Download 1 Introduction Contents

1
Introduction
Contents
1.1
Scope
1.1.1
1.1.2
1.1.3
1.1.4
of the Thesis . . . . . . . . . . . . . .
Models of orogenic plateaus . . . . .
Generalities of orogenic plateaus . .
Central Anatolian Orogenic Plateau Aims of the Thesis . . . . . . . . . .
1.2
Tectonic setting of Turkey . . . . .
1.2.1 Tectonic plates arrangement
1.2.2 Tectonic slabs . . . . . . . .
1.2.3 Temporal evolution . . . . .
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Structure of the Thesis . . . . . . . . . . . . . . . . . . . . . .
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Geologic setup
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and motions
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“Doubt is not a pleasant condition,
but certainty is absurd.”
Voltaire
3
Introduction
1.1
Scope of the Thesis
Research on the mechanics and time-span of the processes behind orogenic plateau
growth currently foments an intense discussion between erodibility-climate and tectonic schools [e.g. Molnar and England, 1990; Sobel and Strecker, 2003; Sobolev
and Babeyko, 2005; Cloetingh and Willett, 2013]. The accurate quantification of
the competing tectonic and climatic processes is key to understanding the main
governing forces and the nature of feedback shaping the Earth’s surface [e.g. Garcı́aCastellanos and Cloetingh, 2011]. Some open questions in this debate are:
• Is the surface uplift, and thus the plateau topography, a consequence of primarily tectonic, geomorphic, or climatic processes?
• What are the time scales of plateau topography development?
• How does the surface morphology and the lithosphere of the plateau evolve in
time and what feedback processes are involved?
1.1.1
Models of orogenic plateaus
While the climatic-erodibility models relate the tectonic activity to climate, rock
erodibility, and precipitation power during incipient relief development [e.g. Sobel,
2003; Garcı́a-Castellanos, 2007], the tectono-structural and thermo-mechanical models understand the plateau buildup in relation to accretion/removal of crustal or
lithospheric material, magmatic/tectonic underplating or rheological changes [e.g.
Molnar, 1984; Allmendinger et al., 1997; Clark, 2012] (Fig. 1.1). Tectono-structural
and thermo-mechanical models are divided into crustal and/or lithospheric shortening, tectonic or magmatic underplating, lower crustal flow, mantle delamination or
detachment, slab break-off, and lithospheric thinning by extrusion. However, these
models are not always able to entirely explain certain features of orogenic plateau
development.
Erodibility models
Tectonic models
Orographic precipitation
Effective
orographic
barrier
Dry intramountain
climate
Lower crustal flow
Intracontinental subduction
Delamination /
Detachment /
Break-off
Extrusion
Shortening
Tectonic
uplift
Endorheism
Sediment trapping,
high plateau
Understrusting /
Tectonic doubling
Deformation
propagates
forelandwards
Higher pressure
under orogen axis
Figure 1.1: Summary of mechanisms of plateau formation. Slightly modified after Garcı́aCastellanos [2007] and http://www.geo.arizona.edu/.
4
Chapter 1
The evolution of the plateau morphology over time may be due to:
Tectonic uplift and outward orogenic propagation. Leading to the transferral of foreland terrains into intramountane regions and the transformation
of former foreland basins into younger interior basins. This tectonic process
modifies the sedimentary dynamics of these basins, now internally drained
by river networks that are incapable of ejecting sediments out of the system.
This decrease in erosional capacities, caused by margin growth, forces internal aridification, overfill, and amalgamation of the intramountane basins that
eventually flatten the orogen interior.
Climatic contrast caused by relief initiation. Leading to a protracted contrast
in precipitation and run-off, and therefore, in erosional power. This climatic
effect, caused by long-lasting wind and rain shadows, leads to progressive
aridification, hydrologic isolation and sediment trapping in the leeward side
of the orogen, and high-discharge river networks with strong erosional capacity in the windward areas. The sedimentary basins shift from exo- to endorheic
and their sedimentary accumulations create loads in the interior of the plateau
that eventually force the propagation of the deformation forelandwards, orogen
outward growth, and consequently tectonic uplift [e.g. Strecker et al., 2009a].
