DEVELOPMENT OF A REGIONAL HIGH-RESOLUTION

STRATlGRAPHlC FRAMEWORK FOR THE

LATE ALBIAN VIKING FORMATION IN EAST-CENTRAL

ALBERTA AND WEST-CENTRAL SASKATCHEWAN.

A Thesis Submitted to the Faculty of Graduate Studies and Research

In Partial Fulfilment of the Requirements For the Degree of Master of Science

In Geology

University of Regina

Jeffrey O. Webber December, 1997

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Abstract

The Lower Cretaceous Albian Viking Formation can be traced as a

continuous sandstone and shale unit across the entire WCS8 from the western

margin in Alberta to the eastem margin in Saskatchewan. Early interpretations of

Viking sand bodies suggested that much of the sand was deposited in a shelf

setting. However, method of transport and modes of reworking remained

unclear. Features contained in the Viking sand bodies include regionally

extensive depositional discontinuities marked by abrupt juxtapositions of facies,

Glossifungites ichnofacies, chert pebbles, eroded rnud clasts and glauconite.

These features suggest that during Viking time fluctuations in relative sea level

were important, causing shifts in depositional environrnents and reworking of

older sediments.

Regional high-resolution stratigraphie analysis of Viking deposits in

western Alberta have led to the development of a chronostratigraphic framework

based on the recognition and correlation of regionally extensive bounding

discontinuities interpreted to have fomed as a result of basinwide fluctuations in

relative sea level. These fluctuations will also be preserved in the deposits of the

eastem margin of the seaway, but there has been little analysis of the Viking in

Saskatchewan. Base of Fish Scales (BFS) - previously interpreted to die out in

mid-basin - and VE4 and their correlative conformities are traced across the

basin to the eastem margin using well log cross-sections and drill cutting

samples. VE4 is truncated proximal to the eastern margin, and structure contour

maps of the VE4, BFS and one other marker show that solutioning of the Prairie

Evaporite has affected the structure of the interval. The Flotten Lake Sandstone,

previously interpreted as a Viking equivalent is interpreted to be younger.

Extending this high-resolution stratigraphie analysis across the basin

enables a chronostratigraphic framework to be established. Using tnis

framework, the stratigraphy can be traced south into the Dodsland Hoosier area

and beyond, allowing the Viking deposits of southem and eastern Saskatchewan

to be interpreted in cmiext with the entire Foreland Basin.

Acknowledgements

First, I wish to thank Bev, my life partner, my sou1 mate, my wife. You've helped me deal with the stress, and shared in the sacrifices as well as the accomplishments. You've been beside me al1 the way, supporting without question. You deserve this as much as 1.

Second, I must thank Katherine Bergman, first for the opportunity, then for the direction, guidance and arguments. I also greatly appreciate her friendship and patience, as I have been known to be quite thick-headed.

1 wish to thank al1 Faculty and Staff of the Department of Geology at the University of Regina for their guidance, and for pushing me to develop a questioning and curious attitude.

I would like to thank Nurnac Energy Ltd., for allowing me to use GeographixTM, especially Judy Pickering, for her help, patience and expertise .

I wish also to gratefully acknowledge PanCanadian Petroleum Limited for the final push, and for their assistance with reproduction.

Table of Contents

Abstract Acknowledgments Table of Contents List of Figures List of Tables

1. Introduction 1 .1 Reg ional Geology and Stratigraphy 1.2 Objectives 1.3 Study Area and Database

2. Previous work. 2.1 lntroduction 2.2. Recent Viking lnterpretations 2.3 Viking High-Resolution Stratigraphic Framework

3. Base of Fish Scales

4. Correlation Markers 4.1 Introduction 4.2 Marker Surfaces 4.3 Relationship to Defined Lithostratigraphic Units

5. Regional Allo-Stratigraphie Correlations 5.1 Correlation of Markers

6. Mapped Structural and S tratigraphic Trends 6.1 Data Base and Computer Mapping 6.2 Structure Contour Maps 6.3 lsopach Maps 6.3 Discussion

7. Discussion 61

8. Conclusions

References Appendix 1: List of Well Locations 1-1 through 5-5' Appendix II: Drill Cutting Descriptions. Appendix I II: Mapping Database

i

iii i v v vii

List of Figures

Fig 1.1

Fig 2.1

2.3

Fig 3.1

3.2

3.3

3.4

3.5

3.6

Fig 4.1 4.2

Stratigraphic Chart showing the division of Lower Colorado Group. Viking oil and gas fields in Alberta and Saskatchewan.

Study area with cross-sections.

Diagram illustrating the equivalence of the eastern margin Flotten Lake Sandstone to the Viking Fomation. lsopach map of the Viking Formation (south) and the Flotten Lake Sandstone (north) with a thin gap between the two sand bodies. Diagram showing the interpreted framework for the Viking Fomation in Alberta.

