10 km,
but reach ca. 25 km on the major E-W trending fault in Block 3b, immediately east of the Amber well. The age
of the strike-slip offset is constrained to mostly pre-Late Miocene because onlap edges of Late Miocene strata
onto the 10 Ma unconformity are hardly offset across lateral ramps which show large offsets of Middle Miocene
structures.
Thus, it is clear that substantial eastward-lengthening of the Middle Miocene orogen was also occurring
at the same time as, or just after, initial thrusting and that the normal faults which bound Late Miocene
depocenters reused these pre-existing lateral ramps, without significant further strike-slip offset.
A reconstruction of the configuration of the Middle Miocene orogen at its culmination must thus attempt
to estimate the extent of tightening of older structures during the Late Miocene to Recent, and restore the effects
of Late Miocene extension which formed the Manzanilla depocenters. Reconstruction of the margin prior to the
Middle Miocene deformation requires not only estimation of cross-strike shortening but also assessment of the
cumulative offsets on the numerous E-W-trending lateral ramps.
In our view, the Point Radix-Darien Ridge Fault is not simply another one of these east-west trending
lateral ramps, although it may have originated as one. A substantial (up to 50 km) eastward motion of the blocks
on the north side of the fault is required during the Late Miocene opening of the Gulf of Paria, and must match
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
49 of 76
NORTH
Block 3b
Corridor
Topaz-Emerald
Corridor
MA = Mokatika Arch
EM = Emerald imbricate stack
A
EMERALD?
MA?
Mokatika
Corridor
B’
Ramp 3
EMERALD
Mokatika Arch
A’
B
Ramp 2
EMERALD?
Combination of dextral shear and extension
Ramp 1
ca. 10 km
Extract from tectonic elements map:
Fig. 22
Area of “Topaz Anticline”
if mapped at ca. 5 Ma level
Fig. 6
Figure 25. Sketch map showning the relationship between Mokatika Arch, Emerald Imbricate Stack and Topaz Anticline,
showing significant apparent dextral offsets between Middle Miocene structures. Lateral ramps were reactivated as extensional faults during Manzanilla deposition, subsequently overprinted by renewed tightening of underlying structures. Cross
sections are Figures 22-24.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
50 of 76
the measured extension in the Gulf of Paria. The measured offset across the fault today will be substantially
smaller, because the rocks of the Southern Basin has also moved some distance to the southeast during
subsequent oblique shortening.
One important, and disturbing to some, conclusion that should be pointed out here is that the evidence
for material moving in and out of the plane of any long cross-section through Trinidad is substantial. Only
relatively short sections, drawn between major lateral ramps and limited by the major through-going strike-slip
faults can even be approximately balanced. Any long cross-section (i.e. extending from the Caribbean Plate to
the Guayana Shield) that is rigorously balanced along its full length will inherently have error and have
potentially negative predictive value.
Geometry and age of structures in the Southern Basin, Trinidad
Our work on the Southern Basin focussed on structures at top Cretaceous level, on the geometric
relationship between deeper strata and the Late Miocene and younger normal-faulted package above, and on the
relationship of Miocene foredeep and wedge-top fill to pre-Lengua-Cruse structures. Our maps are based on a
detailed interpretation of all available seismic and well data in the Southern Basin, integrated with 2D and 3D
data from the Soldado area, the Columbus Channel and limited Venezuelan data. Figures 26 and 28 show some
examples of seismic structural styles in the basin.
Figure 26A is a composite line running from the eastern Central Range through Guayaguayare and into
the Columbus Channel. The broadly imbricate structural style is clear, particularly in the shallow Nariva FoldThrust Belt, which detaches above Cretaceous strata south of the Central Range. Deep Cretaceous structure is
generally poorly imaged except in the Mayaro area and the major strike-slip zones are only seen as “no data
zones” across which no sensible seismic ties can be made. Oblique strike-lines across the Point Radix Fault
indicate a steep northward dip on that fault. Cretaceous culminations are present in the Lizard and Guayaguayare
areas where they are truncated beneath Late Miocene Cruse and younger strata. The Central Range itself appears
to comprise thrust sheets of Cretaceous which overlie Southern Basin type Cretaceous (drilled in the Esmeralda
well, west of this line) which drive the Nariva Fold-Thrust Belt. These Cretaceous sheets are overlain by tightly
deformed Paleogene rocks in the Mt. Harris area, which may detach above the Cretaceous and derive from yet
farther north. These upper Paleogene rocks appear on this and other seismic lines nearby to be unconformably
overlain by Brasso, at least on the north flank of the Central Range. The apparent southward dip of the basal
detachment of the Nariva Fold-Thrust Belt close to the Central Range is probably a pull-up due to higher
velocity rocks shallow in the section. At present, the south flank of the Central Range is bounded by the Central
Range Fault, and a further lineament with slivers of Paleogene faulted against Brasso (the Bocono Hill-Fishing
Pond Lineament) lies close to the north side of the range. Seismic continuity across these is poor, and we suggest
that strike-slip on both of these faults has disrupted a once more continuous fold-thrust belt.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
51 of 76
3400
3200
3150
3050
2800
2700
2600 BC2
BC1
2550
2350
GY614
prj.
u/
as
so
p
To
CRET
Nariva
“South Basin”
Cretaceous?
TOP
TOP
NORTHERN SLICE CARRIES NORTH
BASIN STRATIGRAPHY ONTO FORMER
COUVA??
(BARRANQUIN, CUCHE-AGE) SHELF
e
us
1
CRET
TOP CRET?
?
3
PRE-CRUSE ANGULARITY
SOUTHERN PLATFORM STRATIGRAPHY
SOUTHERN PLATFORM STRATIGRAPHY
90120
N
S
NBC-12
TD90-311
TD90-120 (traced from final DMO migration)
Folded growth wedge of “Cruse” age
TD90-321
TD90-325
80-O-24
TD90-341
DIG-04
Fo
d
2500
no
3000
rm
al
fa
ult
4000
4500
4500
4000
Near top Lengua?
5
2500 m
5000
5500
6000
6500
10 km
NNW
MarabellaColenso
Lineament
CRF
SPRV
PAP1
To
PRF
Debe-St Croix wrench
HH3 HH1 HH2
CH2
NA
nilla u/c
4
p
as
Br
Nap. Hill. to Navet?
BP343 BP pr.
AD
ZAB
?FY .
NTH UST
THR E
SLIC
-61° 05'
-61° 00'
160
P
TO
us
TO
TOP
E
CR
T?
BAD
THRU
P CR
ST
ET
?
SLIC
TD91-311
TD91-316
T?
TOP CRE
TD90-321
200
120
140
10° 00'
NNW
5000m
10000m
9° 50'
-61° 40'
-61° 35'
-61° 30'
-61° 25'
-61° 20'
-61° 15'
-61° 10'
0
1
1.8 Ma?
La
2
Start uplift?
s
Ta
bl
as
=La
Palmiste Clay?
wai
or
.C
Mayaro=Casa Cruz=Forest
la
y
3
3
4 Ma?
Upper Cruse = Trinity Hills over Gros Morne
)
A (S E?
UG SLIC
OR
?M RUST
TH
TD91-323
TD90-331
2.6 Ma??
3.5 Ma??
2
=Lr
.F
4
5
4
A Fault
Growth Fault
TD91-343
5
Lower-Middle Cruse?
10 Ma?
6
Paleogene-Mid. Miocene
E=
TICLIN
ICE?
S. AN RUST SL
TH
DEEP
A’RE
GUAY
COUVA??
REGIONAL DEEP DETACHMENT
FR
LR
TA
ON
P
AM
EASY-SLIP COUVA
PINCHES OUT?
2500 m
Upr. Cret.
Top Barr?
Lower Cret.
Jurassic or older?
B) Lines 160, 71 Pointe-a-Pierre to Rock Dome and Colombus Channel
1cm. = 1000 meters
-61° 45'
ET
22-25 km shortening south of Point Radix Fault
9° 55'
0m
-61° 50'
S
102 77
10° 00'
9° 55'
-61° 55'
10
10° 10'
10° 05'
10° 05'
CR
BARRANQUIN
EQUIV. AT DEPTH?
10° 15'
10° 15'
12
5
Deep rooted fault bend fold?
Suggest possible evaporite
or Jur. red bed detachment
COUVA??
10° 10'
ME
DO LICE
CK
RO UST S
T HR
E
FYZA
10° 20'
10° 20'
N
NH?
o?
Bed-parallel detachments
drive high-level thrusting
on Rock Dome Anticline
CENTRAL RANGE AND POINT RADIX
FAULTS MERGE IN SAN FERNANDO BAY
-60° 55'
10° 25'
Tectonic
Analysis
0
0
OUT-OF-SEQUENCE
ROCK DOME THRUST
SFd
Location map
9° 50'
-62° 00'
HER
BRIGHTON-FYZABAD
THRUST STACK
-61° 10'
COLUMBUS CHANNEL
SSE
Disharmonic,
diapiric?
1
R?
NA
etaceo
Top-Cr
ment?
detach
5
MRC2 MRC1
BP510
ELEVATED, FOLDED
NORMAL FAULTS
Southern
Anticline
R
PENAL-BARRACKPORE
FOLD-THRUST BELT
TOP CRET?
CUCHE
Rock Dome
“Anticline”
Cruse
so
5
-61° 15'
8500
9000
Ortoire
Syncline
NARIVA THRUST BELT
3
-61° 20'
8000
BEYOND EASY-SLIP COUVA PINCHOUT??
9000
YAJT-027
2
-61° 25'
7500
8500
Top Manza
-61° 30'
7000
8000
REGIONAL DEEP DETACHMENT
1
-61° 35'
6500
THICK STRATIGRAPHY INCLUDES
BARRANQUIN TO SOUTH
7500
0
-61° 40'
4500
5000
5000
ORIGINAL THICKNESS OF
POST-RIFT STRATIGRAPHY
0
-61° 45'
IA
Z4
3500
“REGIONAL” LEVEL OF
FOLDED NORMAL FAULTS
6000
Caroni Basin
-61° 50'
2500
3000
3500
4000
A) Lines 120, 027 Mount Harris to Guayaguayare
-61° 55'
LA
P9
2000
3000
7000
10° 25'
-1
04
-1
IA
DH
1500
PLIO.-PLEIST.
5500
S”
CRETACEOU
“REGIONAL
Dip of Central Range Fault and Pt. Radix Fault not constrained,
but appears to be to north. Our current thinking is that these
both splay off the same ultimate ca. 9-10s detachment as the
deepest thrusting and are entirely confined to within the
allochthons. Deep basement not involved.
6A
-B
-1
A
1000
2000
lde
5
5
500
1000
1500
3500
4
mig080001
2000
0
ELEVATED, FOLDED
NORMAL FAULTS
2500
?
CRET
We speculate that Central Range Fault
may be oblique inversion of pre-existing
rift-phase faults, reworking parts of the
Nariva FTB hangingwall
4500
1000
1500
2
Projection of south-dipping
reflectors in North Basin =
detachment driving Nariva FTB?
4000
Cr
?
3000
3500
Lr
e
us
2500
?
?
ne
Cr
TOP
“North Basin”
Cretaceous?
BALATA THRUST STACK
Nariva
s Mor
SSE
0
500
t op
Brasso
2000
Gro
0
500
ar
Paleogene?
1500
Trin
NNW
0
2000
GY391 GY660
0 0
88
SSE
2100
GY249
08
Mayaro
Syncline
2200
LZ1RD prj.
-1
Lizard
Anticline
2300
Lawai
lls
ity Hi
Ne
?
Mayaro
IA
DH
1
34
90
23
L-
2450
Normal faults,
near parallel to
line of this section
NARIVA THRUST BELT
Lt. Miocene
10001
5
1
2850
Br
Pliocene
500
5000
Ortoire
Syncline
90
31
90
2950
c
3300
32
1
Nariva FTB
Mt. Harris
3500
41
Point Radix Fault
Bocono Hill Fault
3550
0
pro
j.