The determination of the causation relationship between these obviously interconnected cycles remains elusive. Orogenic plateaus are great “natural laboratories”
to unravel the feedbacks amongst surface and deep-seated processes, and the relative
relevance of each individual factor.
1.1.2
Generalities of orogenic plateaus
Orogenic plateaus are tectonomorphic features characterized by elevated yet subdued
semi-arid interiors, flanked by steep humid margins up to several kilometers high.
Despite the broad range of scales and possible forming mechanisms shown by orogenic plateaus around the globe, they share some unifying characteristics (Fig. 1.2);
(i) they can be described morphologically as a broad, roughly-flat, high surface,
bounded by elevated steep margins; (ii) they display a high climatic precipitationerosion contrast between the arid, mainly endorheic basins in the interior with limited sediment circulation, and the humid, rainy flanks with exorheic rivers of high
discharge; (iii) they have a thick crust, in excess of 40 km, and often a thin mantle
lithosphere of ∼40−50 km. Thus, they have an anomalously high heat flow.
Orogenic plateaus develop in a variety of contractional settings as integral parts
of the largest modern mountain ranges on Earth. Some outstanding examples are the
Colorado Plateau in the North America Cordillera, the Tibetan Plateau in the Himalayas, the Puna-Altiplano Plateau in the Central Andes, and the Iranian Plateau
[e.g. Bird, 1979; Nelson et al., 1996; Allmendinger et al., 1997; Şengör et al., 2003].
This Thesis’ case study, the Central Anatolian Plateau [Strecker et al., 2009b], is
not an exception, and is developing in the complex convergence zone between the
Eurasian, African, and Arabian plates.
5
Introduction
100’s Km
Endorheism
2-8 Km
40-80 Km
Km
10
Endorheism
S.L.
40-50 Km
35-50 Km
Crust
Mantle Lithosphere
0
50
100
Asthenosphere
150
Figure 1.2: Conceptual sketch of orogenic plateaus seen in cross section (not to scale).
1.1.3
Central Anatolian Orogenic Plateau - Geologic setup
The Vertical Anatolian Movements Project (VAMP), a multidisciplinary effort built
within the TOPO-EUROPE large-scale collaborative research program (EUROCORES) of the European Science Foundation (ESF) [Cloetingh et al., 2009], first
identified the Central Anatolian Orogenic Plateau (CAP) as a young, but fully representative, continental plateau [Strecker et al., 2009b]. The CAP, located in Central
Turkey, is a more accessible (smaller size and lower relief) orogenic plateau when
compared with other more notorious orogenic plateaus (such as the Tibetan Orogenic
Plateau), which therefore makes it ideal to deepen our understanding of orogenic
plateau formation. However, until recently, the CAP has been disregarded, while
many studies have centered their attention around bigger orogenic plateau systems
[e.g. Powell, 1986; Yin and Harrison, 2000; Clark et al., 2006; Rowley and Currie,
2006].
The CAP covers a ∼350 km wide area between the Aegean extensional province
and the Bitlis-Zagros contractional domain. It extends, in the N−S direction, from
the Black Sea to the Mediterranean (see Fig. 1.3). The Pontides and Taurus mountain ranges, in the north and south, represent the flanks of the plateau and reach
elevations of more than 3000 m. The roughly flat CAP interior, represented by Central Anatolia, is located at elevations of 1000 − 1300 m. Two major rivers dissect the
higher elevations of the flanking mountain ranges. In the north, the Pontide Mountains are incised by the Kızılırmak River, which discharges in its delta after a journey
of ∼1350 km in the plateau interior. In the south, the Göksu River, which feeds the
homonym delta, transects the Taurus Mountains and enters the Mediterranean at
Silifke.
Based on Pn tomography and receiver function analysis [Mutlu and Karabulut,
2011; Vanacore et al., 2013, respectively], the CAP crust in Central Anatolia is
reported to be 35±2 km or thicker, up to ∼47 km. These thicknesses increase towards
the east, reaching up to ∼55 km, and the south, ranging from 40 to 47 km on the
south Turkish coast. Further south, normal thicknesses are observed, with Moho
depths of ∼30 km in Cyprus. Decreasing thicknesses are also found for West Anatolia
and the Aegean Sea, with values between 28±2 and 33±2 km. Central Anatolia
presents a hot and thinned mantle lithosphere, as seen in high heat flow values,
normally in excess of 50 mW/m2 [Ateş et al., 2005; Dolmaz et al., 2005].
