Wong, 2011 (B.Sc.G.Sc.Hons.Thesis-Final).compressed

Lithofacies Analysis and Stratigraphic Correlation of the Upper Ordovician Red
Head Rapids Formation, Hudson Bay Basin, Northeastern Manitoba
By
May E. Wong
A Thesis submitted to the Department of Geological Sciences of
The University of Manitoba
in partial fulfilment of the requirements of the degree of
BACHELOR OF SCIENCE
IN GEOLOGICAL SCIENCES (HONOURS)
Department of Geological Sciences
University of Manitoba
Winnipeg
April 2011

i
ABSTRACT
As part of the Geo-mapping for Energy and Minerals program, initiated
by the Geological Survey of Canada, the Upper Ordovician Red Head Rapids
Formation in the Hudson Bay Basin is being evaluated as a potential petroleum
source rock. Cores from the Houston Oils et al. Comeault STH No. 1 and
Sogepet-Aquitaine Kaskattama Province No. 1 wells located in the Hudson Bay
Lowland, northeastern Manitoba, were examined and analyzed as part of this
study. Representative samples were studied in detail using thin section
petrography, and selected samples from the greyish-green dolomudstone units
were further analyzed using organic geochemistry and X-ray diffraction.
The Red Head Rapids Formation (32-41.9 m thick) in the study area is
composed of mostly dolomudstones with intervals of evaporite rocks. Six
lithofacies are recognized: A) greyish-green dolomudstone, B) skeletal
wackestone, C) mottled-nodular lime mudstone, D) massive-laminated
dolomudstone, E) interlaminated dolomudstone, anhydrite and halite, and F)
anhydrite. These lithofacies are grouped into three lithofacies associations: 1)
open subtidal, 2) saline subtidal and 3) saline mud flat.
The Red Head Rapids Formation in the study area comprises four
meter-scale, shallowing and brining-upward carbonate-evaporite cycles. The
open subtidal lithofacies association, overlain by the saline subtidal lithofacies
association and capped by the saline mud flat lithofacies association form a
transgressive-regressive cycle in response to sea-level fluctuations. From the

ii
correlation of the lithofacies associations between the Comeault No. 1 and
Kaskattama No. 1 wells, the tidal flat island model is proposed to explain the
shallowing-upward cycles and laterally discontinuous lithofacies in the study
area. Comparison of the cycles in these wells to those recognized in the Red
Head Rapids Formation in the offshore Polar Bear C-11 well and in outcrops at
Cape Donovan, Southampton Island suggests that the study area during the
Late Ordovician was in a basin-margin position, based on the abundance of
peritidal lithofacies and the absence of organic-rich lithofacies and argillaceous
lithofacies. Southampton Island is interpreted to have been situated in a basin-
central position, based on the presence of oil shales and argillaceous rocks.
Based on limited Rock Eval™ 6/total organic carbon results, lithofacies
A (greyish-green dolomudstone) in the study area appears to have low source
rock potential. Controlling factors are poor productivity and/or poor
preservation of organic matter and insufficient burial conditions.

iii
ACKNOWLEDGEMENTS
First I would like to thank my thesis advisors, Dr. Nancy Chow and
Ms. Michelle Nicolas. Dr. Chow and Ms. Nicolas were tremendously
supportive and helpful throughout this project. I am heartily thankful for
Dr. Chow’s supervision and support which has enabled me to gain a
better understanding in the subject. I would also like to extend my thanks
to Dr. Ian Ferguson for being the thesis coordinator.
I would also like to thank Dr. Denis Lavoie from the Geological
Survey of Canada for funding and supporting this project. Thanks also to
Mr. Gerry Benger, Mr. Rick Unruh and Mr. Vioŕel Varga from the Midland
Core Storage Facility for their assistance while I was examining cores.
I am grateful to all the staff in the Department of Geological
Sciences at the University of Manitoba for providing a stimulating and fun
environment to learn and grow. Special thanks to the technical staff, Mr.
Neil Ball and Ms. Ravinder Sidhu for helping me with the laboratory
equipment. Thanks also to Dr. Bob Elias for providing his insights.
Finally, I am indebted to my family and friends for their unceasing
encouragement and support during my university career.

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TABLE OF CONTENTS
ABSTRACT........................................................................................................i
ACKNOWLEDGEMENTS................................................................................iii
TABLE OF CONTENTS...................................................................................iv
LIST OF FIGURES...........................................................................................vi
LIST OF TABLES ...........................................................................................vii
LIST OF APPENDICES ..................................................................................vii
CHAPTER 1: INTRODUCTION .........................................................................1
1.1 Prologue............................................................................................................. 1
1.2 Geological Setting............................................................................................. 2
1.3 Previous Work ................................................................................................... 4
1.4 This Study.......................................................................................................... 5
1.4.1 Study Area.................................................................................................... 5
1.4.2 Objectives..................................................................................................... 7
1.5 Methodology...................................................................................................... 7
1.5.1 Core Examination......................................................................................... 7
1.5.2 Thin Section Petrography............................................................................. 8
1.5.3 X-ray Diffraction............................................................................................ 8
1.5.4 Rock Eval™ 6............................................................................................... 9
1.5.4 Datum........................................................................................................... 9
CHAPTER 2: STRATIGRAPHY.......................................................................10
2.1 Regional Stratigraphy..................................................................................... 10
2.2 Upper Ordovician in the Hudson Bay Lowland............................................ 10
2.3 Stratigraphy of the Red Head Rapids Formation in the Study Area........... 11
CHAPTER 3: LITHOFACIES ANALYSIS........................................................14
3.1 Introduction ..................................................................................................... 14
3.2 Lithofacies A: Greyish-Green Dolomudstone .............................................. 14
3.2.1 Description ................................................................................................. 14
2.2.2 Interpretation .............................................................................................. 23
3.3 Lithofacies B: Skeletal Wackestone.............................................................. 23
3.3.1 Description ................................................................................................. 23
3.3.2 Interpretation .............................................................................................. 25
3.4 Lithofacies C: Mottled-Nodular Skeletal Lime Mudstone............................ 27
3.4.1 Description ................................................................................................. 27
3.4.2 Interpretation .............................................................................................. 27
3.5 Lithofacies D: Massive-Laminated Dolomudstone ...................................... 30
3.5.1 Description ................................................................................................. 30
3.5.2 Interpretation .............................................................................................. 33
3.6 Lithofacies E: Interlaminated Dolomudstone, Anhydrite and Halite.......... 33
3.6.1 Description ................................................................................................. 33
3.6.2 Interpretation .............................................................................................. 35
3.7 Lithofacies F: Anhydrite ................................................................................. 37

v
3.7.1 Description ................................................................................................. 37
3.7.2 Interpretation .............................................................................................. 40
CHAPTER 4: LITHOFACIES ASSOCIATIONS AND METER-SCALE
CYCLICITY.......................................................................................................41
4.1 Lithofacies Associations................................................................................ 41
4.2 Meter-Scale Cyclicity ...................................................................................... 42
4.3 Correlation of Meter-Scale Cycles................................................................. 45
CHAPTER 5: STRATIGRAPHIC CORRELATION..........................................49
5.1 Introduction ..................................................................................................... 49
5.2 Correlation Between Comeault No. 1, Kaskattama No. 1 And Polar Bear C-
11 Wells.................................................................................................................. 49
5.3 Correlation with the Cape Donovan Outcrop, Southampton Island........... 52
CHAPTER 6: ORGANIC GEOCHEMISTRY....................................................54
6.1 Introduction ..................................................................................................... 54
6.2 Results For Total Organic Carbon (TOC), Maximum Temperature (Tmax) and
Production Index (PI) ............................................................................................ 55
6.3 Hydrogen Index-Oxygen Index (HI-OI) Plot................................................... 56
6.4 Comparison to the Red Head Rapids Formation, Cape Donovan,
Southamption Island............................................................................................. 58
CHAPTER 7: DISCUSSION.............................................................................60
7.1 Introduction ..................................................................................................... 60
7.2 Tidal Flat Island Model.................................................................................... 67
7.3 Paleogeography of the Hudson Bay Basin................................................... 64
7.4 Petroleum Source Rock Potential ................................................................. 64
7.5 Future Work ..................................................................................................... 65
CHAPTER 8: CONCLUSION...........................................................................67
REFERENCES.................................................................................................69

vi
LIST OF FIGURES
Figure 1.1. Geological setting of the Hudson Bay Basin ................................... 3
Figure 1.2.Geologic map of the Hudson Bay Lowland ...................................... 6
Figure 2.1. Stratigraphy of the Hudson Bay Lowland ...................................... 12
Figure 3.1. Lithofacies A: greyish-green dolomudstone .................................. 21
Figure 3.2. Lithofacies A: greyish-green dolomudstone .................................. 22
Figure 3.3. Lithofacies B: skeletal wackestone................................................ 24
Figure 3.4. Lithofacies B: skeletal wackestone................................................ 26
Figure 3.5. Lithofacies C: mottled-nodular lime mudstone .............................. 28
Figure 3.6. Lithofacies C: mottled-nodular lime mudstone .............................. 29
Figure 3.7. Lithofacies D: massive-laminated dolomudstone .......................... 31
Figure 3.8. Lithofacies D: massive-laminated dolomudstone .......................... 32
Figure 3.9. Lithofacies E: interlaminated dolomudstone, anhydrite and halite 34
Figure 3.10. Lithofacies E: interlaminated dolomudstone, anhydrite and halite36
Figure 3.11. Lithofacies F: anhydrite ............................................................... 38
Figure 3.12. Lithofacies F: anhydrite ............................................................... 39
Figure 4.1. Stratigraphic section of the Red Head Rapids Formation in Comeault
No. 1 well ......................................................................................................... 43
Figure 4.2 (a). Correlation between the Comeault No. 1 and Kaskattama No. 1
wells................................................................................................................. 47
Figure 4.2 (b). Legend for Figure 4.2............................................................... 48
Figure 5.1 (a). Correlation between the three wells and Cape Donovan outcrop
on Southampton Island.................................................................................... 50
Figure 5.1 (b). Legend for Figure 5.1............................................................... 51
Figure 6.1. HI-OI plot of the lithofacies A samples .......................................... 57
Figure 6.2. HI-OI plot of lithofacies samples with samples from Southampton
Island ............................................................................................................... 59
Figure 7.1. Tidal flat island model.................................................................... 61
Figure 7.2. Modified tidal flat island model proposed for the Red Head Rapids
Formation......................................................................................................... 63

vii
LIST OF TABLES
Table 3.1. Lithofacies Analysis ............................................................................15
Table 4.1. Lithofacies Associations ....................................................................41
Table 6.1. Summary of organic geochemistry results..........................................55
 
LIST OF APPENDICES
Appendix A: Core descriptions ........................................................................... A1
Appendix B: Thin section descriptions................................................................ B1
Appendix C: X-ray diffraction results (see also enclosed CD-ROM) .................. C1
Appendix D: Rock Eval™ 6 results..................................................................... D1

1
CHAPTER 1: INTRODUCTION
1.1 Prologue
The sedimentology of the Paleozoic succession in the Hudson Bay
Basin has not been studied extensively. Limited petroleum exploration has
been conducted in the region because it was previously hypothesized that the
lower Paleozoic succession in the Hudson Bay Basin is thin and has no
petroleum source rock or reservoir potential (Nelson and Johnson, 1966;
Hamblin, 2008). However, more recent studies have compared the Hudson
Bay Basin to the Michigan Basin and Williston Basin, which are petroleum
producing regions, and have postulated that the Hudson Bay Basin has good
petroleum prospects (Hamblin, 2008). As such, the Hudson Bay Basin is
currently viewed as an important frontier prospect. The Geo-mapping for
Energy and Minerals (GEM) program, being led by the Geological Survey of
Canada, focuses mainly on mapping and using modern geological methods to
identify the potential for energy and mineral resources in northern Canada
(Nicolas and Lavoie, 2009).
As part of the GEM program, the Upper Ordovician Red Head Rapids
Formation is being evaluated as a potential petroleum source rock. In the
Houston Oils et al. Comeault STH No. 1 and Sogepet-Aquitaine Kaskattama
Province No. 1 wells in northeastern Manitoba, which are the focus of this
study, the formation consists of carbonate and evaporite rocks. The greyish
green dolomudstone units in these wells have been hypothesized to be

2
stratigraphically equivalent to oil shales in the northern part of the basin which
are well-exposed in outcrops on Southampton Island, Nunavut.
1.2 Geological Setting
The Hudson Bay Basin is a large intracratonic basin in northern Canada,
covering approximately 600,000 km2
, and consists of undeformed sedimentary
rocks of Paleozoic and Mesozoic age (Nelson and Johnson, 1966; Norris,
1993a, 1993b). In the southern part of the Hudson Bay Basin, the Cape
Henrietta Maria Arch separates the Hudson Bay from James Bay in the south
(Fig. 1.1). In the northern part of the Hudson Bay Basin, Southampton Island is
flanked by the Keewatin Arch to the west and the Boothia-Bell Arch to the east.
The Hudson Bay Basin records several tectonic events, including the
Proterozoic Trans-Hudson orogen and the development of an intracratonic
Paleozoic-Mesozoic Hudson Bay Basin (Eaton and Darbyshire, 2010).
Paleozoic sedimentation in the Hudson Bay Basin began with thin
craton-derived siliciclastic and carbonate rocks of Early Ordovician age which
unconformably overlie the Precambrian basement (Sanford and Grant, 1990).
During the Late Ordovician, the uplift of the Cape Henrietta Maria Arch
separated the Hudson Bay Basin and Moose River Basin and a marine
transgression resulted in carbonate and siliciclastic deposition (Sanford and
Grant, 1990). Major glaciation near the end of the Ordovician was recorded as
a major unconformity in the Hudson Bay Basin (Norris, 1993a; 1993b).