Northern Nariva FTB
Central Range Fault Zone
NNW
0
-61° 05'
-61° 00'
0
0
AL-1
N DEEP-ROOTED MOBILE SHALE. MUDFLOWS FROM
10 MA. NOT TRULY DIAPIRIC? MAY RISE EPISODICALLY KEEPING PACE WITH SEDIMENTATION
SSE
Southern Anticline
Erin M.V.
Erin-Siparia
Syncline
ERIN-91 ERIN-1
S
Jump tie to
DiCroce9a
0
0
0
1
1
1
2
2
3
3
4
4
5
5
6
6
0
BASE ERIN
1
C
ER
UPP
2
LOWER CRUSE
Gr7?
LIZARD SPRIN
GS ± NAVET?
TOP
AC
CRET
NR
“CHRISTMAS
TREE” FOSSIL
MUDFLOWS
Gr1
4
5
E
RUS
SOUTHERN
ANTICLINE
DIAPIR
3
5
Note onset of
onlap = uplift
10.5
U/C
(Top
Le
ngua
)
SOLDADO ETC
“OLISTOLITHS”
?
EOUS
6
“EL FURRIAL”??
7
TD90-313w
TD91-307
TD90-321
7
2500 m
TOP CRETACEO
US
2
DiCroce base top Pliocene
3
4
5
5
DiCroce base top Middle Miocene
THIN, SHALLOW PALEOGENE
DiCroce base top LR. MIOCENE
7
REGIONAL CRETACEOUS
6
7
8
8
Line drawing from Venezuelan data immediately to south of marine border
C) Lines 200, 39 Southern Range Anticline and Colombus Channel
Figure 26. Onshore seismic examples of structural styles. Data are computer filtered from original seismic provided by Petrotrin & BPTT. Simplified from Tectonic
Analysis, 2007 (seismic interpretations done with Bruce Eggertson).
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
52 of 76
The stratigraphic template for any interpretation and structural cross-section can be seen offshore to the
south, where there is a northward thickening wedge at least 3 seconds (ca. 4-5 km?) of Cretaceous strata, which
have been drilled in Venezuelan waters and include Barranquín-equivalent strata at their base. This sediment pile
includes several more or less competent units (Barranquín sands and limestones, unproven by drilling in
Trinidad, Naparima Hill argillites, Paleogene marls, Middle Miocene) and several shale-prone incompetent units
(Cuche, Guayaguayare, Nariva shales) and resulting in ramp-flat-ramp thrust trajectories. We can thus estimate
“regional” top and base Cretaceous underneath Trinidad (ca. 7-10s) and see that Cretaceous has been lifted at
least 3-4s above regional across onshore Trinidad.
Figure 26B is a composite line running from San Fernando into the central Columbus Channel. Here,
the convergence of the Central Range and Point Radix Faults has reduced the width of the Nariva Fold-Thrust
Belt to less than 10 km, and the combined strike-slip offsets on these faults has juxtaposed the relatively
hinterlandward rocks of the Gulf of Paria and Caroni Basins with the relatively forelandward rocks of the
Southern Basin. The three characteristic cross-sectional structural domains of the Southern Basin are especially
clear:
•
Imbricates of Cretaceous strata which ramp from a deep (ca. 8-10s) detachment with local flats in Albian
Cuch shales and possibly Nariva shales, repeating the Cretaceous and locally placing Gautier and Naparima
Hill strata above Middle Miocene Retrench (Marac-1 well),
•
Imbricated Early and Middle Miocene strata (Penal-Barrackpore Fold-Thrust Belt) which lie entirely above
the Cretaceous imbricates and,
•
Late Miocene and younger strata abeove folded extensional detachments in the Ortoire Syncline.
Of particular note on this line is the Rock Dome Thrust which repeats the Cretaceous with about 10 km
overlap. Mapping of the detachments at the base of the Cruse on this and adjacent lines shows the base Cruse
and top Cretaceous more or less parallel, suggesting that this Cretaceous thrust sheet, at least, was emplaced only
relatively recently.
Offshore seismic lines are not deep enough to constrain the Cretaceous section, but E-W lines in the
Columbus Channel do constrain the offshore depth the detachment for Cruse-Mayaro-aged listric faults.
Figure 26C shows an example of a line to the west of the Los Bajos Fault. Here the structure is
apparently simpler than to the east. The Cruse and younger section is apparently parallel-bedded and was
deposited updip from the extensional breakaways so typical farther east. Cretaceous structure at depth is
hypothetical and largely based on analogues in the El Furrial area (Duerto and McClay, 2002 and Jacomé et al.,
2003a,b).
The Southern Anticline here is interpreted as cored by mobile mud and, as at El Furrial, the tent-like
anticline with dips up to 60-70° on each limb is thought to be offset from, and south of, the nearest deeper
Cretaceous culmination. Field evidence shows that mudflows have been erupting along this trend since Lengua
time and through Cruse and this too points to the existence of a deeper pre-existing Cretaceous culmination
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
53 of 76
which overthrusts overpressured Miocene mudstones. In this section, the regional level of Cretaceous strata in
the Columbus Channel is constrained by Venezuelan seismic lines (e.g. di Croce et al., 1999); top Cretaceous
shallows from about 7.5s (ca. 12 km?) at the south coast to about 6s (ca. 7.5 km?) off Punta Pescadore. The
Cretaceous culminations shown are in part constrained by poorly imaged patches of high-amplitudes comparable
to drilled Cretaceous east of the Los Bajos Fault and appear to be uplifted about 2s or ca. 3.5 km above
“regional”.
Cross-sections based on the seismic data indicate that about 1.5-3s of Cretaceous strata are present in
each thrust slice. The Cuche shale (Middle to Upper Albian in the Southern Basin) or base Gautier (mainly
Cenomanian sandstones) acts as an intermediate detachment level, and the deeper, thicker parts of the thrust
slices may contain a section comparable to the Barranquín sandstones outcropping in Venezuela, and drilled
south of the Columbus Channel (Orinoco and Guarao wells, see di Croce et al., 1999). We speculate that the
deep detachment level is equivalent to the Couva evaporites drilled in the Gulf of Paria and that no rift phase
stratigraphy is involved in Central and Southern Trinidad thrusting. The abrupt southern termination of
Cretaceous culminations, and the fact that thrusting did not propagate farther south since the Late Miocene,
suggests a fundamental stratigraphic control on thrusting, possibly the southern pinchout or fault truncation of an
evaporite.
A top Cretaceous form map (Fig. 27) shows multiple, en-echelon, doubly-plunging culminations,
including the Rock Dome, Moruga, Guayaguayare and, possibly, Galeota structures. The relationship of these
structures to the Late Miocene and younger section demonstrates that they must have been uplifted prior to
deposition of the Cruse Formation (see below). The angularity between Cretaceous and Cruse is particularly
clear on a seismic line through the Moruga area (Fig. 28) which also shows triangular north-thickening wedges
of imbricated Cenozoic strata between the Cretaceous highs. Internal unconformities within the Herrera,
Karamat and Lengua indicate that the Penal-Barrackpore-Balata imbricate stacks of Cenozoic strata are slightly
older than the deeper Cretaceous culminations. The en-echelon geometry of the Cretaceous culminations
suggests that they may be synchronous, and may have formed in a dextral transpressive setting.
Mapping the Cretaceous structures also provides an insight into the nature and origin of the Los Bajos
Fault. There are no known analogues to the Moruga and Guayaguayare culminations on the west side of the
fault, suggesting that the Los Bajos originated as a dextral lateral ramp during Middle Miocene thrusting. This is
supported by mapping in the Soldado area, where there is a Cretaceous-cored antiformal stack with an apparent
>20 km offset across the Los Bajos Fault from a similar thrust stack in the Brighton area. These antiformal
stacks are cored by Cretaceous thrust sheets which appear to drive Retrench-Herrera-Karamat imbrication to the
south prior to 10 Ma. They continued to tighten during Cruse time, separating the Cruse and Manzanilla basins.
They could not have formed entirely since 10 Ma because there appears to be significantly more shortening at
Cretaceous level than in Cruse and younger rocks. Much of this offset must have occurred when the Moruga and
Guayaguayare culminations were forming, and fits well with our estimates of pre-Cruse shortening either side of
the fault. Our mapping of young structures supports the ca. 10 km Pleistocene offset of the Skinner Fault
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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-61° 55'
-61° 50'
-61° 45'
-61° 40'
-61° 35'
-61° 30'
-61° 25'
-61° 20'
-61° 15'
-61° 10'
-61° 05'
-61° 00'
-60° 55'
10° 25'
10° 25'
Tectonic
Analysis
Top Cretaceous
Cretaceous penetrations (N=41)
Additional Paleogene penetrations (N=27)
10° 20'
10° 20'
Point Radix Fault Zone
Brighton
10° 15'
10° 15'
Soldado
10° 10'
Los
Bajo
s
Galeota
Rock Dome
F au
lt
Moruga
Hypothetical culminations
10° 10'
Guayaguayare
10° 05'
10° 05'
Southern Anticline
10° 00'
10° 00'
9° 55'
9° 55'
0m
Simplified from Tectonic Analysis (with Bruce Eggertson) 2006 report on Southern Basin.
9° 50'
-62° 00'
-61° 55'
-61° 50'
-61° 45'
-61° 40'
-61° 35'
-61° 30'
-61° 25'
-61° 20'
5000m
10000m
1cm. = 1000 meters
9° 50'
-61° 15'
-61° 10'
-61° 05'
-61° 00'
Figure 27. Structure form map of Southern Trinidad showing en-echelon culminations at top Cretaceous level. Structures
involving Cretaceous deep section were mapped in detail in Southern Basin from all available seismic, controlled by 68 Cretaceous and Paleocene-Eocene well penetrations. Note the overlapping, en-echelon fault bend or fault propagation folds east
of the Los Bajos Fault, which has its origin as a Middle Miocene lateral ramp. Most culminations are “old”, but refolded,
with the exception of the Rock Dome culmination which formed only since the Late Pliocene. There has been no southward
propagation since the beginning of the Late Miocene, and source kitchens were compartmentalised by that time.
Lizard
“Anticline”
NNW
CA2 CA1
ME10pr.
ME15 ME63pr. ME53
AT36
SSE
N
Disharmonic folding of
sediments bounded by
rotated growth faults
RAFTS OF PRE-CRUSE
Gros Morne
CA109
Mayaro
Syncline
ME3pr.
0
ca. 55°
Ne
Kara.-Leng. locally above
ext. detachments defining
Cruse-Mayaro Basin
Base
L
au
engu
/c
KARAMAT
KARAMAT
2
GG
IMBRICATED HERRERA
ET.
R.
CR
NA
GS
4=
RIN TOP
. SP
LIZ
.
AYA
L
GU
HIL
AP.
.N
R
)
UP
ST
L (S
HIL
AP.
LT. EOC. at TD!!
.N
LR
GROWTH FAULTS
OVER MID-MIO. U/C
T?
CRE
TOP
1
Ne
ar
ar
t op
t op
Fo
re s
Cr
us
t
e
2
Buried Guayaguayare
Culmination
OP C
est. T
RET.
3
Seismic cannot
image steep dips?
4
POORLY IMAGED
DEEP CRETACEOUS
COUVA??
TD90-341
80-O-24
REGION
TD91-343,45
COUVA??
TD90-140
5
ACEOUS
AL CRET
2500 m
Figure 28. Part of line 140 shows angular unconformity of end Middle Miocene age reused as extensional detachment.
Location shown on inset of Figure 26. Simplified from Tectonic Analysis, 2007 (seismic interpretations done with Bruce
Eggertson).
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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(Wilson, 1968), commonly considered as the type offset marker for the fault. It matches our shortening estimate
for the Rock Dome thrust slice, which appears to be the only Cretaceous thrust slice that entirely post-dates the
Cruse, and for which there is no equivalent on the west side of the Los Bajos Fault, and it also matches the offset
between the Santa Flora Fault and the Papure Syncline Fault which we propose to be segments of a once
continuous Cruse-Forest-aged growth fault.
