Download The Evaporites of the Upper Ordovician Strata

REPORT NO. 46
The Evaporites of the Upper
Ordovician Strata
in the
Northern Part of the Williston Basin
by
D. M. KENT
1960
DEPARTMENT OF MINERAL RESOURCES
Geological Sciences Branch
Sedimentary Geology Division
A summary of this report was read before a meeting of the Saskatchewan
Geological Society, Regina, Saskatchewan, September 29th, 1959.
ABSTRACT
As a result of epeirogenic movements of the basin and surrounding
metastable shelf areas, the Upper Ordovician sediments of the northern
part of the Williston Basin are composed of four depositional cycles, each
of which contains an evaporitic sequence. Each cycle consists of five
phases, each phase being represented by a specific lithology:
1. fossiliferous fragmental limestone
2. argillaceous dolomite
3. anhydrite
2. argillaceous dolomite
I. fossiliferous fragmental limestone.
The evaporites are considered to be primary and were laid down as intra..
basin deposits due to a restriction of circulation in the northern part of
the Williston Basin. A shoal region towards the open sea formed a physical
barrier to circulation, and a dynamic barrier developed between the
denser saline brine in the evaporating basin and the less dense, near
shore, waters provided restriction on the landward side.
The evaporitic basin reached its maximum areal extent when the
" A" Evaporite of the Herald Member was laid down. After that time,
the limits of the evaporite basins did not extend much beyond the Inter ..
national Boundary area of Saskatchewan and North Dakota.
Stratigraphic traps, consisting of a porous fades overlain by an
impervious layer such as the evaporite deposits, probably form the best
reservoirs for the accumulation of hydrocarbons'. Where the evaporites
overlie radial domes or pitching anticlines, and the facies is favourable,
oil may also be accumulated. Oil accumulations may be present along
tectonic hinge lines, to which the absence of Middle Devonian Prairie
Evaporites is thought also to be indirectly related.
TABLE OF CONTENTS
Page
ABSTRACT ..................... ..... .
LIST OF ILLUSTRATIONS
3
. ·························. 5
ACKNOWLEDGMENTS ..
7
INTRODUCTION ............ .
8
GENERAL STRATIGRAPHY
... 10
Origin of Stratigraphic Nomenclature........................................ ........... .... .10
Outcrop Nomenclature......................................................................................... .... 10
Subsurface Nomenclature and Correlation Criteria .........................10
Red River Formation ....................................................................................................... .12
Yeoman Member ............................................................................................................ 12
Herald Member........................ . ......... .... ... .............. ... ....................... .............. 13
Oolitic Limestones .................................................................... ...................... 15
Argillaceous Dolomites ...................................................................................... 15
Evaporites........................................................................................................ 17
Fossiliferous Fragmental Limestones .................................................. 18
Stony Mountain Formation.......................... ............................................................... 20
Stoughton Member .............................. .....................................................................20
Shale fades .. .................... ...................... .. ........................................................ 20
Carbonate facies .........................................................................................................20
Gunton Member .......................................................................................................... 21
Gunton Evaporite ........................................................................................21
Stonewall Formation....................................................................................................................22
Stonewall Evaporite .......................................................................................22
PETROLOGY OF THE ANHYDRITES AND EVAPORITIC DOLOMITES........................ 24
The Origin of the Anhydrites ............................................................................................ 24
Secondary Anhydrite....................................................................................................................26
Evaporitic Dolomites..................................................................................................................28
STRUCTURE .........................................................................................................................................................32
SEDIMENTATION .............................................................................................................................................35
Depositional Environment......................................................................................................35
Evaporitic Cycles..............................................................................................................................38
PETROLEUM PROSPECTS ........................................................................................................................... 39
BIBLIOGRAPHY ................................................................................................................................................ 41
APPENDIX .................. .......................................................................................................................................... 43
LIST OF ILLUSTRATIONS
Tables
Table 1
Table 2
Figures
Figure I
Figure 2
Page
Upper Ordovician Nomencl ature ....
......... 12
Shows relationship between phases of the evaporitic cycles,
the lithologies a nd tectonic movements .. .
. ... 38
Key Map ..
8
Characteristic Section of Upper Ordovician Strata in the
Southeast Corner of Saskatchewan. Gamma ray and neutron
curves from logs of the Imperial Silverton No. 3, 18 well
(Lsd 3-18,3,32wl, Saskatchewan ). Lithology from cutting
samples and cored sections of several wells in the southeast
portion of the area of study .
14
Figure 3
Characteristic Section of Upper Ordovician Strata of the
International Boundary Area, Saskatch ewan. Gamma ray
and Neutron curves from logs of the Imperial Herald No.
1,31 well (Lsd 1,3 I, 1-20w2, Saskatchewan ). Lithology from
several cored sections in the International Boundary Area
of southeastern Saskatchewan ... .
.... ...... ............ ......16
Figure 4
East, West Stratigraphic Cross Section (Section A-A' ) of
Upper Ordovicia n Strata from the British American Baciu
No. 15-36 well (Lsd 15,36,6-9w3 ) to the Socony Western
Prairie Imperial Carievale No. I well (Lsd 16-4-3,32wl ).
( In Pocket )
Figure 5
North-South Stratigraphic Cross Section (Section B-B ' ) of
Upper Ordovician Strata from the Tidewater Bladworth
Crown No. 1 well (Lsd 16,36,17,29w2 ) to the Imperia l
. . (In Pock et )
Herald No. 1-31 well (Lsd 1-3 1-1-20w2 )
Figure 6
North-South Stratigraphic Cross Section (Section C-C 1 ) of
Upper Ordovician Strata from the Canadian Gulf Margo
No. 8, 11 well (Lsd 8, l 1-33,9w2 ) to the Imperial Silverton
No.3,18well (Lsd3, 18,3,32wl )...... .... .....
( In Pocket )
Figure 7
Projected Panel Diagram of Herald Member ....... (In Pocket )
Figure 8
Structure Contour Map on Top of the Yeoman M ember .... 33
Figure 9
Tectonic Map of the Prairie Provinces and Northwestern
United States illustrating the positive and negative ele,
ments (After Borden, 1956 ) and the maximum area covered
by evaporite deposits during Red River times.....
........... .34
Figure IO Generalized section through the region of study illustrating
the sedimentary environments present during the time when
the "A" Evaporite of the Herald Member was deposited ......... 36
Figure 11 Tectonic Map of the Prairie Provinces and Northwestern
United States illustrating the positive and negative ele,
ments (After Borden, 1956 ) and the distribution of the
evaporitic basins during Gunton,Stonewall times...
.........37
LIST OF ILLUSTRATIONS- (Continued )
Plates
Page
Plate I
....23
Plate 2
.... 25
Plate 3
...... 27
Plate 4 ............. .
......29
Plate 5............. . .
... JO
ACKNOWLEDGMENTS
The writer wishes to acknowledge the generous assistance
and constructive criticisms rendered him by his colleague~·
in the Department of Mineral Resources and theco,operation
of the staff of the Department of Geology, University of
Saskatchewan, who permitted the author the use of their
special equipment to take the photomicrographs used in the
text.
INTRODUCTION
The increased interest in recent years in the possible oil producing
horizons of the Lower Palaeozoic strata of southern Saskatchewan has
made a better understanding of the stratigraphy and sedimentation of
these rocks desirable. The presence of evaporitic deposits in the Upper
Ordovician rocks gives rise to the possibility of reservoir conditions
similar to those found in the Mississippian strata of southeastern Sask,
atchewan. In the latter both primary and secondary anhydrites form
excellent reservoir cap rocks. The purpose of this paper is to study the
stratigraphy of the evaporites of the Upper ·Ordovician, their areal dis,
tribution and their relationship to possible oil reservoirs.
The area covered by this report consists of that part of southern
Saskatchewan within the - Williston Basin which is underla\n by the
KEY MAP
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Repo,t Ano
SCALE IN MILES
Nole:- Willlston Basin boundary is ofter
Porter ond Fuller (1959)
Figure 1- Map of Williston Basin region showing area of study.
8
evaporites of Upper Ordovician age (Figure l ). It is bounded on the
east by the Manitoba / Saskatchewan Interprovincial boundary, on the
west by the 108th meridian of longitude, on the south by the International
boundary and on the north by the 52nd meridian of latitude.
The rocks pertinent to this study occupy approximately the middle
portion of a 1400 foot succession of Silurian and Upper Ordovician car;
bonates and evaporites. The sequence studied attains a maximum thick;
ness of 335 feet within the report area and includes only those rocks of
Upper Ordovician age that contain evaporitic deposits.
The report area includes about 90 deep wells which have penetrated
Ordovician or deeper strata. However, only 14 of these wells were cored
in Upper Ordovician beds. Sample cuttings and mechanical logs are
available for all wells. All the cored intervals pertinent to this study were
examined together with samples from another 50 wells. Sixty thin sec;
tions of the anhydrite and associated rocks were made and were found to
be invaluable aids in investigation of the sedimentation and diagenesis
of the rocks.
9
GENERAL STRATIGRAPHY
ORIGIN OF STRATIGRAPHIC NOMENCLATURE
Outcrop Nomenclature
The Ordovician System in Western Canada was first described by
Dowling (1900) from the outcrops of Manitoba. He subdivided these
rocks into five units, in descending order:
Stony Mountain Formation
Upper Mottled limestone
Cathead limestone
Lower Mottled limestone
Winnipeg sandstone.
Dowling's classification was used for many years, but in 1928 and
again in 1929 Foerste, who did considerable work on the fauna of the
Ordovician strata of the Arctic and Subarctic regions, suggested that the
fauna of Dowling's middle three units very closely resembled the Galena
phase of the Trenton limestone, as exposed in the Upper Mississippi
Valley. For this reason he proposed the collective name, Red River
Formation, to include all three units and added the name Selkirk limestone for the Upper Mottled limestone and Doghead limestone for the
Lower Mottled limestone. In 1943 Okulitch worked on the Stony Mountain Formation in the outcrops of Manitoba. He set up a four-fold classification of that formation, based largely-on faunal evidence. His four
units were, from top to bottom:
Birse Member
Gunton Member
Penitentiary Member
Stony Mountain Shale Member.
Baillie produced a detailed study of the Manitoba outcrop rocks in 1952.
He relied on Foerste's classification of the carbonate rocks immediately
overlying the Winnipeg sandstone, but he found that a three-fold classi,
fication of the Stony Mountain Formation was more workable, since he
was unable to distinguish Okulitch's Birse Member from the Gunton
Member and included the former in the latter.
Until 1953 the Stonewall Formation (which overlies the Stony
Mountain Formation ) was generally thought to be Silurian in age, but
Stearn (1953 ) in a paper presented to the Geological Society of America
in Toronto, Ontario, suggested that the fauna of this formation was of
Upper Ordovician age. Later, in 1956, he published further faunal evi,
dence supporting his conclusions.
Subsurface Nomenclature and Correlation Criteria
The first subsurface study of the Ordovician rocks of the Williston
Basin and adjacent areas was carried out by Rader (1952) in the central
portion of the Williston Basin. He made little attempt at correlation
with the strata of the Manitoba outcrops, and based his subdivisions
on lithologic differences and mechanical log characteristics. This resulted
in the inclusion of the Gunton Member of the Stony Mountain Formation
in the overlying Interlake Group and the insertion of the Penitentiary
Member of the same formation in the Stony Mountain Shale Member.