3
Figure 1.1. Geological setting of the Hudson Bay Basin showing the distribution
of the Precambrian, Paleozoic and Mesozoic rocks, associated location of
various wells in the region (modified from Zhang and Barnes, 2007).

4
During the Middle Ordovician to Early Cretaceous, the Hudson Bay
Basin was situated close to the paleoequator (Cumming, 1971; Hamblin,
2008). At that time, the region had a dry tropical climate (Cumming, 1971).
1.3 Previous Work
Numerous regional studies of the Hudson Bay Basin have been
conducted and they include Nelson and Johnson (1966), Norford (1970, 1971)
and Norris (1993a, 1993b). Regional stratigraphic studies of the Hudson Bay
Basin have been done by Nelson (1964), Cumming (1971) and Sanford and
Grant (1990).
Paleozoic outcrop studies in the Hudson Bay Basin and Southampton
Island include Heywood and Sanford (1976) and Norris (1993a, 1993b). More
recently, Nelson and Johnson (2002) examined the Ordovician-Silurian strata
in the Churchill area of the Hudson Bay Lowland, and Zhang (2010) studied
Southampton Island. Biostratigraphic studies of Ordovician conodonts were
described by Branson et al. (1951), Le Fèvre et al. (1976), Barnes et al. (1995)
and Zhang and Barnes (2007). Other biostratigraphic studies of the other
marine fossils include Berry and Boucot (1970), Elias (1991) and Jin et al.
(1993).
Petroleum exploration efforts conducted in the late 1980s in the Hudson
Bay Lowland did not result in any commercially viable discoveries (Hamblin,
2008). However, most of the wells that were drilled focused on the thin

5
Devonian succession. Organic geochemical studies on the Ordovician oil
shales on Southampton Island were initiated by Macauley (1986) and further
advanced by Hamblin (2008), Zhang and Barnes (2007) and Zhang (2008).
In recent years, the potential for hydrocarbon resources in the Hudson
Bay Basin have been re-assessed in greater detail as part of a new Geo-
mapping for Energy and Minerals (GEM) program, initiated by the Geological
Survey of Canada (Nicolas and Lavoie, 2009, 2010; Lavoie et al., 2010; Zhang,
2010).
1.4 This Study
1.4.1 Study Area
Houston Oils et al. Comeault STH No. 1 and Sogepet-Aquitaine
Kaskattama Province No. 1 wells are located at 56.66666N/90.82222W and
57.07181N/90.17484W, respectively, in northern Hudson Bay Lowland,
northeastern Manitoba (Fig. 1.2). The Houston Oils et al. Comeault STH No. 1
(abbreviated as Comeault No. 1) well was studied in detail over the depth
interval of 472.4- 421.2 m (1550-1382 ft) and the Sogepet-Aquitaine
Kaskattama Province No. 1 (abbreviated as Kaskattama No. 1) was studied in
detail from 654.1-704.1 m (2310-2146 ft).

6
Figure 1.2. Geologic map of the Hudson Bay Lowland in northeastern Manitoba
showing the location of wells in the region, including the Comeault No. 1 and
Kaskattama No. 1 wells in this study (modified from Nicolas and Lavoie, 2009).

7
1.4.2 Objectives
The main objectives of this study of the Red Head Rapids Formation in
the Comeault No. 1 and Kaskattama No. 1 wells are to: 1) characterize the
lithofacies and the lithofacies associations based on cores and thin sections,
(2) interpret the depositional environments, (3) correlate the distinctive units in
the study area to the units in the offshore Hudson Bay Basin using available
core and well-log data, (4) evaluate the petroleum source rock potential of Red
Head Rapids Formation in the study area, and (5) compare the greyish-green
dolomudstone units in the Red Head Rapids Formation in the study area to the
oil shales in the Red Head Rapids Formation on Southampton Island.
1.5 Methodology
1.5.1 Core Examination
For this study, the Red Head Rapids Formation in two wells, the
Comeault No. 1 (465.3-423.4 m) and Kaskattama No. 1 (699.5-667.6 m), was
examined and described. Core descriptions included colour, lithology, texture,
physical sedimentary structures, and the nature of bedding contacts. Core
photographs were taken using a Canon PowerShot SD890 IS. Forty samples
from representative lithologies and from intervals showing interesting features
were chosen for preparation of standard-size thin sections (27x46 mm).
Limestone nomenclature was based on classification scheme of Dunham
(1962) as modified by Embry and Klovan (1972).

8
1.5.2 Thin Section Petrography
Transmitted light petrography was done on all forty thin sections. The
thin sections were stained with Alizarin Red-S to distinguish calcite from
dolomite, and with potassium ferricyanide to identify ferroan calcite and
dolomite (Dickson, 1966). Descriptions included colour, texture, composition of
allochems and matrix, porosity, cements and other diagenetic features. Visual
estimates were made of the percentages of the different components.
Photomicrographs were taken using a Nikon polarizing microscope with an
attached ECLIPSE 50i POL digital camera and edited using NIS ELEMENTS
F3.0 Software.
1.5.3 X-ray Diffraction
Powder X-ray diffraction (XRD) was used for bulk analysis of the
mineralogy of three samples of lithofacies A (greyish-green dolomudstone;
described in Section 3.2) and one sample of lithofacies B (skeletal wackestone;
described in Section 3.3) to complement the thin section petrography. A
Siemens D5000 automated powder diffractometer was utilized, using CuK!
radiation ("=1.5406 Å), and operated at 40 kV and 40 mA. All four samples
were analyzed from 6 to 66° 2#, using a 0.05 2# step width with 1.0 s per step.
The data were collected using Bruker’s DIFFRAC plus software and processed
using MDI Jade 7.5 XRD search match software.

9
1.5.4 Rock Eval™ 6
Rock Eval™ 6 pyrolysis analysis, conducted in the Organic
Geochemistry Laboratory at Geological Survey of Canada (GSC) in Calgary,
was done on three samples of lithofacies A (greyish-green dolomudstone;
described in Section 3.2) from the Comeault No. 1 and Kaskattama No. 1 wells
to evaluate the petroleum source rock potential (refer to Chapter 5). The
pyrolysis results for one lithofacies A sample from the Comeault No. 1 well at a
depth of 423.4 m was provided by M. Nicolas from the Manitoba Geological
Survey (MGS). Rock Eval™ 6 pyrolysis involves a gradual heating of samples
from 300 to 550 °C to monitor the released hydrocarbons, carbon dioxide and
carbon monoxide using a flame ionization detector (Behar, 2001). The
procedure ends with complete combustion of the residual rock.
1.5.4 Datum
The stratigraphic datum used for constructing the stratigraphic cross-
section of the Red Head Rapids Formation in the study area is the top of the
Churchill River Group.

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CHAPTER 2: STRATIGRAPHY
2.1 Regional Stratigraphy
The Hudson Bay Basin sequence consists of Ordovician, Silurian and
Devonian rocks with a total thickness of at least 1575 m in the central offshore
part of the basin (Sanford et al., 1973). The maximum thickness of the
Ordovician strata varies from 180 m in the Manitoba part of the Hudson Bay
Basin (Cumming, 1971) to 160 m on Southampton Island (Heywood and
Sanford, 1976). The Upper Ordovician succession, in ascending order,
consists of the Bad Cache Rapids Group, Churchill River Group and Red Head
Rapids Formation (Nelson, 1964; Cumming, 1971). The units are of Edenian to
Richmondian age (Zhang and Barnes, 2007). The maximum thickness of the
lower Silurian strata varies from 617 m in the offshore central part of the
Hudson Bay Basin to 305 m on Southampton Island (Norris, 1993b). The
Lower Silurian succession, in ascending order, consists of the Severn River
Formation, Ekwan River Formation and Attawapiskat Formation (Norris, 1993b;
Jin et al., 2003). These formations in the Lower Silurian succession are
predominantly composed of carbonate rocks.
2.2 Upper Ordovician Stratigraphy in the Hudson Bay Lowland
Upper Ordovician strata in the Hudson Bay Lowland are composed of
carbonate, evaporite and siliciclastic rocks which are interpreted to have been
deposited in arid, shallow-marine environments (Nelson, 1964; Cumming,

11
1971; Norris, 1993a). The Churchill River Group is composed of skeletal
limestones in the lower units and grades upward into dolostones and evaporite
rocks with variable thicknesses ranging from 13 to 90 m (Norris, 1993b) (Fig.
2.1). The Churchill River Group consists of the Caution Creek Formation and
the overlying Chasm Creek Formation (Zhang and Barnes, 2007; Nicolas and
Lavoie, 2010).
Overlying the Churchill River Group, the Red Head Rapids Formation in
the Hudson Bay Lowland is composed of dolomudstones, skeletal
dolomudstones and evaporite rocks with variable thicknesses ranging from
25.6 to 92.2 m (Zhang and Barnes, 2007). The Red Head Rapids Formation
can be correlated with the Stonewall Formation of southern Manitoba (Norford,
1970; Cumming, 1971; Zhang and Barnes, 2007).
2.3 Stratigraphy of the Red Head Rapids Formation in the Study
Area
In the study area, the Red Head Rapids Formation is 41.9 m thick
(465.3-423.4 m) and 31.9 m thick (699.5-667.6 m) in the Comeault No. 1 and
Kaskattama No. 1 wells, respectively. The formation consists of fine-crystalline
dolostone and limestone with sparse fossils, greyish-green dolomudstone and
anhydrite units. The bottom of the Red Head Rapids Formation is defined by
lithostratigraphic studies (discussed in Section 2.2.1). The top of the Red Head

12
Figure 2.1. Stratigraphy of the Hudson Bay Lowland, northeastern Manitoba
(modified from Nicolas and Lavoie, 2010).

13
Rapids Formation is marked by a disconformity with the Lower Silurian Severn
River Formation representing the Ordovician-Silurian boundary (Le Fèvre et al.,
1976; Norris, 1993b; Zhang, 2008).
The Red Head Rapids Formation is in the Rhipidognathus symmetricus
Zone. The Rhipidognathus symmetricus Zone has a narrow stratigraphic
distribution in the Hudson Bay offshore area and is interpreted to be associated
with the terminal Ordovician Gondwanan glaciation (Barnes et al., 1995;
Zhang, 2008).
!