On all these seismic lines (Figs. 26 and 28), the “10 Ma unconformity surface” at the base of the Cruse
has been re-used as the basal detachment for younger gravity-driven listric normal faults which generally dip to
the east. The overall thickness of the Cruse-Forest-Mayaro section deposited within this normal fault belt
remains fairly constant (about 8000’) from the axis of the Erin-Siparia Syncline and into the Columbus Channel,
suggesting that the base Cruse was not perched higher onshore than in the Columbus Channel. Thus, we can use
the base Cruse surface as a structural datum. Furthermore, this surface is the only reliable structural datum or
paleo-horizontal (or approximately so) that can be used to restore cross-sections to a pre-Cruse state in this area
and understand the origin of the Cretaceous culminations.
The very steep dips recorded in the Cruse and Forest strata on the flanks of the southern anticline do not
represent limb dips of the deeper structures and are generally not coaxial with those deeper structures. The steep
dips result from the superimposition of two distinct tilts with different orientations. Late Miocene growth fault
bounded sediment wedges generally roll back towards the west, and the steepest bedding in these wedges had a
more or less N-S strike and perhaps 30°-45° westward dip. These wedges were then refolded when the
Cretaceous cored culminations were reactivated from the Late Pliocene to Recent. The refolding pattern is
spectacularly clear on the geological map (Kugler, 1996; Saunders et al., 1997) of the south coast (especially
between Negra Pt. and Moruga Bay, and between Canari Bay and the St. Hilaire River) and Lizard Springs, Salt
Spring areas.
The only paleo-horizontals in the Cruse-Mayaro section are to be expected downdip from, or east of,
rollover sections, but these are hard to identify because we typically find the next downdip listric fault and an
associated rollover sediment wedge. The post-growth overlap section (Upper Forest and younger formations in
the west and Palmiste and younger formations in the east) can be used locally as a paleo-horizontal but only
shows that significant reactivation of the Cretaceous culminations occurred during Late Pliocene and younger
time. The available well and seismic data does not allow us clearly pick the exact equivalents of onshore
formations in the Columbus Channel, so flattening on these young surfaces is subject to some error. In contrast,
the seismic and well data do allow us to pick with confidence the surface into which the rollover faults detach
both onshore and in the Columbus Channel.
Figure 29 shows an attempt to map these folded normal faults, and is based on the entire Southern Basin
Consortium seismic dataset and some older data where quality is good, together with well data. The refolding of
normal faults which sole into base-Cruse or Lengua is particularly clear around the Rock Dome culmination and
we can also trace several of the major faults on strike-lines in the Columbus Channel into the faults which bound
the tilted growth sections on the south coast. This remapping of growth faults and our attempts to tie sections
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
56 of 76
-61° 55'
-61° 50'
-61° 45'
-61° 40'
-61° 35'
-61° 30'
-61° 25'
-61° 20'
-61° 15'
-61° 10'
-61° 05'
-61° 00'
10° 25'
A full SBC seismic database, and some older lines, allows mapping of normal faults in
greater detail than before. Most dip east and show expanding growth wedges of Late Cruse
through Forest-Mayaro age (mostly Latest Miocene and Early to Middle Pliocene). Some,
such as the Skinner fault, are west-dipping anticthetic faults of limited extent.
10° 20'
10° 20'
All normal faults upturned during Pliocene
and younger reactivation of folds, thrusts
in the P-Barrackpore, Balata trends
Fault trends are horseshoe-shaped, swinging to NW-SE along the buried Cretaceous shelf
edge to the south, and to N-S or even NNE-trending in the Ortoire Syncline. This shape
has been tightened and exaggerated by later folding and thrusting.
Mayaro
Coastal
Fault
Total extension is estimated at up to 25 km, approximately half during late Cruse (= Gros
Morne through Trinity Hills, pre-Lawai or Lr. Forest Clays) time, and half during Forest,
Mayaro, Casa Cruz time).
10° 15'
10.5 km offset Lr. Morne
L’enfer channel system
10.5 km offset Skinner
Fault
10° 10'
10° 10'
Folded
growth
wedges
10.5 km offset
Santa FloraPapure Faults
Normal faults detach at about the level of base Cruse or Lengua, carrying some
hangingwall slivers of Karamat and Lengua strata. They only appear to cut deeper down to
Cretaceous where there were pre-existing Cretaceous-cored thrust highs (e.g. Moruga,
Guayaguayare). They do not cut to Cretaceous in the central Columbus Channel, and thus
can be used as an approximate datum for structural restorations.
10° 00'
Folded
growth
wedges
Santa
Flora
Fault?
Columbus A Fault
Columbus
B Fault
Separation at top
Cruse level
-61° 50'
-61° 45'
-61° 40'
10° 00'
9° 55'
Southern limit of normal faulting is “Escalera” Fault Zone
1) Soldado-Stollmeyer incision at base of Lr. Morne L’enfer channel complex (after Archie).
2) Skinner Fault (after Wilson).
3) Santa Flora = Papure Syncline Forest-age growth fault (this report)
4) All these match the LBF-parallel estimate for Rock Dome thrust shortening.
-61° 55'
BP-Amoco
A Fault
Columbus
C Fault
Four ca. 10 km offset markers for the 2.5-1.5 Ma interval on the Los Bajos Fault are also
worth noting:
9° 50'
-62° 00'
10° 05'
Folded side views of normal
faults seen on north flank of
Rock Dome and along S. coast
Also shown are revisions to the Kugler map pattern based on our seismic interpretation.
9° 55'
10° 15'
Papure
Syncline
Fault
Skinner
Fault E.
Santa
Flora
Fault
Skinner
Fault W.
10° 05'
-60° 55'
10° 25'
Tectonic
Analysis
-61° 35'
0m
5000m
10000m
1cm. = 1000 meters
9° 50'
-61° 30'
-61° 25'
-61° 20'
-61° 15'
-61° 10'
-61° 05'
-61° 00'
Figure 29. Folded normal faults, onshore and offshore southern Trinidad. Cruse-Mayaro growth faults reflect eastward
growth of Orinoco Delta and bury older structures, but are folded above Middle Miocene culminations retightened during
Plio-Pleistocene, resulting in complex outcrop patterns in Late Miocene and younger growth strata. In general shallow structure is a poor indicator of structure at depth. The stratigraphy in the Late Miocene and Pliocene compartments is not a good
fit to layercake stratigraphy. This new (ish) paradigm may offer opportunities in young sandstone fairways.
-62
-61
-60
What would the orogen look like if we remove estimated Late Miocene and younger deformation?
Leading edge of
Caribbean Plate
Tectonic
Analysis
12
Leading edge of accreted
Proto-Caribbean Ridge
11
Angostura
Topaz
200 km
Spitfire
Mt. Harris
Couva
El Pilar FZ
11
Emerald
Plaisance
Diamond
S. Fdo.
Brighton
50 km
10
10
Leading edge of accreted
deep basement slice
Deformation Front
9
9
Late Middle Miocene, 12 Ma
Locations & Palinspastic Grid
-67
-66
50 km
-65
-64
-63
-62
-61
-60
Figure 30. Palinspastic reconstruction for 12 Ma, close to the end of Middle Miocene orogeny. Distorted latitude-longitude
grids account for cumulative deformation and the resulting map is analagous to a restoration of a balanced structural crosssection. Restoring even Late Miocene and younger deformation dramatically distorts the shape of Trinidad (paleoshape
shown in heavy blue lines). To make this map we used relatively conservative shortening and shear estimates south of El
Pilar, Caroni Fault. Northern Range position is more model constrained; e.g. is unroofing driven by Caribbean wedging?; is
there a match between Caracas-Araya-Paria. The map provides a geographic framework for plotting and reconstructing
Middle Miocene deformation.
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across growth faults revealed some significant miscorrelations or misnaming of Formations across Trinidad and
resulted in a sketch attempt to modify the geological map as shown in Figure 29. In particular, it seems clear
that:
•
What is picked as “Cruse” is often rotated growth section (upper slope facies”) and what is picked as
“Forest” is often the topset to these growth wedges, is usually parallel-layered on seismic (but with small
scale foresets).
•
These young consistently from west to east, and the “Forest” in the Catshill area appears to be younger than
“type Forest” and ties to Lower Morne L’enfer reflectors to the west.
•
The Gros Morne is a growth section approximately equivalent to the Forest and Lower Morne L’enfer Silt
farther west and the Mayaro is a growth section approximately equivalent to the slightly younger Lower
Morne L’enfer sandstone.
•
The Lower and Upper Forest Clays are slightly older (albeit still within the P. Margaritae biozone) than the
Lawai Clay and St. Hilaire Silt in the southeast, and the Palmiste Clay appears to tie better with the Lot 7 Silt
reflector than with either Forest Clay.
•
The poorly-dated Morne L’enfer may thus be slightly older than thought, given that the Palmiste Clay lies at
the top of the P. Margaritae biozone.
•
The Erin onshore may also be slightly older than usually considered. This is consistent with the observations
from Soldado area seismic that “Erin” is folded and truncated by the base Talparo unconformity.
The basic constraint on these proposed ties is the requirement to make all apparently normal growth
faults on seismic have net normal displacement however small, whereas the correlation scheme used on the
Saunders et al. (1997) revision of the geological map of Trinidad results in some growth faults having to have
reverse offset. Kugler’s original 1959 geological map (republished in 1996) better represents the geology of the
Siparia-Ortoire Syncline (for instance, there is no culmination where they syncline crosses the Moruga Road),
albeit mapping lithofacies (the growth vs topset distinction noted above) rather than chronostratigraphy.
Flattening on the “10 Ma unconformity surface” datum reveals that Late Cretaceous or Paleocene strata
were exposed immediately below the surface at latest Middle Miocene time in the Lizard Springs and MorugaGuayaguayare areas (Figs. 26a & 28). The synclines between culminations preserve imbricated sections of
Eocene (Navet or San Fernando) through Middle Miocene (Retrench-Herrera-Karamat-Lengua) strata. This
wedge of pre-Cruse Cenozoic sediment reaches a maximum thickness of about 8000’ thinning to zero over the
Cretaceous anticlines. The thinning is too abrupt to be the southern pinchout of a foreland basin and this thick
section is generally absent in the hanging walls of Cruse-aged normal faults. If it had been present, the CruseMayaro section would have to double in thickness in these areas, to about 16000’, which it does not. Thus, the
culminations must be late Middle Miocene in age. Only the Rock Dome thrust slice, in which Cretaceous
through Cruse-aged strata are more or less parallel to each other, was emplaced later, during Late Pliocene or
Early Pleistocene time.
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We have not constructed rigorously balanced cross-sections of the Southern Basin and Nariva FoldThrust Belt, because of uncertainties in true shortening direction, motion of material through sections, and timedepth conversion. Semi-balanced cross-sections indicate that we can assess the uplift of the folded base Cruse
growth faults above regional and also the uplift of Cretaceous above regional. A simple excess area calculation
on the latter suggests ca. 45-55 km apparent total shortening required to uplift the Cretaceous to its present level,
assuming that only more or less layer-cake post-rift stratigraphy is involved, and that perhaps 50% of this
occurred before 10 Ma and 50% since the Late Pliocene. The overall shortening direction was approximately
towards the southeast, with perhaps a minor dextral component.
Late Middle Miocene reconstruction of the orogen
Using semi-balanced cross-sections, excess-area calculations, estimated extension in the Gulf of Paria,
correlation of piercing points across strike-slip faults, such as offset Nariva sand fairways (De Verteuil and
Eggertson, 2000) and offset older faults, and regional assessments of the position of the Caribbean Plate at 12
Ma, we have built a palinspastic latitude-longitude grid (Fig. 30) which reasonably captures the shape change of
the Trinidad area since that time. Note the contrast between 12 Ma and present shapes of Trinidad.