Structure Contour map of the Base of Fish Scales (BFS) in Al berta (after Walker, 1 995). lsopach map of the interval between BFS and VE4 in Al berta (after Walker, 1 995). Paired gamma ray and resistivity log signatures for Well C l . Paired gamma ray and resistivity log signatures for Well C25. Paired gamma ray and resistivity log signatures for Well A46. Section 1'-ld, isolated to show the gradua1 change in gamma ray and resistivity log signatures of BFS toward the basin margin. Paired gamma ray and resistivity log signatures for Well A41. Paired gamma ray and resistivity log signatures for Well A42.

Type Well showing marker surfaces. Paired gamma ray and resistivity log signatures for Well A41. Paired gamma ray and resistivity log signatures for Well A42. Paired gamma ray and resistivity log signatures for Well A46.

List of Figures (cont'd.)

Plate 1 Plate 2 Plate 3 Plate 4 Plate 5

Fig. 6.1

6.2

6.3 6.4 6.5 6.6 6.7 6.8 6.9

Fig. 7.1

7.2

7.3

7.4

Section 1-1' Section 2-2' Section 3-3' Section 4-4' Section 5-5'

In Pocket In Pocket In Pocket In Pocket In Pocket

Diagram showing the area (shaded) of more detailed regional mapping. Diagram showing the data points used for regional mapping. Structure Contour rnap of BFS. Structure Contour map of MSA. Structure Contour rnap of VE4. lsopach map: BFS to MSA. lsopach map: MSA to VE4. lsopach map: BFS to VE4. lsopach rnap of the St. Walburg Sandstone.

Summary of the stratigraphic relationships of Late Albian Deposits, eastem margin of the Foreland Basin. Diagram showing the revised stratigraphy of the Lower Colorado Group along the eastem margin of the Foreland Basin Diagram showing the area in which VE4 is variably removed by MSC Cross-section la-1 showing three markers: A, 6, and C.

vii

List of Tables

Table 1. Location of occurrences where MsC tnrncates VE4. 47

1. Introduction

1.1 Regional Geology and Stratigraphy

The Colorado Group was deposited along the margins of the Western

Canada Sedimentary Basin (WCSB) during Cretaceous time. It consists of a

series of shales and sandstones deposited in a marine to marginal marine

environment. In Saskatchewan, the lower portion of the Colorado Group is

divided (Fig. 1 .l ) into the following units from base to top: Joli Fou Fonation,

Viking Formation, Westgate Formation, Fish Scales Zone and an un-named

shale. The Joli Fou Formation is a laterally continuous marine shale which

extends across the entire basin, except along the eastem margin where laterally

continuous sandstones (Spinney Hi Il Member) are developed. The Viking

Formation consists of an interbedded succession of shallow marine-shelf

sandstone, siltstone and shale, which also extend across the basin. The

Westgate Formation contains the previously unnamed Colorado shales and the

St. Walburg Sandstone (Bloch et al, 1993). The Base of the Fish Scales Zone is

interpreted to be a condensed section (Leckie et al. 1994) and is often used as a

datum in regional studies. The primary focus of this study is the Viking Fonation

in west-central Saskatchewan and east-central Alberta.

The Viking Formation was first described by Slipper (1 91 7) in the Viking-

Kinsella gas field in Alberta, and can be traœd across the WCSB as a laterally

continuous sandstone, siltstone and shale unit (Beach, 1955, 1956, 1961, 1962;

DeWiel, 1956; Gammel, 1955; Magdich. 1955). It varies from multiple warsening

upward cycles to a single sandstone body only meters thick, and in places

Stratigraphy of the Viking Formation

East-cen tral West-central B iozones Al beria Saskatchewan -- -

Fish Scales Zone

- - -

"Mdlanrni ma Westgate rnanmbensrs"zone

Formation Placenrrceraslrardense

Pense Formation

Fig. 1.1 Stratigraphic Chart showing the division of Lower Colorado Group, matched with biozones used by Stelck (1 958) to define Stratigraphic position of the Viking Formation.

sandstone and conglomerate channel fills have also been described (Leckie et

al, 1994). The stratigraphie position of the Viking Fonation was first described

by Stelck (1 958). The Viking contains an inadequate fossil record for precise

correlation, but Stelck bracketed it between the fossil zones of the Westgate and

Joli Fou Formations which are well defined (Fig.l.1). The Joli Fou shale contains

lnoceramus cornancheanus and 1. bellvuensis as well as Haplophragmoides

gigas (Stelck, 1958). The Westgate Fonation contains the well recognized

Miliammina manitobensis fauna and also two distinct ammonites: Placenticeras

liardense and Diploceras cf. fredencksburgense (Stelck, 1 958). The Viking

Formation is contained between these two zones at the top of the Lower

Cretaceous Albian Stage (Stelck, 1958).