14
CHAPTER 3: LITHOFACIES ANALYSIS
3.1 Introduction
The Red Head Rapids Formation in the study area consists of a cyclical
sequence of limestones and dolostones interbedded with minor anhydrite.
Based on the available core data (Appendix A) and thin section descriptions
(Appendix B), six lithofacies are recognized in the Red Head Rapids
Formation: A) greyish-green argillaceous dolomudstone, B) skeletal
wackestone, C) mottled-nodular skeletal lime mudstone, D) massive-laminated
dolomudstone, E) interlaminated dolomudstone, anhydrite and halite, and F)
anhydrite. The characteristics of each lithofacies are summarized in Table 3.1.
3.2 Lithofacies A: Greyish-Green Dolomudstone
3.2.1 Description
Lithofacies A consists of light grey to greyish-green dolomudstone and
ranges from 0.076 to 1.59 m thick (Fig. 3.1). The lower and upper contacts are
sharp. Thin to thick laminations occur commonly and vary from wavy to
straight. Massive dolomudstone is also present in this unit. Palaeophycus
burrows are recognized at 447.5 m in the Comeault No. 1 well.
The dolomudstone is composed of very finely crystalline to
aphanocrystalline, planar-subhedral dolomite and minor micrite occurring in
intercrystalline areas (Fig. 3.2). Locally, there are trace amounts of 4-12 !m
size opaque minerals, most of which are rounded to very rounded. Interparticle

15
Table 3.1. Summary of the main characteristics of lithofacies in the Red Head Rapids Formation from Houston Oils et al.
Comeault STH #1 and Sogepet-Aquitaine Kaskattama Province No.1 wells in the study area.
Lithofacies Colour Lithology Thickness
(m)
Contacts Sedimentary
Structures
Allochems Terrigenous
Grains
A Greyish-green
dolomudstone
Light
grey to
dark
grey, or
greyish
green
Dolomudstone,
composed of
extremely finely
crystalline to
aphanocrystalline
dolomite
0.076-1.59 Lower and
upper:
sharp
Very thin to thin
laminations vary
from straight and
parallel to wavy.
Massive in some
intervals.
Recognizable
Palaeophycus-like
burrows
None <1%.
Opaque,
rounded
to very
rounded
(12 µm)
B Skeletal
wackestone
Light
brown
to buff
Skeletal
wackestone to
rudstone
0.02-0.60 Lower and
upper:
sharp
Massive 10-50%. Fragments of:
crinoids (96-2400 µm,1-
20%), bryozoans (600-
1400 µm, 1-10%),
brachiopods (80-520 µm,
10-20%), tabulate coral
(7000 µm, <1%),
calcareous sponge
spicules? (600 µm, <1%).
Undifferentiated skeletal
fragments (400-2800 µm,
tr-7%). Peloids (40-80 µm,
tr-3%), microbial structure?
(600-1200 µm, tr-2%)
<1%.
Quartz,
subangular
to rounded
(120-200
µm)
*Note: ?=uncertain, tr=trace amounts. Percentages are listed as a percentage of total whole rock volume, unless specified.

16
 
Table 3.1 (Continued)
Lithofacies
Name
Matrix Cements Authigenic
components
(excluding cements)
Porosity Depositional
Environment
Lithofacies
Association
A Greyish-green
dolomudstone
100%. Non-ferroan
dolomicrite
None Not distinguishable <1%.
Intercrystall-
ine
Low energy,
restricted subtidal
environment below
storm wave base
Open subtidal
B Skeletal
wackestone
10-30%. Non-ferroan
micrite
1-3%. Mostly blocky
cement (400 µm) in
interparticle pores
<5%. Anhydrite
needles as cements
(400-2000 µm, tr-2 %),
halite (60 µm, tr-2%) in
intraparticle pores (60
µm, tr-2%), celestine
filling fractures (40-200
µm, tr)
<5%.
Interparticle
and moldic
porosity
Low energy,
restricted subtidal
environment below
storm wave base
Open marine
Subtidal
*Note:?=uncertain, tr=trace amounts. Percentages are listed as a percentage of total whole rock volume, unless specified.

17
(m)
Contacts Sedimentary Structures Allochems Terrigenous
Grains
C Mottled-
nodular
skeletal lime
mudstone
Light
brown
to buff
Skeletal lime
mudstone to
peloidal packstone
0.20-4.04 Lower
and
upper:
sharp
Mottled-nodular; size of
nodules ranging from
0.8-2.5 cm);1 cm
intervals of thin
laminations, distinct to
faint, varying from wavy
to straight.
5-50%. Fragments of:
crinoids (40-360 µm,
1-35%), brachiopods
(80-520 µm, <1%),
solitary rugose corals
(400-600 µm, 0-2%),
gastropods (320-500
µm, tr-3%).
Undifferentiated
skeletal fragments
(80-640 µm, 1-10%).
Peloids (40-100 µm,
0-30%).
0-2%.
Opaques
(16 µm)
D Massive-
laminated
dolomudstone
Light
brown
to light
grey
Dolomudstone
composed of very
fine to fine
crystalline non-
ferroan dolomite
0.73-0.91 Lower:
sharp.
Upper:
slightly
erosional
and
sharp
Thin laminations vary
from straight and parallel
to wavy near the top
contact
Angular-rounded
micritic intraclasts (up
to 4 mm in size) near
the top contact.
<1%.
Opaques (20
µm, tr-3%),
quartz (40
µm, tr)

18
Lithofacies
Name
Matrix Cements Authigenic components
(excluding cements)
Environment
Lithofacies
Association
C Mottled-
nodular
skeletal lime
mudstone
35%. Non-
ferroan micrite,
microspar and
dolomicrite
10%. Coarsely-
blocky and bladed
prismatic, non-
ferroan calcite (5-
10%) in
interparticle pores
3-10%. Planar-euhedral to
planar-subhedral, finely
crystalline dolomite partly
replacing matrix (<64 µm,
<7%). Anhydrite needles
(480-3000 µm, 1-2%) in
matrix and interparticle
pores, halite (40 µm, tr) in
interparticle porosity
<5%.
Interparticle
(tr) and
moldic (60-
80 µm,
<5%)
Shallow subtidal
environment, open
circulation with low-
moderate energy
conditions
Open subtidal
D Massive-
laminated
dolomudstone
85-100%. Non-
ferroan
dolomitic
aphano-
crystalline-
micrite
3-15%. Anhydrite
cement in
interparticle pores.
None <1%.
Interparticle
(tr), vuggy
(tr)
Shallow subtidal
environment,
restricted circulation
and saline conditions
Saline-
subtidal

19
(m)
Contacts Sedimentary Structures Allochems Terrigenous
Grains
E Interlaminated
dolomudstone,
anhydrite and
halite
Brown
to buff
Dolomudstone,
composed of very
finely crystalline to
aphanocrystalline
dolomite; anhydrite,
coarsely crystalline;
and halite, medium
crystalline
0.11-2.70 Lower
and
upper:
sharp
Thin to thick laminations,
varying from straight and
parallel to wavy. 3 to 8
cm-thick anhydrite beds
(with needle like texture)
and 0.2 cm to 1.3 m-thick
dolomudstone
0-20%. Peloids (16-
80 µm, 5-7%). Sub-
angular to rounded
micritic intraclasts
0-3%.
Opaques
(840-
1800
µm)
F Anhydrite Bluish
grey to
white
and
translu-
cent
Anhydrite, medium
crystalline to
extremely coarsely
crystalline; finely
crystalline
displacive halite,
medium crystalline
gypsum and very
finely crystalline
dolomite in matrix
0.16-3.80 Lower
and
upper:
sharp
Anhydrite typically in the
following succession
(bottom to top):
1. massive anhydrite (up
to 0.3 m thick)
2. laminated anhydrite
(up to 1 m thick) with
disseminated dolomite
3. nodular anhydrite (up
to 1.8 m thick)
4. mosaic anhydrite (up
to 1.2 m thick)
5. rare enterolithic (up to
0.08 m thick)
6. chicken-wire anhydrite
and rarely gypsum (up to
0.05 m thick)
None <1%.
Opaques (16
µm)
*Note: ?=uncertain, tr=trace amounts. Percentages are listed as a percentage of total whole rock volume, unless specified.

20
Lithofacies
Name
Matrix Cements Authigenic components
(excluding cements)
Environment
Lithofacies
Association
E Interlaminated
dolomudstone,
anhydrite and
halite
2-25%. Non-
ferroan
dolomicrite
10-40%. Drusy to
blocky, non-
ferroan calcite
cement (4 µm, tr-
10%)
interparticle.
Planar-subhedral
and planar-
euhedral, finely
crystalline
dolomites in
interparticle
porosity (8-12
µm, 10-50%).
Anhydrite cement
in interparticle
porosity (4-10
µm, tr-5%)
<5-10%. Planar-euhedral
to subhedral, finely
crystalline dolomite,
replacing dolomites matrix
in interparticle porosity
(<64 µm). Anhydrite
needles in interparticle
porosity (200-1600 µm, tr),
euhedral halite crystals in
interparticle porosity (16
µm, tr)
<1%.
Intraparticle
and vuggy
porosity
Low energy, saline to
restricted
environment, shallow
subtidal.
Saline-
subtidal
F Anhydrite 0-10%. Non-
ferroan dolo-
micrite (16-40
µm, <5%); non-
ferroan micrite
(aphano-
crystalline, <5%)
occurring in
intercrystalline
pores
None <1%. Displacive halite (16
µm, tr), gypsum in
interparticle porosity (0.4-1
cm, tr), anhydrite (white
and translucent) filling
millimeter-wide fractures
near top contact
- Low energy,
hypersaline
conditions.
Saline mud
flat

21
Figure. 3.1. Core photographs of lithofacies A: greyish-green dolomudstone.
(A) Bioturbated dolomudstone with burrows (pink arrows) and a sharp upper
contact with lithofacies B (skeletal dolowackestone), Comeault No. 1, 447.5 m,
1468.3 ft. (B) Dolomudstone with Palaeophycus burrows (green arrows),
Comeault No. 1, 448 m, 1470 ft.

22
Figure 3.2. Lithofacies A: greyish-green argillaceous dolomudstone. (A) Core
photograph of massive dolomudstone. Red box indicates area of thin section
shown in (B), Kaskattama No. 1, 695.06 m, 2280 ft. (B) Photomicrograph of
massive dolomudstone from (A) showing very finely crystalline to
aphanocrystalline, planar-subhedral dolomite (white) and micrite (brown).
Plane polarized light, Kaskattama No. 1, 695.06 m, 2280 ft.

23
and intraparticle porosity is <1%.
X-ray diffraction (XRD) analysis on two selected samples from the
Comeault No. 1 well (432.21 m and 432.51 m) and one sample from the
Kaskattama well (669.04 m) indicates that the samples are composed of
primarily dolomite and anhydrite (refer to Appendix C). The clay mineral
content was insufficient for any further XRD analysis.
2.2.2 Interpretation
The greyish-green dolomudstone lithofacies is interpreted to have been
deposited in a low energy subtidal environment. The greyish green colour of
the argillaceous mudstone suggests decomposition of organic matter under
oxidizing conditions. The presence of laminations indicates that the sediments
probably accumulated below storm wave base. The abundance and
preservation of straight and parallel laminations, undisturbed by bioturbation,
suggest restricted conditions.
3.3 Lithofacies B: Skeletal Wackestone
3.3.1 Description
Lithofacies B consists of light brown to buff, skeletal wackestone to
rudstone and ranges from 0.02 to 0.60 m thick (Fig. 3.3). The lower and upper
contacts are sharp. This lithofacies is generally massive.

24
Figure 3.3. Core photographs of lithofacies B: skeletal wackestone. (A)
Skeletal wackestone-floatstone with large crinoid fragments (red arrows) and
some unidentifiable skeletal fragments, Comeault No. 1, 457.02 m, 1499.4 ft.
(B) Skeletal wackestone with fractures filled by celestine (black arrow) and
displacive anhydrite needles (blue arrows), Comeault No. 1, 446.93 m, 1466.3
ft.