Rader also subdivided the Red River into two units, a lower normal
10
marine unit and an upper evaporitic unit. The lower unit was considered
equivalent to the combined Doghead and Cathead limestones, while the
upper one was thought to be equivalent to the Selkirk limestones. In
1953 Rader carried the same subdivisions of the Upper Ordovician rocks
into northeastern Montana. Other subsurface studies were performed by
Ower ( 1953 ) in southwestern Manitoba, Stanton ( 1953 ) in western
Saskatchewan, and Ross ( 1957 ) in eastern Montana. In all cases a three,
fold classification of the Ordovician rocks was followed:
Stony Mountain Formation
Red River Formation
Winnipeg Formation.
Ower attempted to correlate the subsurface with the surface exposures.
He found that the Red River of southwestern Manitoba could not be
subdivided and that the Penitentiary Member could not be distinguished
in the subsurface. Stanton found a parallel between the Ordovician sediments of his area and those studied by Rader. He, too, subdivided the
Red River into two units with lithologic characteristics similar to the
units proposed by Rader. Both Stanton and Ower included the lower part
of the Stonewall Formation, as now picked, in the Stony Mountain
Formation. Ross (1957 ) also assigned the Stonewall Formation to the
Stony Mountain Formation and placed all the sediments from the top
of his Stony Mountain Formation to the base of the Red River Formation
in the Big Horn Group.
In the spring of 1958 Porter and Fuller presented a paper entitled
"Lower Palaeozoic Rocks of the Northern Williston Basin and Adjacent
Areas" to the Second International Williston Basin Symposium in Regina,
Saskatchewan. This paper was later published in the January 1959 issue
of the bulletin of the American Association of Petroleum Geologists and
also in the Symposium Volume. It was the first published, comprehensive
subsurface study of the pre-Devonian strata in Saskatchewan. In this
paper Porter and Fuller found a close correspondence between widespread
non-sequential arenaceous and argillaceous beds observed in the sub,
surface and beds of similar lithologies that mark the formation boundaries
in the outcrops. They were of the opinion that these non-sequential beds
were the result of temporary interruptions in carbonate deposition of
great areal extent, and that they represented para-time markers. Porter
and Fuller initiated a four-fold classification of the Ordovician rocks,
(Table 1) as they included the Stonewall Formation in the strata of this
age, following the suggestion of Stearn (1953, 1956 ). The Penitentiary
Member was again found to be indistinguishable in the subsurface and
was included in the Stony Mountain Shale, while the Red River was
subdivided into a lower and an upper unit similar to those proposed by
Rader (1952, 1953) and Stanton (1953 ).
Following the work of Porter and Fuller the Saskatchewan Geological
Society set up a Lower Palaeozoic Names and Correlation Committee
with the object of standardizing the nomenclature, choosing type sections
and publishing these together with stratigraphic cross sections illustrating
correlations of the Lower Palaeozoic strata. The committee retained the
Note: Since this manuscript was completed, a comprehensive paper by J. M. Andrichuk•
entitled "Ordovician and Silurian Stratigraphy and Sedimentation in Southern
Manitoba, Canada," was published (Bull. Amer. Assoc. Petrol. Geo!., Vol. 43,
No. 10, pp. 2333-2398) . The conclusions reached by the present author are in
general agreement with those of Andrichuk.
11
TABLE I
NOMENCLATURE OF PART OF THE UPPER ORDOVICIAN
OF
SOUTHERN SASKATCHEWAN
PORTER
SASK. GEOLOGICAL SOCIETY
STONEWALL
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REPORT
STONEWALL FORMATION
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FULLER
STONEWALL FORMATION
BEDS
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AND
(1959)
(1958)
V)
Stony Mountoln Shale
ond
Lateral Equivolents
Upper Red River
Table 1-
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Yeoman Member
Upper Ordovician Nomenclature.
unit boundaries established by Porter and Fuller, but appl ied the names
"Yeoman" and "Herald" to their Lower and Upper Red River units.
They also gave the name Stoughton Beds to the Stony Mountain Shale
and equivalents (Table I ). Other changes included the application of
names to Porter and Fuller's marker defined units in the Interlake Group
and the introduction of the term "Beds" for these . para-time marker
defined units.
The term "Beds" was previously used to describe para-time marker
defined units in the Mississippian System in southeastern Saskatchewan.
In these strata there is a marked discordance between the lithologic
units (magnafacies of Caster, 1934 ) and the stratigraphic units as defined
by para-time marker beds. The term "Beds" may also be applicable
to the stratigraphic units of the Lower Palaeozoic rocks, but the discordance between magnafacies and marker defined units is more subtle
and within certain ?teas, the markers also separate different lithologies.
In this case, the terms Formation and Member could also be applied to
the stratigraphic units. In the area covered by this report the markers
separate different lithologies, also some of the units within the area
of study may be subdivided into smaller local units. Since a hierarchy
of stratigraphic units is not provided for by the use of the term "Beds,"
the author concluded that Formation and Member were more applicable
in the report area, therefore, the terminology as presented in Table 1 is
proposed for these strata.
RED RIVER FORMATION
Within the area of this report the Red River Formation is divisible
on lithological grounds into two major units, the Yeoman Member and
the Herald Member. The lithologies of these two members reflect dif,
ferent environments of deposition, and therefore the divisions may also
be considered to be based on depositional environments.
Yeoman Member
The Yeoman Member is the lower division of the Red River Forma,
12
lion. The rocks compnsmg this unit underlie the entire area of study
and range from about 350 feet thick in the southeast part of the area
to about 140 feet at the northern and western limits of the map area.
The rocks of the Yeoman Member in the region of this report consist
mostly of dolomitized, mottled, fossiliferous,fragmental limestones. The
colour of the mottling ranges from tan to light brown. The fossil fragments
are often in a poor state of preservation due to the effects of dolomitiza,
rion, while original textures have been affected also by this process. The
mottling is a characteristic feature of this unit and is in the form of
irregularly branching structures of a dense, tan, microcrystalline•,
dolomite. The interstices in these structures are occupied by light brown
carbonate with a sucrosic, microcrystalline texture and intergranular
porosity. Towards the northern and western limits of the report area,
the rocks of the Yeoman Member become increasingly dolomitic and
consist of tan, microcrystalline, very dolomitic limestone, or dolomite,
with some poorly preserved fossils.
The lower boundary of this member (the base of the Red River
Formation ) is represented by a marked change to carbonate rocks from
the elastic rocks of the underlying Winnipeg Formation. The upper
contact of this member has been established by the author at the base of
an argillaceous dolomite horizon which underlies the lower evaporite of
the overlying Herald Member. In the southeastern portion of the report
area, the argillaceous dolomite is not present and the upper contact of
the Yeoman Member is then based on a lithological change from fossili,
ferous fragmental limestones to oolitic limestones. The choice of the upper
contact is different from that of Porter and Fuller (1959 ) and the Sask,
atchewan Geological Society (1958 ) who both chose the top of the
argillaceous dolomites. The alteration was made because the writer was
of the opinion that the argillaceous dolomites in question belong more
properly with the overlying evaporite sequence than with the underlying
dolomitized fossiliferous limestones. They appear to have been laid down
under conditions similar to the "earthy textured dolomites" of Edie
(1958), which underlie the anhydrites in the Mississippian rocks of south,
east Saskatchewan, and which he considers to be part of the deposits of a
lagoonal environment where the Mississippian anhydrites were precip,
itated. The Saskatchewan Geological Society ( 1958) established Shell
Yeoman No. 6-32 (Lsd 6, Sec. 32, Twp. 8, Rge. 16, w2M ) as the type
well of the Yeoman Beds. The top of the Yeoman Member, in this well,
as picked by the writer is at 8038 feet below the kelly bushing (elevation
1926 feet ).
Herald Member
The Herald Member conformably overlies the Yeoman Member.
It has an overall thickness of 120 feet in the southeastern portion of the
area thinning to 50 feet along the western edge, to 35 feet in the northwest
and to 30 feet in the northeast parts of the region of study. The Herald
Member comprises several smaller lithologic units including oolitic
limestones, argillaceous dolomites, evaporites and dolomitized fossilifer,
ous fragmental limestones (FigurPS 2 and 3 ).
I In the sense of Williams, Turner and Gilbert (1955, pp.276-277) . Their classification
of non-elastic textures and grain sizes is as follows:
Crystalline Granular-Coarse greater than 5 mm.
- Medium 1-5 mm.
- Fine
less than 1 mm.
Microcrystalline
0.01 mm.,0.2 mm.
Cryptocrystalline
less than O.IJI mm.
13
IMPERIAL SILVERTON
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CHARAC TERISTIC SECTION
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FIG. 2
Flcure 2-Characterlstlo Section of Upper Ordovician Strata In the Southeaat
Corner of Saskatch ewan. Gamma ray and Neutron curves from lop of the
Imperial Silverton No. 8·18 well (Lsd 3-18-3-82w1, Saskatchewan) . Litholocy from cuttlnc samples and cored sections of several wells In the southeast portion of the area of study.
14
Oolitic Limestones- The oolitic limestone deposits of the Herald
Member have a north-northeasterly trend along the eastern edge of the
area of study. They underlie a region along the Manitoba / Saskatchewan
Interprovincial Boundary limited by Range 2 west of the second meridian
on the west, and probably extend eastward into Manitoba and southward
across the International Boundary into North Dakota. (Figure 8 and 9 ).
The thickest section of oolitic limestones was observed in the sample
cuttings of the Imperial Silverton No. 3, 18 well (Lsd 3, Sec. 18, Twp.
3, Rge. 32, wlM ) (Fig. 2 ). Sixty-nine feet of oolitic limestones were
encountered between the intervals 7531 feet and 7600 feet below kelly
bushing. Northward and westward from this well the oolitic limestones
gradually thin and die out (Figure 4 and 6 ).
Micro-oolites, oolites and pseudo-oolites (No. 1 Plate 1) are the major
constituents of these rocks along with some crinoid ossicles and brachio,
pod remains. The oolities and pseudo-oolites range from 0.08 mm. to
0.7 mm. long, along their major axis; the average is about 0.25 mm. The
matrix of the rock consists of cryptocrystalline' dolomite with irregularly
shaped grains (No. 2 Plate 1). Occasionally, however, the space between
the oolites is infilled by cryptocrystalline anhydrite in the form of ir,
regularly shaped crystals (No. 1 Plate 1). Pieces of dolomitic material,
which appear to be corroded remnants of the original matrix, are often
isolated in the anhydrite. Where dolomite infills the interstices between
the oolites elongated euhedral crystals of anhydrite have been observed
cutting through the oolites (No. 2 Plate 1). The pseudo,oolites have no
concentric interior structure, they are often tightly packed together, the
convex side of one fitting into a concave depression In another (No. I
Plate 5 ). Some of the ovoid or sub-ovoid forms which lack concentric
structure may have been oolites in which dolomitization has reached a
more advanced state and destroyed all evidence of concentric layering.
The oolitic limestones of the Herald Member conformably overlie
the dolomitic, mottled limestones of the Yeoman Member, but where the
oolitic limestones pass laterally into evaporites and fossiliferous fragmental
limestones, they usually overlie argillaceous dolomites. (Figures 4, 6 and
7 ). Over the rest of the map area, these dolomites lie between the lowest
anhydrite bed and the Yeoman Member. Along the eastern edge of the
map area the oolitic limestone interfingers with anhydrites. Where the
oolitic limestones overlie the mottled limestones of the Yeoman Member,
the contact between the two members is not obvious on the mechanical
logs and was based on visual examination of cores and samples. A similar
situation arises with regard to the upper contact between the oolitic
limestones and the overlying fossiliferous fragmental limestones (Figure
2).