6
Chapter 1
In the CAP, widespread Mid-Cenozoic rocks cover the Mesozoic to Palæogene
rocks, related to amalgamated microcontinents [e.g. Şengör and Yılmaz, 1981; Robertson, 1998b]. In this Thesis, these rocks are assigned as basin basement rocks, independently of their nature (metamorphic or otherwise). Overlying basement, the
basin infill contains continental pre-Miocene rocks, named here pre-Miocene substratum (PMS), marine Miocene rocks, and Plio-Q rocks, again continental in character.
The interior of the Central Anatolian Orogenic Plateau
In the interior of the CAP, at elevations around 1 km, thick lake and fluvial deposits
form a series of Miocene-Quaternary sedimentary basins. In many of these interior
basins, Miocene and older rocks are covered by important sequences of Pliocene and
Quaternary deposits, a result of the confinement caused by the north and south orogenic barriers. For most of Central Anatolia, Neogene deposits are continental and
poorly dated, and outcrops are limited, with some notable exceptions, such as the
Çankırı Basin [Kaymakci, 2000]. Miocene kinematic and structural data is relatively
minor and the tectonic regime of the area is a matter of debate, with possibilities
ranging from strike-slip [e.g. Şengör et al., 1985] or extension [e.g. Dhont et al., 1999]
to coeval extension and compression [Genç and Yürür, 2010]. Moreover, no link has
been established with the uplift events in the margins of the CAP-system. In a
central position, the Tuz Gölü Basin is a major representative amongst the CAP
interior basins [Dirik and Erol, 2000]. Understanding the Miocene structural evolution of the Tuz Gölü Basin in its regional picture will provide relevant information
on the genetic nature of the CAP.
The southern margin of the Central Anatolian Orogenic Plateau
With elevations locally in excess of 3000 m, the arcuated Taurus Range forms the
southern flank of the Central Anatolian Orogenic Plateau (SCAP). Basin basement
rocks are in the Taurus Mountains unconformably overlay by PMS and Miocene
rocks. As an outstanding example, the incision of the Göksu River in the modern
Taurus exposes thicknesses of this Miocene sequence up to 1600 m (up to 2300 m,
considering the PMS [Cosentino et al., 2012]). These Miocene marine sediments
were deposited in a single basin and have been related to those found in the east
(Adana Basin) and west (Antalya Basin) [Karabıyıkoğlu et al., 2000]. Towards the
north, in the Karaman region, an erosional surface marks the transition of these
marine rocks to the Anatolian basement. This erosive termination might correlate
with similar erosive surfaces seen between the thick Miocene-Recent continental
rocks and the aforementioned basement [Monod et al., 2006]. Towards the south,
correlative sediments are found in the offshore Cilicia Basin [Aksu et al., 2005a],
in the Kyrenia Range, and in the Messaoria Basin in north and central Cyprus
[McCay, 2010] (See Fig. 1.5). It can therefore be assumed that these sediments
initially belonged to one single subsiding area during Early to Middle Miocene times
and that progressive formation of the SCAP caused the end of marine sedimentation
of the northern areas, which is dated as Late Tortonian (∼8 My) by Cosentino et al.
[2012]. This evolution is in agreement with the disruption of a palæoriver network
and the reestablishment of a younger one, as observed by Monod et al. [2006] in SW
Turkey. North of Manavgat, fossil river morphologies are seen at an elevated high
surface only partially affected by the modern drainage system. The high surface
represents an Early Miocene NE-SW directed palæodrainage, disrupted by Late
Miocene.