Overall apparent shortening as measured between Piarco Airport and Galeota Point is approximately 85
km, but this is composed of about 40-50 km true southeastward shortening and about 50 km of dextral strikeslip. Piarco restores to about 110 km west of its present position. Although this cumulative apparent strike-slip
total appears worryingly large to some, the process of building this map is analogous to balancing and restoring a
cross-section; the strain is distributed across numerous faults. The largest single offset proposed is across the
South Boundary Fault which bounds the Gulf of Paria extensional basin. Approximately 70 km of eastward
extension must be balanced by dextral offset, which (when we account for other strains) reaches a maximum of
ca. 50 km somewhere northwest of Soldado, but the displacement drops to the east and is probably not more
than ca. 30 km anywhere along the trace of the Point Radix and Darien Ridge Faults between San Fernando and
Block 2ab. This matches the maximum allowable offset of Cretaceous facies belts (Tony Ramlackhansingh,
pers. comm., 2007). The Angostura area restores to about 125 km WNW of its present position at 12 Ma and
Tobago restores 240 km west of its present position.
The position of the Northern Range is more model dependent than the restoration for areas south of the
El Pilar and Caroni Faults. Features along the North Coast Fault Zone suggest not more than about 25-40 km of
dextral offset since 12 Ma, and GPS data indicate it is now inactive, requiring a dextral offset across the Caroni
Fault of about 70 km. There are a few direct offset markers: a possible basement slice accreted to the leading
edge of true Caribbean igneous crust in the Tobago area restores to the northeast edge of a basement wedge (see
Fig. 21) thought to underlie the Gulf of Paria; the tilted base Late Miocene unconformity in the “North Basin”
offshore restores to a paleoposition north of a similar surface in the Caroni Basin; the slope sediments of the
Northern Range restore close to the Serranía Oriental shelf stratigraphy with which plausible correlations have
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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been proposed (e.g. Algar, 1998); the restoration also closes the Late Miocene Gulf of Cariaco pull-apart basin
and restores the west end of the Araya Peninsula against the Caracas Group basement of central Venezuela.
A paleogeographic map (Fig. 31) drawn on the Figure 30 base shows the Caribbean Arc north of
present day Margarita, separated from the emergent orogen by the Caracolito-Tobago forearc basin. By this time,
underthrusting of the Caribbean forearc beneath the former Proto-Caribbean Prism of the Araya-Paria-Northern
Range block was complete and southward thrusting of this block had imbricated Cretaceous strata as Brighton
and the culminations in the Southern Basin were about to form. The emergent orogen is limited in the north by
the backthrusts which formed as Caribbean crust wedged under the Araya-Paria-Northern Range block. To the
south, the Guarico Fold-Thrust Belt, Northern Serranía Oriental, Northern Range, Caroni Basin and Central
Range are uplifting and eroding.
The Nariva Fold-Thrust Belt has already shortened and is starting to be uplifted above deeper
Cretaceous thrust sheets. The Brasso Formation was deposited in a wedge-top setting above the Central Range
Thrusts and Nariva Fold-Thrust Belt and comprises relatively shallow water (shelfal) silts and limestones. To the
south, the Nariva thrusts drive imbrication of the Late Middle Miocene Retrench-Herrera sandstones and shales
which we interpret as largely axial-fed turbidites carried down the axis of the Caribbean foredeep, and
containing a substantial component of high-grade metamorphic minerals derived from the Villa de Cura area in
Central Venezuela.
There are also more proximal facies derived from the mountain front, such as the Morichito
Conglomerate of the Serranía Oriental and Herrera cobble conglomerates found at Galfa Point on Trinidad’s
south coast. Some of the Herrera sands may also be derived from areas of the South American margin uplifted
on the crest of the Caribbean forebulge (the equivalent Oficina Formation onlaps bare Guayana Shield or
Cretaceous rocks on the south side of the Maturín Basin). During the interval 10-12 Ma, the Cretaceous
culminations of the Southern Basin began to form. On the crests of some of these, Tamana-like limestones may
have been deposited, and we suggest this is a more plausible origin for “olistoliths” such as the Morne Diablo
Quarry limestone than derivation from the Central Range (some 100 km to the northwest at this time).
A semi-schematic cross-section (Fig. 32) can now be drawn across the orogen (in this case, though the
eastern Central Range and Brighton areas) which puts end Middle Miocene structural elements in the correct
order, without the juxtapositions of hinterlandward and forelandward elements (and some elements missing
entirely) that we have on any present day cross-section. We highlight:
•
Caribbean forearc basement overthrusting South American basement and wedging beneath a largely eroded
Proto-Caribbean Accretionary Prism which had previously been overthrust by an entirely eroded Caribbean
Accretionary Prism.
•
The Northern Range, interpreted as part of the highest Caribbean allochthons above South American
basement. Timing constraints on deformation and uplift indicate that at the same time as it was being
underthrust by Caribbean crust (ca. 23-20 Ma) it was also driving thrusting of Paleogene sediments in the
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-68
-67
-66
-65
-64
-63
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14
-60
Proto-Caribbean
seafloor
CARIBBEAN
PLATE
13
P
a
bbe
e
to-
P ro
r
Ca
ea
ibb
idg
nR
13
VOLCANIC ARC
ted P-
Slope or
deeper
Backthrust domain
coincides with predicted ProtoCaribbean Prism
ri
Ca
Tectonic
Analysis
sm
C. Rid
ge
At 12 Ma the underthrust
Caribbean wedge beneath
Serrania left in place to south
of new El Pilar Fault. Gulf of
Paria starts to open on releasing bend between El Pilar and
Point Radix Fault.
18-12 Ma
orot
ri
nP
-59
14
12
A c c re
12
Outer shelf
Tobago
Margarita
11
El Pilar Fault
Caroni Faul
12 M
a fro
nt ?
Proto-Tobago
Angostura
t
Brasso/Tamana
Spitfire
Mt. Harris
Emergent
Future
Brighton
eme
Bas
10
.
nt F
Darien
FZ
11
“Tamana” on uplifts
10
Herrera
Quiamare
Slope or
deeper
Upper Cipero
Outer shelf
Carapita
Shallow, inner shelf
9
Fluvial-Deltaic
9
With transition from 12 Ma to dominant
strike-slip Orinoco Delta will prograde
towards present day shelf edge.
Late Middle Miocene, 12 Ma
e
ulg
eb
For
SOUTH
AMERICAN
PLATE
100 km
8
8
-68
-67
-66
-65
-64
-63
-62
-61
-60
-59
Figure 31. Palinspastic reconstruction and paleogeography for 12 Ma, close to the end of Middle Miocene orogeny showing the geometry of the orogen before Late Miocene and younger strike-slip-dominated deformation. Distorted latitude-longitude grids account for cumulative deformation and the resulting map is analogous to a restoration of a balanced structural cross-section. Restoring even Late Miocene and younger deformation dramatically distorts the shape of Trinidad (paleoshape shown in
heavy blue lines). By this time, substantial areas of the former foreland basin had been incorporated into the orogen. Proximal fine through coarse-grained clastic and
carbonate facies accumulated on the north side of the foreland basin, deposited in shallower water conditions than in the axial trough to the south. Proximal sands were
sourced from nearby pre-Miocene outcrops, including reworked foreland basin sediment. Significant W-E extension in the orogen is indicated by thick carbonate and
clastic sediments (Brasso Formation) deposited in a wedgetop setting in waterdepths far less than the sediment thickness. True basement subsidence is indicated by continued foredeep subsidence beyond the deformation front, and additional accommodation space resulted from thinning of the allochthons. With the end of SE-directed
relative plate motion we see continued subsidence driven by the distant but encroaching load of the Caribbean Plate but not, in most areas, by active continued foreland
shortening. As a result, Orinoco Delta sediments, although of the same origin as older foredeep axis sediments, are able to overstep and bury the active thrust front.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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Eroded former Caribbean Prism
N.C.F.Z.?
Folded thrust?
N.R.
C.R.
N.F.T.B.
HER.
COU.
S.B.T.S.
Underthrust
Caribbean Plate
B.S?
C.T.T.S.
So. Am. basement and rift fill.
?Easy slip Couva tips out
Figure 32. Cartoon cross-section showing the configuration of the orogen before young strike-slip, at the end of Caribbean oblique convergence. Abbreviations: N.R. =
Northern Range; B.S? = Basement slice?; COU. = Couva-Cuche in Paria, at or near uplifted detachment?; C.R. = Ancestral Central Range; C.T.T.S. = Deep Central
Trinidad Thrust Stack (Brighton?, deep Emerald?); HER. = Imbricated Herrera-Karamat foredeep and piggyback fill; S.B.T.S. = Southern Basin Thrust Stack (detached
at base “Barranquín”).
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Central Trinidad Trough (now in upper part of Central Range). Top to the west, shearing within S1 cleavage
in the Northern Range may possibly relate to early partitioning of strain between dextral strike-slip and
southeastward shortening, and this dextral shear may have surfaced in the vicinity of the North Coast Fault
Zone.
•
The basal detachment of the Northern Range is interpreted to be folded up and over a sheet of South
American basement under the Gulf of Paria, and may lie at the same Couva evaporite level proposed for the
Southern Basin. Ramps from this higher detachment drove imbrication of high-level Paleogene strata in the
Central Range (Mt. Harris area) above less tightly deformed Cretaceous, and then thrust Cretaceous rocks
(Central Range Cuche) south towards the Nariva Fold-Thrust Belt.
•
The Nariva Fold-Thrust Belt appears to comprise an upper allochthon (reaches the Nariva Thrust as mapped
by Kugler), probably driven by the Paleogene thrust sheets in the upper Central Range, and a lower
imbricate stack driven by the Central Range Cretaceous thrust sheets. Both detach at about Middle
Oligocene level. Because early exploration onshore was focussed on Nariva sands, there are few wells which
test the possibility of subthrust Angostura sand beneath this imbricate stack.
•
At the culmination of Northern Range exhumation, the leading edge of the Caribbean reached far enough
south to entrain a slice of South American basement at its leading edge. Thrusts rising from the leading edge
of this slice include the Pirital Thrust in Venezuela. In Trinidad, we propose that this basement slice
underlies the elevated Couva in the Gulf of Paria, and that it forms the cores of the NW-SE-trending
structural highs which formed during Late Miocene pull-apart formation. This coupling appears to coincide
with the deepening of the detachment below the Nariva Fold-Thrust Belt into the Cretaceous, resulting in
imbrication of the Upper Cretaceous in the Brighton area, and in the uplift and erosion of the top of the
Nariva Fold-Thrust Belt (note that the NFTB is placed north of the Brighton imbricates in this section, a
result of restoring ca. 50 km dextral motion on the Point Radix Fault). These Cretaceous thrust slices in turn
ramp up to drive imbrication of the Retrench-Herrera-Karamat Middle Miocene sandstones in the PenalBarrackpore and Balata trends.
•
The deepest and southernmost imbricates detach on base Cretaceous (Couva evaporites?), deform the
previously imbricate Middle Miocene strata, and bring Cretaceous to the surface by ca. 10 Ma along the
Moruga and Guayaguayare culminations.
•
Only after the time represented by this section did the El Pilar Fault and South Boundary Fault become
active, dissecting the orogen.
Late Oligocene, pre-orogenic, reconstruction of the orogen
Reconstruction of the Trinidadian margin early in the history of Caribbean thrusting is rather more
difficult. Shortening estimates based on cross-sections are only minima, because almost all the structures formed
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between 25 Ma and 12 Ma are relatively high-level. Hanging wall cut-offs are almost entirely eroded in, for
example, Angostura area and the Nariva Fold-Thrust Belt. However, we can establish some reasonable
shortening and strike-slip estimates:
•
As for the 12 Ma reconstruction, we can use an area balance to crudely estimate NW-SE-directed shortening
in the Southern Basin, this time flattening top Cretaceous. Approximately 30 km shortening between the
Brighton through Guayaguayare Cretaceous slices is sufficient to elevate the Cretaceous to its estimated
position at 12 Ma, locally eroded at the base Cruse unconformity.