Argillaceous Dolomites- The argillaceous dolomites of the Herald
Member underlie most of the map area and extend beyond the limits of
this region in all directions. They attain their greatest thickness within
the report area, averaging about 20 feet in the International Border area
and become thinner towards the north, west and east. Towards the
southeast corner of the region of study and along the southern part of the
extreme eastern edge to about township 21 (Figure 8 ), the argillaceous
dolomites thin to zero against the oolitic limestones of the Herald Mem,
ber. According to Porter and Fuller (1959 ) the argillaceous dolomites
also have been observed in southern Manitoba.
These rocks consist of a "chalky" argillaceous dolomite, buff in colour
with an earthy, cryptocrystalline texture and grain size. Towards the
north they appear more crystalline and less argillaceous. Poorly preserved
fossil remains occasionally occur. The most easily identified of these
1
See footnote, p. 13.
15
z
IMPERIAL HERALD No, I-31
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CHARACT ERISTIC SECTION
OF
UPPER ORDOVICIAN STRATA OF THE INTERNATIONAL BOUNDARY AREA
SASKATCHEWAN
SHOWING PHASES OF EVAPORITE CYCLES
(AFTER PORTER ANO FULLER, 19!59)
LEGEf'fO
..
,...._,.,..,.._.
Figure 3- Characterlstlc Section of Upper Ordovician Strata of the Int!l,rna•
tlonal Boundary Area, Saskatchewan. GaD1JDa ray and Neutron cur ves
from logs of the Imperial Herald No. 1-31 well (Lsd 1-31-1-20w2, Saskatche·
wan) . Lithology from several cored sections In the International Boundary
Area of southeastern Saskatchewan.
16
remains were scolecodonts, ostracods and crinoid stems taken from the
cored interval 7050.2 feet to 7054.5 feet below kelly bushing, in the
Tidewater Panamerican White Bear Crown No. 5-15 well (Lsd 5, Sec.
15, Twp. IO, Rge. 2, w2M ). Dark brown euhedral crystals of anhydrite
are often disseminated through the rock, as radiating clusters or single
crystals.
The argillaceous dolomites are represented on radiation logs by an
increase in gamma radiation counts and a corresponding increase in
induced radiation counts as compared to the underlying and overlying
strata (Figure 3 ), and the upper and lower boundaries were established
by the author at the deflection points on the gamma ray well logs. The
lower inflection on the neutron curve will also be found useful in establishing the base of the argillaceous dolomite, but the upper inflection
cannot be used as an accurate means of limiting the upper boundary.
These rocks are underlain by the mottled dolomitic limestones of the
Yeoman Member .and overlain by the lowest evaporite deposits of the
Herald Member (Figures 5 and 7 ).
Evaporites- The Herald Member contains two evaporite horizons,
termed the "A" and "B" Evaporites by the author. The "A" Evaporite
is the lowest, stratigraphically, and underlies most of the map area
(Figure 8 l. The unit for the most part is composed of the following
lithologies in ascending order:
5 feet of evaporitic, argillaceous dolomite,
5 feet of anhydrite,
3 feet of evaporitic argillaceous dolomite,
12 feet of anhydrite.
The maximum overall thickness of the unit ranges from 23 feet to 25 feet.
Towards each limit of the "A" Evaporite (Figure 8 ) the two anhydrites
merge into a single bed about 15 feet thick (Figure 7 ) ; this is usually
overlain by a thin evaporitic, argillaceous dolomite bed.
The second evaporitic layer or "B" Evaporite underlies an area along
the International Boundary extending from range 2 to range 24 west
of the second meridian, and from township IO southward across the
Saskatchewan-North Dakota border. The "B" Evaporite includes an
anhydrite bed about IO feet thick between two thin (about 5 feet ) eva,
poritic, argillaceous dolomites. It attains a maximum thickness of 20 feet
in the south-central portion of the map area and thins to a depositional
thickness of about 5 feet towards its limits (Figure 4 and 5 ).
These evaporitic units of the Herald Member are composed of massive
or poorly bedded anhydrite and thin evaporitic dolomites. 1 The anhydrite
is dark brown to gray (occasionally pink) in color with a cryptocrystalline
to microcrystalline, sugary texture. The middle portion of the anhydrite
beds is usually relatively free of dolomite and is composed of irregularly~
shaped grains with interlocking boundaries. The grain size ranges from
0.01 mm. to 0.05 mm. More elongated grains have also been observed;
they are usually arranged in imperfectly radiating clusters or groups
of subparallel grains. The subparallel orientation of the grains is not
1
Edie (1956) describes evaporitic dolomites as having the following characteristics:
"1.- Dense (cryptocrystalline texture)
2.- Non-porous
3.- Sharp-bedding laminae ("varved")
4.- Interbedded with and intermixed with anhydrite
5.- Nonfossiliferous
6.- Non-cherty
7.- Salt-casts
8. - Argillaceous
9.-Quartz silt absent or negligible."
17
necessarily in the same direction from group to group (No. I Plate 2 ).
Any dolomite that may be present in the middle portion of the anhy;
drite beds is in the form of veins. In the vicinity of the dolomite veins
the anhydrite is in the form of thin, elongated grains with lengths from
0.05 mm. to 0.3 mm. They are aligned parallel or subparallel to one
another, with microfolds and crenulations occurring in the zone immed;
iately surrounding the vein;like dolomite (No. 2 Plate 2 ) .
The anhydritic layers are gradational with dolomites, and as the
contact between the two lithologies is approached lenses and interbeds
of dolomite and anhydrite are common occurrences. The anhydrite grains
near the contacts take on an irregularly-shaped ha bit or are in the form
of rounded grains less than 0.01 mm. in diameter. Layers and clusters
of rounded, cryptocrystalline dolomite are present in the anhydrite
(No. 1 and No. 2 Plate 3 ) a nd suggest lenses or stringers when observed
in thin section. Aggregates of irregularly-shaped anhydrite grains enclosed
in thin layers of argillaceous, cryptocrystalline dolomite have also been
observed (No. 1 Plate 4 ). Thin elongated crystals of anhydrite are dis,
persed through the dolomite s_urrounding the aggregates. Carbonaceous
material is commonly present in thin beds in the anhydrite and is often
intermixed with the lenses and interbeds of anhydrite and dolomite near
the contact of the two rock types.
The evaporitic dolomites which have been included in the evaporitic
units are found at the upper boundary of the "A" Evaporite and the top
and bottom boundary of the " B" Evaporite. These dolomites are usually
thinly bedded (varve,like ), lithographic and slightly argillaceous.
Occasionally interstitial anhydrite grains are present. The dolomites do
not usually exceed 5 feet in thickness, but near the northern and western
limits of the evaporitic accumulations, the anhydrites very often pass
laterally into thicker beds of evaporitic dolomite. The top few inches of
the uppermost dolomite in each evaporitic unit is frequently composed
of a breccia of dolomite pebbles and sand grains with an argillaceous
matrix.
The "A" Evaporite is conformably overlain by a sparsely fossiliferous
to coquina;like dolomitized limestone while the underlying rocks are
argillaceous dolomites. The contact between the "A" Evaporite and
overlying rocks is usually relatively sharp and is represented by a breccia
or slump zone in the thin dolomite beds. Along the eastern edge of the
map area the " A" Evaporite interfingers with the oolitic limestones
(Figure 6 ) but in the western a nd northern portions of the area of study
it passes laterally into thinly bedded, lithographic dolomites and these
in turn into microcrystalline, dense dolomites.
The "B" Evaporite divides the fossiliferous fragmental limestone into
upper and lower units. On the northern and eastern limits this evaporite
passes laterally into the fossiliferous fragmental limestones, but towards
the west it thins out against the top of the Herald Member.
Fossiliferous Fragmental Limestones- The fossiliferous fragmental
limestones lie between the evaporitic units and between the "B" £vapor;
ite and. the top of the Herald Member, and are widespread over the area
of study. In the south central portion of the map area these rocks are
subdivided into an upper and lower unit by the "B" Evaporite (Figure 3 ).
The areal extent of both the upper and lower division is similar to the
area underlain by the " B" Evaporite (Figure 8 ). The lower fossiliferous
fragmental limestone attains a maximum thickness of 40 feet in the
Imperial Halkett No. 15;7 well (Lsd 15, Sec. 7, Twp. 3, Rge. 8, w2M),
but thins to about 20 feet towards the north, east and west from this
well. The upper fossiliferous fragmental limestone is more consistent and
18
has an average thickness of about 15 feet. Beyond the limits of the "B"
Evaporite (Figure 8 ) the fossiliferous fragmental limestone is a single
unit. It has a wide and varying range of thickness, being about 25 feet
thick along the western edge, and thinning to about IO feet in the northwest corner of the area studied. Along the eastern side of the map area
outside the area underlain by the "B" Evaporite, the fossiliferous fragmental limestones (Figure 6 ) form a single unit ranging in thickness
from IO feet in the north to 30 feet in the southeast corner of the map
area.
The fossiliferous fragmental limestones are buff to tan in color with a
microcrystalline texture. Dolomitization is evident in these rocks and
increases in intensity from the center of the basin (Figure 9 ) towards the
peripheries. Beyond the limits of the "A" Evaporite (Figure 8 ) the fossiliferous fragmental limestones pass laterally into dense microcrystalline
dolomites. In the southeast portion of the area of study the fossil fragments are often so tightly packed as to form a coquina with little matrix
present. For the most part the rocks of the unit consist of fossil remains
in a partially or highly dolomitized, microcrystalline, sucrosic matrix.
The fossils present include brachiopods, cephalopods, bryozoa, corals
and crinoid ossicles and plates. A considerable amount of anhydrite is
dispersed throughout the rock, particularly in those portions of the
fossiliferous fragmental limestones which underlie the evaporitic deposits.
The anhydrite is present in four forms :
I. Pseudomorphs of fossil fragments, particularly crinoid ossicles and
brachiopod remains.
2. Radially arranged clusters or isolated subhedral to euhedral
porphyrocrysts.
3. Blebs of massive anhydrite.
4. Veins of anhydrite.
The porphyrocrysts and blebs of anhydrite are the most common forms
of anhydrite in the fossiliferous fragmental limestones. The porphyrocrysts usually range in length from 0.2 mm. to 1 mm., occasionally longer.
They are tabular, rectangular crystals, dark brown in color. The blebs,
ranging from 7 mm. to 90 mm. in diameter, often appear to represent
infilled vugs and passages in the rock. They consist of white, translucent
cryptocrystalline to microcrystalline anhydrite. In thin section the grains
are irregular with interlocking margins (No. 2 Plate 5 ) and are 0.001 mm.
to 0.1 mm. in size. Veins or veinlets of dark brown, microcrystalline anhydrite have been observed cutting both previously crystallized anhydrite
and the enclosing rock.
Gypsum and chert also occur in small quantities in the fossiliferous
fragmental limestones. The gypsum is usually in the form of selenite
crystals, radially arranged satin-spar, or veins. It was also observed in
the form of microcrystalline grains infilling the ta bulae of a favositid
coral.