7
Introduction
A’
Kasta o u
-4500
Fault
North A atolia
VAMP
profile
Ankara
40°N
Kız
ıl
ır
ak
Tuz Gölü
Cappadocia
Ma
av
ga
t
A talya
Kara a
Göksu
Ada a
Mut
30°E
Silike
0
75
150
A
kilometers
Central Anatolia Plateau (CAP)
South
Ele aio [k ]
40°N
36°N
Messaoria
Rainfall [mm/yr]
102
36°N
Cilicia Basi
Kyre ia Ra ge
2
1 Cyprus
0
-1
-2
-3 African
Rainfal
[mm/yr]
1930
34 °E
Sinop
Topography a d rai fall s ath profile
3600
2000
0
30 °E
34°E
Ele aio
[m]
Cilicia
Basin
Tauride Mt s
Mut Basin
.. ..
Tuz Golu Basin
Ankara
Neogene marine/
co i e tal sedi e ts
Black
Sea
?
?
plate
North
North Anatolian Fault
Po ide Mt s
Metamorphic rocks
Intrusive rocks
1500
Rainfall
1000
500
Ele aio [ ]
2000
1000
0
Topography
-1000
-2000
0
A
100
200
300
400
500
600
700
800
Distance along swath [km]
A’
Figure 1.3: Vertical Anatolian Movement Project (VAMP) study area. Slight modification
from figures shown in the VAMP proposal [unpublished], showing a schematic geologic section, as drawn by Prof. Dr. Helmut Echtler, Prof. Dr. Andreas Mulch and Prof. Dr. Giovanni Bertotti [unpublished], and the elevation and 1998-2006 precipitation profiles by
Dr. Bodo Bookhagen [unpublished].
S
N
Central Anatolian Plateau
EMed
Cyprus
African mantle lit
CTM
hosph
ere
Asthenosphere
CPM
TGB
Eurasian continental crust
Eurasian mantle lithosphere
Asthenosphere
BkS
~200 km
Figure 1.4: Schematic representation of the crustal and lithospheric thicknesses in
the Central Anatolian Plateau. Extracted and simplified after Stephenson et al. [2004].
Topography-bathymetry is exaggerated three times. For the acronyms see Appendix C.
8
Chapter 1
The high reliefs found in the area, the Taurus Mountains and the Kyrenia Range,
must have therefore mostly developed at later stages, effectively dismembering this
northeast Mediterranean basin into the modern basins seen in the area (Fig. 1.5).
While the growth of the Kyrenia Range occurs in relation to south-verging thrusts
[Calon et al., 2005a, b; McCay, 2010], the growth of the Taurus Mountains and that of
the SCAP remains enigmatic, with the apparent absence of regional accommodating
structures. The present configuration, age, and distribution of the marine sediments
in the margin and further south implies that during the Late Tortonian, a change in
the vertical kinematics led to the coeval uplift and subsidence of the northern and
southern areas of the Miocene basin, respectively.
Between these two areas, the Miocene sediments were gently tilted southwards.
Accordingly, a N−S section transecting the central area of south Turkey and its
offshore area show a Miocene monocline [Çiner et al., 2008]. Onshore subhorizontal
sediments at ∼2 km in the Mut Basin and offshore flat-lying deposits at ∼−2 km in
the Cilicia Basin are connected by a transitional area, gently south-dipping.
Relevant information is preserved in these Miocene marine sediments (Figs. 1.3
and 1.5), such as the youngest age for initiation of the uplift, marked by the disruption of the marine sedimentation in Late Tortonian times [Cosentino et al., 2012],
or the type of uplift and the nature of its accommodation structures, registered in
the sedimentary architecture of the basins being studied in this Thesis.
1.1.4
Aims of the Thesis
This Thesis aims at achieving a deeper understanding on the regional tectonic evolution and formation mechanisms of the CAP-system in relation to that of the Cyprus
subduction system, located immediately south of the plateau. More specifically, this
contribution intends to quantify and characterize the type of tectonic motions, both
in the vertical and in the horizontal directions, and unravel the genetic nature of the
CAP by means of fieldwork, structural techniques, basin analyses, and geodynamic
modeling. To gain these goals, this Thesis focuses on the SCAP and its onland and
offland adjacent regions before and during its growth.