25
The major allochems in lithofacies B are fragments of crinoids,
bryozoans, brachiopods and tabulate corals (Paleofavosites), and
undifferentiated skeletal fragments (Fig. 3.4). Peloids and silt- and sand-size
quartz are minor constituents. The matrix consists of non-ferroan micrite.
Blocky calcite cement (~400 !m crystal size) occurs commonly in interparticle
pore spaces. Anhydrite needles (up to 1.2 cm length) in the matrix, and very
fine crystalline halite crystals in intraparticle pores, respectively, are scattered
throughout the lithofacies. Medium crystalline celestine fills in millimetre-wide
fractures and fine crystalline anhydrite lines fracture walls. The mineral
identification was done on a sample from Comeault No. 1, 446.93 m, 1466.3 ft.
using XRD analysis. Interparticle and moldic porosity is <1% of total porosity.
Lithofacies B is interpreted to have been deposited in a low to moderate
energy, open subtidal environment. The abundance of crinoids and
brachiopods suggests open circulation in waters of normal marine salinity (cf.
Flügel, 2010). The micrite matrix indicates generally quiet conditions. Silt- and
sand-size quartz is interpreted as eolian in origin, possibly having been
transported from a distant landmass. Anhydrite and celestine, which fill
fractures, are diagenetic.

26
Fig. 3.4. Photomicrographs of lithofacies B: skeletal wackestone (cross
polarized light). (A) Skeletal wackestone with brachiopods (Br), crinoids (C)
and micrite matrix (m), Comeault No. 1, 457.02 m, 1499.4 ft. (B) Skeletal
wackestone showing a tabulate coral (Paleofavosites) (Co) that is mostly
infilled with micrite (m) and blocky calcite cement (Cc), and a crinoid fragment
(C) and brachiopod fragment (Br), Comeault No. 1, 457.97 m, 1509.1 ft. (C)
Skeletal wackestone with fractures filled by celestine (Cs) and anhydrite (An),
Comeault No. 1, 446.93 m, 1466.3 ft.
1 mm

27
3.4 Lithofacies C: Mottled-Nodular Skeletal Lime Mudstone
3.4.1 Description
Lithofacies C consists predominantly of light brown to buff, mottled to
nodular, skeletal lime mudstone and peloidal packstone, ranging from 0.20 to
4.04 m thick (Fig. 3.5). The lower and upper contacts are sharp. Thin
laminations occur in centimetre-thick intervals and vary from wavy to straight.
Light brown to buff nodules range in size from millimetres to centimetres and
typically decrease in size and are more irregular in shape up-section. The
internodular matrix is darker in colour and consists of micrite.
The major allochems in lithofacies C are fragments of crinoids,
brachiopods, solitary rugose corals and gastropods, and undifferentiated
skeletal fragments (Fig. 3.6). The matrix consists of non-ferroan micrite and
dolomicrite, composed of finely crystalline, planar-euhedral dolomite. Coarse-
blocky and bladed prismatic, non-ferroan calcite cement occurs commonly in
interparticle pore spaces. This lithofacies has <5% interparticle and moldic
porosity.
Lithofacies C is interpreted to have been deposited in a low to moderate
energy, open subtidal environment. As previously discussed for lithofacies B,
the abundant fragments of crinoids and brachiopods suggest open circulation
in waters of normal marine salinity (cf. Flügel, 2010). The mottled texture

28
Figure 3.5. Core photographs of lithofacies C: mottled-nodular skeletal lime
mudstone. (A) Mottled-nodular lime mudstone with lighter nodules (black
arrows) that decrease in size and are more irregular in shape near the top,
Comeault No. 1, 440.44 m, 1455 ft. (B) Skeletal lime mudstone with mottled-
nodular texture (red arrow) and brachiopods (black arrow) and anhydrite laths
(indicated by blue arrows), Comeault No. 1, 441.35 m, 1448 ft.

29
Figure 3.6. Photomicrographs of lithofacies C: mottled-nodular skeletal lime
mudstone (cross polarized light). (A) Skeletal wackestone composed of crinoid
(C), equant calcite micrite and microspar in nodules (n), micrite as internodular
matrix and undifferentiated skeletal fragment (Sk) in micrite with a nodular
texture, Comeault No. 1, 471. 53 m, 1547 ft. (B) Peloidal packstone showing
peloids (P) and a gastropod fragment (G) infilled with blocky and bladed
prismatic calcite cement, Comeault No. 1, 441.35 m, 1448 ft.

30
suggests bioturbation occurred where sedimentation rates were sufficiently
low to have allowed the organisms to have reworked the substrate (cf. Flügel,
2010). The nodular texture is diagenetic and probably caused by selective
calcite cementation within the sediment (cf. Flügel, 2010). The abundance of
peloids indicates deposition in a tropical shallow marine environment.
3.5 Lithofacies D: Massive-Laminated Dolomudstone
3.5.1 Description
Lithofacies D consists of light brown to light grey dolomudstone and
ranges from 0.73 to 0.91 m thick (Fig. 3.7). The lower contacts are sharp and
the upper contacts are slightly erosional and sharp. This lithofacies has
centimetre- to millimeter-thick laminations which vary from straight and parallel
to wavy.
The massive-laminated dolomudstone is composed mostly of
aphanocrystalline non-ferroan dolomicrite (Fig. 3.8). Sub-angular to rounded
dolomicrite intraclasts (up to 4 mm in size) with a micrite rim occur locally.
Equant, finely crystalline calcite and euhedral, medium crystalline halite
occurring as cement in intraparticle pore spaces. Interparticle and vuggy
porosity is <1%.

31
Figure 3.7. Core photographs of lithofacies D: massive-laminated
dolomudstone. (A) Dolomudstone with thin to thick planar laminations (black
arrow), Comeault No. 1, 458.2 m, 2295 ft. (B) Dolomudstone with fine laminae
(black arrow), Kaskattama No. 1, 669.5 m, 2195 ft.

32
Figure 3.8. Photomicrographs of lithofacies D: massive-laminated
dolomudstone (crossed polarized light). (A) Dolomudstone with anhydrite (An)
and halite (Ha), dolomicrite (dm) and dolomicrite intraclast (int), Kaskattama
No. 1, 673 m, 2208 ft. (B) Laminated dolomudstone with micrite (m),
dolomicrite (d) and finely crystalline halite crystals (Ha) in dolomicrite,
Kaskattama No. 1, 669.5 m, 2195 ft.

33
Lithofacies D is interpreted to have been deposited in a low energy,
restricted, saline subtidal environment. The abundance of dolomicrite and
presence of planar laminations are interpreted to represent deposition under
quiet energy conditions (cf. Folk, 1959; Flügel, 2010). The lack of bioturbation
and skeletal components suggests a depositional setting that has more
restricted circulation than lithofacies B and C (cf. Flügel, 2010). The
laminations suggests deeper water setting below wave base (Flügel, 2010).
The presence of late-diagenetic halite crystals suggests elevated salinities.
3.6 Lithofacies E: Interlaminated Dolomudstone, Anhydrite and Halite
3.6.1 Description
Lithofacies E consists of light and medium brown to buff, interlaminated
and interbedded dolomudstone, anhydrite and halite (Fig. 3.9), ranging from
0.11 to 2.70 m thick (Fig. 3.9). The lower and upper contacts are sharp. Thin
to thick laminations vary from straight and parallel to wavy. Individual
dolomudstone laminations are millimeter thick and typically occur
interlaminated with centimeter-thick massive anhydrite beds. Halite beds, 2-5
cm thick, are rare.
The dominant allochems in lithofacies E are peloids. Sub-angular to
rounded micritic intraclasts (up to 1.8 mm in size) occur locally and most are
elongate and sub-parallel to bedding. Most of the porosity is cemented by the

34
Figure 3.9. Core photographs of lithofacies E: interlaminated dolomudstone,
anhydrite and halite. (A) Dolomudstone interlaminated with anhydrite laminae
composed of fine anhydrite needles (An-n), Kaskattama, 477.45 m, 2222.6 ft.
(B) Dolomudstone beds (d-b; black arrows indicating interval) interlaminated
with anhydrite laminae (An), Comeault, 471.53 m, 1547 ft. (C) Anhydrite and
halite interlaminated (An-l) with finely laminated dolomudstone, Kaskattama,
696.97 m, 2286.65 ft.

35
coarse crystalline, planar- euhedral-subhedral dolomite and drusy to blocky
calcite. Intraparticle and vuggy porosity is <1%.
Lithofacies E is interpreted to have been deposited in a low energy,
saline subtidal environment. The straight and parallel millimeter scale
dolomicrite laminations intercalated with thin anhydrite and halite laminations
and thick dolomudstone beds are indicative of low energy conditions.
Interlaminated anhydrite and dolomudstone is common in elevated
salinity environments of relatively shallow water depths (Kendall, 1992; Flügel,
2010). The relative abundance of displacive anhydrite needles and subhedral
halite crystals in this lithofacies suggests that salinities were sufficiently
concentrated to preserve precipitate halite in a dolomudstone from an
evaporative drawdown (cf. Kendall, 1992). No obvious evidence of subaerial
exposure was observed in this lithofacies.

36
Figure 3.10. Photomicrographs of lithofacies E: interlaminated dolomudstone,
anhydrite and halite (plane polarized light). (A) Dolomudstone (d) with
interlaminated anhydrite (An) and large, acicular anhydrite needles at the base
of the lamina, Comeault No. 1, 458.5 m, 1504.4 ft. (B) Dolomudstone (d) with
halite crystals (Ha) Kaskattama No. 1, 667.5 m, 2190 ft.

37
3.7 Lithofacies F: Anhydrite
3.7.1 Description
Lithofacies F consists of bluish-grey to white, translucent anhydrite and
ranges from 0.16 to 3.80 m thick (Fig. 3.11; 3.12). The lower and upper
contacts are sharp. Thin to thick laminations occur in centimetre-thick intervals
and vary from wavy to straight.
This lithofacies is composed of various lithologies: massive anhydrite
(up to 0.3 m thick), laminated anhydrite (up to 1 m thick), nodular anhydrite
with a mean size of 3.5 cm (up to 0.18 m thick), mosaic anhydrite with a size
range of 0.5 to 1.0 cm (up to 1.2 m thick), enterolithic anhydrite (up to 0.08 m
thick), and chicken-wire anhydrite (up to 0.05 m thick). Massive anhydrite is
typically found near the base, and is overlain by laminated anhydrite with
dolostone laminae, followed by nodular anhydrite. Anhydrite nodules increase
in size upward in the unit. Enterolithic anhydrite and chicken-wire anhydrite are
rarely observed near the top.
Non-ferroan dolomicrite and/or non-ferroan micrite occur in
intercrystalline spaces in the laminated anhydrite. Coarsely crystalline
anhydrite and extremely coarsely crystalline gypsum fill near-vertical,
millimeter-wide fractures.

38
Figure 3.11. Core photographs of lithofacies F: anhydrite. (A) Chicken-wire
anhydrite, Comeault No. 1, 461.25 m, 1436.8 ft. (B) Interlaminated dolostone
and anhydrite, Comeault No. 1, 463.3 m, 1520 ft. (C) Enterolithic anhydrite
with arrows pointing to the folded anhydrite layers, Comeault No. 1, 637.9 m,
1513 ft.

39
Figure 3.12. Lithofacies F: anhydrite. (A) Mosaic anhydrite (black arrows
indicating the mosaic interval) underlain and overlain by laminated anhydrite,
Comeault No. 1, 433.2 m, 1421.1 ft. (B) Massive anhydrite, Comeault No. 1,
434.5 m, 1426.7 ft. (C) Photomicrograph of anhydrite needles (An) and
dolomicrite (dm) (crossed polarized light), Comeault No. 1, 677.5 m, 2222.6 ft.

40
Lithofacies F is interpreted to have been deposited under low energy,
hypersaline conditions as evidenced by the predominance of anhydrite but
suggests elevated salinity compared to lithofacies E (interlaminated
dolomudstone, anhydrite and halite). The presence of massive anhydrite near
the base, suggests formation from gypsum mush layers (cf. Kendall, 1992).
This lithofacies is suggested to be of a saline mud flat depositional
setting. The presence of nodular anhydrite and mosaic anhydrite, formed by
replacing earlier gypsum (cf. Hardie and Shinn, 1986; Kendall, 2010) in some
intervals, suggests an increasingly restricted circulation (cf. Warren, 2006).
Upward in the succession, chicken-wire anhydrite reflects a supratidal zone
(cf. Warren, 2006) and enterolithic anhydrite is formed by irregular and folded
anhydrite layers with continual growth in quiet environments in a supratidal
zone (cf. Kendall, 1992; Warren, 2006). However, the anhydrite nodules
typically are formed by replacing gypsum crystals during early diagenesis, but
may also be influenced by later diagenesis such as burial and compaction (cf.
Kendall, 1992; Warren, 2006) (Fig. 3.12). The absence of desiccation cracks
and tepee structures suggests that the saline mudflat was probably subaerially
exposed for relatively short periods of time (cf. Kendall, 1992).