The top of the Herald Member (the top of the Red River Formation )
is marked in two distinct ways in different parts of the area. In the southeastern portion of the area of study, where the shale facies of the Stony
Mountain Formation is fully developed, the base of this shale facies
marks the top of the Red River Formation. This contact has been observed in the Imperial Arm River Annandale No. 6-23 well (Lsd 6, Sec.
23, Twp. 8, Rge. 32, wlM) as a sharp Iithologic break. At the contact the
Red River Formation consists of an extremely dense, lithographic dolomite with disseminated and veined pyrite; some pyrite crystals are also
present in the small vugs in the rock. Conical shaped tubes extend down
19
into the dolomite from the bedding plane between the dolomite and over,
lying shale. The tubes are infilled with calcareous material and appear
to be worm or pelecypod borings. From its appearance, the contact
between the two formations probably represents a short period of nondeposition.
The shale facies of the Stony Mountain Formation thins rapidly in a
northwesterly direction and the top of the Red River Formation is then
marked by a thin bed of argillaceous dolomite which appears at the top
of the fossiliferous fragmental limestone, and shows increase in gamma
radiation on the radioactivity well logs (Figure 3 ). This marker becomes
less conspicuous towards the western and northern edges of the map
area until it is almost impossible to distinguish between the underlying
and overlying rocks.
STONY MOUNTAIN FORMATION
The Stony Mountain Formation overlies the Red River Formation
and appears to be conformable with it but for a break in sedimentation,
which seems to have occurred especially in the eastern part of the studied
area. This formation is widespread over the entire report area, but toward
the northern and western edges of this region, it becomes less distinctive
and more difficult to distinguish from the underlying and overlying strata.
The Stony Mountain Formation has an average thickness of about 110
feet, varying but little over the whole area. It has been subdivided into
two members, the Stoughton Member and the Gunton Member.
Stoughton Member
The Stoughton Member comprises the lower rocks of the Stony
Mountain Formation. The name Stoughton Beds was -applied to these
strata by the Lower Palaeozoic Names and Correla tion Committee of the
Saskatchewan Geological Society (1958 ) (Table 1), while the term
Stoughton Member was introduced by the present author for the same
sequence of rocks. The Stoughton Member occurs only in the south,
eastern part of the map area. It has a maximum thickness of 70 feet in
the Socony Western Prairie Imperial Carievale No. 16-4 well (Lsd 16,
Sec. 4, Twp. 3, Rge. 32, wlM ) and thins to zero feet in a westerly and
northerly direction from that well. This member may be subdivided into
two smaller units, a calcareous shale facies and a carbonate facies (Fig,
ures 2 and 3 ).
Shale f acies- The shale fades underlies the region southeast of an
irregular line (hereinafter referred to for simplicity as the "shale line" )
running diagonally across the southeast corner of the map (Figure 8 )
from township 1, range 24, west of the second meridian to township 34,
range 30, west of the first meridian. The shale fades also reaches its
maximum thickness of about 70 feet in the Socony Western Prairie Im,
perial Carievale No. 16-4 well (Lsd 16, Sec. 4, Twp. 3, Rge. 32, wlM )
but it thins more rapidly than the entire Stoughton Member and is about
15 feet thick at the "shale line" where it passes laterally into the car,
bonate fades (Figures 4, 5 and 6 ).
The.shale fades consists of interbedded dark grey, highly calcareous,
fossiliferous shales and an extremely argillaceous, fossiliferous limestone.
Both lithologies are so closely associated that one can only be differen,
tiated from the other with extreme difficulty.
Carbonate jacies- As the shale fades thins towards the north and
west from the southeast corner of the map area an increasing thickness
of limestones makes up that part of the member between the base of ths
shale fades and the top of the Red River Formation. These carbonates
20
thicken from about 5 feet in the southeast (Figure 4 a nd 6 ) to about
35 feet on the north and west sides of the "shale line." However, beyond
this line they become less limey and more dolomitic until they can not
be distinguished from the overlying or underlying strata.
The carbonate facies is made up of a dark brown, fossiliferous frag;
mental, occasionally slightly argillaceous limestone. It has a crystallin.:>
granular texture (medium to fine ) and is often so highly fossiliferous as
to warrant the term coquina. The fossils present are mostly brachiopods
and corals with some crinoid ossicles and bryozoa. Thin, gray, calcareous
shale streaks are sometimes present. The brown coloration of this hori zon
is distinctive and is easily distinguished in sample cuttings.
The lower contact of the Stoughton Member is represented by different markers from east to west. In the southeast, where the shale facies
attains its maximum thickness, the base of the shale facies and the
contact of the Stoughton Member with the Red River Formation are
coincident. This is represented by a sharp lithological break previously
described. As the shale thins northward and westward the contact
between the Stoughton Member and Red River Formation is represented
by the top of an argillaceous dolomite horizon. The upper contact between
the Stoughton Member and the overlying Gunton M ember is dependent
on the top of the shale facies as far as the "shale line." On the north
and western side of this line the top is placed at the top of an argillaceous
dolomite marker which eventually thins over a very short distance, when
the Stoughton and Gunton Members coalesce into one unit.
Gunton Member
The Gunton Member conformably overlies the Stoughton Member.
In the northern and western parts of the map area where these units
can no longer be distinguished from one another, they form one single
unit: the Stony Mountain Formation. The Gunton Member thickens
slightly from about 55 feet in the southeast corner to about 75 feet where
it coalesces with the Stoughton Member (Figures 4, 5 and 6 ).
The Gunton Member comprises mostly buff and tan mottled, nodular,
slightly argillaceous, fossiliferous, dolomitic limestones. The buff areas
are of a soft, sucrosic (microcrystalline ) and porous lithology, while
the tan areas are hard, dense and cryptocrystalline to microcrystalline.
Some thin dark grey, dolomitic shale beds are present as stringers in the
rocks, along with black carbonaceous material which infills the internodular regions.
Gunton Evaporite- The Gunto11 Evaporite occurs near the top of the
Gun ton Member (Figure 3 ). It occupies an area almost coincident with
that underlain by the "B" Evaporite of the Red River Formation (Figure
8), but it extends into Manitoba as an east-northeastward trending arm
underlying the region between Townships 13 to 21 along the ManitobaSaskatchewan Interprovincial Boundary (Figure 8). The evaporitic unit
has an average thickness of about 5 feet. At its limits it passes laterally
into the dolomitic limestones which comprise the rest of the c ~mton
Member.
Dark brown, microcrystalline, sucrosic, dense anhydrite containing
stringers and laminations of dark brown, lithographic, dense dolomite
make up most of the evaporite sequence. A bed of evaporitic dolomite
(see footnote p. 17 ) about 21 feet thick which underlies the anhydrite
has also been included in the evaporitic sequence.
The Gunton Evaporite is overlain by a bed of elastic material which
marks the top of the Gunton Member and the Stony Mountain Forma;
tion (Figures 2 and 3 ). This bed is marked by a distinct increase in gamma
21
radiation counts and can be traced over the entire report area. It is one
of the most consistent marker horizons in the Lower Palaeozoic strata
and can be traced into the outcrops in Manitoba. This marker horizon
thickens from about 5 feet in the west and north to 10 feet in the southeast
corner of the area of study. (Figures 4, 5 and 6 ). In the north and west
of the report area the marker is composed of argillaceous dolomites.
These pass south and east into grey, hard and blocky, dolomitic shales
and these in turn into brownish-red, silty, dolomitic shales still further
east.
STONEWALL FORMATION
The Stonewall Formation is conformable with the underlying strata.
It represents the end of Ordovician sedimentation in the area and the
uppermost part of this unit may even be Silurian in age. This unit may
also be traced over most of the area of study but on the western and
northern edges of the map area the lithology becomes increasingly like
that of the overlying Interlake strata and finally becomes indistinguish,
able from it. The Stonewall Formation maintains a fairly uniform thick,
ness of about 100 feet over most of the area studied; however, in the
northwest portion it thins to about 60 feet and in the west to a bout 75
feet.
It is composed principally of carbonate rocks with a relatively thin
evaporite horizon near the base. The carbonate rocks consist of tan and
brown mottled, sometimes nodular and argillaceous, dolomitic limestone.
Some poorly preserved fossils have been observed in these rocks, including
brachiopods, bryozoa and crinoid ossicles and plates. A few ostracods
were also seen in what appear to be lenses of argillaceous dolomite in the
dolomitic limestone. Blebs of white translucent anhydrite and brown,
tabular porphyrocrysts of anhydrite similar to those reported from the
fossiliferous fragmental limestones of the Red River Formation are
present, particularly in the rocks underlying the evaporite sequence.
Stonewall Evaporite- The limits of this evaporite unit are almost
identical to those of the underlying Gun ton and "B" Evaporites (Figure
8 ). The Stonewall Evaporite underlies a region along the International
Boundary which extends from range 23 west of the second meridian
eastward into southwestern Manitoba, and from township 10 southward
into North Dakota. It has an overall average thickness of about 12 feet
but thins slightly in an easterly direction into Manitoba.
The evaporite consists of about 5 feet of dark brown, microcrystalline,
sucrosic, dense anhydrite with stringers of dolomite bounded by two
beds of lithographic, thinly bedded, slightly argillaceous dolomite, each
about 3 feet thick.
The presence of a second evaporite near the top of the Stonewall
Formation has been suggested by Porter and Fuller (1959 ) but the
author has found little evidence of this.
There is a prominent marker horizon near the middle of the Stonewall
Formation which was called the "t" horizon by Porter and Fuller (1959 ).
It is easily traced over most of the report area and is characterized by
an increased gamma radiation count on the radiation logs. The marker
bed is about 7 feet thick and consists of argillaceous dolomite with
"floating," frosted and well-rounded quartz grains. Eastward this horizon
becomes a gray sandy dolomite which grades into brownish-red sandy
shales. A second but less prominent marker bed marks the top of the
Stonewall Formation. This marker is not as extensive as Porter and
Fuller's ( 1959 ) " t" horizon and is not easily observed beyond the western
and northern limits of the area of study. It is made up of about 5 to 15
feet of argillaceous dolomite with occasionally well-rounded and frosted,
"floating" quartz grains.
22
Plate 1
Photomlcrographs (all transmitted light and crossed nlcol11 )
No. 1 Red Ri ver Formation X 45. Oolitic limestone showing matrix replaced by
microcrystalline anhydrite. Some corroded pieces of matrix are isolated in the
anhydrite. Dolomitization has destroyed much of the structure of the oolites.
The California Standard-Tidewater Camoustie Province No. 4-20 well (Lsd
4-20-17-32wl ) Saskatchewan; 4615 foot depth.
No. 2 Red River Formation X 15. Oolomitized oolitic limestone Matrix dolomite.
Anhydrite in the form of elongated crystals cutting oolites. Concentric layering
in oolites poorly preserved due to dolomitization. The Canadian Devonian,
Tidewater Rupe.rt No. 15,28 well (Lsd 15,28-12,2w2) Saskatchewan; 6302 foot
depth.
23
PETROLOGY OF THE ANHYDRITES AND EVAPORITIC
DOLOMITES
THE ORIGIN OF THE ANHYDRITES
Anhydrites that are the result of replacement of carbonate rocks are
of little value for correlation or subdivision purposes, though they may
affect the porosity and permeability of a potential or actua l oil reservoir.
The anhydrites that are end-products of dessication in a restricted basin
are more useful. This latter type of anhydrite deposit has certain identifying characteristics that assist in distinguishing it as primary rather than
a secondary deposit.