Specific goals
The specific targets of this Thesis are to (i) determine the structures responsible
for the growth of the SCAP, (ii) understand the development of the margin from
Miocene to the present, constraining the ages of the main tectonic events, and (iii)
propose a regional quantitative model to explain the tectonic and geodynamic evolution of an area stretching from the CAP interior to the Cyprus arc-trench system.
i) Recognize the structures behind the formation of the SCAP. The causes driving
the tectonics motions in the southern margin of the CAP influence the character, distribution and direction of the tectonic structures accommodating the
movements. Recognizing these structures is therefore essential to understand
the mechanisms. As two simple possibilities, in the case of the surface uplift,
the motion might be accommodated by S-verging thrusts faults or by S-dipping
extensional faults, intrinsically implying entirely different uplift mechanisms.
9
Introduction
ii) Determine the age of the tectonics events in the SCAP. The spatio-temporal
evolution of vertical motions in the margin can be determined by analyzing
the geometries of the accommodation structures and the sedimentary growth
patterns, as well as by subsidence curves and kinematic reconstructions.
■
■
iii) Quantitatively understand the evolution of the SCAP in its regional tectonic
setting. Quantitative geodynamic modeling is used to understand the largescale tectonic framework during the Miocene to Present evolution of an area
between the CAP interior and Cyprus. Constrained by an integration of new and
available geologic data, the models provide insights into the thermo-mechanical
controls of the■ vertical motions.
■
Z
■
EF
34ºE
36ºE
38ºE
■
Ab
AB
MB
rusEBM ounta
ins
CB
▲
▲
▲
32ºE
Ab Antalya basins
MaB Manavgat Basin
▲
▲
▲ ▲ ▲ ▲
ge ▲
K
▲yre
a R▲an▲
▲ni▲
34ºE
EB
MB
▲
▲
▲
▲
35º30´N
35º30´N
MaB
Ta
u
36ºN
36ºN
36º30´N
36º30´N
■■
32ºE
▲
Km
0
36ºE
Ermenek Basin
Mut Basin
100
200
38ºE
AB Adana Basin
CB Cilicia Basin
Figure 1.5: Map of the Miocene marine basins seen in the SCAP and further south. These
basins were formed in a broad subsiding area in the Early Miocene.
1.2
1.2.1
Tectonic setting of Turkey
Tectonic plates arrangement and motions
Turkey occupies a western position in the Arabian-Eurasian collision zone, which
is an extensive region of intracontinental convergent deformation, and represents a
transitional area separating a shortening domain in the east (Iran) and an extensional domain in the west (Aegean). Turkey represents an accretionary orogen in
which a diachronous collision led to continent-continent collision in its eastern section and an ocean-continent collisional setting in its western section [e.g. Robertson,
2000]. Intracontinental convergent deformation results in the present-day convoluted (macro/micro) tectonic plate puzzle. This complicates the determination of
10
Chapter 1
boundaries and mutual influences amongst the different tectonic plates, and has fomented a long-lasting scientific discussion [e.g. Wortel et al., 2010] (see Fig. 1.6).
This discussion is, however, outside the scope of this Thesis.
Several tectonic boundaries coalesce in the eastern Mediterranean. The southeastern boundary of the Eurasian Plate in the north, and the northeast limit of the
African Plate in the south, merge in the eastern Mediterranean. Since the AfricanEurasian collision, which probably started 30 − 25 Ma [e.g. Jolivet and Faccenna,
2000; McQuarrie and van Hinsbergen, 2013], the African Plate has moved in a counterclockwise manner with velocities ranging from 3,3 mm/y in the west to 10 mm/y
in the easternmost Mediterranean [McClusky et al., 2000]. This collision led to a
complex subduction area all over the Mediterranean that developed, among others,
the Cyprus Arc. To the east of these arc-trench systems, the current northward motion of the Arabian Plate (20 − 24 mm/y) leads to rifting in the Red Sea [McClusky
et al., 2000].