Colorado deposits are much thicker on the western margin because the

accretion of terranes provided a ready source of available sediment, and

associated crustal shortening increased isostatic loading (Simpson, 1980a)

giving nse to increased accommodation space. The Viking Formation records

one episode of major tectonic activity along the marginal orogenic belt (Reinson

et al, 1994), and as downwarping occurred, the increased supply of sediments

prograded rapidly into the basin (Simpson, 1988). Differences in the evolution of

the clastic wedge along stnke are reiated to differences in tectonic processes,

relative sea level changes, basin tilting and rate of sediment accumulation

(Peper, 1994). In contrast, the eastem margin had less accommodation space,

and received much less sediment because the central craton was tectonically

quiet (Simpson, 1986). Viking deposition was terminated by a basin wide rise in

relative sea level, depositing the shales of the Westgate Formation (Simpson,

1986).

1.2 Objectives

In Alberta, where the Viking produces oil and gas (Fig.l.2), many studies

of individual sandbodies and several regional studies (Barr, 1987; Boreen, 1989;

Boreen and Walker, 1991 ; Davies, 1990; Davies and Walker, 1993; Downing,

1986; Downing and Walker, 1988; Hadley, 1992; Pattison, 1991 ; Pattison and

Walker, 1994; Power, 1987, 1988; Pozzobon, 1987; Pozzobon and Walker,

1990; Raddysh, 1986; Raychaudhuri, 1989; Walker, 1995; Walker and Wiseman.

1995) have led to the proposal of a regional allostratigraphy. In contrast, there

have been very few published studies of the Viking Formation in Saskatchewan,

and a corresponding regional allostratigraphic framework has not been proposed.

The Viking Sandstone in Alberta contains several regionally extensive

erosional discontinuities which have been interpreted to have formed in response

to fluctuations in relative sea level. The detaiis of the interna1 Viking stratigraphy

are also well documented (Leckie and Reinson, 1993; Pattison and Walker,

1994; Posamentier et al, 1992). However, the only discontinuity which has been

traced over a large area of Alberta is the Viking Erosion 4 (VE4) surface defined

by Walker (1995). There has been no published attempt to extend this

stratigraphic framework across the basin into Saskatchewan. On the eastem

margin, in the time equivalent Flotten Lake Sandstone (Simpson, 1982) bounding

Viking Oil And Gas Fields

Fig. 1.2 Viking oil and gas fields, western Saskatchewan and east-central Alberta

discontinuities were identified by Webber (1 995) and were interpreted to have

formed in response to base level changes.

The primary objective of this thesis is to develop an allostratigraphic

framework for the interval between the Base of the Fish Scales Zone (BFS) and

the top of the Joli Fou Formation. This is accomplished by tracing the VE4

discontinuity eastward and extending the allostratigraphy of Alberta across the

basin. This correlation will establish a link to the eastem rnargin time equivalent

deposits of the Flotten Lake Sandstone, and provide a basis from which other

more detailed studies of the Viking in Saskatchewan can be launched.

1.3. Study Area and Database

The area of study wvers Townships 40 to 65, from Ranges 15W3 to

16W4 inclusive (Fig. 1.3) The datum used for correlation of the cross-sections is

BFS and is identified from geophysical well logs and drill cuttings in three

Saskatchewan wells (Section 1-1 '; Plate 1). Cuttings were examined from top

down to identify potential cavings, and to define the litholopic changes across

other surfaces recognized on the cross-sections. These will be diswssed in

more detail in Chapter 3. Five cross-sections were constructed using gamma

ray-resistivity logs (Plates 1 through 5). Sections 1 -1'' 2-2', and 3-3' trend

southwest to northeast (Fig. 1.3,) while 4-4' and 5-5' trend northwest to

southeast. These will be fumer discussed in Chapter 4. A smaller area

(Township 45 to 62, Ranges 18W3 to W4) was defined to wnstruct subsurface

isopach and structure maps using three of the stratigraphie horizons identified on

the cross sections. Maps are discussed in Chapter 5.

Al berta Saskatchewan

Fig. 1.3 Area of study, showing location of cross-sections 1 through 5.

2. Previous Work

2.1 Introduction

Early interpretations of the Viking Formation were regional in extent and

invoked several mechanisms of deposition, such as: 1) turbidity currents (Beach,

1955, 1956; Staubo, 1955); 2) nearshore deposition (DeWiel, 1956; Jones,

1961 a 8 1961 b); and 3) tsunamis (Beach, 1956; 1961 ; 1962; Jones, 1962).