41
CHAPTER 4: LITHOFACIES ASSOCIATIONS AND METER-
SCALE CYCLICITY
4.1 Lithofacies Associations
!
The six lithofacies identified in the Red Head Rapids Formation in the
study area, as described in Chapter 3, can be grouped genetically into three
lithofacies associations: 1) open subtidal; 2) saline subtidal and 3) saline mud
flats (Table 4.1).
Table 4.1. Lithofacies associations recognized in the Red Head Rapids
Formation in the study area.
The open-subtidal lithofacies association consists predominantly of
lithofacies A, greyish-green dolomudstone; lithofacies B, skeletal wackestone;
and lithofacies C, mottled-nodular skeletal lime mudstone. The latter two
lithofacies are interpreted to have been deposited in normal subtidal
Lithofacies Name Lithofacies Association
F Anhydrite Saline mud flat
E Interlaminated dolomudstone,
anhydrite and halite
D Massive-laminated dolomudstone
Saline subtidal
C Mottled-nodular skeletal lime
mudstone
B Skeletal wackestone
A Greyish-green dolomudstone
Open subtidal

42
conditions, between fair-weather and storm wave base, as discussed in
Sections 3.3 and 3.4. However, lithofacies A is interpreted to represent more
restricted conditions (discussed in Section 3.2).
The saline subtidal lithofacies association consists of lithofacies D,
massive-laminated dolomudstone, and lithofacies E, interlaminated
dolomudstone, anhydrite and halite. Both lithofacies are interpreted to have
been deposited in low energy, saline subtidal environments, as discussed in
Sections 3.5 and 3.6. The evenly laminated nature of lithofacies E suggests
that this lithofacies represents a slightly deeper water setting below wave base
than lithofacies F.
The saline mudflat lithofacies association consists of lithofacies F,
anhydrite. As discussed in Section 3.7, lithofacies F is interpreted to have
been deposited in a low energy, supratidal to intertidal environment.
4.2 Meter-Scale Cyclicity
The three lithofacies associations in the Red Head Rapids Formation in
the study area comprise four meter-scale cycles, 9.4 to 19 m thick (Fig. 4.1).
Individual cycles consist of an open subtidal lithofacies association, is overlain
by the saline subtidal lithofacies association, which is, in turn, overlain by the
saline mud flat lithofacies association. The lower part of cycle 1, which occurs
in the Churchill River Group, was not fully described for this study.

43
Figure 4.1. Stratigraphic section of the Red Head Rapids Formation
in the Comeault No. 1 well, showing the lithofacies and lithofacies
associations. The lower part of cycle 1 was not described.
Stylolites
Corals
Gastropods
Crinoids
Brachiopods
Skeletal fragments
(undifferentiated)
Symbols
Churchill
River
Group
Severn
River
Formation

44
In the Comeault No. 1 core, cycle 3 (432.9-449.1 m; 1420.3-1473.4 ft.)
is the thickest cycle and is considered to be the most complete. The lower
open subtidal lithofacies association consists of lithofacies A (greyish-green
dolomudstone) which is overlain by lithofacies B (skeletal wackestone) and
then by lithofacies C (mottled-nodular skeletal lime mudstone). Cycles 2 and 4
are missing lithofacies C and F, respectively.
In the Kaskattama No. 1 core, cycle 2 (696.6 to 682.6 m; 2285.4-2239.5
ft.) is considered to be the most complete. The lower open subtidal lithofacies
association consists of lithofacies A (greyish-green dolomudstone) which is
overlain by a thin bed of lithofacies D and is, in turn, overlain by lithofacies B
and C. Cycle 2 is capped by alternating intervals of lithofacies E and F.
Lithofacies B is absent in cycle 3 and lithofacies B, C, D, E and F are absent in
cycle 4.
The four cycles are interpreted to be shallowing and brining-upward
cycles (cf. Warren, 2006). In the Kaskattama No.1 well, the repeated interbeds
of lithofacies E and F in cycles 2 and 3 shows evidence of a fluctuating water
depth during deposition from the saline mud flat lithofacies association to the
saline subtidal lithofacies association.

45
4.3 Correlation of Meter-Scale Cycles
The four cycles, described previously, can be readily correlated
between the Comeault No. 1 and the Kaskattama No. 1 wells (Fig. 4.2). This
correlation reveals some significant lithofacies variations between the two
wells.
Cycle 1 in both wells has thick successions (9 to 14.6 m) of the open
subtidal and saline subtidal lithofacies. The Comeault No. 1 well is capped by
a thick saline mudflat succession lithofacies association with nodular
anhydrite, whereas in the Kaskattama No. 1 well, the saline mud flat lithofacies
association is represented by a thin interval of laminated anhydritic
dolomudstone.
Cycle 2 in the Comeault No. 1 well has a thinner succession of the
open subtidal lithofacies association, and a thicker saline subtidal lithofacies
association than the Kaskattama No. 1 well.
In the Kaskattama well, cycle 3 is 12.2 m thick, and is capped by a
thicker saline mud flat lithofacies association, compared to the cycle 3 in the
Comeault No. 1 well.
Cycle 4 was described only in the basal portion of the Comeault No. 1
well. In the Kaskattama well, cycle 4 is truncated by dolofloatstone and is
considered to represent the disconformity between the Red Head Rapids

46
Formation and the overlying Lower Silurian Severn River Formation (Le Fèvre
et al., 1976; Jin et al., 1993).

47
Figure4.2(a).CyclicalcorrelationbetweentheKaskattamaNo.1andComeaultNo.1wellsinthestudyarea.

48
Figure 4.2 (b). Legend for Figure 4.2 (a).

49
CHAPTER 5: STRATIGRAPHIC CORRELATION
5.1 Introduction
To better understand the lateral facies variation of the Red Head
Rapids Formation in the Hudson Bay Lowland, correlation was attempted
between the Comeault No. 1 and Kaskattama No. 1 wells, the offshore Polar
Bear C-11 well and the Cape Donovan outcrop on Southampton Island
(Fig.1.1).
5.2 Correlation Between Comeault No. 1, Kaskattama No. 1 And
Polar Bear C-11 Wells
In the offshore Polar Bear C-11 well (5959121N/ 8678847W), the Red
Head Rapids Formation is 87.5 m thick, occurring at a depth of 1399.1 to
1311.6 m (4306-4591 ft.) (Aquitaine Company of Canada, 1974). Based on
the drill cuttings, the formation has been described as consisting of white to
brown limestone and tan to brown dolomitic limestone with minor amounts of
anhydrite and halite. Although detailed lithologic relationships cannot be
worked out, three carbonate-evaporite cycles can be identified in the Polar
Bear C-11 well (Fig. 5.1).
Cycle 1 in the Polar Bear C-11 well is 29 m thick has a basal shale unit,
which is overlain by dolostone and capped by a thick sequence of gypsum and
anhydrite. Cycle 2, 22.3 m thick, is composed of interbedded evaporite rocks
and dolostone with an interval of dolostone with gypsum and anhydrite in the

50
Figure.5.1(a).CorrelationofthethreewellswiththeoutcropatCapeDonovan,Southampton
Island(ref).TheCapeDonovanoutcrophasadifferentscale.

51
Figure 5.1 (b). Legend for Figure 5.1 (a).

52
lower portion of the cycle. Cycle 3 is 36.2 m thick and is dominated by
intervals of anhydrite and gypsum.
In comparison to the 3 cycles identified in the Comeault No. 1 well and
Kaskattama No. 1 well, the cycles in the Polar Bear C-11 are generally thicker.
Cycle 2 in the Comeault No. 1 well, Kaskattama No. 1 well and the Polar Bear
C-11 well has variable thicknesses. In the Comeault No. 1 well, the evaporite
interval is thin, whereas in the Kaskattama No. 1 well and Polar Bear C-11
well, the evaporite is interbedded with dolomudstone. In the Polar Bear C-11
well, cycle 3 has the thickest evaporite bed, consisting of salt, gypsum and
anhydrite. Similar to the Kaskattama No. 1 well, cycle 4 is absent in the Polar
Bear C-11 well in the Red Head Rapids Formation.
In addition, using biostratigraphic studies, the Rhipidognathus
symmetricus Zone (Branson et al., 1951), as discussed in Chapter 2, has been
recognized in the Red Head Rapids Formation in both the Comeault No. 1 and
Polar Bear C-11 wells (Le Fèvre et al., 1976; Zhang and Barnes, 2007) and is
used for correlation (Fig. 5.1).
5.3 Correlation With The Cape Donovan Outcrop, Southampton
Island
Recent studies of the Red Head Rapids Formation exposed in outcrops
at Cape Donovan on Southampton Island have focused on the Ordovician-
Silurian boundary and the petroleum potential of the oil shales in the formation
(Zhang, 2008).

53
The exposed Red Head Rapids Formation on Southampton Island is
46.2 m thick with each shale interval 0.3 to 1.0 m thick (Zhang, 2008) (Fig.
5.1). Cycle 1 consists of oil shale in the lower portion of the succession and
brecciated dolomudstone and laminated dolostone in the upper portion of the
succession. Cycle 2 has a thin bed of oil shale in the basal portion which is
overlain by argillaceous dolomudstone, massive dolomudstone, laminated
dolomudstone. Cycle 3 consists of thin beds of oil shales overlain by
brecciated dolomudstone and massive limestone at the top of the cycle.
Three intervals with positive kicks from the gamma ray log from the
Polar Bear C-11 well have been correlated with the three oil shale intervals in
Cape Donovan (Zhang, 2008) (Fig. 5.1).

54
CHAPTER 6: ORGANIC GEOCHEMISTRY
6.1 Introduction
Three samples of lithofacies A (greenish-grey dolomudstone), in the
Red Head Rapids Formation in the study area, previously described in Section
3.2, were analyzed using Rock Eval™ 6 pyrolysis to evaluate the source rock
potential of the lithofacies. The results were compared to oil shale intervals in
the Red Head Rapids Formation on Cape Donovan, Southampton Island,
which have been studied in detail by Zhang (2008).
By convention, an excellent source rock has a total organic carbon
(TOC) value of >10 wt.%, a good source rock has a TOC value of 2-10 wt.%
and an uneconomical source rock has a TOC value <2 wt.% (Allen and Allen,
1990). The production index (PI) is a measure of hydrocarbon generation,
where S1 and S2 are the areas below the two peaks recorded from Rock
Eval™ 6 pyrolysis (Lafargue et al., 1998). S1 represents the volume of the free
hydrocarbons in the sample, and S2 represents the hydrocarbons that could
still be generated during thermal cracking of the kerogen in the sample. A PI
ratio of 0.1 is the minimum for oil generation. The Tmax value correlated to the
maximum temperature a sample has been subjected to during burial and thus
indicates the maturity of the sample (Hunt, 1996). The temperature range,
435-465 ºC, is considered a potential source rock in conventional oil and gas
systems (Hunt, 1996) when using Rock Eval™ 6 instrumentation (Lafargue et
al., 1998). Rock Eval™ 6/ TOC data are best interpreted using large

55
databases. Given the small number of samples analyzed, interpretation is
limited for this study.
6.2 Results For Total Organic Carbon (TOC), Maximum Temperature
(Tmax) and Production Index (PI)
The results of the Rock Eval™ 6/TOC analysis for the three samples of
lithofacies A (greyish-green argillaceous dolomudstone) are summarized in
Table 6.1. Detailed data are provided in Appendix D.
Table 6.1. Summary of Rock Eval™ 6/TOC results from the Red Head Rapids
Formation in the study area.
Well Depth
(m)
Depth
(ft)
Total
Organic
Carbon,
TOC (wt. %)
Production
Index, PI
Maximum
Temperature,
Tmax (ºC)
Comeault No. 1 432.2 1418 0.37 0.19 431
Comeault No. 1 423.4 1389 0.42 0.27 415
Kaskattama No. 1 669.3 2195 0.34 0.11 440
The TOC values for the three samples range from 0.34 to 0.42 wt.%,
and are too low to indicate a good source rock. Only one sample (Kaskattama
No. 1 well, 669.3 m, 2195 ft.) plots in the oil window with a Tmax of 440 ºC. The
other two samples have Tmax values that are slightly below the oil window and
are considered to be thermally immature. The PI ratios range from 0.11 to 0.27
and are at the lower end of the PI range expected for a thermogenic system
(0.1 to 1.0) (cf. Lafargue et al., 1998). This suggests that very light