•
The southernmost thrusts in the Cretaceous appear to be blind (fault propagation folds) but the Brighton
imbricates ramp up and imbricate Middle Miocene strata; we estimate total shortening at about 20 km
between San Fernando and Penal based on seismic data, comparison of present structured thickness and prethrust stratigraphic thickness, and published sections.
•
At least 5-6 imbricate slices are present in the Nariva fold thrust belt, resulting in a structured thickness of
Nariva of about 12000’ compared to a likely stratigraphic maximum thickness of between 2000’ and 4000’
(assuming no repetition in the type Nariva Hill section, which appears to be the south flank of a relatively
simple syncline on seismic). Given the width of the belt, this would suggest an absolute minimum shortening
of 25 km, without accounting for any erosion of hanging wall cutoffs.
•
Shortening within the upper levels of the Central Range is hard to estimate. However, sub-Brasso bedding
within the Paleogene of the Mt. Harris area is typically steeply-dipping and tightly chevron-folded over the
ca. 10 km width of the outcrop, and so ca. 20 km shortening and overthrusting detached above Cretaceous
could reasonably be hidden within this area.
•
In the Angostura area offshore short semi-balanced cross-sections can be drawn more or less normal to fold
axes and in the areas between the major E-W-trending lateral ramps (see Fig. 25) and these too suggest some
tens of kilometres of shortening in these areas, truncated to the north by the Central Range and Scorpion
Faults, and to the south by the Darien Ridge Fault.
•
We noted above that the lateral ramps in the Angostura area appear to show dextral offsets of 10-25 km of
apparently similar structural elements from one structural corridor to the next, and the relationships of these
faults to Late Miocene and younger strata indicate that these offsets largely happened during or immediately
after thrusting, allowing the orogen to lengthen from west to east. Thus, we must also restore these offsets
when making a 25 Ma palinspastic latitude-longitude grid.
•
We estimate that the Caribbean forearc has wedged perhaps 20 km underneath the Northern Range in
Trinidad, and this process seems to have started at about 25-20 Ma. Thus, we must also pull the Northern
Range to a position about 20 km SE of its position shown on the 12 Ma map.
The position of the Caribbean Plate provides the ultimate boundary condition for a 25 Ma
reconstruction. Super-regional features such as the rate of foredeep migration and timing of deformation along
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the Northern Caribbean margin constrain its position and a palinspastic grid must restore the Northern Range far
enough to the northwest to be influenced by the Caribbean forearc at this time.
Figure 33 shows the result of the iterative process required to build a satisfactory palinspastic grid from
these estimates. Note that the paleoshape of Trinidad is elongated substantially farther towards the northwest
than on Figure 30. Again, although this may at first sight appear a rather extreme reconstruction of the
paleoshape of Trinidad, it is simply the cumulative result of restoring a large number of relatively small strains
such as thrusting, extension and generally conservative dextral strike-slip offset estimates.
The key features of this restoration (Fig. 33) are:
•
Cretaceous shelfal rocks all restore to the southwest side of the estimated Early Cretaceous shelf edge
(projected from Guyana-Suriname, parallel to, but inboard of, the Guyana Transform continent-ocean
boundary).
•
Cretaceous shelf rocks in the footwall of the Central Range and deep beneath the thrust sheets at Angostura
define a minimum position of a northwest-facing Cretaceous shelf-slope break and the Angostura area
restores into the axis of a newly-defined “Central Trinidad Trough” (CRT), indicating about 80-100 km of
southeastward thrusting of the Angostura between 25 Ma and 12 Ma, consistent with the estimates above.
•
The SW flank of the CRT is defined by the Bohordal escarpment, which limits the Serranía Oriental
Cretaceous shelf, and its NW flank is defined by the Proto-Caribbean Ridge and the Proto-Caribbean
Trench.
•
The northern edge of the Caroni Basin (Piarco area) is restored to the south side of the Proto-Caribbean
Ridge, but no rocks of this age are preserved in this area. The Cuche of the Caroni Basin may underlie a
significant thrust detachment and may belong farther southeast on a Cretaceous palinspastic reconstruction,
close to the southeastern edge of the trough.
•
The Northern Range is restored about 120 km to the northwest of its 12 Ma position. The 40 km excess
relative to the Central Trinidad Trough is probably accounted for by internal Northern Range strain and by
overthrusting onto rocks of the Central Range Trend. The Northern Range is thus shown immediately ahead
of the Caribbean forearc (Tobago Terrane) at this time.
•
Similarly, the Araya-Paria Terrane is restored to the northwest and rotated slightly counterclockwise to
match total shortening estimates (at least 80 km) in the Serranía Oriental (Roure et al., 1993; 2003).
Paleogene Caribbean-South America interactions
Looking back to the pre-Late Oligocene, the pre-orogenic stage of Figure 19B is applicable to the
Eocene Eastern Venezuela and Trinidad, while the syn-collisional stage of Figure 19C is applicable to the
Eocene of Central Venezuela (Caribbean Mountains and the Guarico Basin). And concerning western
Venezuela, establishment of the Proto-Caribbean subduction zone likely provided additional first order controls
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Tectonic
Analysis
What would the orogen look like if we remove estimated Early and Middle Miocene deformation?
CARIBBEAN
PLATE
F
ACE O
ST TR TRENCH
THRU
N
OVER ARIBBEA
O-C
PROT
11
C
A
BE
IB
R
A
N
P
S
RI
M
PR
-CA
OTO
B
RIB
E AN
G
RID
E
NORTHERN
DEPOCENTRE
(DEEPER?)
12
Continent-Ocean
Boundary?
11
=
SOUTHERN
DEPOCENTRE
10
Buried
early Cret.
shelf edge.
10
PALEOSHAPE
OF TRINIDAD
9
9
Late Oligocene, 25 Ma
-67
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50 km
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Figure 33. 25 Ma palinspastic reconstruction, showing the geometry of the orogen before Early and Middle Miocene deformation. Note that the distortion in the shape of Trinidad indicates that apparent N-S facies changes in present-day geographic coordinates are in fact NW-SE facies changes along, not across, the margin. One important effect of the distortion is to
place the northern depocenter (Central Trinidad Trough) adjacent to the Serranía Oriental, such that Paleogene sands can be
derived from the west or southwest without crossing Southern Trinidad, where carbonates prevailed, and large Early Cretaceous clasts (such as in the Plaisance conglomerate) can derive from the NE-facing Bohordal slope, or the north-facing Central Range slope through incision of bypass surfaces with little Late Cretaceous or Paleogene cover. The map hints strongly
at a point source for sediment from what we refer to as the “Espino-Maturín River” and that the sediment source and
paleoflow orientation may in fact be orthogonal to the apparent fining direction across Trinidad.
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on deposition there as well, but these will be harder to identify because the effects of Caribbean-South America
collision are more coeval with those of initial Proto-Caribbean hanging wall uplift, and the two may have
mutually interfered in as yet unclear ways. However, it is tempting to speculate such things as the intraPaleocene top Guasare-base Misoa unconformity (Zambrano et al., 1971) representing the hanging wall uplift
stage, and the down-dip continuation of the Misoa depositional system being at least partly if not entirely to the
ENE along the coeval Guarico Trough (in which the Guarico Formation was deposited), between the Shield to
the south and the “Caracas Group Prism high” to the north.
Concerning the syn-collisional stage of Figure 19C, our Miocene discussion above allows us to
generalise the Caribbean-South America collision as encapsulating the following steps at any given location east
of the Urica Fault:
•
The Caribbean Prism overthrust the Proto-Caribbean Prism. In Venezuela, the Caribbean Prism is
represented by the Manicuare and Copey Formations and Gulf of Barcelona volcanics. In Trinidad, we
believe it is represented by the ?Toco and ?Galera Formations and the Sans Souci volcanics of the Northern
Range. In Barbados, we believe it comprises the Oceanic Complex and the northerly parts of the Basal
Complex. The Proto-Caribbean Prism is represented by the Guinimita, Carupano, and Tunapui Formations
of Araya-Paria, the Maraval, Maracas, Chancellor, and Rio Seco of the Northern Range, and much, but not
all, of the “Basal Complex” (Speed, 2002) of Barbados.
•
When the Caribbean crystalline forearc reached the overthrust Proto-Caribbean prism, the forearc did not
also overthrust the Proto-Caribbean prism (being too rigid and dense) but rather wedged under or into it, thus
driving a wedge of Proto-Caribbean prism and overlying Caribbean prism onto the Caribbean forearc
basement. SE-vergent thrusting on the SE flank of the Proto-Caribbean prism began as a result, carrying
both prisms onto the South American shelf/autochthon and leading to imbrication thereof.
•
When the Caribbean forearc basement encountered South American basement, the former overthrust the
latter, causing wedges of Caribbean forearc to be emplaced above South American basement but beneath the
Proto-Caribbean prism and, in the Serranía del Interior at least, beneath outer shelf strata as well (see
Passalacqua et al., 1995 for evidence of a deep, dense wedge of Caribbean lithology south of El Pilar Fault
and beneath the Barranquín Formation of the NW Serranía Oriental). In addition, large wedges or former
Jurassic rift blocks of outer South American basement were likely imbricated subjacent to the obducted
Caribbean forearc bodies, thereby elevating the outer portions of the margin relative to inner ones. For
example, the Lower Cretaceous carbonates and evaporites of the northern Gulf of Paria Basin likely overlie
southwardly emplaced continental basement (thin skinned but basement involved), thrust ahead of a blind
wedge of Caribbean forearc beneath the Araya-Northern Range Terrane. The Gulf of Paria Cretaceous is far
shallower, structurally, than the autochthonous Cretaceous of Southern Trinidad, and a tectonic elevation of
it is required.
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West of the Urica Fault, the equivalent rock units to those noted in step (1) above are: the Villa de Cura
Complex and the Early Eocene Garrapata and Middle Eocene Los Cajones Formations of central Venezuela
(Caribbean Prism and syn-collisional detritus); much of the Caracas Group, i.e., the meta-sedimentary Las
Brisas, Mercedes, and other sections that were once part of the Mesozoic passive margin sequence along
northern Venezuela (Proto-Caribbean Prism). In addition, the margin west of the Urica Fault has a fundamental
difference to that to the east, namely that Caribbean lithosphere presently underthrusts (is subducted beneath)
South American basement (Figs. 15B,D,F). That is, west of the Urica Fault, there was a fourth step in the
marginal evolution during collision with the Caribbean. The backthrusting seen within the Caribbean lithosphere
at the South Caribbean foldbelt and Bonaire Basin is tied into this subduction process; the upper level of the
lithosphere (including the Aruba-Orchila Ridge) is imbricated above the lower Caribbean lithosphere, and it is
the lower lithosphere only which underthrusts South America as a result. This last stage of shortening was
necessary in the west (extending from Orchila to southern Panama) in order to allow the Caribbean collision to
progress to closure by 10 Ma in Eastern Venezuela and Trinidad. Many hundreds of km of Caribbean lithosphere
stripped of its upper level now underlies NW South America (Van der Hilst and Mann, 1994; Fig. 15D), and the
upper level is accreted into the San Jacinto and Sinú foldbelts of Colombia and the South Caribbean Foldbelt
north of the Aruba-Bonaire-Curacao (or ABC) islands. This stage of development has not occurred east of the
Urica Fault, where Caribbean lithosphere still overlies the South American basement, thereby driving load
subsidence manifested as the greater East Venezuelan Basin. However, with the E-W Caribbean-South America
motion since 10 Ma, the subducted slab is migrating eastward and progressively expanding the scissoring on the
Urica Fault at the South American basement level (Fig. 15F).