Garnmel (1 955) interpreted the Viking to be the result of a momentary

(geological) acceleration of the degradation of the highland, while Stansberry

(1 957) argued that the Viking of central Alberta showed no evidence of

diachronism and was derived from existing sediments to the west. Price (1 962)

interpreted the Viking in Saskatchewan as a brief depositional interruption within

a period of progressive deepening.

A 'typical' Viking succession is descnbed as a marine sandstone encased

in marine shales (Boethling, 1977). Individual sandbodies of the Viking in Alberta

have been interpreted as: offshore and barrier ban (Boethling, 1976; Tiuard and

Lerbekmo, 1 975); tide dominated barrier islands (Amajor, 1980; Amajor, 1984;

Amajor and Lerbekmo, 1980; 1990a; 1990b; Ryer, 1987); tidally influenced

deposits (Ryer and Kauffrnan, 1980); andlor some variation of al1 of the above.

Based on the rounded nature of tourmaline, rutile, apatite, zircon and sphene

crystals found in Viking a res of western Alberta, Young (1 964; 1965) argued that

the Viking was sourced mainly from pre-existing sedimentary rocks. This is

supported by Amajor and Lerbekmo, (1990a, 1990b) who argued that the Joli

Fou was scoured to provide sediment for the Viking.

A number of Viking sand bodies (e.g. Joffre) in Alberta tend to be long and

linear (Fig. 1.2), and were are encased in marine rnudsto~es several tens of

kilometers from their supposedly coeval shoreline deposits. In this setting, these

sand bodies were interpreted to have fonned in an offshore environment with

coarse sediment transported several tan's of kilometers from the shoreline to

depositional sites in the basin (Hein et al, 1986; Koldijk, 1976). This

interpretation poses serious problems in terms of; i) how coarse sediment was

transported to depositional sites in the basin, and ii) how it was subsequently

reworked into long linear sand bodies with coarsening upward facies

associations. This interpretation does not account for many of the features

contained in the Viking, such as the presence of regionally extensive depositional

discontinuities commonly marked by abrupt juxtaposition of facies, lags and

Glossifungites ichnofacies (Walker, 1995). An altemate interpretation

(Beaumont, 1980 & 1984; Reinson et al, 1983; Reinson, 1985; Leckie, 1986;

Ryer, 1987) suggested that a change in relative sea level had caused a shift of

environments. Thsse lowstand deposits were reworked to varying degrees during

a subsequent transgression.

The Viking in Saskatchewan is interpreted as recording deposition in a

shoreline through marine shelf environment (Simpson, 1 980a). Tidally influenced

deposits were reported in several studies (Staubo, 1 970; Boethling, 1 976;

Simpson, 1975; Simpson and O'Connell, 1979; Simpson, 1980b;

O'Connell, 1981). Thickness changes within the Viking appear to occur at the

expense of the Joli Fou (Simpson, 1980c), and were attributed to channel

erosion. The Viking of southem Saskatchewan was interpreted as a regressive

deposit by both O'Connell (1 982) and Koziol (1 988).

In southwestern Saskatchewan, Crockford (1 962) interpreted the Viking at

Dodsland-Hoosier as a continental shelf deposit. Evans (1 970), in a more

detailed analysis, defined six imbricate members younging to the south, and

interpreted them as tidal bars deposited by eastward directed tidal currents.

Pouobon (1987) interpreted the Viking in the Eureka field (Dodsland-Hoosier

area, Saskatchewm) to have formed either through offshore bar migration or

redistribution of barrier island sediments.

The Flotten Lake Sandstone in west central Saskatchewan was

interpreted by Simpson (1 982) as an eastern margin stratigraphic equivalent of

the Viking Formation (Fig. 2.1). Simpson describes the Flotten Lake in very

general terms as a coarse grained siliciclastic wedge, thickest just south of 4-1 0-

65-1 NV3, and thinning to zero (Fig. 2.2) toward the southwest (Simpson, 1979b,

1982). Simpson interprets a relativey narrow area of non-deposition between the

Flotten Lake and the Viking (Fig. 2.2) which trends northwest to southeast.

2.2. Recent Viking lnterpretations

Many recent studies of the Viking Formation in Alberta have used high-

resolution stratigraphic methods to interpret depositional events. Sequence and

allostratigraphy subdivide stratigraphic units on the basis of bounding

discontinuities, which are interpreted to have chronologie significance. These

bounding surfaces are identified on the basis of anomalous facies relationships,

changes in strata andor biostratigraphy (Battacharya and Posamentier, 1 994).

South

Stngie I White - Speckleo ------------

Shalc

BIG S t Wolburg _ _ _ - - - - - 7 Sorrdstonc Fish- Scale Marker __------

RIVER - I m .