In the case of the "A" and " B" Evaporites of the Herald Member
and of the Gunton and Stonewall Eva porites, the criteria for the primary
rather than secondary origin of these deposits may be divided into macroscopic and microscopic classes. The macroscopic features include:
(1) The areal extents of the anhydrites, which were discussed under
the section concerned with the stratigraphy.
(2) The relatively uniform thickness of the anhydrites over wide,
spread areas, also considered under the stratigraphy of these
rocks.
(3 ) The cyclic nature of the anhydrites as they are repeated throughout Upper Ordovician times.
Hollingworth (1947 ) observed similar physical characteristics in other
evaporite deposits, and he concluded that any anhyd rite containing the
above features was laid down in an evaporite basin.
(4) Thin carbonaceous layers were observed in the anhydrites and
associated dolomites, and it has been suggested that these layers
represent decayed organic material that was washed into the
evaporating basin, and therefore indicate that the anhydrites
were primary deposits and not secondary.
(5 ) Numerous microfaults, microfolds and thin intraformational
breccia are present in the anhydrites and associated dolomites.
These structures appear to be the result of preconsolidation
slumping in the precipitated material lying on the bottom of the
evaporite basin. Fowler (1944 ) a nd Hollingworth (1947 ) observed similar microstructures in anhydrite deposits and attributed them to this cause. On the other hand Ogniben (1957 ) and
Groves (1958 ) favour the theory that these structures were due
to the expansion of the anhydrite with the addition of water to
form gypsum. The fact that anhydrite is now present in the
sequence would require a dehydration of the gypsum at a later
stage of diagenesis. The load pressure caused by the overlying
sediments and increased temperature with depth of burial may
have caused the dehydration of the gypsum. Ogniben (1957 )
calls this second-cycle anhydrite "epigenic anhydrite."
If the diagenetic process favoured by Ogniben and Groves did take place
in the ·rocks of this report area, relic gypsum crystals would be expected
to be present, but the author did not observe any in thin sections. However, some or indeed all of the secondary anhydrite may be second cycle
or "epigenic anhydrite" as some of them show blastomylonitic zones
(No. 2 Plate 4) around the peripheries. These zones are thought by
Ogniben (1957 ) to represent the fragments left after the expansion and
rupture of anhydrite crystals.
Several microscopic features may indicate the primary nature of the
24
Plate 2 - Photomicrographs ( all transmitted light and crossed nicols)
No. l
"A" Evaporite. X 45. Anhydrite composed of elongated, roughly rectangular
grains with irregular margins. Grains orientated more or less parallel in groups
but orientation varying from group to group. The Imperial Hummingbird No.
6-13 well (Lsd 6-13-2-19w2) Saskatchewan; 9846 foot depth.
No. 2 "A" Evaporite. X 45. E longated, microcrystalline grains of anhydrite with
parallel alignment (gneissoid texture) . Microfolds due to foreign carbonate
bodies. The Imperial Muscowpetung No. 1-9 well (Lsd 1-9-21-16w2) Saskatchewan; 5806 foot depth.
25
anhydrites of the Upper Ordovician in the report area. These features
include:
(1) The crystals of the anhydrite are commonly orientated in patches,
but the orientation of one patch is not necessarily the same as
that of another (No. 1 Plate 2 ). Unless this orientation is inherited from a previously existing rock, it seems probable that the
anhydrite was the result of direct precipitation. Dunham (1948 l
considers these patches of oriented grains to have been caused by
a disturbance of the accumulated crystals by eddies and currents
during deposition. He says that rocks of this type which lack
fully developed idiomorphic crystals, either as phenocrysts or
constituents of a groundmass, suggest that the anhydrite began
to crystallize in suspension in the brine, and that crystallization
completed on the evaporitic basin fl oor, resulting in mutually
interfering crystal boundaries. Some recrystallization of the
anhydrite may have occurred after deposition producing the
gneissoid texture (Bundy, 1956 ) observed in some specimens
(No. 2 Plate 2 ).
(2 ) The occurrence in these rocks of anhydrite blebs enclosed by a
thin layer of cryptocrystalline dolomite, as illustrated in No. 1,
Plate 4, is further proof of the primary nature of the anhydrite.
Each Ienticle is piled on the others, and separated from them by
a thin layer of marl. The lenticles probably represent gell-Iike
balls of anhydrite which were formed on the floor of the evaporating basin and which were later enclosed in dolomitic marl. This
hypothesis is in accordance with a similar one proposed by Dunham (1948) for anhydrite showing the same characteristics in the
Permian-evaporites of northeastern England.
The anhydrites appear to be primary, having been laid down in an
evaporitic basin and later covered over by younger sediment. Since most
of the diagnostic features can be attributed to first-cycle anhydrites 1,
they can be considered to have gone through very little alteration or
recrystallization.
SECONDARY ANHYDRITE
The secondary anhydrite is found in the dolomitic limestones in the
form of porphyrocrysts, large blebs, and pseudomorphs of fossil remains.
The mechanisms which produced these secondary deposits are not
entirely clear. The porphycrocrysts and pseudomorphs of fossil remains
may be attributed to seepage of the concentrated brine through the
underlying poorly consolidated muds with the subsequent replacement
of the carbonate material by the sulphate material. But in the case of
the blebs of anhydrite this theory does not account for the facts, since
in thin section the anhydrite of the blebs has a crystal habit similar to
the primary anhydrites,- that is, idiomorphic crystals with interlocking
boundaries (No. 2 Plate 5 )-and it would appear that this anhydrite
was deposited after consolidation and infilled vugs in the rock. Adding
weight to this idea is an observation made by Fowler (1944 ) concerning
parallel conditions in some anhydritic sequences in the Cleveland Hills
area in England. Stylolitic sutures are common in these carbonate rocks
of Fowler's area and he suggested that, if the anhydrite blebs were preconsolidation features they too should have stylolitic structures, since
the anhydrite is more soluble than the carbonate. He also found bluishwhite granular anhydrite intruded along the sutures. Stylolites are also
1
Anhydrite as it was laid down in the evaporite basin, as opposed to anhydrite obtained from the dehydration of gypsum at depth.
26
Plate 3 - Photomicrographs (all transJ:Ditted light and crossed nicols)
No. 1 Red River Formation. X 45. Rounded anhydrite grains with interstitial rounded
dolomite grains in clusters or thin layers. The California Standard- Tidewater
Carnoustie Province No. 4,20 well (Lsd 4,20,17,32wl ) Saskatchewan; 4606.8
foot depth.
No. 2 Red River Formation. X 45. Rounded anhydrite grains with interstitial dolomite
grains in clusters or thin layers. The Imperial Arm River Annandale No. 6,23
well (Lsd 6,23,8,32wl ) Saskatchewan; 6334.0 foot depth.
27
common in the Upper Ordovician rocks of the area of study and large
quantities of bluish;white granular an hyd rite was observed infilling low
areas along the stylolite sutures. From this evidence, it appears that the
anhydrite blebs are post;consolidation fe:1tures. The wri ter feels that the
anhydrite could have been brought to these vugs in one of t wo ways:
(1 ) by circulating sulfate;rich ground waters.
(2 ) by the waters resulting from the dehydration of gypsum.
Since most of the anhydrite blebs underlie an impervious layer of evapo;
rites, it seems unlikely that sul fate;bearing ground waters could circulate
through the rock sequence to any great extent, and only a portion of
the blebs can be attributed to this mechanism. If the anhydrites of the
" A" and "B" Evaporites, and of the Gunton and Stonewall Evaporites
were considered to be epigenic, then the sulfate;bearing waters could be
attributed to the diagenetic processes that took place to form the "epi;
genie anhydrite" in that, following the deposition of the anhydrites
in the evaporitic basins, they would have been hydrated to gypsum with
the return to normal marine conditions. As more and more sediments were
laid down, the pressure on the gypsum and the temperature of the buried
sediments would increase and finally, when the temperature and pressures
were too extreme for gypsum to exist any longer, the water of hydration
would be driven off and anhydrite formed again. The water of hydration
would probably still contain a certain amount of calcium sulfate, and as
it came in contact with the underlying carbonate rocks, would deposit it
in the porous zones and vugs.
If this hypothesis is correct, then the microscopic features of the
primary anhydrites which were described in the previous section are
not the result of the deposition of the anhydrite, but were produced by the
recrystallization of the anhydrite from gypsum.
EVAPORITIC DOLOMITES
The possibility or otherwise of the primary deposition of dolomite
has been a controversial issue for many years. Bury (1947 ) says that
primary dolomite cannot be formed because the carbonates of calcium
and magnesium are formed under such different chemical conditions.
Twenhofel is also of the opinion that the primary deposition of dolomite
is purely hypothetical, but Sanders, as quoted by Edie (1956), found
thinly laminated dolomites with penecontemporaneous slumping which
he felt demonstrated the feasibility of the theory that dolomite muds
may be deposited under proper conditions. A recent paper by Alderman
and Skinner (1957 ) describes dolomite sedimentation in the southeast
of South Australia. They observed that a close relationship existed
between plant growth, rise in pH value, and the precipitation of dolomitic
sediments in evaporating basins. Laboratory experiments were carried
out by Graf and Goldsmith (1956) in an attempt to precipitate dolomite
from solutions under a wide range of temperatures and pressures. They
found that the stable form of dolomite, 1:1 Ca :Mg, could only be obtained
under extreme conditions of temperature and pressure, but an unstable
form, which they called protodolomite (dolomite;like rocks ), may be
deposited at temperatures and pressures app roaching standard conditions.
These protodolomites may later pass into a more stable phase. This may
be a mechanism by which primary dolomites are formed.
The rocks of Upper Ordovician age in the report area that are thought
to be evaporitic dolomites are:
(1) Thinly laminated
(2 ) Dense (cryptocrystalline texture )
28
Plate 4- Photomicrographs {all transmitted light and crossed nicolsJ
No. 1 Red River Formation. X 45. Aggregates of cryptocrystalline, irregular, anhydrite
crystals enclosed by thin layers of lithographic dolomite containing acicular
crystals of anhydrite. The [mperial Hummingbird No. 6, 13 well (Lsd 6, 13,2,19
w2) Saskatchewan; 9848.5 foot depth.
No. 2 Red River Formation. X 45. Microcrystalline, dolomitic limestone (D ) with
large (2cm.) chert nodules (C). Subhedral crystals of anhydrite (A) as meta,
somatic replacement of dolomite. The Canadian Devonian,Tidewater Rupert
No. 15, 28 well (Lsd 15,28, 12,2w2) Saskatchewan; 6297 foot depth.
29
Plate 5- Photomicrographs (all transmitted light and crossed nicols)
No. I Red River Formation. X 45. Dolomitized limestone with deformed pseudo,
oolites and subhedra l secondary anhydrite crystals. The Imperial Hartaven
No. 2,11 well (Lsd 2-l l , 10,9w2) Saskatchewan; 7499.0 foot depth.
No. 2 Red River Formation. X 45. Dolomitized fossiliferous fragmental limestone with
anhydrite infilling vugs. Zone closest to the anhydrite (A) has well preserved
fossil remains, but these are more indistinct farther away due to more intense
dolomitization. The Imperial Arm River Annandale No. 6,23 well (Lsd 6, 23,
8,32wl ) Saskatchewan ; 6356.5 foot depth.