Two microplates are generally recognized between the African and the Arabian plates in the eastern Mediterranean, the Sinai and the Anatolian−Aegean microplates. The Sinai Microplate, in the southeasternmost of this collisional area,
shears along the Dead Sea Fault to the east and along a diffusive boundary in the
western Gulf of Suez, creating the Sinai peninsula. The Sinai Block moves northward relative to the African Plate at ∼1,4 − 2,4 mm/y [Wdowinski et al., 2004;
Mahmoud et al., 2005]. The Cyprus Arc-trench System bounds the Sinai Block to
the north, where it comes in contact with the Anatolian−Aegean Microplate. The
Cyprus Arc, active since the Early Miocene [e.g. Robertson, 2000; Stephenson et al.,
2004], presently accommodates convergence by frontal accretion at velocities between
18 mm/y (in the west) and 9 mm/y (in the east) [Reilinger et al., 2006]. The CAP
develops in a northward position, within the Anatolian−Aegean Microplate. The
Anatolian−Aegean Microplate rotates counterclockwise, while moving W to SSW
as it is extruded from the Arabian−Eurasian collision zone along the right-lateral
North Anatolian Fault Zone (NAFZ) and the left-lateral East Anatolian Fault Zone
(EAFZ). The rates increase in a westward direction from 20 mm/y in Central Anatolia to 30 mm/y in the Hellenic trench [Jiménez-Munt et al., 2003]. This westward
extrusion is also driven by slab pull in the Aegean region [Jiménez-Munt et al., 2003].
At present, the Hellenic Arc is affected by arc-parallel extension while SSW-directed
extension affects the Aegean-West Anatolian region [Hatzfeld, 1999].
1.2.2
Tectonic slabs
In the eastern Mediterranean, the African slab sinks under the European lithosphere.
Remnants of the Neotethys Ocean presently appear as a broken slab beneath the
Iranian Plateau [e.g. Keskin, 2003], subducting northwards along the Cyprus arctrench system under the Anatolian region [e.g. Bakırcı et al., 2012], maybe partially
breaking-off, and as a retreating slab in the Aegean [e.g. Jolivet, 2001]. Differential
motions of the slab and tearing create a variety of shapes, geometries and processes
that strongly influence the upper crustal deformation mechanisms. Seismic tomography studies show a slab detachment beneath eastern Anatolia, with a slab remnant
separated from the lithosphere and presently seen at ∼600 km [Piromallo et al., 2003;
Faccenna et al., 2006; Hall et al., 2009] (see Fig. 1.7).
Introduction
11
Figure 1.6: Simplified tectonic map of the eastern Mediterranean Sea and surrounding
regions. The original compilation by Aksu et al. [2005a] is slightly modified here to include
the position of the marine Oligo-Miocene basins (grey) in the south of the CAP and Cyprus.
Figure 1.7: 3-D diagram of the resolved segmented geometry of the subducting African
lithosphere beneath Anatolia inferred from Biryol et al. [2011] tomographic model, as seen
in their contribution.
12
Chapter 1
The detachment of the African slab caused the uplift in the East Anatolian
Plateau [e.g. Keskin, 2003] and is presumably related to the activation of the NAFZ
[Faccenna et al., 2006] and the EAFZ. This model would imply relevant subsidence in
the center of the SCAP (Mut area), contrary to the observed uplift. The activation of
the sinistral EAFZ might be linked with the disruption and tearing of the subducting
slab below the northeasternmost Mediterranean coast [Govers and Wortel, 2005;
Biryol et al., 2011] and the volcanism seen in SE Anatolia [Arger et al., 2000].
Further to the west, the African slab seems to be attached [Faccenna et al., 2003;
Biryol et al., 2011; Bakırcı et al., 2012] and reaches relevant depths in the Cyprus
and Hellenic arcs, where it has been imaged at a depth of ∼1500 km [Wortel and
Spakman, 2000]. Yet another relevant slab tear is seen separating the Hellenic and
the Cyprus slabs [Faccenna et al., 2006; Biryol et al., 2011].
1.2.3
Temporal evolution
Starting in Cretaceous times, the evolution of the area has been controlled by the
northward subduction of the northern side of the Neotethys Ocean. This process
led to collision of several northward-drifting continental fragments [e.g. Şengör and
Yılmaz, 1981; Görür et al., 1984; Williams et al., 1995; Robertson, 1998b; Okay
and Tüysüz, 1999; Hüsing et al., 2009; Pourteau et al., 2010, 2013a] (see Fig. 1.8).