\ FORMATION

ÇOU FORMATION JOLI Sand

MANNVILLE GROUP

Fig. 2.1 Diagram illustrating the equivalence of the eastern margin Flotten Lake Sandstone to the Viking Formation. (after Simpson, 1982)

Fi. 22 Isopach Map of the Viking Formation (south) and the Fiotten Lake Sandstone (north) with a thin gap between (rnodified from Simpson 1982).

During the foreland basin phase of sedimentary deposition in Alberta,

there was no discrete shelflslope break on the gently sloping sea floor

(Battacharya and Posamentier, 1994). Lowstand deposition in the Foreland

Basin is characterized by isolated lowstand deposi ts, without recogniza ble feeder

channels, often tens to hundreds of kilometers from recognized preserved

shoreface deposits (Battacharya and Posamentier, 1994). These types of

deposits were commonly interpreted as offshore bars (e.g. the Shannon

Sandstone, Tillman and Martinsen, 1987). Recent interpretations of the Viking

(Downing and Walker, 1988) Cardium (Bergman and Walker, 1987) and the

Shannon Sandstone (Bergman, 1994) recognize that these isolated sandbodies

are bounded by depositional discontinuities and are not related genetically to

their encompassing shales. The discontinuities are interpreted by the authors

listed to have formed in response to base level change.

The Middle to Late Albian is a period of overall sea level rise, punctuated

by periods of stillstand. Allen and Posamentier (1 991) suggested that Viking

incised valleys formed during third order eustatic cycles, resulting in several

superimposed sharp-based transgressive units. Leckie and Reinson (1 993)

identified three major erosional unconfomities within Late Albian time: a basal

Joli Fou unconfomity, an incised valley surface marking the base of the Viking in

the Crystal area, and the transgressive lag that marks the top of the Viking in

most of central and southern Alberta. These surfaces are interpreted to have

forrned in reponse to fluctuations in relative sea level (Leckie and Reinson,

1 993). The Viking was wrrelated (Leckie and Reinson, 1 993) with Caldwell's

(1 984) Kiowa-Skull creek and Greenhorn transgressive-regressive cycles in the

mid-western United States. Secondary cycles are superimposed on

transgressive-regressive cycles and are manifested as 1 ) stacked progradational

shoreline sequences 2) incised valleys and fills, 3) unconformities, 4) condensed

sections and 5) paleosols.

Several recent studies of the Viking in Al berta ( e.g.: Walker, 1 995; Walker

and Wiseman, 1995; Davies and Walker, 1993; Posamentier et al, 1992;

Pouobon and Walker, 1990; and Downing and Walker, 1988) employ sequence

and allostratigraphic techniques to develop a stratigraphic framework based on

the recognition and corelation of several regionally extensive erosional

discontinuities. These erosion surfaces are interpreted to have formed in

reponse to basin wide fluctuations of relative sea level. These recent

interpretations of the Viking Formation focussed on allochthonous wntrols. The

Alberta Viking can be divided into four different types of sedimentary packages:

regional. valley fill, shoreface and transgressive deposits (Pattison 1 991 ).

Pattison defines a 63 kyr cyclicity in fluctuation of sea level for the deposits.

Applying sequence stratigraphic tenninology leads to problems, induding

simplification of the VE3 transgression into one surface, and under-emphasis of

transgressive erosion. However, use of allostratigraphic concepts allow for

subdivision based on rock packages and bounding surfaces.

For the purposes of this study, a comprehensive review of individal Viking

fields in Alberta is unnecessary. However, in order to describe the stratigraphic

framework developed, several examples will be very briefly described first, to

establish the key points that lead to the development of the stratigrapihic

framework.

Crvstal: The Viking in the Crystal Field was interpreted as an incised

shoreface, (Barr, 1987). Crystal was reinterpreted as a multistage estuary

fiIl deposit (Reinson et al, 1988). In this interpretation relative sea level

dropped at least thirty meters to incise the valley. Later, Pattison and

Walker (1 994) also interpreted the Crystal deposits as two incised valleys

filled with estuarine deposits and showing little evidence of tide dominated

deposits.

Joffre: The linear Viking sand body at Joffre Field in Alberta is interpreted

as an incised shoreface deposit, (Downing and Walker, 1988) cut during a

sea level lowstand. The subsequent transgression planed off any

evidence of subaerial exposure, and deposited mudstone above.

Gilbv: The Gilby '6' field was interpreted as a stom deposit (Koldijk,

1976). Raddysh (1 986) in a study of Gilby A and B fields reinterpreted

Gilby based on the erosive bottom contact and the chaotic nature of the

conglomerate overlying the erosional surface. Raddysh suggested two

possible formation rnethods: transgression followed by regression or rapid

regression followed by slower regression.