30
(3 )
Argillaceous
(4 ) Interbedded and intermixed with anhydrite
(5 ) Non-fossiliferous.
These features are similar to those described by Edie (1956 ) and Illing
( 1959 ) as characteristic of primary or evaporitic dolomites. The close
association of dolomite and anhydrite as illustrated by Nos. 1 and 2,
Plate 3 further adds to the evidence that evaporitic dolomites are present
in Upper Ordovician rocks. Dunham ( 1948 ) said that rounded dolomite
granules enclosed by anhydrite suggest minute foreign particles which
acted as nuclei for the deposition of dolomite, the composition of the
brine changing before crystallization could go further resulting in th e
inclusion of dolomite in anhydrite.
In conclus;on, it seems evident from the foregoing observations that
primary or evaporitic dolomites are not an impossibility, and that such
are indeed present in rocks of Upper Ordovician age of this area.
31
STRUCTURE
The structure contours on top of the Yeoman Member illustra te
the northern part of a basinal feature with radial dip s teepening towards
the center of the basin (Figure 8 ). The arcuate sweep of the contour
lines is interrupted in the southwestern part of the map area where the
contour lines swing to a north-south direction on the flanks of the Bow,
doin Dome (Porter and Fuller, 1959 ) (Figure 8 ).
The distribution of deep wells that penetrated the Red River Formation within the limits of the area of study makes it possible to illustrate
only the regional structural features. However, due to the closeness of
two wells about 22 miles southeast of Moose Jaw and with the a id of
seismic information, a small structural high was outlined. This structure
is probably the result of an erosional high on the Precambrian uncon,
formity reflected in the overlying rocks, including those of the Cretaceous
System. The southern side of this anomaly forms a southward pitching
anticline which eventually grades into the regional dip. Geophysical
methods were also useful in locating a second structural high about 12
miles south of Swift Current (Figure 8 ). This feature, along with another
high just outside the map area about 24 miles northwest of Swift Current,
is also thought to reflect erosional highs on the Precambrian unconformity
and they, too, affected the overlying sediments. These highs grade into
an east-southeastward trending, pitching anticline, which occupies the
site of Kamen-Kaye's (1953 ) Mesozoic Swift Current Anticline, but soon
disappears downdip in the regional contours. On the northeast flank of
the structural basin, a third local anomaly has been outlined in the
vicinity of townships 7 to 10, ranges 32 and 33. It consists of a poorly
developed anticline with a southwesterly pitch which as in the case of the
previously mentioned features is eventually lost downdip.
Because of the sparse well control, some known structural anomalies
have not been illustrated in Figure 8. Most noteworthy among these is
the structural high in the Elbow area, a very prominent feature on the
seismic maps. In the south-central portion of the map area, in the vicinity
of range 19 west of 2nd meridian, there is thought to be a tectonic hinge
line trending north-northwest from the International Boundary. However,
this hinge cannot be observed on the structure contour map, and can
only be inferred from geophysical data.
32
I
.
I
I
"
"
.:
.
N
If
U
II
U
U
ff
- ti
10
1•
•
0,
..
.. -
M
q,
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,a
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-
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'-·
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..
-
...
I
. I./
..
.
-
ct.
,- I/'
,<
>
'(..
~
/
/
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v
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v
r
/
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.
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\
"\ I\
.;,,":':-..- -~ .J-.;-t J
1or --,- -,-
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)
I
STRUCTURE CONTOUR MAP
LEGEND
ON THE TOP OF THE
YEOMAN MEMBER
' coNTOUR INTERVAL 200'
Flrure 8- St ructure Contour Map on Top of the Yeoman Member
33
HUDSON
BAY
I
l
,
\...
\ .,
.\
i
HELENJI
i( r.
\
·,
/
gJ
..
~
Metastable posit ive areas.
B
Stobie positive areas
D
Ne9at ive areas
~
Region of most extensive
evoporite deposi tion
WYOMING
SCAL E I N MILES
Figure &-Tectonic niap of the Prairie Provinces and Northwestern United
States illustrating the positive and negative elenients (After Borden,
1958) and the D1anID\UJl area covered b:y the evaporite depollits
during Ordovician tlnies.
34
SEDIMENTATION
DEPOSITIONAL ENVIRONMENT
The Upper Ordovician rocks of southern Saskatchewan were laid
down in an intracratonic basin, the axis of maximum sedimentation of
which occupied two separate positions during that time. During the
period of Red River and Stoughton sedimentation the axis was present in
the region northeast of Bismarck, North Dakota (Figure 9 ). The center of
maximum sedimentation during the period of Gunton and Stonewall
sedimentation shifted to a position about 100 miles northwest of its
previous position.
Repeated minor epierogenic movements in the basin resulted in
periodic restriction of circulation and cyclic deposition, including eva,
porites in the vicinity of the center of sedimentation. Since the evaporites
are surrounded by sediments which were laid down in a marine environ,
ment, Krumbein (1951 ) felt that the restriction of circulation in this
basin was due to tectonically imposed barriers. In the case of the " A"
Evaporite of the Herald Member, the presence of stratigraphically
equivalent oolitic and pelletoidal limestones in the Herald Member along
the Manitoba,Saskatchewan border indicates a shoal (Figure 9) which
may have acted as a tectonic barrier in the region. But on the northwest
side of the "A" Evaporite the evidence for a barrier is lacking, and the
author feels that another mechanism may account for the restriction of
the basin in this region. This mechanism, a dynamic barrier (Scruton,
1953 ) is mentioned in Figure 10. Scruton described a dynamic barrier as
a strong friction surface created between fresh water, or water of normal
salinity, and highly saline solutions. According to him the friction is
great enough to inhibit the intrusion of the less dense water by the more
dense. Barriers of this nature have been observed in the Gulf of Mexico
off the distributaries of the Mississippi River, and Scruton felt that
barriers of a similar nature may be essential to the entrapment of the
brine in many evaporitic basins. To explain the presence of a dynamic
barrier in the case of the "A" Evaporite, the lithology on the landward
side of the evaporitic environment (Figure 10 ) must be considered first.
The rocks of this area are similar to those described as "pseudomarine"
by Sloss (1953 p. 160 ). Where rocks of this type are laid down Sloss
considered the brine to have been diluted, probably by fresh water from
the hinterland. The author feels that this theory is applicable to the
region between the hinterland and the evaporitic environment (Figure IO )
and 'because of this dilution a dynamic barrier was formed which re,
stricted the highly saline solutions to the area now occupied by the "A"
Evaporite. The conditions of deposition for the " B" Evaporite of the
Herald Member may have been similar to those under which the " A"
Evaporite was laid down, but there is no lithological evidence of a barrier
bank type environment being present in southern Saskatchewan. How,
ever, this environment might have existed farther south in North Dakota
or east in Manitoba and lithological evidence for its existence may be
found in either place.
Unlike the evaporites of the Herald Member, the Gun ton and Stone,
wall Evaporites straddle the axis of maximum sedimentation (Figure 11 );
therefore the depositional environments for these later evaporite deposits
are different from those of the earlier evaporites. These evaporites were
probably laid down in shallow evaporating basins and represent the
standstill period at the end of an epeirogenic uplift of the depositional
basjn. The evaporating basin was probably surrounded by a calcareous
mud,flat at about sea level. This flat was probably flooded periodically
35
SE
NW.
POSITIVE
-
PSEUOO·MARINE ENVlRO,otENT
- --+-- - - - - - - - (VAPORITIC
ENVIRONMENT
- - - - - - --+-- - BARRIER
AREA
BANK
- --+-- -
8.ANK MARGIN -
ENVIRONMENT
ENVIRONMENT
Ool1t 1c ond Ptlltl L1mutone1
Foss,hferous Fro9ffltntol
Oohtes ond Pellet::.
Limestone C11no,d On1clu,
Co,o l and 8'od11opod Fro;rMnts
SEA LEVEL
OYNAMIC BARRIER
REGION
.,,,,/!)
c,,stolhnt Dolomite w,th poorlJ p,esuved Fosslts
EwopMlttS ond
•ctto111f
Ar91ttoceovs Oolom,1ts w11h some Ost,ocods
Figure 10- Generallzed section through the region of study illustrating the
sedimentary environment present during the time when the "A"
Evaporite of the Herald Member was deposited.
causing an influx of normal sea water into the restricted basin; the addi;
tion of normal sea water probably kept the salinity of the restricted basin
at the proper concentration for the precipitation of anhydrite at all times.
Since the Gunton and Stonewall Evaporites are extremely thin, this
physical characteristic may be interpreted as an indicator of the shallow;
ness of the basin and the relatively short period of time of deposition.
The presence of silty, dolomitic shales and argillaceous dolomites im~
mediately overlying the anhydrites probably represents the end of the
"stand;still" and the initiation of the return of the deposition basin
to normal marine conditions.
HUDSON
BAY
Unstable poslli\le areas
WYOMING
Metostob1e positive areas
,oo
,oo
zoo
Stable posit1ve areas
SCALE IN MILES
Negative oreos
Figure 11-Tectonlc Map of Prairie Provinces and Northwestern United States
illustrating the positive and negative elements (After Borden,
1966) and the distribution of the evaporltic basins during GuntonStonewall times.
37
EVAPORITIC CYCLES
Each evaporite deposit in the Upper Ordovician strata of southern
Saskatchewan is part of a cycle of sedimentation consisting of five phases
(Figure 3 and Table 2 ).
TABLE 2
Phase Lithology
Cyclic Stages
Limestone (D olomitized, sometimes fossilif,
erous)
Hemicycle of
subsidence
Phase Number
2
Argillaceous Dolomite or Dolomitic shale
3
Anhydrite
2
Argillaceous Dolomite
period of
standstill
Limestone (Dolomitized, sometimes fossili,
ferous)
Hemicycle of
uplift
The lithology of phase 1 of the hemicycle of uplift is that which would
be expected to have been deposited under normal marine conditions. The
normal marine sedimentation was gradually brought to a close as the basin
shallowed due to epeirogenic uplift; Phase 2 represents the transition
phase from a normal marine environment to one of evaporation. The
uplifted basin then entered a period of tectonic standstill and evaporites,
such as those of Phase 3, were laid down in the restricted portions of
the basin. In the hemicycle of subsidence the rocks of Phase 2 represent
a second transition phase from dessicating conditions to a normal marine
environment. Finally, Phase 1 of the upper hemicycle indicates a return
to normal marine sedimentation.
There were two cycles of uplift and subsidence during the period
when the rocks of the Red River Formation were deposited. These cycles
of sedimentation were interrupted by an upwarp (Ballard, 1942, p. 1577 )
southeast of the axis of maximum sedimentation (Figure 9 ). The move,
ment was in the vicinity of the Sioux uplift according to Ballard, which
occupied part of the area covered by the Transcontinental Arch of
Devonian times (Eardley, 1951 ). The uplift resulted in an influx of fine
elastic material into the basin from the southeast (shale facies of the
Stoughton Member- Figures 2 and 3 ). There was also a shift of the
center and axis of maximum sedimentation about 100 miles northwest,
ward from their previous locations (Porter and Fuller, 1959 ) with the axis
receiving a more northeasterly trend (Figure 11 ). Followir•g this shifting
of the basin center two more cycles I of uplift and subsidence were initiated
producing the deposits of the Gunton Member of the Stony Mountain
Formation and the Stonewall Formation. A third shift of the center and
axis of sedimentation to a position slightly farther west (Porter and
Fuller! 1959 ) brought to a close sedimentation in Upper Ordovician times.