Following the ocean closure, a possible delamination-induced event in the Eocene
epoch is recorded by related magmatism [Kadioglu and Dilek, 2010]. These events
occurred before the time-span considered in this Thesis, and will not be discussed
in any detail.
The initial formation of relief in both the Pontides by Eocene times [e.g. Şengör
and Yılmaz, 1981] and the Taurides by Early Oligocene [e.g. Jaffey and Robertson,
2005; Eriş et al., 2005], is shown by the absence of Upper Palæogene and non-marine
deposition in the north [e.g. Robinson et al., 1995] and terrestrial sedimentation in
the south [e.g. Bassant et al., 2005; Şafak et al., 2005] by Oligocene to Early Miocene
time. This continental deposition is broadly contemporaneous with the Cyprus arc
activation during the Early Miocene [e.g. Robertson, 2000; Stephenson et al., 2004]
and the initiation of E−W extension in Central and West Anatolia [Whitney and
Dilek, 1997].
Continued variable extension in both Central and West Anatolia may be linked
with the westward escape of Anatolia, which probably commenced during the Middle
Miocene (∼17 My or earlier times). The extrusion tectonics led to up to 40◦ clockwise
rotation in the west by ∼15 − 8 My, and possibly accelerated subduction during
latest Miocene-Pliocene times ∼5 My [Armijo et al., 1996, 1999; Jolivet and Patriat,
1999; Van Hinsbergen et al., 2005]. The tectonic escape of Anatolia was facilitated
by the activation of the main transpressional structures observed today in the North
Anatolian Fault Zone (NAFZ) and the East Anatolian Fault Zone (EAFZ), probably
in relation to the detachment of the slab in east Anatolia [Faccenna et al., 2006].
Although highly debated, activation of the main transform faults is assumed as
Middle Miocene for the NAFZ [e.g. Şengör et al., 2005] and latest Miocene for the
EAFZ [e.g. Robertson, 2000].
13
Introduction
32ºE
A
36ºE
Sinop
ISTANBUL
ZONE
Boyabat
40ºN
40ºN
Istanbul
zmir
40ºE
Kastamonu
e Suture
Intra-Pon t i d
SAKARYA
ZONE
Çankιrι
Ankara
Eskişehir
ir-Anka r a S
uture
İzm
e
Inne
r-Ta
ur
38ºN
Bi t l i s - Z
Ermenek
ARABIAN
PLATFORM
Adana
Mut
ture
Su
os
r
ag
36ºN
36ºN
Kayseri
Karaman
Antalya
38ºN
Aksaray
Konya
Aydιn
re
Erzincan
re
KIRŞEHIR
utu
MASSIF d S
i
Kιrşehir
MENDERES-TAURUS
BLOCK
ut u
Ankara-Erzin c an S
Mersin
34ºN
34ºN
40ºE
Km
0
32ºE
Faults
■
■
■ Normal faults
▲
▲▲
Thrust faults
Strike-slip faults
100
200
300
36ºE
E(CA)FZ
EKT
KMATZ
LFZ
Marine Miocene Basins
East Anatolian Fault Zone
North Anatolian Fault Zone
Tüz Gölu Fault Zone
EAFZ
NAFZ
TGF
32ºE
Ecemis (Central Anatolian)
Ekinveren Thrust
Kyrenia-Misis-Adrın Thrust
Levanine Fault Zone
36ºE
B
40ºE
Sinop
▲
▲
▲
▲
▲ ▲
40ºN
EKT
40ºN
Istanbul
PONTIDES
zmir
N AF
Z
Çankιrι
Ankara
AL
R
T
N
E
ANAC
TOLI
A
■
■
■
■
▲
▲
L
Z
Antalya
TAURIDES
Ermenek
▲
K
▲
▲
▲
▲
▲
▲ ▲
40ºE
Km
▲
34ºN
32ºE
▲
▲
▲
34ºN
▲
Adana
Mersin
M AT Z
▲
▲
Mut
L FZ
■
■
EA F
■
■
36ºN
Aksaray
36ºN
N
Konya
▲
■
■
■
■
■
Kayseri
■
■
■
■ ■ ■
■
■
38ºN
■■
■
■
■ ■
■■
■
■ ■ ■ ■
Aydιn
■ ■
■ ■ ■ ■
F
TG
■ ■
Z
EF
38ºN
■
Erzincan
Z)
(C
Kιrşehir
■
■
AF
Eskişehir
▲ ▲
0
100
200
300
36ºE
Figure 1.8: Map A depicts the main palæoterrains/microcontinents and suture zones of
Turkey. A slight modification on the location of the boundaries shown by Okay and Tüysüz
[1999] is based on the analysis of 1 arc DEM and LandSat 7 images set from NASA. Map
B shows the main regional faults of Turkey.