56
hydrocarbons were released during the early heating of the samples (cf.
Lafargue et al., 1998).
6.3 Hydrogen Index-Oxygen Index (HI-OI) Plot
The Hydrogen Index (HI) is the ratio of S2/TOC, and the Oxygen Index
(OI) is the ratio of S3/TOC, where S3 represents the volume of CO and CO2
produced (Peters, 1986; Lafargue et al., 1998). Plots of Hydrogen-Oxygen
indices (HI-OI) are used to determine the kerogen types (Fig. 6.1) (Peters,
1986). Type I and II kerogens are of marine origin and oil-prone. Type III
kerogen is of terrestrial origin and gas prone.
Although the data set is very small, the results are plotted on a modified
van Krevelen diagram for a preliminary evaluation (Fig. 6.1). Two samples
from the Comeault No. 1 well (423.4 m, 1389 ft.; 432.2 m, 1418 ft.) plot close
to the Type III kerogen curve suggesting a possible terrestrial origin for the
organic matter that has been transported into the subtidal depositional setting.
Oxidation of marine organic matter in shallow water could be an alternative
explanation for the Comeault No. 1 sample (432.2 m, 1418 ft.) plotting close to
the Type III kerogen line (cf. Hunt, 1996).The Kaskattama No. 1 sample (669.3
m; 2195 ft.) falls between the Type II and Type III kerogen lines (Fig. 6.1). The
higher proportion of Type II kerogen in this sample suggests that the organic
matter may be a combination of both marine and terrestrial origin.

57
Figure 6.1. Modified van Krevelen HI-OI plot of lithofacies A samples from the
Red Head Rapids Formation in the study area. Comeault No. 1 samples: C-
1418, 432.2 m, 1418 ft. and 106-1-HBL, 423.4 m, 1389 ft. Kaskattama No. 1
sample: K-2195, 669.3 m, 2195 ft. Lines labelled Types I, II, III kerogen are
from Peters (1968).

58
6.4 Comparison to the Red Head Rapids Formation, Cape Donovan,
Southampton Island
!
Rock Eval™ 6 pyrolysis analysis was conducted by Zhang (2008) on
three oil shale intervals in outcrops of the Red Head Rapids Formation at
Cape Donovan, Southampton Island. A total of 52 samples were analyzed.
The TOC values range from 0.19 wt.% to 30.96 wt.%, PI values range from
0.01 to 0.04 and Tmax values range from 409 to 426 ºC. TOC values for the
Cape Donovan samples are significantly higher than the TOC values from the
Comeault No. 1 and Kaskattama No. 1 samples, but the PI values for the
Cape Donovan samples are lower. The Tmax values for the samples from
Cape Donovan and the two wells are similar. The three oil shale intervals from
Cape Donovan and lithofacies A (greyish-green dolomudstone) in this study
have been being interpreted as thermally immature (Zhang, 2008; M. Nicolas,
2010, pers. comm.).
On a modified van Krevelan diagram, most of the samples from Cape
Donovan plot between Type I and II kerogen lines (Fig. 6.2), indicating that the
organic matter is of marine origin and oil-prone. In contrast, the Comeault No.
1 and Kaskattama No. 1 samples which plot closer the Type II and III kerogen
lines contain organic matter that may be both terrestrial and marine in origin.

59
Figure 6.2. Modified van Krevelen HI-OI plot for samples from lithofacies A the
Red Head Rapids Formation in the study area and oil shales at Cape Donovan,
Southampton Island (Zhang, 2008). Comeault No. 1 samples: C-1418, 432.2
m, 1418 ft. and 106-1-HBL, 423.4 m, 1389 ft. Kaskattama No. 1 sample: K-
2195, 669.3 m, 2195 ft. Lines labelled Types I, II, III kerogen are from Peters
(1968).

60
CHAPTER 7: DISCUSSION
7.1 Introduction
In this chapter, the stratigraphy, sedimentology, and organic
geochemistry of the Red Head Rapids Formation are integrated in order to: (1)
interpret the development of cyclicity, (2) understand the paleogeography of
the basin and (3) evaluate the controls on source rock potential.
7.2 Tidal Flat Island Model
The tidal flat island model is considered to be the most suitable
depositional model for interpreting the Red Head Rapids Formation in the study
area (Fig. 7.1). The model was first proposed by Pratt and James (1986) to
explain the peritidal cycles in Lower Ordovician carbonate strata in western
Newfoundland. The subtidal, intertidal and supratidal lithofacies associations in
these cycles are laterally discontinuous. The peritidal cycles are postulated to
represent small tidal flat islands prograding landward and aggrading to sea
levels in large and shallow epeiric seas (Pratt and James, 1986; Pratt et al.,
1992).

61
Figure 7.1 Tidal flat island model illustrating the tidal islands nucleating and
accreting by aggradation and progradation and shifting in response to
hydrographic forces (modified from Pratt et al., 1992).

62
The tidal flat island model provides an explanation for the shallowing-
upward cycles and the laterally discontinuous nature of the lithofacies identified
in the Red Head Rapids Formation (Fig. 7.2). In addition, the brining-upward
nature of cycles, as discussed in Section 4.1 and 4.2, lithofacies F (anhydrite)
caps each shallowing and brining-upward cycle.
A single cycle in the Red Head Rapids Formation in the study area is
interpreted as follows:
Stage 1: During a transgression, the open subtidal lithofacies
association (lithofacies A: greyish-green dolomudstone, lithofacies B: skeletal
wackestone, lithofacies C: mottled-nodular skeletal lime mudstone) was
deposited in the subtidal zone under relatively low energy conditions.
Lithofacies A represents more restricted conditions at the onset of the
transgression. The saline mud flat lithofacies association (lithofacies F:
anhydrite) were deposited in the intertidal to supratidal zones of the tidal flat
islands. Arid conditions favoured the formation of evaporite deposits in these
zones. Continuous carbonate production resulted in aggradation and
progradation.
Stage 2: With regression, the open subtidal zone became increasingly
more restricted and more saline due to the arid climate. The saline subtidal
lithofacies association (lithofacies D: massive-laminated dolomudstone and

63
Figure 7.2. Modified tidal flat island model illustrating deposition of a carbonate-
evaporite cycle in the Red Head Rapids Formation in response to relative sea-
level fluctuations in an arid climate, based on Pratt et al. (1992). This
illustration is vertically exaggerated.

64
lithofacies E: interlaminated dolomudstone, anhydrite and halite) was deposited
under low energy conditions. These deposits aggraded locally toward sea level
forming tidal flat islands. With subsequent transgression, open-subtidal
conditions were re-established and flooded the saline mud flats.
As a result of relative sea-level fluctuations over time, four shallowing
and brining-upward cycles are formed in the Red Head Rapids Formation.
7.3 Paleogeography Of The Hudson Bay Basin
As discussed in Section 5.3, the cycles recognized in the Red Head
Rapids Formation in the Comeault No. 1, Kaskattama No. 1, Polar Bear C-11
wells have been correlated to the cycles in the Red Head Rapids Formation
exposed at Cape Donovan, Southampton Island. Comparison of the cycles
suggests that the region of the Hudson Bay Lowland was in a basin-margin
position based on the abundance of peritidal lithofacies and the absence of
organic-rich lithofacies and argillaceous lithofacies. Southampton Island is
interpreted to have been situated in a basin-central position in the Late
Ordovician based on the presence of oil shales and argillaceous limestone and
dolostone rocks (cf. Zhang, 2008) and limited evidence for thin evaporites (M.
Nicolas, 2011, pers. comm.).
7.4 Petroleum Source Rock Potential
Based on the Rock Eval™ 6/TOC results, lithofacies A (greyish-green
dolomudstone) in the Red Head Rapids Formation study area has low source

65
rock potential (refer to Chapter 6). The three samples have low TOC values
suggesting either poor productivity and/or poor preservation of organic matter
(cf. Parrish, 1982). The basin-margin setting interpreted for the study area
during the Late Ordovician may be a significant factor. Salinity changes may
also trigger algal blooms, but oxidizing conditions which would be typical in
many shallow-marine settings would promote oxidation of organic matter (eg.
Parrish, 1982). In comparison, the high TOC values from the oil shales in the
Cape Donovan outcrop on Southampton Island indicate periods of high
productivity and/or good preservation of organic matter (cf. Parrish, 1982) The
interpreted basin-central location for Southampton Island during the Late
Ordovician would have favoured low energy, anoxic deep water.
The low Tmax values in the Red Head Rapids Formation indicate
insufficient burial history (cf. Hunt, 1996) in the study area and Southampton
Island.
7.5 Future Work
This study has laid the foundation for future stratigraphic and organic
petrological and geochemical studies of the Red Head Rapids Formation in the
Hudson Bay Basin. The following outlines recommendations for future work:
1) Additional sedimentologic and biostratigraphic data from wells with
conodonts such as the Pen Island No. 1 and Narwhal 0-58 wells should be
used for stratigraphic correlation across the Hudson Bay Basin. In particular,

66
the lateral extent and thickness of the lithofacies in the Red Head Rapids
Formation require further detailed examination.
2) More detailed conodont analysis with closer-spaced sampling intervals,
should be carried out for a more precise biostratigraphic correlation in the Red
Head Rapids Formation across the Hudson Bay Basin.
3) Further sedimentology and organic geochemistry of shale intervals in the
other wells located in the Hudson Bay Lowland should be done to further
evaluate the economic potential of the Red Head Rapids Formation in the
Hudson Bay Basin.

67
CHAPTER 8: CONCLUSION
Detailed sedimentological examination of the Red Head Rapids
Formation in the Comeault No. 1 and Kaskattama No. 1 wells in the
northeastern Manitoba has contributed to an improved understanding of the
depositional origin and source rock potential of the formation. A summary of
the key findings of this study is as follows:
1. The Red Head Rapids Formation is composed of six lithofacies which
are grouped into three lithofacies associations. Lithofacies A (greyish-
green dolomudstone), B (skeletal wackestone) and C (mottled-nodular
skeletal lime mudstone) comprise the open subtidal lithofacies
association. Lithofacies D (massive-laminated dolomudstone) and E
(interlaminated dolomudstone, anhydrite and halite) are grouped as the
saline subtidal lithofacies association. Lithofacies E (anhydrite) is the
saline mud flat lithofacies association.
2. The stacking pattern of the lithofacies associations forms four shallowing
and brining-upward, meter-scale cycles, which are readily recognized in
both wells. A complete cycle consists of the lower, open subtidal
lithofacies association, which is overlain by the saline subtidal lithofacies
association and capped by the saline mud flat lithofacies association.
The tidal flat island model is proposed to explain the shallowing-upward
nature of the individual cycles. Sea-level fluctuations are interpreted to
be the main control for the origin for the stacking of the cycles.

68
3. The meter-scale cycles identified in the Comeault No. 1 and Kaskattama
No. 1 wells can be correlated to the offshore Polar Bear C-11 well. The
three thin oil shales intervals in the Red Head Rapids Formation in the
Cape Donovan outcrop are correlated to the three intervals of lithofacies
A in the study area. Comparison of the cycles in the three wells and in
the outcrops at Southampton Island suggests that the study area during
the Late Ordovician was in a basin-margin position based on the
abundance of peritidal lithofacies and absence of organic rich lithofacies
and argillaceous lithofacies. Southampton Island is interpreted to have
been situated in a basin-central position, based on the presence of oil
shales and argillaceous rocks.
4. Based on Rock Eval™ 6 analysis, lithofacies A in the Comeault No. 1
and Kaskattama No. 1 wells has low total organic carbon (TOC) values
and low maximum temperature (Tmax) values. The low source rock
potential in the study area is interpreted to be due to (a) poor
productivity and/or poor preservation of organic matter in a basin-margin
setting and (b) insufficient burial history.