Concerning paleogeography, the 25 Ma palinspastic reconstruction of Figure 33 provides a robust
framework for plotting 25 Ma paleogeographic and paleotectonic elements (Fig. 34). An important aspect of
Figure 34 is that although the foredeep axis was ENE in orientation, the foredeep fill was supplied primarily
along-axis rather than north to south. Most of Trinidad was distal to the ensuing orogeny, either as supaforebulge (Lower Cipero Formation) or outer foredeep basin (early, southerly Nariva), whereas Eastern
Venezuela comprised the coarser, shallower, inner foredeep basin (Areo, Naricual sensu stricto Formations).
East of the Urica Fault, the Gulf of Barcelona volcanics (Ysaccis, 1997), Manicuare schists and Copey
metavolcanics comprise outer Caribbean forearc or basal Caribbean prism rocks thrust onto (and over) the rocks
of the Araya Peninsula, which were reaching peak metamorphism at about this time. The main Caribbean forearc
(e.g. Patao, Tobago Terranes) did not thrust so high, and broke away from this outer forearc/prism wedge and
started to underthrust, uplift and cool the Araya-Paria-Northern Range Terrane, driving deeper-rooted
southeastward thrusting in the northern Serranía Oriental.
In Central Venezuela, the Caribbean subduction complex (Villa de Cura HPLT rocks, Tiara volcanics)
had overthrust the Proto-Caribbean Prism (Caracas Group) and outer margin, thereby driving the low-angle
emplacement of the Garrapata-Los Cajones belt syn-collisional detritus, and subjacent imbrication of the
Guarico fold-thrust belt immediately to the south (note: we do not recognise the Garrapata and Los Cajones units
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14
Proto-Caribbean seafloor
Edge of
Caribbean
Plate
Slope or
deeper
Scotland Domain
VOLCANIC
ARC AXIS
13
ri s m
nP
a
e
b
ge
a ri b
Rid
C
n
to
bea
P ro
ri b
a
C
toP ro
Tectonic
Analysis
-59
14
13
elt
ba
De e p
A
BL
12
N
IL
QU
ust b
ckthr
LA
S
BA
IN
Outer shelf
CO
RA
CA
Margarita
O
L IT
BA
Shall
ura
V. de C
o FT B
G ua r i c
10
E-verging thrust belt driven
by Caribbean Plate overriding Proto-Carib. Ridge.
Tobago
rus
ackth
ow b
12
Slope or
deeper
t belt
ust
thr ge
d
de r
Un ib. we
r
Ca
11
U ri
“Proto-Tobago”
S IN
Nariva
Nariva
Future Pirital thrust
ca F
.
Naricual
11
Paleo-shape
of Trinidad
Lower Cipero
Areo
Outer shelf
10
Merecure
Quebradon
Shallow, inner shelf
Chaguaramus
en
Forebulge
unconformity
in Oficina area
oG
ra b
9
Es
pin
Fluvial-Deltaic
9
100 km
Late Oligocene, 25 Ma
8
8
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Figure 34. Palinspastic paleogeographic map for 25 Ma, Late Oligocene, see text for discussion.
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as members of the Guarico, as was originally mapped). Uplift of this belt diverted the axis of the Caribbean
foredeep into the Serranía Oriental and shut off coarse Eocene clastic sedimentation previously supplied to the
Barbados area to the north (see below). Axially-fed sands with a characteristic high-pressure metamorphic heavy
mineral signature appear for the first time in the Upper Roblecito, Carapita and Nariva Formations of the
foredeep basin. In the Central Range Trend, the mineralogically immature Nariva overlies mature, 2+ Ga zirconbearing sandstones of the Angostura Formation which almost certainly derived from South America (Meyers,
2007 Geological Society of Trinidad and Tobago conference). In what is now Central Trinidad, the Nariva
appears to be shelfal or perhaps uppermost slope (based on lithofacies); the Nariva basin was shallowest toward
the northwest (adjacent to the orogen and toward Venezuela), and deepened from west to east. It appears that the
Caribbean forebulge was situated in southern Trinidad at this time, and that forebulge passage and advance of
the foredeep is indicated by the Silty Cipero burying a widespread latest Eocene or earliest Oligocene erosional
unconformity over much of the western Southern Basin south of the Point Radix Fault. Southern Trinidad lay
sufficiently southeast of the point source of clastics in the axis of the Caribbean foredeep that Nariva-aged facies
are typically marly (i.e., Lower Cipero Formation) with clean-water planktic rather than turbid-water benthic
foraminifera. True Nariva facies are largely restricted to the Central Trinidad Trough and may have onlapped
southward up the former slope, almost but not quite reaching the Eocene-Early Oligocene shelf-slope break,
allowing Cipero Marls to be deposited in upper slope to outer shelf water depths in southern Trinidad. Early and
Middle Miocene thrusting emplaced the Nariva southeastward over the former Cretaceous shelf edge ahead of
slices of Cretaceous rocks derived from the northern or central portions of the Central Range Trend.
Most, if not all, of the tectonic deformation driven by the Caribbean Plate prior to 25 Ma was located
northwest of the Serranía Oriental and Central Trinidad Trough, and thus we use the same basic palinspastic
latitude-longitude grid to plot our older paleogeographic maps of the region. Figure 35 shows the
paleogeography at 31 Ma (Early Oligocene), and Figure 36 at 42 Ma (Middle Eocene), with the Caribbean Plate
shown progressively farther west back in time. At 42 Ma, the Proto-Caribbean Trench and associated basement
ridge and Proto-Caribbean accretionary prism of Central Venezuela had not yet been overridden by the
Caribbean Prism/Plate anywhere east of Golfo de Triste.
Acknowledgements
We are grateful to Petrotrin and the Trinidad and Tobago Ministry of Energy for collaboration and
access to seismic lines and well data; to Johan Erikson, Roger Higgs, and Raj Maraj for field collaboration; to
Rob Van der Hilst and Raul Ysaccis for providing copies of their PhD theses to JP; and to David Wright for
heavy mineral and petrographic analyses on some 150 field and core samples from Venezuela, Trinidad, and
Barbados. Parts of this work were funded by NSF-BOLIVAR and also by a consortium of companies since 2000
including BHP-Billiton, BPTT, ConocoPhillips, ENI, EOG, Hess, Kerr/Anadarko, Oxy, Marathon, PetroCanada, Primera, Repsol, Shell, Talisman, TED, Total, PDVSA, and Venture.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
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14
14
Caribbean Plate
00
10
0
10
0
200
ri
-Ca
to
P ro
Tobago
200
an
bbe
P ri s
t
m
P ro
200
11
e
V. d
Accreted ex-ProtoCarib. prism
Cura
tur
Fu
Co
n
2000
Angostura
Mt. Harris
eG
uar
T
ico
La Pascua Sand
tin
en
10
00
Plaisance
Lecherías
U ri
ca F
.
10
Roblecito Shale
Los Jabillos
hru
b
a ri
o-C
Barbados
(present)
Plata
San Fernando
t -O
ce
an
Bo
u
nd
ar
11
y
Paleo-shape
of Trinidad
Max. NE-ward extent of sub-Nariva u/c here could be later, a
forebulge effect (we see S. Fdo infilling a canyon, then incised
again and covered by a ?Early Miocene conglomerate)
Transgressive
alluvial fringe
13
12
400
0
3000
CENTRAL
TRINIDAD
TROUGH
Wedging leading edge crust
Obducting leading edge crust
elt
st B
ge
Rid
n
ea
b
Caribb
e
13
12
Tectonic
Analysis
m
a n P ri s
20
00
ARC
AXIS
Proto-Caribbean seafloor
Scotland prism
cover domain
0
200
10
Former Espino River uplifted on crest of Caribbean forebulge and
abandoned, with upstream drainage capture by Caribbean axis to north
9
Terrane stacking order:
1) W. of Urica: Caribbean incl. prism over former Proto-Carib. prism (Caracas Gp.)
2) E. of Urica: Carib. prism (red: Manicuare-Copey) over Proto-Carib. prism (Araya), but
Carib. Plate (green) under Araya. Former Proto-Carib. prism becomes preserved as backthrust
belt riding above advancing Carib. Plate. This backthrust belt propagates diachronously NE,
crossing Trin-Bbdos border by 25 Ma and reaching Barbados by ca. 12 Ma.
Espino Graben
Early Oligocene, 31 Ma
9
100 km
8
8
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Figure 35. Palinspastic paleogeographic map for 31 Ma, Early Oligocene, capturing the end of sedimentation in the Central Trinidad Trough and the onset of sedimentation at the leading edge of the SE-migrating Caribbean foredeep in the Serranía. Leading up to this time, a significant area of subaerial exposure had developed in the NE
Serranía and sediment eroded from this surface was deposited directly over the Bohordal shelf edge into the Central Trinidad Trough, or transported via tributaries of our
proposed Espino-Maturín River and discharged into the Trough at a point source upstream of the restored position of the Plaisance Conglomerate. The onset of Caribbean foredeep subsidence drowned this non-angular unconformity beneath the Los Jabillos sandstone, which youngs from possible latest Eocene (but probably Early
Oligocene) in the NW Serranía to Late Oligocene or Early Miocene (where it should be called “Merecure” unit) in the El Furrial area. South of its onlap edge there must
have been a subtle flexural forebulge which helped to constrain the drainage products of the Espino-Maturín River to the foredeep. The Plaisance conglomerate and
Angostura sandstones, which were abruptly buried by shales, represent the culmination of the Espino-Maturín drainage and the uplift of its drainage basin on the crest of
the forebulge. The ensuing shaley sedimentation is the eastern distal and entirely submarine equivalent to the onlap seen in the Serranía.
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-72°
14°
-71°
-70°
-69°
-68°
-67°
-66°
-65°
-64°
-63°
N. Scotland ca. 200
km NW of here?
Caribbean
Plate
-61°
-60°
-59°
14°
Tectonic
Analysis
Bimodal source for
South Scotland?
Proto-Caribbean Crust
i sm
Arc Axis
13°
a ry
re t
ea
nA
cc
lo
na
ce
ean
b
a ri b
to-C
bb
Ba
r
ion
W
ed
ge
Pr
13°
-62°
Vi
ll
ad
eC
ur
a
Ca
ri
12°
11°
E
ng
rodi
ona
c a rb
t e s?
G
ra
ar
ta
pa
n
ajo
,C
no
es
ositio
Paleop
Trenc
aribbean
Proto-C
Proto-Caribbean Ridge
Shall
P ro
Prism
bbean
to-Cari
Toe Pro
ange
hern R
a-Nort
a-Pari
f Aray
ubm
ow S
h
More proximal source for
coarser conglomerates?
pS
De e
Incipi
ubm
e
a ri n
ean
g
Rid
12°
CENTRAL
TRINIDAD
TROUGH
No Navet north of this line
Incipient underthrusting on COB
Pt.-a-Pierre
Co
n
Paleo-shape of Trinidad
Shelf canyons?
“Bo
a ul
e
b
a ri b
o- C
tin
NE Serrania u/c
caF
t
m
gent?
ent emer
arine
U ri
P ro
P ri s
hor
t
GUARICO TROUGH
da l
Fa u
ce
an
Bd
y.
Middle and especially
late Eocene to Early
Oligocene fans reach
Ultradeep Area?
11°
Navet
lt”
Soldado?
Caratas
10°
en
t -O
Caribbean
Foredeep Axis
10°
Edge of stretched crust
Southern Guarico sand/lst fringe?