Joarcam: Power (1988) traced bounding discontinuities tens to hundreds

of kilometers, interpreting them to have fomed by processes affecting the

whole basin. Posamentier and Chamberlain (1 993) suggested that the

main sandstone fomed as a shoreface succession dunng a forced

regression and was later truncated by transgressive ravinement. Walker

and Wiseman (1 995) however, suggested the Joarcam shoreface forrned

during a pause in an overall transgression.

Willesden Green: Boreen (1 989) interpreted the VE2 surface to be a

channel scour, and VE3 as a major transgressive ravinement surface with

significant erosion. VE4 was interpreted as a stepwise ravinement surface

which cut al1 others.

Caroline and Garrinpton: Leckie (1 986) defined WO distinct facies

associations separated by a regional unwnformity in Caroline: a lower

regressive shoreline; and an upper transgressive facies association. The

Viking at Garrington was interpreted as a shelf deposit (Robb, 1985). The

VE3 and VE4 surfaces in the Caroline and Garrington areas were

subsequently reinterpreted (Davies, 1990) to be stepped ravinement

surfaces similar to Willesden Green (Boreen, 1 989).

In Saskatchewan, Pouobon and Walker (1990) suggested the Viking at

Eureka formed as a plume or ridge in front of a delta distributary channel during

regression. Interna1 erosion surfaces were foned during subsequent

transgression as the ridge was bioturbated and later abandoned during the

subsequent transgression.

2.3 Viking High-Resolution Statigraphic Framework

Recognition of the signifimnce cf bounding surfaces has enabled

stratigraphers to remove the genetic links previously interpreted between the

Viking sandstone and its encompassing rnudstone (Reinson et al, 1983, Leckie,

1986, Reinson 1986). Overall interpretation now depends not only upon lithology,

but also on identification and interpretation of the erosion surfaces. Downing

(1 986) and Pattison (1 991 ) recognized that these erosion surfaces could be

traced between fields, and began to build on these relationships. In the Viking of

Alberta, the surfaces were given various names, but were later simplified to VE2,

VE3 and VE4 (Pattison, 1991 ; and Hadley, 1992). The relationships between

these surfaces are shown in Fig. 2.3.

Pattison (1 991 ) and Hadley (1 992) recognized that VE3 and VE4 could be

traced between fields. Both surfaces were correlated through the Harmattan

East and Crossfield area as regionally extensive ravinement surfaces that could

be traced into the Caroline, Gamngton, Crystal and Joffre fields (Hadley, 1992).

VE2 formed as valleys incised at Crystal and Willesdon Green during a relative

sea level fall. During subsequent relative sea level rise, erosion at fair weather

wave base (FWWB) gave rise to the VE3 ravinement surface, and incised

channels were backfilled (Boreen and Walker, 1991 ). VE3 was created initially by

subaerial erosion, (Hadley, 1992) and then non-marine and shallow marine

deposits were eroded during transgression.

VE4 is covered by a transgressive lag of up to 5 m of grave1 which

presumably came from streams originally crossing the floodplain. Walker (1 995)

defines several marker beds which onlap the VE4 surface, forming as a result of

minor forced regressions superimposed upon the transgression (supported by

Leckie and Reinson, 1993). VE4 is interpreted to have been formed by erosion

during subaerial exposure (RSE), and was then modified during subsequent

( CRY STAL 1 45 WG- ,eneu-e 5 \Glt.Bf-* F, WG-S

\ CAR. JOFFRE

- Fig. 2.3 A summary diagram showing the interpreted framework for the Viking

Formation in Alberta. Circled numbers are the Viking Erosion (VE) surfaces. Tracing these surfaces through the Alberta subsurface allows the relationships between the fields to be defined. For discussion, see text (modifieci from Boreen and Walker. 1991).

transgression (TSE) (Walker, 1995). Walker (1 995) predicts a lowstand

shoreface associated with the maximum lowstand of the VE4 transgression,

somewhere to the northeast of his study area (Fig. 3.2), possibly in

Saskatchewan.

In a regional context, VE4 is interpreted by Walker (1995) as a ravinement

surface fonned during the final transgression of the Viking sea. In this context

VE4 defines the base of the Transgressive Systems Tract. In Alberta, Viking

deposits below VE4 form the part of the Lowstand Systems Tract. Deposits

above the VE4 are contained within the Transgressive Systems Tract. BFS is

the condensed section or maximum flooding surface which in this context defines

the base of the Highstand Systems Tract. VE2 and VE3 correspond to higher

order fluctuations of relative sea level within the Lowstand Systems Tract.