1 Porter and Fuller (1959) reported evidence of a third evaporitic cycle extending
to the top of the Stonewall Formation but the present writer has found little evidence
to verify this fact at this time.
38
PETROLEUM PROSPECTS
The prospects for the production of oil and gas from the Lower
Palaeozoic horizons have been discussed at considerable length by Porter
and Fuller (1959 ) and the present author is of the opinion that little
more can be added. They suggested (and the writer agrees ) that the best
petroleum possibilities for the Upper Ordovician strata lie in the central
basin area and on the low inner flank positions where the salinity of the
formation water is high and the porosity of the facies is favourable to
oil accumulation. Some oil has been produced from the Ordovician rocks
in the central basin area and the low inner flank positions of the Williston
Basin in Montana and North Dakota, but so far only three oil shows
have been reported in Saskatchewan. The most significant oil show was
observed in the Imperial Hummingbird No. 6-13 well (Lsd 6, Sec. 13,
Twp. 2, Rge. 19, w2M ) which produced oil for a time from a horizon
at the top of the Yeoman Member of the Red River Formation (Figure
4 ). The reservoir was thought to be a stratigraphic trap capped by dense
evaporitic deposits with minor structural closure. The second oil show
was observed in the drill stem tests of the interval 8264 feet,8309 feet
(below kelly bushing ) in the Imperial Pangman No. 3-14 well (Lsd 3,
Sec. 14, Twp. 8, Rge. 20, w2M ). This showing was from the same horizon
(Figure 5 ) as that of the Imperial Hummingbird No. 6-13 well; both
these wells appear to be on the same trend, which is thought to be a
tectonic hinge area. The third oil show was Jess significant and was ob,
served in the Imperial Herald No. 1-31 well (Lsd 1, Sec. 31, Twp. 1,
Rge. 20, w2M ). One hundred and ten feet of gassy, muddy oil fluid and
salt water were reported from a drill stem test of the Stonewall Formation
between the interval 9321 feet to 9341 feet below the kelly bushing
(elevation 2276 feet above sea level ) (Figure 4 ).
Since the structure contour map on the top of the Yeoman Member
shows few structures favourable to the entrapment of oil or gas, it would
seem that any hydrocarbons present in the Upper Ordovician rocks of
southern Saskatchewan have most likely accumulated in stratigraphic
traps. These traps may be of two types: (a ) where an impervious rock
such as anhydrite or shale forms the cap rock over the reservoir rock
and the porosity pinches out up-dip as a result of a lateral change in
facies, or (b ) where the possible reservoir rocks are bounded at the
top and bottom by anhydrites or other impervious material. The porous
fossiliferous limestones of the Yeoman Member, which underlie the "A"
Evaporite of the Herald Member, and similar rocks which underlie the
Gunton and Stonewall Evaporites and which are confined by the "A"
and "B" Evaporites of the Herald Member, all pass laterally into dense
dolomitic limestones up-dip and p1oduce reservoir conditions as defined
previously.
Recent deep drilling across the International Boundary in North
Dakota has added impetus to a relatively new theory concerning the
discovery of oil in the Lower Palaeozoic rocks of the Williston Basin area.
This theory pertains to the indirect relationship between the accumula,
tion of oil in the Lower Palaeozoic horizons, and the absence of or the
thinness of the Middle Devonian Prairie Evaporites. It is thought that
these "no salt" areas, as they are called, represent tectonic hinge areas
which effected the reservoir conditions in the underlying strata. One
such hinge region may exist in southern Saskatchewan trending north,
ward from the area where the Imperial Hummingbird No. 6, 13 well was
drilled. There are other small areas of "no salt" in southern Saskatchewan
which may be tectonic hinge areas, and which may justify further in,
vestigation, if the facies in the Lower Palaeozoic rocks is the type in
which good reservoirs can be expected. Other evidence presented by
39
Kupsch (1958 ) and Meek ( 1958 ) also illustrates the possible existence
of a tectonic hinge along the edge of the extensive "no salt" region in
southern Saskatchewan which may also warrant further investigation
for favourable oil entrapment conditions in the rocks underlying the
Middle Devonian Prairie Evaporites.
40
BIBLIOGRAPHY
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Baillie, A. D., 1951, "Ordovician Geology of the Lake Winnipeg and Adjacent Areas
Manitoba," Manitoba Mines Branch, Pub. 51-6.
Ballard, N., 1942, "Regional Geology of Dakota Basin," Bull. Amer. Assoc. Petrol.
Geo/., Vol. 26, No. 10, pp. 1557- 1584.
Borden, R . L., 1956, "Historical Geology and Tectonics of the Southern Part of the
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Dowling, D . B., 1900, " Report on the Geology of the West Shore and Islands of Lake
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Dunham, K . C ., 1948, "A Contribution to the Petrology of the Permian Evaporite
Deposits of Northeastern England," Proc. Yorks. Geo/. Soc., Vol. 27, pp. 217-227.
Eardley, A. J ., 1951, "Structural Geology of North America," Harper Bros., New York.
Edie, R. W., 1956, "Origin and Characteristics of Evaporitic Dolomite," ] our. Alta.
Soc. Petrol. Geo/., Vol. 4, No. 1, pp. 16-23.
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- -- - - -, 1929, "Ordovician and Silurian of American Arctic and Subarctic
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and Protodolomite," ]our. Geo/., Vol. 64, No. 2, pp. 173-186.
Groves, A. W. , 1958, "Gypsum and Anhydrite," Her Majesty's Stationery Office,
London, England, pp. 1,8.
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192-198.
llllng, L. V., 1959, "Upper Palaeozoic Carbonate Sediments in Western Canada,"
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Kamen-Kaye, M., 1953, "The Tectonic Patterns of Southwestern Saskatchewan,
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Krumbien, W. C., 1951, "Occurrence and Lithologic Association of Evaporites in the
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41
Kupsch, W. O., 1958, "Subsurface Structures in Southern Saskatchewan," North
Dakota Geol. Soc. Sask. Geol. Soc., 2nd International Williston Basin Symposium
Volume, pp. 118,126.
Macdonald, G. J. F., 1953, "Anhydrite-Gypsum Equilibrium Relations," Amer. ]our.
Sci. , Vol. 251, No. 12, pp. 884-898.
McCamis, J. G., 1958, " Anhydritization in the Mississippian Souris Valley Beds of the
Broadview Area, Saskatchewan," Unpublished Master of Science Thesis, Univ.
Saskatchewan .
Meek, K. S., Jr., 1958, "Precambrian of the Canadian Williston Basin," North Dakota
Geol. Soc. Sask. Geo/. Soc., 2nd International Williston Basin Symposium Volume,
pp. 17,19.
Morris, R. C. and Dickey, P. A., 1957, "Modem Evaporite Deposition in Peru,' •
Bull. Amer. Assoc. Petrol. Geo/., Vol. 41, No. 11 , pp. 2467,2474.
Napier, E., 1948, " The Lower Anhydrite Seams of the Tees Area,'' Proc. Yorks. Geo/.
Soc., Vol. 27, Pt. 3, pp. 210,216.
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Soc. Canada, 3d. Ser., Vol. 37, Sec. 4, pp. 59,73.
Ogniben, L., 1957a, "Secondary Gypsum of the Sulphur Series, Sicily, and the So-called
Integration,'' }our. Sed. Pet. , Vol. 27, No. 1, pp. 64,79.
- - -- , 1957b, "Discussions-Relation of Gypsum and Anhydrite,'' ]our. Sed.
Pet., Vol. 27, No. 4, pp. 469,470.
Ower, J . R., 1953, " The Subsurface Stratigraphy of Southwestern Manitoba,'' Trans.
Can. Inst. Min. and Metal/., Vol. 56, pp. 391,399; Can. Min. and Metal/. Bull., No.
500, pp. 735,743.
Porter, J. W. and Fuller, J . G. C. M. , 1959, "Lo.wer Palaeozoic Rocks of the Northern
Williston Basin and Adjacent Areas," Bull. Amer. Assoc. Petrol. Geo/., Vol. 43, No.
I, pp. 124,189.
Rader, M. T., Jr., 1952, " Ordovician and Silurian Carbonates of the Central Williston
Basin,'' Guidebook Billings Geo/. Soc., 3rd Annual Field Conference, pp. 48-55.
- -
, 1953, " Ordovician, Silurian and Devonian Stratigraphy of a Portion
of Northern Montana," Guidebook Billings Geo/. Soc., 4th Annual Field Conference,
pp. 64-66.
Ross, R. J., Jr., 1957, Ordovician Fossils from Wells in the Williston Basin Eastern
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Saskatchewan Geological Society, 1958, "Report of the Lower Palaeozoic Names and
Correlation Committee.''
Scruton, P. C., 1953, "Deposition of Evaporites," Bull. Amer. Assoc. Petrol. Geo/.,
Vol. 37, No. 11, pp. 2498,2512.
Sloss, L. L., 1953, " Significance of Evaporites,'' ]our. Sed. Pet. , Vol. 23, No. 3, pp.
143-161.
Stanton, M. S., 1953, "Ordovician, Silurian and Devonian Stratigraphy of Western
Saskatchewan,'' Guidebook Billings Geo/. Soc., 4th Annual Field Conference, pp.
59,63.
Stearn, C. W., 1953, "Ordovician,Silurian Boundary in Manitoba," Abstract, Bull.
Geo/. Soc. Amer., Vol. 64, No. 12, Part 2, pp. 1477,1478.
- - - - - -, 1956, "Stratigraphy and Palaeontology of the Interlake Group and
Stonewall Formation of Southern Manitoba," Geol. Survey Canada, Memoir 281
pp. 8-10.
Stewart, F . H., 1949, "The Petrology of the Evaporites of the Eskdale No. 2 Boring,
East Yorkshire, Part I, The Lower Evaporite Bed,'' Min, Mag., Vol. 28, No. 206,
pp. 621-675.
Wflllams, H., Turner, F. J. and Gilbert, C. M., 1955, "Petrography,'' W. H. Freeman
and Co. , San Francisco, Calif.
42
APPENDIX
Well Data
Formation and member tops determined from cores, samples and
mechanical logs.
41
rKelly
Busbin~
Elevation
1
Well Name
Location
1,4,17-30wl... ...
1,16-20-30,wl... ..
16-32-15-31wl...
16-4-3,32wl
3-18-3,32wl.. .....
16-7-6-32wl .
14-19-8,32wl... .
6-23,8,32wl... .... .
Stony Mtn.
Formation
(feet below K .B. )
1580
1647
1731
1690
1733
1949
2097
1981
3963
3576
4462
7191
7265
6703
6310
6097
4043
3658
4557
7278
7362
6808
6416
6204
4161
3773
4662
7401
7482
6914
6533
6321
4218
3827
4722
7524
7580
6991
6588
6387
1791
4381
4469
4581
4642
---
Red River Formation
(feet below K.B. )
Herald
Yeoman
Member
Member
Riddle Tidewater St. Marthe No. 1-4.............. .
Riddle Tidewater Marchwell No. 1- 16............... .
Riddle Tidewater Rocanville No. 16-32 ............ .
Socony Western Prairie Imperia l Carievale No. I
Imperial S ilverton No. 3,18 ........... .. .. . ..... .
Imperial Lightning Creek No. 16-7. ................. .
M.O.W.S. North Redvers No. X- 14-19.... .