9°
9°
Espino River
Caribbean forebulge will roll from west to east,
uplifting and eroding pre-existing Eocene down
to Cretaceous strata, shedding sand and limestone debris into Espino River, which will be
deposited in Central Trinidad Trough
Late Middle Eocene, 42 Ma
of pr
Edge
esent-
day G
uayana
Shield
100 km
8°
8°
-72°
-71°
-70°
-69°
-68°
-67°
-66°
-65°
-64°
-63°
-62°
-61°
-60°
-59°
Figure 36. Palinspastic paleogeographic map for 42 Ma, Middle Eocene, showing the depositional context for the mineralogicaly sub-mature Early and Middle Eocene
Scotland sands of Barbados. At least the Chalky Mount and Bissex Hill sections of the Scotlands were likely deposited in the Proto-Caribbean accretionary prism, but the
finer grained sections (Walker‘s, Morgan Lewis members) may have been originally situated on the Proto-Caribbean basin plain somewhat to the WNW, both about 600700 km downstream of the onshore end of the Caribbean foredeep axis (Pindell and Frampton, 2007). We postulate that the coarser Scotland conglomerate fractions containing Upper Cretaceous mudstones and carbonates may derive from the Proto-Caribbean hanging wall or prism, shed northward to merge with the trench-axis sandstone fairway. It is possible that closer to the Caribbean foredeep axis, the Proto-Caribbean Trench axis was overfilled such that a sediment-confining trench morphology
was limited and easily bypassed. Transport of fine-grained, glaucophane-bearing clastic sediment over these distances is proven by the sands drilled on the Tiburón Rise,
located even farther to the NE than our proposed location for the Scotlands. The map also shows the interpreted setting for the Pointe-a-Pierre (sensu lato, age may be a
little older) sandstones in Trinidad. We infer that the role of the Proto-Caribbean Ridge was only to act as a bathymetric barrier between the immature Proto-Caribbean
(i.e. Scotland) and mature Central Trinidadian (i.e. Chaudière, Pointe-a-Pierre, Charuma) clastic domains. We infer a southwestern sediment source for the mature
Pointe-a-Pierre continental sandstones, possibly from a river which passed through the Quiriquire area, where the “Caratas Formation” is virtually identical in subsurface.
Every characteristic of these sands, including heavy mineral content, points to a mature, shelf-stored, recycled or shield sediment source; nothing supports a northern origin. Objections to a cratonic source due to the occurrence of rare staurolite grains in Pointe-a-Pierre sands are entirely unfounded, as staurolite does occur in distributary
systems on South America. Note that the finer grained facies of southern Trinidad are inferred to have been deposited in slightly shallower conditions, sheltered from the
point sediment source feeding the Central Trinidad Trough. As such, the apparent north to south fining is interpreted as a lateral, not down-dip, fining.
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References
Algar, S. T., 1998. Tectonostratigraphic development of the Trinidad region, in J. L. Pindell, and C. L. Drake, eds.,
Paleogeographic Evolution and Non-glacial Eustasy, northern South America: SEPM Special Publication 58, p. 87-109.
Algar, S. T., and J. L. Pindell, 1993, Structure and deformation history of the Northern Range of Trinidad and adjacent
areas: Tectonics, v. 12, p. 814-829.
Audemard, F. A., 2000. Neotectónica de la Cuenca del Tuy: Observaciones complementarias, in Memorias de las Jornadas
Científicas 55° Aniversario Escuela de Geología, Minas y Geofísica, 1938–1993, Caracas: Boletín GEOS, v. 32
(Diciembre 1997), p. 39–42.
Babb, S., and P. Mann, 1999, Structural and sedimentary development of a Neogene transpressional plate boundary between
the Caribbean and South American plates in Trinidad and the Gulf of Paria, in P. Mann, ed., Caribbean basins:
Sedimentary Basins of the World, Elsevier Science B.V., Amsterdam, The Netherlands, v. 4, p. 495–557.
Banks, L. M. and E. S. Driver, 1957, Geologic history of Santa Ana structure, Añaco structural trend, Anzoátegui,
Venezuela: AAPG Bulletin, v. 41, p. 308-325.
Bellizzia G., A., 1985, Sistema montañoso del Caribe: Una cordillera alóctona en la parte norte de América del Sur:
Memorias del IV Congreso Geológico de Venezuela, v. 10, p. 6657-6836.
Bird, D. E., S. A. Hall, J. F. Casey, and P. S. Millegan, 1999. Tectonic evolution of the Grenada Basin, in P. Mann, ed.,
Caribbean basins: Sedimentary Basins of the World, Elsevier Science B.V., Amsterdam, The Netherlands, v. 4, p. 389416.
Boettcher, S. S., J. L. Jackson, M. J. Quinn, and J. E. Neal, 2003, Lithospheric structure and supracrustal hydrocarbon
systems, offshore eastern Trinidad, in C. Bartolini, R. T. Buffler and J. F. Blickwede, eds., The circum-Gulf of Mexico
and the Caribbean: hydrocarbon habitats, basin formation, and plate tectonics: AAPG Memoir 79, p. 529-544.
Case, J. E., and T. Holcombe, 1980, Geologic-tectonic map of the Caribbean region: USGS Miscellaneous Investigation
Series, Map I-1100, 1:2,500,000.
Clark, S. A., A. Levander, M. Beatrice Magnani, C. A. Zelt, D. S. Sawyer, H. G. Avé Lallemant, M. C. Guedez, and the
BOLIVAR Working Group, 2004, Crustal Structure of the Caribbean-South American Diffuse Plate Boundary,
Subduction Zone Migration and Polarity Reversal Along BOLIVAR Profile 64W: AGU Fall Meeting, abstract T11B0390.
Cruz, L., A. Fayon, C. Teyssier, and J. Weber, 2004, Structural, Thermochronological, Topographic, and Precipitation data
of the Transpressional Orogen of the Venezuelan Paria Península, SE Caribbean-South American Plate Boundary:
AGU Fall Meeting, abstract T33B-1377.
Cruz, L., A. Fayon, C. Teyssier, and J. Weber, in press, Exhumation and deformation processes in transpressional orogens:
The Venezuelan Paria Peninsula, SE Caribbean-South American plate boundary, in SE Caribbean-South American
plate boundary, and the Southern Alps, New Zealand, forthcoming GSA Special Paper.
Deng, J. S. and L. R. Sykes, 1995. Determination of Euler pole for contemporary relative motion of Caribbean and North
American plates using slip vectors of interplate earthquakes: Tectonics, v. 14, p. 39-53.
De Verteuil, L., and Eggertson, B., 2000, Stratigraphic and structural evolution of the western Central Range: GSTT 2000
SPE, 29pp.
Dewey, J. F. and J. L. Pindell, 2006, Tectonic significance of the Caribbean Plate as a reference frame since 100 Ma: the
“Backbone” explained, in GSA Conference “The Backbone of the Americas”: Geological Society of America Abstracts
with Programs, Speciality Meeting No. 2, p. 118
Dewey, J. F., and J. L. Pindell, 1985, Neogene block tectonics of eastern Turkey and northern South America: Continental
applications of the finite difference method: Tectonics, v. 4, p. 71-83.
Dewey, J. F. and J. L. Pindell, 1986, Reply to comment on "Neogene block tectonics of Eastern Turkey and northern South
America: continental applications of the finite difference method": Tectonics, v. 5, p. 703-705.
Di Croce, J., A. Bally, and P. Vail, 1999, Sequence stratigraphy of the Eastern Venezuelan Basin, in P. Mann, ed.,
Caribbean basins: Sedimentary Basins of the World, Elsevier Science B.V., Amsterdam, The Netherlands, v. 4, 419476.
Duerto, L., and McClay, K., 2002, 3D Geometry and evolution of shale diapirs in the Eastern Venezuelan Basin, Search and
Discovery Article #10026. http://www.searchanddiscovery.net/documents/duerto/index.htm (last accessed 14/08/07).
Erlich, R., and S. F. Barrett, 1990, Cenozoic plate tectonic history of the northern Venezuela-Trinidad area: Tectonics, v. 9.
p. 161-184.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
73 of 76
Erlich, R. N., T. Villamil, and J. Keens-Dumas, 2003, Controls on the deposition of Upper Cretaceous organic carbon– rich
rocks from Costa Rica to Suriname, in C. Bartolini, R. T. Buffler and J. F. Blickwede, eds., The circum-Gulf of Mexico
and the Caribbean: hydrocarbon habitats, basin formation, and plate tectonics: AAPG Memoir 79, p. 1–45.
Flinch, J. F., V. Rambaran, W. Ali, V. De Lisa, G. Hernández, K. Rodrigues and R. Sams, 1999, Structure of the Gulf of
Paria pull-apart basin (Eastern Venezuela-Trinidad), in P. Mann, ed., Caribbean basins: Sedimentary Basins of the
World, Elsevier Science B.V., Amsterdam, The Netherlands, v. 4, p. 477–494.
Foland, K. A., R. Speed, and J. Weber, 1992, Geochronologic studies of the Caribbean mountains orogen of Venezuela and
Trinidad: GSA Abstracts with Programs, 24, A148.
Gibson, R., K. Meisling, and J. Bhajan, 2004, Tectonically-driven Plio-Pleistocene structural development of the Columbus
Basin, offshore Trinidad, West Indies: AAPG/GSTT Hedberg Conference, “Mobile Shale Basins – Genesis, Evolution
and
Hydrocarbon
Systems”,
June
4-7,
2006,
Port
of
Spain,
Trinidad
&
Tobago,
http://www.searchanddiscovery.net/documents/2006/06087heberg_abs/abstracts/gibson.htm (last accessed 20/8/07).
Gonzalez de Juana, C., J. M. Iturralde de Arozena and X. Picard Cadillat, 1980, Geologia de Venezuela y de sus cuencas
petroliferas (Geology of Venezuela and its petroliferous basins): Ediciones FONINVES, Caracas, Venezuela, 1031 p.
Hedberg, H. D., 1950. Geology of the eastern Venezuela Basin (Anzoategui-Monagas-Sucre-eastern Guarico portion):
Geological Society of America Bulletin, v. 61, p. 1173-1215.
Hung, E. J., 2005. Thrust belt interpretation of the Serranía del Interior and Maturín Subbasin, eastern Venezuela, in H. G.
Ave Lallemant and V. B. Sisson, eds., Caribbean-South American plate interactions, Venezuela: GSA Special Paper
394, p. 251-270.
Jacomé, M. I. N., N. J. Kusznir, F. Audemard, and S. Flint, 2003a, Formation of the Maturín Foreland Basin, eastern
Venezuela: Thrust sheet loading or subduction dynamic topography: Tectonics, v. 22, p. 1029-1046.
Jacomé, M. I. N., N. J. Kusznir, F. Audemard, and S. Flint, 2003b, Tectonostratigraphic evolution of the Maturín Foreland
Basin: Eastern Venezuela, in C. Bartolini, R. T. Buffler and J. F. Blickwede, eds., The circum-Gulf of Mexico and the
Caribbean: hydrocarbon habitats, basin formation, and plate tectonics: AAPG Memoir 79, p. 735–749.
Klitgord, K. D., and H. Schouten, 1986, Plate kinematics of the Central Atlantic, in P. R. Vogt and B. E. Tucholke, eds.,
The Western Atlantic Region: GSA, Geology of North America, v. M, p. 351-378.
Kugler, H. G., 1959, Geologic map of Trinidad: Trinidad and Tobago: Petroleum Association of Trinidad, Port of Spain,
Trinidad and Tobago.
Kugler, H. G., 1996, Treatise on the Geology of Trinidad, detailed geological maps and sections, H. G. Bolli and M.
Knappertsbusch, eds.: Natural History Museum of Basel, Switzerland.
Leroy, S., A. Mauffret, P. Patriat, and B. Mercier de Lepinay, B.M., 2000, An alternative interpretation of the Cayman
trough evolution from a reidentification of magnetic anomalies: Geophysical Journal International, v. 141, p. 539-557.
Liska, R.D., 1988, The Río Claro Boulder Bed of central Trinidad: a sedimentary or tectonic event?: Transactions of the
11th Caribbean Geological Conference, Barbados, 1984, 12.1-12.7.
Locke, B., and J. Garver, 2005, Thermal evolution of the eastern Serranía del Interior foreland fold and thrust belt,
northeastern Venezuela, based on apatite fission track analyses, in H. G. Ave Lallemant and V. B. Sisson, eds.,
Caribbean-South American plate interactions, Venezuela: GSA Special Paper 394, p.315-328.