3. Base of Fish Scales

The Base of the Fish Scale Zone (BFS) is a basin wide marker which

defines the boundary between the Albian and Cenomanian stages of the Lower

and Upper Cretaceous. In Alberta BFS contains fish scales and skeletal

remains within finely laminated and non-bioturbated sandstone and siltstone

(Leckie et al, 1994). It has a high organic carbon content, suggesting deposition

under poorly oxygenated conditions (Leckie et al, 1994). BFS is a condensed

section and is interpreted as a maximum flooding surface (mfs), representing a

major hiatus with substages missing from above and below (Leckie et al, 1994).

Most recent studies of the Viking Formation in Alberta have used BFS as

a datum. In Alberta, BFS structure contours (Fig. 3.1 ) show an extremely

shallow dip (4') to the southwest (Walker, 1995). Walker argues that BFS is

essentially horizontal. If this is the case then an isopach of the interval between

BFS and VE4 (Fig. 3.2) is essentially a structure contour map showing the

topography on the VE4 surface.

To extend the existing stratigraphy across the fourth Meridian and remain

consistent with recent studies of the Viking in Alberta, it is necessary to use BFS

as a datum. In the Alberta and central Saskatchewan portions of the WCSB,

BFS is easily identified on well logs, however, near the eastern margin of the

basin, itsJ characteristic log signature becomes difkult to distinguish. In the

western and central portions of the basin, BFS is characterized by an abrupt

increase on the gamma ray log, while the corresponding changes on

Fig. 3.1 Structure Contour map of the Base of Fish Scales (BFS) in Alberta (after Wal ker, 1 995).

Fig. 3.2 lsopach map of the interval between BFS and VE4 in Alberta. (after Walker, 1 995).

the resistivity log are more subtle. This is well illustrated at the west end of

section 3-3' on Well C l (Fig. 3.3). At a location farther northeast, Well C25 (Fig.

3.4), the signatures have changed somewhat, and BFS becomes more dificult to

identify. Along the eastern margin the characteristic BFS signature has al1 but

disappeared. In Well A46 (Fig. 3.5), BFS is almost lost in a silty shale signature.

There are several depths on the log that could be interpreted as BFS signature.

where a slight increase of the gamma ray corresponds to a resistivity peak.

The gradational eastward change in BFS is well illustrated on cross-

section 1' -ld (Fig. 3.6). At the western end, in Well A36, BFS is easily identified

by the pronounced increase in the gamma ray. In the unit above BFS however,

the gamma ray decreases and the log is funnel shaped, suggesting a

coarsening/sand ier upward trend. Tracing th is funnel-shaped log response

toward the east. the log signature shows this upward coanening unit becoming

more blocky and thickening at the expense of the shalier unit above (Fig 3.6).

As well the increase in the gamma ray at the BFS horizon becomes less abrupt

to the east, and almost disappears in Well A43 (Fig 3.6). Two townships farther

east in Well A46, BFS is difficult to identify in the relatively undifferentiated

siltstones and shales between the tops of the lower Colorado and the St

Walburg Sandstone (Fig. 3.5).

Because of the difficulty in correlating BFS in Saskatchewan, more

evidence was needed. In Alberta, BFS is a condensed section, containing

spines, fish scales and skeletal remains within finely laminated and

BFS

Fig. 3.3 Paired gamma ray and resistivity log signatures for Well C l (Plate 3. 4-1740-28w3) BFS correlates to the abrupt increase on the gamma ray and the conesponding but more subtle response of the resistivi log. This signature is consistent throughout the western and central basin.

BFS

Fig. 3.4 Paired gamma ray and resistivity log signatures for Well C25 (Plate3, A10-2348-19~3). BFS has changed, no longer a distinct gamma ray increase, but is süll recognized on the resistivity log.

BFS

Fig. 3.5 Pairea gamma ray and resistivity log signatures for Well A46 (Platel, 16-1 8-65-22W3). Note that the characteristic gamma ray signature is gone and BFS is now lost in a silty shale unit. Chip sarnples were used to identify BFS in this well (see text).

Fig. 3.6 A portion of Section 1, (Plate 3) isolate gamma ray and resistivity log signature

iolâted to show the gradua1 change in iatures of BFS toward the basin margin.

non-bioturbated sandstone and siltstone (Leckie et al, 1994). Drill cuttings were

examined in 3 wells (Figs. 3.5, 3.7, 3.8; App[endix II) along section 1 to identify

the same types of materials and aid cmelations. Observations were made with

an Olympus Tokyo binocular microscope having magnification settings ranging

from 6 . 3 ~ to 40x. In each case, samples were examined from the top down, to

identify potential cavings in lower samples.

In Well A46 (Fig 3.5) the top of the Lower Colorado Group lies at 262.5 m.