Imperia l Arm River Annandale No. 6-23 . ..
California Standard Tidewater Carnoustie
Province No. 4-20 .... ..................................
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Tiit~~~tC~~~:t~~ f~.~ ri~~ .'.~~~i~l····· ....... .
Riddle Tidewater Clayridge No. 16-14............. .
Neumann No. 12 .. . .... .. ....... ... ... ... ... . .
.
Tidewater Panamerica nWhite Bear No. 5-15 ....
Canadian Devonian Tidewater Rupert No. 15,28
Riddle Tidewater Atwater No. 4-16....... ..
Imperial Douglaston No. J2,6 ... ....... ... ..
British American Canadian Devonian Quinn
No. 9-34X ........................................... .
Triton Tidewater Dubuc No. 15-22............. .
Canadian Gulf Myrfield No. 12.......... .
Tidewater Imperia l South Kisbey No. I. ..... .
Texas Pacific South Rama No. 4-27 .............. .
Imperial Halkett No. 15-7 ............................. .
Imperia l Canadian Superior Stoughton No. 3-27
Husky Phillips Fitzmaurice No. I
Imperial Hartaven No. 2, 1
Tidewater Beaverhills No.
Canadian Gulf Margo No. 8-1 1............... . ....... .
Texas Pacific Pig Lake No. 12,18........... ............ .
Compagnie Francaise Des Petroles
Outram No.
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
1-4-20,32wl... ..... .
16,14- 17-1 w2 .. .
12-29-2-2w2 .. .
5-t5- 10-2w2..
15,28-12,2w2
4-16-20-2w2.... .
12-6,5-3w2 .. .
1666
1971
1722
2464
21 89
1722
1938
3912
4790
825.4
6794
6048
4253
7904
3995
4882
8355
6878
6140
4334
8008
4115
5001
8473
6999
6265
4454
8 125
4180
5072
8556
7079
6330
4520
8200
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
9-34-3-4w2 ..... .
15-22- 19,4w2 ..
12-18-32-5w2
16-34-7-6w2....
4-27-31,7w2.... .
15-7-3,8w2 .... .
3-27,8,8w2...... .
16- 18-27-8w2 .. .
2-l l - 10-9w2 .. .
16-23-26-9w2... ..
8-11-33-9w2 ...... .
I 2, t 8,34,9w2 ..
1935
1808
1688
2011
1765
1933
2058
2046
2054
2168
1845
1919
8311
4618
3103
7523
3410
9165
7606
4250
7258
4463
3420
3410
8419
471 8
3175
7630
3482
9265
7705
4346
7372
4548
3489
3487
8536
4845
3285
7750
3590
9384
7827
4452
7490
4658
3603
3600
8622
4909
3320
7832
3626
9484
7923
4484
7582
4699
3630
3628
1856
9146
9245
9360
9465
I Lsd 4,20,17-32wl ... .
~
~
(feet above
sea level )
Stonewall
Formation
(feet be,
low K.B.)
Lsd l- 19-3, 10w2.......... ..
""'
I.I\
Shell Midale No. A-6-18 .................................. ......
Socony Star Blanket No. 1..................................
Imperial Kuroki No. 7-30......................................
Tidewater Foam Lake No. 1..................................
Shell Yeoman No. 6-32.......... ................................
Imperial Muscowpetung No. 1-9..........................
Tidewater Krasne No. 1.. ....................................
Imperial Humm~bird No. 6-13 .................. ........
Imperial Herald o. l-31... ...................................
Imperial Pangman No. 3-14..................................
Shell Big Muddy No. 1.......... ................................
Shell Fangman No. 1..............................................
Norcanols Parry No. 1.. ........................................
Sohio Socony Avonlea No. 1.. ..............................
Socony Sohio Nokomis No. 29-10 ......................
Socony Sohio Hatfield No. 11- 14........................
Norcanols Ogema No. 1........................................
Amerada "S-AC" No. 13-16................................
Imperial Guernsey No. 13-34................................
Imperial Carville No. B-23 ....................................
Amerada "S-AD" No. 13-12...... ..........................
Woodley Mobil Horizon No. 11-34......................
Tidewater Stalwart No. 1... ............................. ....
Pacific Mobil Harptree No. 1-28......................... .
Socony Sohio North Ormiston No. 13-13 ..........
Ceepee Baildon No. 2-11... ...................................
Dillman Tuxford No. 1.. ........................................
Imperial Long Range No. 4-31.. ..........................
Socony Sohio Verwood No. 1................................
Tidewater Allen bee & Associa tes Nash No. 1.. ...
Richfield Killdeer No. 12-21... .............................
Imperial Constance No. 8-36.... ...........................
Tidewater Bladworth No. 1.. ..............................
Tidewater Eyebrow No. 2 ....................................
Tidewater Allan No. 1..........................................
Johnstone Lake No. 1.. .... ...................................
El Centro and Associates No. 12-35..................
Socony Sohio Strathallen No. 23-5 ......................
Tidewater Parkbeg No. 1.. ............... .... ............. ..
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Ls<l
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
Lsd
6-18-6,10w2............
15-6-23-10w2..........
7-30-34- 10w2..........
l-29-32-12w2..........
6-32-B-16w2............
l-9-21-16w2..........
16-14-30-16w2........
6-13-2-19w2............
l-31-l-20w2............
3-14-B-20w2............
14-12-3-2lw2..........
9-28-8-21 w2............
16-8-9,21 w2............
15-7- 12-21w2..........
10-29-29-2lw2.......
l l -14-28-22w2........
4-24-7-23w2...........
13-16-14-23w2.......
13-34-33-23w2........
B-23-3-24w2............
13-12-14-24w2... .....
l l-34-7-25w2..........
14-10-27-25w2........
l-28-3-26w2............
13-13-10-26w2.......
2-11-15-26w2.........
l-3-19-26w2..........
4-31-l-27w2............
9-9-7-28w2.............
l -17-27-28w2..........
12-21-2-29w2.........
B-36-3-29w2............
16-36-27-29w2.......
5-30-23-1 w3...........
4-10-33-lw3 ...........
9-20-12-2w3 ............
12-35-22-2w3..........
5-23-2-3w3 ..............
10-32-18-3w3 ..........
2006
2206
1882
1776
1926
1994.6
2163
2458.5
2276
2212
2518
2489
2547
1942
1757
1718
2420
1870
1791
2524
1878
2536.5
1692
2749
2403
1937
1955
2734
2525
2010
2781.5
2844
2014
1917
1762
2421
1885
3026
2217
8355
5150
3455
3703
7715
5596
4525
9542
9310
7951
9170 (?)
8145
8060 (?)
6952
4591
4705
8120 (?)
6547
4240
8784
6374
8050
4909
8620
7500
6418
6081
8553
7780
5323
8337
8354
5262
5598
4567
6863
5620
8075
6262
8463
5247
3535
3782
7817
5682
4609
9647
9406
8055
9258
8243
8167
7043
4668
4788
8265
661 8
4331
8872
6462
8130
4978
8719
7585
6495
6158
8643
7850
5385
8421
8438
5322
5668
4624
6926
5689
8153
6339
8584
5355
3622
3885
7933
5789
4714
9765
9523
8165
9353
8367
8270
7158
4775
4888
8344
6720
4415
8980
6570
8250
5078
8840
7687
6612
6257
8753
7970
5489
8525
8523
5425
5772
4718
7003
5796
8260
6442
8675
5400
3658
3920
8038
5828
4751
9875
9629
8260
9497
8448
8370
7238
4804
4918
8442
68 15
4459
9069
6647
8304
5124
8910
7745
6670
6330
8830
8010
5526
8601
8631
5460
5812
4748
7050
5835
8332
6480
Well Name
~
British American Baciu No. 15-36......................
Quintana Melaval No. 1........................................
Sun Christie Gravelbourg No. 7-16................... .
Stanolind Tidewater Wood River No. A-1 ..........
Imperial Tidewater Strontield No. 12-16.........
Tidewater Placid Hawar en No. I.. ..................
Tidewater Dundum No. 2 ....................................
Imperial Lawson No. 1..........................................
Imperial Morse No. !... .........................................
Tidewater Outlook No. 1.......... .............. ..... .......
Tidewater Birsay No. 1 ........................................
Tidewater Swanson No. 2........ ............................
Gulf Tidewater Vindeg No. 6 ..............................
Tidewater Braddock No. 1.. .... ............................
Gulf Tidewater Sabine No. 9 ... .............................
Imperial Rossduff No. 4-2 ..... ......................... ... ...
Amerada Shell "S-A" No. 5-31.. ...................... ....
Shell Wood Mountain No. !... .............................
Gulf Tidewater Meaden No. 12............... .............
Tidewater Beechy No. I.. ....................................
Shell Wood Mountain No. 2 ........ .... .... .... ............
Amerada Shell "S-E" No. 10-26..........................
lm~al Swift Current No. I.. ............................
Ti ewater Wymark No. 1....... ....... .......... ............
British American Wilhelm No. 1-9.....................
Location
Kelly Bushing
Elevation
(feet above
sea level)
Stonewall
Formation
(feet below K .B.)
Stony Mtn.
Formation
(feet below K.B. )
2531
2562
256 1
2308
2000
2014
1726
2214
2332
1776
2166
1753
2216
2654
2591
2129
2735
2544
2339
2411
2687
2691
2893
2788
2387
7356
7300
7218
6897
5427
5197
4675
6020
6385
4920
5749
4763
5939
6565
6601
5728
6627
6703
6079
6039
6522
6291
6702
6607
6003
7430
7362
7302
6967
5486
5253
4732
6125
6442
4980
5807
4832
5990
6661
6689
5822
6690
6783
6129
6093
6580
6349
6795
6697
6082
·- - Lsd 15-36-6-4w3...........
Lsd 2-14-8-4w3 ...........
Lsd 7-16-9-4w3 ......... ..
Lsd 4-18-10-4w3...........
Lsd 12-16-26-4w3 .....
Lsd 12-10-29-5w3 ....... .
Lsd 8-17-32-5w3 ..
Lsd 16-13-21-6w3
Lsd l-6-18-7w3............
Lsd 7-20-30-7w3 .. ..
Lsd 13-4-25-8w3 .......
Lsd 16-9-32-8w3............
Lsd 6-28-22-9w3 ............
Lsd 5-7-14-10w3 ............
Lsd 9-27-14-!0w3.........
Lsd 4-2-24-10w3 ...........
Lsd 5-31-2-llw3...........
Lsd 7-34-9-11 w3 ...........
Lsd 12-35-21-11 w3 ......
Lsd l-29-23-llw3 ..........
Lsd 13-36-1-12w3..........
Lsd 10-26-l-13w3..........
Lsd 11-20-13-13w3.......
Lsd 3-10-14-14w3..........
Lsd l-9-17-14w3 ............
Red River Formation
(feet below K.B.)
Herald
Yeoman
Member
Member
I
7540
7449
7374
7041
5589
5356
4832
6190
6545
5081
5898
4932
6093
6730
6748
5880
6749
6857
6241
6198
6630
6436
6853
6755
6132
7594
7545
7470
7125
5630
5396
4872
6240
6600
5122
5942
4958
6135
6180
6814
5936
6804
6902
6275
6241
6690
6495
6898
6796
6 172
RECINA, SASKATCHEWAN
Printed by
LAWRENCE AMON,
Printer to the Queen's Most Excellent Majesty.
1959
~
·