MacDonald, K. C. and T. L. Holcombe, 1978, Inversion of magnetic anomalies and sea-floor spreading in the Cayman
Trough: Earth and Planetary Science Letters, v. 40, p. 407-414.
Mann, P. and K. Burke, 1984, Neotectonics of the Caribbean: Review of Geophysics and Space Physics, v. 22, p. 309-362.
Maresch, W. V., 1974, Plate tectonics origin of the Caribbean Mountain System of northern South America: Discussion and
proposal: GSA Bulletin, v. 85, p. 669-682.
Müller, R. D., J.-Y. Royer, S. C. Cande, W. R. Roest, and S. Maschenkov, 1999, New constraints on the Late
Cretaceous/Tertiary plate tectonic evolution of the Caribbean, in P. Mann, ed., Caribbean basins: Sedimentary Basins of
the World, Elsevier Science B.V., Amsterdam, The Netherlands, v. 4, p. 33-57.
Passalacqua, H., Fernandez, F., Gou, Y., and Roure, F., 1995, Crustal architecture and strain partitioning in the Eastern
Venezuelan Ranges, in A. J. Tankard, R. Suarez-Soruco, and H. J. Welsink, eds., Petroleum basins of South America:
AAPG Memoir 62, p. 667-680.
Perez, O., R. Bilham, R. Bendick, J. Velandia, N. Hernandez, C. Moncayo, M. Hoyer, and M. Kozuch, 2001, Velocity field
across the southern Caribbean plate boundary and estimates of Caribbean/South-American plate motion using GPS
geodesy 1994-2000: Geophysical Research Letters, v. 28, p. 2987-2990.
Pindell, J. L., 1985, Plate tectonic evolution of the Gulf of Mexico and Caribbean region, Durham University, England,
Ph.D. thesis, 227 p.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
74 of 76
Pindell, J. L., S. Cande, W. C. Pitman III, D. B. Rowley, J. F. Dewey, J. LaBrecque, and W. Haxby, 1988, A platekinematic framework for models of Caribbean evolution: Tectonophysics, v. 155, p. 121-138.
Pindell, J. L., and S. F, Barrett, S. F., 1990, Geologic Evolution of the Caribbean Region: a Plate-Tectonic Perspective, in J.
E. Case, and G. Dengo, eds., The Caribbean Region: GSA, Geology of North America, v. H, p. 405-432.
Pindell, J. L., J. P. Erikson, and S. T. Algar, 1991, The relationship between plate motions and sedimentary basin
development in northern South America: from Mesozoic passive margin to Cenozoic eastwardly-progressive
transpressional orogen, in Gillezeau, K., ed., Transactions of the 2nd Geological Conference, Geological Society of
Trinidad and Tobago, p. 191-202.
Pindell, J. L., and J. P. Erikson, 1994, The Mesozoic passive margin of northern South America, in J. A. Salfity, ed.,
Cretaceous Tectonics of the Andes: International Monograph Series, Vieweg, p. 1-60.
Pindell, J. L., R. Higgs, and J. F. Dewey, 1998, Cenozoic palinspastic reconstruction, paleogeographic evolution, and
hydrocarbon setting of the northern margin of South America, in J. L. Pindell, and C. L. Drake, eds., Paleogeographic
Evolution and Non-glacial Eustasy, northern South America: SEPM Special Publication 58, p. 45-86.
Pindell, J. L., and Kennan, L., 2001, Processes and events in the terrane assembly of Trinidad: GCSSEPM 21st Annual Bob
F. Perkins Research Conference, p. 159-192.
Pindell, J. L, L. Kennan, W.V. Maresch, K.-P. Stanek, G. Draper, and R. Higgs, 2005, Plate-kinematics and crustal
dynamics of circum-Caribbean arc-continent interactions: Tectonic controls on basin development in Proto-Caribbean
margins, in H. G. Ave Lallemant and V. B. Sisson, eds., Caribbean-South American plate interactions, Venezuela: GSA
Special Paper 394, p. 7–52.
Pindell, J. L., L. Kennan, L., K.-P. Stanek, W. V. Maresch, and G. Draper, 2006, Foundations of Gulf of Mexico and
Caribbean evolution: Eight controversies resolved: Geologica Acta, v. 4, p. 89-128.
Pindell, J. L. and Frampton, J., 2007, Fieldguide: Geology and Tectonic Evolution, Scotland District, Barbados, 4th
Geological Conference, Geological Society of Trinidad and Tobago.
Prentice, C. S., J. Weber, and C. J. Crosby, 2001, Paleoseismic and Geomorphic Evidence for Quaternary Fault Slip on the
Central Range Fault, South American-Caribbean Plate Boundary, Trinidad: EOS, Transactions of the American
Geophysical Union, v. 82, p. F928.
Robertson, P. and K. Burke, 1989, Evolution of southern Caribbean Plate boundary, vicinity of Trinidad and Tobago:
AAPG Bulletin, v. 73, p. 490-509.
Rosencrantz, E., 1995. Opening of the Cayman Trough and the evolution of the northern Caribbean Plate boundary. GSA
1995 Annual Meeting, Abstracts with Programs, v. 27, p. 153.
Rosencrantz, E., M. I. Ross, and J. G. Sclater, 1988, Age and spreading history of the Cayman Trough as determined from
depth, heat flow, and magnetic anomalies: Journal of Geophysical Research, v. 93, p. 2141-2157.
Roure, F., N. Bordas-Lefloch, J. Toro, C. Aubourg, N. Guilhaumou, E. Hernandez, S. Lecornec-Lance, C. Rivero, P.
Robion, and W. Sassi, 2003, Petroleum systems and reservoir appraisal in the sub-Andean basins (eastern Venezuela
and eastern Colombian foothills), in C. Bartolini, R. T. Buffler and J. F. Blickwede, eds., The circum-Gulf of Mexico
and the Caribbean: hydrocarbon habitats, basin formation, and plate tectonics: AAPG Memoir 79, p. 750–775.
Saleh, J., K. Edwards, J. Barbaste, S. Balkaransingh, D. Grant, J. Weber, and T. Leong, 2004, On some improvements in the
geodetic framework of Trinidad and Tobago: Survey Review, v. 37, p. 604-625.
Saunders, J. B., C. Roberts, W. M. Ali, and B. Eggertson, 1997, Geological Map, Trinidad and Tobago, Ministry of Energy
and Energy Industries, Trinidad and Tobago.
Schubert, C., 1981, Are the Venezuelan fault systems part of the southern Caribbean plate boundary?: Geologishe
Rundschau, v. 70, p. 542-551.
Senn, A., 1940. Paleogene of Barbados and its bearing on history and structure of Antillean-Caribbean region: AAPG
Bulletin, v. 24, p. 1548-1610.
Sisson, V. B., H. G. Ave Lallemant, M. Ostos, A. E. Blythe, L. W. Snee, P. Copeland, J. E. Wright, R. A. Donelick, and L.
R. Guth, 2005, Overview of the radiometric ages in threre allochthonous belts of northern Venezuela: old ones, new
ones, and their impact on regional geology, in H. G. Ave Lallemant and V. B. Sisson, eds., Caribbean-South American
plate interactions, Venezuela: GSA Special Paper 394, p. 91-117.
Snoke, A.W., D.W. Rowe, J. D. Yule, and G. Wadge, 2001, Petrologic and structural history of Tobago, West Indies: A
fragment of the accreted Mesozoic oceanic-arc of the southern Caribbean: Geological Society of America Special Paper
354, 56 p.
Sobiesiak, M., L. Alvarado, and R. Vásquez, 2002, Sismicidad reciente del oriente de Venezuela: XI Congreso Venezolano
de Geofísica, 4 p. http://www.congresogeofisica-sovg.org/dyncat1.cfm?catid=2653# (last accessed 16/08/07).
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
75 of 76
Speed, R. C., 1985, Cenozoic collision of the Lesser Antilles Arc and continental South America and the origin of the El
Pilar Fault: Tectonics, v. 4, p. 41-69.
Speed, R. C., 2002, Field trip to the Scotland District: Exposed example of an accretionary prism. Field Guide, 16th
Caribbean Geological Conference, Barbados, June 16-23, 2002.
Speed, R. C., G. Westbrook, A. Mascle, B. Biju-Duval, J. Ladd, J. Saunders, S. Stein, J. Schoonmaker, and J. C. Moore,
eds., 1984, Lesser Antilles Arc and Adjacent Terranes: Ocean Margin Drilling Program, Regional Atlas Series. Marine
Science International, Woods Hole, MA, 27 sheets.
Sykes, L. R., W. R. McCann, and A. L. Kafka, 1982, Motion of the Caribbean plate during last 7 million years and
implications for earlier Cenozoic movements: Journal of Geophysical Research, v. 87, p. 10656-10676.
Tectonic Analysis (Pindell, J. and Kennan, L.), 2005, Paleogeographic mapping and documentation of sandstone/reservoir
systems, Paleogene to Middle-Miocene of Trinidad and Eastern Venezuela, unpublished non-exclusive report.
Tectonic Analysis (Pindell, J. and Kennan, L.), 2007, Age, provenance, and structural setting of
Trinidadian/Barbadian/Venezuelan clastic reservoir systems, unpublished non-exclusive report.
Ten Brink, U. S., D. F. Coleman, and W. P. Dillon, 2002, The nature of the crust under Cayman Trough from gravity:
Marine and Petroleum Geology, v. 19, p. 971-987.
Torrini, R., and R. C. Speed, 1989, Tectonic wedging in the forearc basin-accretionary prism transition, Lesser Antilles
forearc, Journal of Geophysical Research, v. 94, p. 10,549-10,584.
Trenkamp, R., J. N. Kellogg, J. T. Freymueller, and H. P. Mora, 2002, Wide plate margin deformation, southern Central
America and northwestern South America, CASA GPS observations: Journal of South American Earth Sciences, v. 15,
p. 157-171.
Van der Hilst, R., 1990, Tomography with P, PP , pP delay-time data and the three-dimensional mantle structure below the
Caribbean region: University of Utrecht Ph.D. thesis, 250 p.
Van der Hilst, R. and P. Mann, 1994, Tectonic implications of tomographic images of subducted lithosphere beneath
northwestern South America: Geology, v. 22, p. 451-454.
Vierbuchen, R., 1984. The geology of the El Pilar Fault Zone and adjacent areas in northeastern Venezuela, in W. Bonini,
R. Hargraves, and R. Shagam, eds., The Caribbean-South American Plate Boundary and Regional Tectonics: GSA
Memoir 162, p. 189-212.
Weber, J. C., T. H. Dixon, C. DeMets, W. B. Ambeh, P. Jansma, G. Mattioli, J. Saleh, G. Sella, R. Bilham, and O. Perez,
2001, GPS estimate of relative motion between the CA and SA plates, and implications for Trinidad and Venezuela:
Geology, v. 29, p. 75– 78.
Wilson, C. C., 1968, The Los Bajos Fault, in J. B. Saunders, ed., Transactions of the Fourth Caribbean Geological
Conference, Port of Spain, 1965, p. 87-90.
Wood, L. J., 2000, Chronostratigraphy and tectonostratigraphy of the Columbus Basin, eastern offshore Trinidad: AAPG
Bulletin, v. 84, p. 1905-1928.
Ysaccis, B., 1997, Tertiary Evolution of the northeastern Venezuela offshore: Rice University, Ph.D. Thesis, 285p.
Zambrano, E., E. Vásquez, B. Duval, M.Latreille, and B. Coffinières, 1971, Síntesis paleogeográfica y petrolera del
occidente de Venezuela: IV Congreso Geológico Venezolano, Caracas, Ministerio de Minas Hidrocarburos, Venezuela,
Boletín de Geología, Publicación Especial, no. 5, v. 1, p. 483-552.
Pindell and Kennan, SE Caribbean, Trinidad & Venezuela, for GCSSEPM 2007
76 of 76