14
Chapter 1
The Eratosthenes Seamount must also be considered to complete the tectonic
picture of the east Mediterranean. This continental fragment drifted northward on
top of the Levantine oceanic (or thinned continental) crust [e.g. Rabinowitz and
Ryan, 1970; Woodside, 1977; Makris and Stobbe, 1984] and collided with the Cyprus
arc-trench system in Messinian times [e.g. Stephenson et al., 2004]. Southward
overthrusting of the Cyprus margin drove crustal flexure and tectonic subsidence
in the lower plate and rapid surface uplift of the Troodos Ophiolite on the upper
plate, and perhaps in southern Turkey, by Late Pliocene-Early Pleistocene times
[e.g. Robertson, 1998b; Schildgen et al., 2012a]. This collision slowed or even locked
subduction in southern Cyprus.
1.3
Structure of the Thesis
In this Thesis, a variety of approaches have been used, ranging from fieldwork and
finite element thermo-mechanical modeling to seismic interpretation, backstripped
subsidence curves, and kinematic and palinspastic restorations. A detail explanation
of the methods used is given in Chapter 2.
Chapter 3 aims at constraining the tectonic evolution of the interior of the CAP
before and during its uplift. In Chapter 3, seven depth-converted seismic reflection
profiles and the analysis of backstripped subsidence curves, isochore maps, and a
palinspastically restored cross section are used, and a new 3D tectonic model is
proposed for the Cenozoic evolution of the Tuz Gölü Basin and surroundings.
Chapter 4 deals with the Miocene evolution of the Manavgat, Ermenek-Mut,
and West Adana basins. Here, fieldwork, structural data and subsidence analysis
allows for the reconstruction of the present day architecture of the basins capping
the SCAP. These studies shed light on the mode of deformation and the type and
time of vertical motions in the margin.
In Chapter 5, three offshore depth-converted seismic reflection sections and onshore fieldwork constraints were used to unravel the evolution of the transitional
area between the Mut Basin and Cilicia Basin in its regional context. The seismic
data is linked to the data from the northern and southern onshore areas to analyze the vertical motions and kinematic history of the area, and the formation of
the southern margin of the Central Anatolian Plateau in relation to the Northeast
Mediterranean tectonics.
The newly acquired structural and basin analysis data is finally integrated with
previous studies and tested in coupled finite element thermo-mechanical models in
Chapter 6. The models successfully reproduce the vertical tectonic history, presentday geometries, and major structures seen in the area, thus providing a valid alternative to explain the SCAP tectonic evolution through time, while questioning
the detachment and slab break-off theories. The proposed mechanism relates the
evolution of the area and the Central Anatolian Plateau formation to the onset of
subduction in a position similar to present day, and the posterior growth of the
Anatolian upper plate and that of its associated forearc basin system.
A final overview of the work presented in this Thesis and its placement in a
broader scientific context is given in Chapter 7.
15
Introduction
Study area
7
as
E
ter
Chapter 3
ap
Ch
Turkey
tM
ed
i te r
ra n e a
n
Ch
a
pte
Syria
Chapter 5
r4
Lebanon
East
Mediterranean
Chapter 6
Cyprus
Figure 1.9: Map of the eastern Mediterranean and its onland areas, showing the areas
covered by each individual chapter of this Thesis. The base map used comes from the
morpho-bathymetric map of the Mediterranean [Loubrieu, B. and Mascle, J., 2008]