69
REFERENCES
Allen, P.A. and Allen J.R. 1990. Basin analysis: Principles and applications.
Blackwell Scientific, Oxford, London, 451 pp.
Aquitaine Company of Canada, 1979. Polar Bear C-11 Log Evaluation.
Barnes, C.R., Fortey, R.A. and Williams, S.H. 1995. The pattern of global bio-
events during the Ordovician Period. In: Global events and event
stratigraphy. O. H. Walliser (ed.). Springer-Verlag, Berlin, p. 139-172.
Behar, F., Beaumont, V., Penteado, H.L.D.B. 2001. Rock-Eval 6 Technology:
Performances and Developments. Oil and Gas Science and Technology, v.
56, no. 2, p. 111-134.
Berry, W.B.N. and Boucot, A.J. 1970. Correlation of the North American
Silurian Rocks. Geological Society of America, Special Paper 102, 289 p.
Branson, E.B., Mehl, M.G., and Branson, C.C. 1951. Richmondian conodonts
of Kentucky and Indiana. Journal of Paleontology, v. 25, p. 1-17.
Cumming, L.M. 1971. Ordovician strata of the Hudson Bay Lowlands in
northern Manitoba. In: Geoscience Studies in Manitoba. A. C. Turnock
(ed.). Geological Association of Canada. Special Paper no. 9, p. 189-197.
Dickson, J.A.D. Carbonate identification and genesis revealed by staining.
Journal of Sedimentology Research, v. 36, no. 2, p. 491-505.
Dunham, R.J. 1962. Classification of carbonate rocks according to depositional
textures. In: Ham, W. E. (ed.). Classification of carbonate rocks. American
Association Petroleum Geologists Memoir 1, p. 108-121.
Eaton, D.W. and Darbyshire, F. 2010. Lithospheric architecture and tectonic
evolution of the Hudson Bay region. Tectonophysics, v. 480, p. 1-22.
Elias, R.J. 1991. Environmental cycles and bioevents in the Upper Ordovician
Red River-Stony Mountain solitary rugose coral province of North America.
In: Advances in Ordovician Geology. C.R. Barnes and S. H. Williams (ed.).
Geological Survey of Canada, Paper 90-9, p. 205-211.
Embry, A.F. and Klovan, J. E. 1972. Absolute water depth limits of Late
Devonian paleoecological zones. Geol. Rundschau, v. p. 730-781.
Flügel, E. 2010. Microfacies Analysis of Carbonate Rocks. Springer, Berlin,
984 pp.

70
Folk, R.L. 1959. Practical petrographic classification of limestones. American
Association Petroleum Geologists Bulletin, v. 43, p. 1-38.
Hamblin, A. 2008. Hydrocarbon potential of the Paleozoic succession of
Hudson Bay/James Bay: Preliminary conceptual synthesis of background
data. Geological Survey of Canada, Open File 5731, 12 p.
Hardie, L.A. and Shinn, E. A. 1986. Carbonate depositional environments,
modern and ancient: Part 3: Tidal Flats. Colorado School of Mines
Quarternary, v. 81, p. 1-74.
Heyward, W.W. and Sanford, B.V. 1976. Geology of Southampton, Coats and
Mansel Islands, District of Keewatin, Northwest Territories. Geological
Survey of Canada, Memoir 382, 35 p.
Hunt, J.M. 1996. Petroleum Geochemistry and Geology. Freeman, San
Francisco, 743 p.
Jin, J., Caldwell, W.G.E, and Norford, B.S. 1993. Early Silurian brachiopods
and biostratigraphy of the Hudson Bay Lowlands, Manitoba, Ontario, and
Quebec. Geological Survey of Canada, Bulletin 457, 221 p.
Kendall, A.C. 1992. Evaporites. In: Facies Model - A response to sea level
change. Walker, R. G. and James, N.P (ed.): Geological Association of
Canada, Geotext 1, p. 375-409.
Kendall, A.C. 2010. Marine Evaporites. In: Facies Model-A response to sea
level change. James, N.P and Dalrymple R.W. (ed.): Geological
Association of Canada, Geotext 6, p. 541-576.
Lafargue, E., Marquis, F. and Pillot, D. 1998. Rock Eval 6 applications in
hydrocarbon exploration, production, and soil contamination studies.
Revue de I’Institut Français du Pétrole, v. 53, p. 421-437.
Lavoie, D., Dietrich, J., Duchesne, M., Zhang, S., and Pinet, N. 2010.
Geological setting and petroleum potential of the Paleozoic Hudson
Platform, Northern Canada. Abstract for GeoCanada 2010, Calgary.
Le Fèvre, J., Barnes, C.R. and Tixier, M. 1976. Paleoecology of Late
Ordovician and Early Silurian conodontophorids, Hudson Bay Basin. In:
Conodont Paleoecology. C.R. Barnes (ed.). Geological Association of
Canada, Special Paper, no. 15, p. 69-89.
Macauley, G. 1986. Geochemistry of the Ordovician Boas Oil Shale,
Southampton Island, Northwest Territories. Geological Survey of Canada
Open File 1285, 15 pp.

71
Nelson, S.J. 1964. Ordovician stratigraphy of northern Hudson Bay Lowland,
Manitoba. Geological Survey of Canada, Bulletin 108, 36 pp.
Nelson, S.J. and Johnson, R.D. 1966. Geology of Hudson Bay Basin. Bulletin
of Canadian Petroleum Geology, v. 14, p. 520-578.
Nelson, S.J. and Johnson, M.E. 2002. Jens Munk Archipelago: Ordovician-
Silurian Islands in the Churchill Area of the Hudson Bay Lowlands,
Northern Manitoba. Journal of Geology, v. 110, p. 577-589.
Nicolas, M.P.B. and Lavoie, D. 2009. Hudson Bay and Foxe Basins Project: an
introduction to a GEM Energy initiative, northeastern Manitoba (parts of
NTS 54). In: Report of Activities 2009, Manitoba Science, Technology,
Energy and Mines, Manitoba Geological Survey, GS-16, p. 160-164.
Nicolas, M.P.B. and Lavoie, D. 2010. Hudson Bay and Foxe Basins Project:
Update on a Geo-mapping for Energy and Minerals Program (GEM)
initiative, northeastern Manitoba (part of NTS 54). In: Report of Activities
2010, Manitoba Innovation, Energy and Mines, Manitoba Geological
Survey, p. 186-192.
Norford, B.S. 1970. Ordovician and Silurian biostratigraphy of the Sogepet-
Aquitaine Kaskattama Province No. 1 well northern Manitoba. Geological
Survey of Canada, Paper 69-8, 36 pp.
Norford, B.S. 1971. Silurian stratigraphy of northern Manitoba. In: Geoscience
studies in Manitoba. A. C. Turnock (ed.). Geological Association of
Canada, Special Paper no. 9, p. 199-207.
Norris, A.W. 1993a. Hudson Platform-Introduction. In: Sedimentary Cover of
the Craton in Canada. D.F. Stott and J.D. Aiken (eds.) Geological Survey
of Canada, Geology of Canada, no. 5, p. 643-651 (also Geological Society
of America, The Geology of North America, V. D-1).
Norris, A.W. 1993b. Hudson Platform-Geology. In: Sedimentary Cover of the
Craton in Canada. D.F. Stott and J.D. Aiken (eds.) Geological Survey of
Canada, Geology of Canada, no. 5, p. 653-700 (also Geological Society of
America, The Geology of North America, V. D-1).
Peters, K.E. 1986. Guidelines for evaluating petroleum source rock using
programmed Pyrolysis. American Association of Petroleum Geologists
Bulletin, v. 70, no. 3, p. 318-329.
Pratt, B.R. and James, N.P., 979. The St. George Group (Lower Ordovician), of
western Newfoundland: tidal flat model for carbonate sedimentation in
epeiric seas. Sedimentology, v. 33, p. 313-343.

72
Pratt, B.R., James, N.P., and Covina, C.A. 1992. Peritidal carbonates. In:
Walker, R. G., James, N. P. (eds.): Facies models. Response to sea level
change. Geological Association of Canada, p. 303-322.
Parrish, J.T. 1982. Upwelling and petroleum source beds, with reference to
Paleozoic American Association of Petroleum Geologists Bulletin, v. 66, p.
750-774.
Sanford, B.V., and Grant, A.C. 1990. New findings related to the stratigraphy
and structure of the Hudson Platform. Geological Survey of Canada, Paper
90-1D, p. 17-30.
Sanford, B. V., Norris, A. W., and Cameron, A. R. 1973. Hudson Platform-
Economic Geology. In: Sedimentary Cover of the Craton in Canada. D.F.
Stott and J.D. Aiken (eds.) Geological Survey of Canada, Geology of
Canada, no. 5, p. 701-707 (also Geological Society of America, The
Geology of North America, V. D-1).
Warren, J. K. 2006. Evaporites. Springer, Berlin, 1035 pp.
Zhang, S. 2008 New insight into Ordovician oil shales in Hudson Bay: their
number, stratigraphic position, and petroleum potential. Bulletin of
Canadian Petroleum Geology, v. 56, p. 300-304.
Zhang, S. 2010. Upper Ordovician stratigraphy and oil shales on Southampton
Island (Field Trip Guidebook). Geological Survey of Canda, Open File
6668, 42 pp.
Zhang, S. and Dewing, K. 2008. Rock-Eval data for four hydrocarbon
exploration wells in the Hudson bay and Foxe Basins. Geological Survey of
Canada, Open File 5872, 23 pp.

B1 
 
 
 
 
APPENDIX B:
THIN SECTION DESCRIPTIONS

APPENDIX B: THIN SECTION DESCRIPTIONS
             
   
B2 
 
 
DepthWell
location
Meter Feet
Sample
ID
Lithofacies Lithology Sedimentary
Structures
Allochems
Houston Oils
et al.
Comeault
STH #1
471.5
3
1547 1 C lime wackestone - 10-20%. 100-1200; moderately to
poorly sorted; crinoids (50-60%, 120-
360); brachiopods (5%, 80-400);
fragments (35-45%, 520-640).
Houston Oils
et al.
Comeault
STH #1
464.4 1523.8 2 E dolomudstone
and anhydrite
finely laminated. (~3
mm)
-
Houston Oils
et al.
Comeault
STH #1
404.0
6
1522.5 3 E dolomudstone
and anhydrite
finely laminated -

             
   
B3 
Houston Oils
et al.
Comeault
STH #1
463.5
1
1520.7 4 F anhydrite massive -
*Note Size range of allochems in micrometers unless specified.
Well
location
Depth (m) Matrix Cement Authigentic components
(not including cements)
Porosity
Houston
Oils et al.
Comeault
STH #1
471.53 40%. Non-ferroan micrite,
planar subhedral to
euhedral, finely crystalline
dolomite
coarse-blocky and bladed
prismatic non-ferroan calcite
- -
Houston
Oils et al.
Comeault
STH #1
464.4 - - 20%. Anhydrite in fractures
and voids (0.2 mm); acicular
anhydrite (280–480)
randomly orientated
--
Houston
Oils et al.
Comeault
STH #1
404.06 - - 20%. Anhydrite in fractures
anhydrite(280 – 480)
randomly orientated
-

             
   
B4 
Houston
Oils et al.
Comeault
STH #1
463.51 ‐  ‐  1%. Displacive halite (16, tr),
gypsum in secondary porosity
(0.4-1 cm, tr), anhydrite
(white and translucent) in-
filled porosity and fractures 
‐ 
*Note Size range of authigenic components in micrometers unless specified, tr=trace amounts.

             
   
B5 
 
DepthWell
location
Meter Feet
Sample ID Lithofacies Lithology Sedimentary
Structures
Allochems
Houston Oils
et al.
Comeault
STH #1
462.47 1517.3 5 F anhydrite massive -
Houston Oils
et al.
Comeault
STH #1
459.67 1508.1 6 F anhydrite massive -
Houston Oils
et al.
Comeault
STH #1
and anhydrite
laminations -
Houston Oils
et al.
Comeault
STH #1
457.78 1501.9 8 B skeletal
dolowackestone
massive 45-50%. 800 - 7000; moderately to poorly
sorted; tabulate corals (Paleofavosites)
(< 1%, 7000); brachiopods (20%, 800-
7000); crinoids (50%, 720-2400);
bryozoans (15%, 1200-1400). Algal (<5%,
600-2000). Fragmented skeletals (10-
15%, 400-2800).

             
   
B6 
 
Well
location
Porosity
Houston Oils
et al.
Comeault
STH #1
462.47 - anhydrite and
dolomite cement
1-3%. Displacive halite (16, tr),
gypsum in secondary porosity
(0.4-1 cm, tr)
-
Houston Oils
et al.
Comeault
STH #1
459.67 - anhydrite and
dolomite cement
<40%. Anhydrite needles (280
– 480) randomly orientated
-
Houston Oils
et al.
Comeault
STH #1
458.54 - blocky calcite cement <40%. Anhydrite needles (280
– 480) randomly orientated
<1%. Interparticle and moldic
porosity porosity
Houston Oils
et al.
Comeault
STH #1
457.78 45%
micrite 
  <5%. Anhydrite needles (400-
2000), halite crystals in
intraparticle pores
<1%. Interparticle and moldic
porosity porosity.
 

             
   
B7 
 
DepthWell
location
Meter Feet
Sample
ID
Structures
Allochems
Houston Oils
et al.
Comeault
STH #1
457.41 1500.7 9 B skeletal
dolowackestone-
floatstone
- 50%. 800 - 7000; moderately to poorly
sorted; tabulate corals (Paleofavosites)
(<1%, 7000); brachiopods (20%, 800-
7000); crinoids (50%, 720-2400);
bryozoans (15%, 1200-1400). Algal (<5%,
600-2000). Fragmented Skeletals (10%,
400-2800).
Houston Oils
et al.
Comeault
STH #1
457.02 1499.4 10 B skeletal
dolowackestone-
floatstone
same as sample 9.
Houston Oils
et al.
Comeault
STH #1
and anhydrite
laminations -
Houston Oils
et al.
Comeault
STH #1
447.37 1467.8 12 F anhydrite - -

             
   
B8 
 
 
Well
location
Porosity
Houston
Oils et al.
Comeault
STH #1
457.41 20% micrite  blocky calcite cement same as sample 8 <1% Interparticle and moldic
porosity porosity.
Houston
Oils et al.
Comeault
STH #1
457.02 35% micrite  blocky calcite cement same as sample 8 <1% Interparticle and moldic
porosity porosity.
Houston
Oils et al.
Comeault
STH #1
449.98 45% micrite  - 20%. Anhydrite in fractures
and voids (200); acicular
anhydrite needles (280–480)
randomly orientated
-
Houston
Oils et al.
Comeault
STH #1
447.37 ‐  - 1-5%. Displacive halite (16
µm, tr), gypsum in secondary
porosity (0.4-1 cm, tr),
anhydrite (white and
translucent) filling porosity
and fractures
-

             
   
B9 
 
Depth (m)Well
location
Meter Feet
Structures
Allochems
Houston
Oils et al.
Comeault
STH #1
446.93 1466.3 13 B dolomudstone - 40%. Mostly undifferentiated skeletal
fragments, crinoids are sparse.
Houston
Oils et al.
Comeault
STH #1
446.11 1463.6 14 C skeletal lime
mudstone
thin laminations 50%. 800 - 7000; moderately to poorly
sorted; tabulate corals (paleofavosites)
(< 1%, 7000); brachiopods (20%, 800-
7000); crinoids (50%, 720-2400);
bryozoans (15%, 1200-1400); Algal
(5%, 600-2000); Fragmented Skeletals
(10%, 400-2800).
Houston
Oils et al.
Comeault
STH #1
mudstone
thin laminations same as sample 14
Houston
Oils et al.
Comeault
STH #1
mudstone
thin laminations 10-20%. 100-1200; moderately to
poorly sorted; crinoids (50-60%, 120-
360); brachiopods (5%, 80-400);
fragments (35-45%, 520-640).

             
   
B10 
Well
location
Depth (m) Matrix Cement Authigentic components (not
including cements)
Porosity
Houston Oils
et al.
Comeault
STH #1
446.93 45% micrite dolomite and blocky
calcite cement
anhydrite needles (1.2 cm) in
the matrix, and very fine halite
crystals in intraparticle pores,
respectively. Millimetre scale
fractures filled by celestine
<1%. Interparticle and
moldic porosity porosity.
Houston Oils
et al.
Comeault
STH #1
446.11 30% micrite coarse-blocky and
bladed prismatic non-
ferroan calcite
- <5%. interparticle and
moldic porosity.
Houston Oils
et al.
Comeault
STH #1
ferroan calcite
moldic porosity.
Houston Oils
et al.
Comeault
STH #1
ferroan calcite
moldic porosity.

             
   
B11 
 
DepthWell
location
Meter Feet
Structures
Allochems
Houston Oils
et al.
Comeault
STH #1
mudstone
- same as sample 14
Houston Oils
et al.
Comeault
STH #1
435.16 1427.7 18 E dolomudstone - -
Houston Oils
et al.
Comeault
STH #1
434.87 1426.8 19 F anhydrite - -
Houston Oils
et al.
Comeault
STH #1
433.61 1422.6 20 F anhydrite -

             
   
B12 
 
Well
location
Depth (m) Matrix Cement Authigentic components (not
including cements)
Porosity
Houston
Oils et al.
Comeault
STH #1
ferroan calcite
- <1% interparticle and
moldic porosity.
Houston
Oils et al.
Comeault
STH #1
435.16 45% dolomicrite  - 20%. Anhydrite in fractures and
voids (200); acicular anhydrite
needles (280–480) randomly
orientated
-
Houston
Oils et al.
Comeault
STH #1
434.87 -  - 1-5%. Displacive halite (16, tr),
gypsum in secondary porosity (0.4-
1 cm, tr), anhydrite (white and
translucent) filling porosity and
fractures
None
Houston
Oils et al.
Comeault
STH #1
433.61 ‐  ‐  1-5%. Displacive halite (16, tr),
gypsum in secondary porosity (0.4-
1 cm, tr), anhydrite (white and
fractures
None

             
   
B13 
 
DepthWell
location
Meter Feet
Sample
ID
Structures
Allochems
Houston
Oils et al.
Comeault
STH #1
432.66 1419.5 21 A dolomudstone massive -
Houston
Oils et al.
Comeault
STH #1
Houston
Oils et al.
Comeault
STH #1
423.82 1390.5 23 E dolomudstone,
anhydrite, halite
finely laminated
(3 mm)
-
Sogepet-
Aquitaine
Kaskattama
Province
No.1
699.52 2295.0 24 E dolomudstone,
anhydrite, halite
finely laminated
(3 mm)
-

             
   
B14 
 
Well
location
Porosity
Sogepet-
Aquitaine
Kaskattama
Province
No.1
432.66 - - - <1%. Interparticle
and intraparticle
porosity.
Sogepet-
Aquitaine
Kaskattama
Province
No.1
432.30 - - - <1%. Interparticle
and intraparticle
porosity.
Sogepet-
Aquitaine
Kaskattama
Province
No.1
423.82 35%-40%. Non-
ferroan dolomicrite
10-40% dolomite and
anhydrite cement
10-20%. Anhydrite and
halite in fractures and
voids (mostly 0.2 mm);
acicular anhydrite needles
(280–480) randomly
orientated
-
Sogepet-
Aquitaine
Kaskattama
Province
No.1
699.52 35%-40%. Non-
ferroan dolomicrite
10-40% dolomite and
anhydrite cement
5-15%. Anhydrite and
halite in fractures and
voids (mostly 0.2 mm);
acicular anhydrite needles
(280–480) randomly
orientated
-
*Note Size range of authigenic components in micrometers unless specified.

             
   
B15 
 
Depth (m)Well
location
Meter Feet
Structures
Allochems
Sogepet-
Aquitaine
Kaskattama
Province
No.1
698.90 2293.0 25 E dolostone,
anhydrite, halite
finely laminated
(3 mm)
-
Sogepet-
Aquitaine
Kaskattama
Province
No.1
697.32 2287.8 26 E dolostone,
anhydrite, halite
finely laminated
(3 mm)
-
Sogepet-
Aquitaine
Kaskattama
Province
No.1
696.97 2286.7 27 E dolostone,
anhydrite, halite
finely laminated
(3 mm)
-
Sogepet-
Aquitaine
Kaskattama
Province
No.1
695.65 2282.3 28 E dolostone,
anhydrite, halite
finely laminated
(3 mm)
-

             
   
B16 
 
Well
location
Porosity
Sogepet-
Aquitaine
Kaskattama
Province
No.1
698.90 30-40%. Non-ferroan
dolomicrite
10-40%.Dolomite and
anhydrite cement
20-30%. Anhydrite in
fractures and voids (0.2
mm); acicular anhydrite
needles (280 – 480)
randomly orientated
<1%. Intraparticle
and vuggy porosity
Sogepet-
Aquitaine
Kaskattama
Province
No.1
697.32 30-40%. Non-ferroan
dolomicrite
10-40%.Dolomite and
anhydrite cement
20%. Anhydrite in fractures
anhydrite needles (280 –
480) randomly orientated
<1%. Intraparticle
and vuggy porosity
Sogepet-
Aquitaine
Kaskattama
Province
No.1
696.97 35%. Non-ferroan
dolomicrite
10-40%.Dolomite and
anhydrite cement
20%. Anhydrite in fractures
anhydrite needles (280 –
480) randomly orientated
<1%. Intraparticle
and vuggy porosity
Sogepet-
Aquitaine
Kaskattama
Province
No.1
695.65 30-40%. Non-ferroan
dolomicrite 
10-40%.Dolomite and
anhydrite cement 
15-20%. Anhydrite in
fractures and voids (0.2
mm); acicular anhydrite
needles (280 – 480)
randomly orientated
<1%. Intraparticle
and vuggy porosity 
*Note Size range of authigenic components in micrometers unless specified.

             
   
B17 
 
DepthWell
location
Meter Feet
Structures
Allochems
Sogepet-
Aquitaine
Kaskattama
Province
No.1
Sogepet-
Aquitaine
Kaskattama
Province
No.1
692.32 2271.4 30 C dolowackestone massive same as sample 14
Sogepet-
Aquitaine
Kaskattama
Province
No.1
694.33 2278.0 31 C dolowackestone massive 5-10%. 100-1200; moderately
to poorly sorted; crinoids (50-
60%, 120-360); brachiopods
(5%, 80-400); fragments (35-
45%, 520-640)
Sogepet-
Aquitaine
Kaskattama
Province
No.1
685.31 2248.4 32 F anhydrite massive None

             
   
B18 
Well
location
Porosity
Sogepet-
Aquitaine
Kaskattama
Province
No.1
695.06 100%. Non-ferroan
dolomicrite
None Not distinguishable <1%. Intercrystalline
porosity
Sogepet-
Aquitaine
Kaskattama
Province
No.1
692.32 -35%. Non-ferroan micrite
and dolomicrite, partly
dolomitized and planar-
subhedral to planar-euhedral,
finely crystalline dolomite
10%. Coarsely-
blocky and bladed
prismatic, non-
ferroan calcite (5-
10%) in interparticle
pores
3-10%. Planar-euhedral to
planar subhedral, finely
crystalline dolomite partly
replacing matrix (<64, <7%).
Anhydrite needles (480-3000,
1-2%) in matrix and
interparticle pores, halite (40,
tr) in interparticle porosity
<5%. Interparticle
(tr) and moldic (60-
80 µm, <5%)
Sogepet-
Aquitaine
Kaskattama
Province
No.1
694.33 -35%. Non-ferroan micrite
and dolomicrite, partly
dolomitized and planar-
subhedral to planar-euhedral,
finely crystalline dolomite
10%. Coarsely-
blocky and bladed
prismatic, non-
ferroan calcite (5-
10%) in interparticle
pores
same as sample 30 <5%. Interparticle
(tr) and moldic (60-
80 µm, <5%)
Sogepet-
Aquitaine
Kaskattama
Province
No.1
685.31 - - 1-5%. Displacive halite (16
µm, tr), gypsum in secondary
porosity (0.4-1 cm, tr),
anhydrite (white and
fractures
None

Wong, 2011 (B.Sc.G.Sc.Hons.Thesis-Final).compressed

Wong, 2011 (B.Sc.G.Sc.Hons.Thesis-Final).compressed

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