Below this pick on the resistivity and gamma ray logs there is no obvious

correlation with BFS of the central basin as discussed above. Samples were

taken at three meter intervals, and al1 depth samples in this well contain between

five and ten percent warse upper to very coane lower quartz and feldspar

clasts. The grains were angular and poorly sphericial. These are interpreted as

cavings from above the section. From 230 to 281 m. the cuttings comprise a

medium grey silty shale which may wntain small amounts of CaC03 and what

appears to be a dark mica. There are no phosphatic clasts. At 284 rn

phosphatic grains begin to appear in trace quantities in the shales, although no

identifiable fragments were observed. At 287 m. the medium grey silty shale

wntains about 15% phosphatic material. There are recognizable spines and

fragments that appear to have been scales andlor teeth, as well as nondescript

bits of organic debris in the shales. At 290 ml al1 traces of organic and

phosphatic material have disappeared from the shales. On the basis of the

samples and the corresponding well log information, the BFS pick was made at

286 m (fig 3.4).

In Well A41 (Fig 3 3 , samples were taken at five meter intervals.

Samples correlating with the top of the Lower Colorado, between 190 and 21 0

m, consist of dark grey silty shales, with almost no phosphatic particles. In this

well, cavings do not appear to be as straight forward as in Well A46. Individual

lithologies appear to be spread over several samples as cavings. For example,

siltstone particles first seen at 180m are still appearing in traces at 205 m. At

21 5 rn, spines are observed, as well as bioclasts (teeth?) with nondescript

phosphatic material and traces of pyrite. This phosphatic material is observed

down to 235 m. but remains poorly preserved and difficult to identify. Trace

amounts of pyrite can also be seen at 220 and 225 m, along with small amounts

of (medium upper sized) quartz grains which show medium sphericity and are

subangular to subrounded. Drill cutting evidence from this well suggests that

BFS occurs at 217 m.

Well A42 (Fig. 3.8) shows the top of the Lower Colorado at about 165 m.

The uppemost strata (1 65 -1 75 m) are again comprised of medium grey silty

shales down to 180 m. Phosphatics appear in traces at 170m, and are seen in

al1 samples to 270 m, with varying concentrations. Grain size increases

gradually downward to siltstone at 185 m. The sample at 205 m wntains a

similar medium grey siltstone and 25% clear quartz grains, suggesting that the

St Walburg Sandstone has been intercepted. Between 170 and 200 m the

background phosphatic concentration appears to be about 2-3s except at 190

and 195 m. Here the concentration increases to 10 and 8% respectively, and ai

190m. spines and possibly teeth are recognizable. Just above, at 185 m.

Fig. 3.7 Paired gamma 8-5-62-26\1113). (see text).

ray and resistivity log signatures for Well Drill cutîing evidence was used to define

A41 (plate 1, BFS in this well

BFS

Paired gamma ray and resistivity log signatures for Well A42 (Plate 1. IO-2342-25W). Drill cuttîng evidence was used to define BFS in this well (see text).

pyrite concretions are found, suggesting reducing conditions. At 200m. the

phosphatics return to a trace, and quartz grains have appeared. On the basis of

lithology and phosphatic concentration, BFS was chosen at 191 m.

Using the sample descriptions and the presence and concentration of

phosphatics, BFS was correlated to the geophysical well logs. This supported

the correlations on the cross sections. Correlation of BFS was aided with the

use of bulk density logs in the mapping portion. as the Density logs appeared to

showed a consistent increase at the approximate level of BFS.

4. Correlation Markers

4.1 Introduction

To aid the correlation of the regional cross sections through Alberta and

into Saskatchewan, the intewal between BFS and Joli Fou was subdivided using

several markers (Fig 4.1) which are defined according to their respective log

signatures. In total six surfaces are correlated along the cross sections. In

descending order these aïe BFS, MARKER SURFACE A (MsA), MARKER SURFACE 6

(MsB), MARKER SURFACE C (MsC), Viking Erosion 4 Surface (VE4), and MARKER

SURFACE D (MsD). With the exception of MSB and VE4, al1 markers can be traced

across the basin to the eastem margin.

As previously discussed in Chapter 3, drill cuttings were used to aid the

correlation of BFS. Where possible cuttings were examined down to the lower

marker surfaces. The surfaces themselves could not be described, but changes

in lithology could. Cuttings were compared to the log signatures, and

relationships inferred. Because BFS has been described in detail in Chapter 2, it

will not be discussed here. MSB and MSD cannot be described in terrns of

lithological changes, because MsB could not be correlated into the area in which

cuttings were examined. and cuttings were not examined to the depth needed to

document MSD.

4.2 Marker Surfaces

MARKER SURFACE A (MsA) is distinguishable on logs by a change from a

blocky signature below to a coanening upward sigature above (Fig. 4.1). It is

BFS

MSB

MSC

VE4

Fig. 4.1 Type Well showing marker surfaces. Well A4 (ï-3-52-15W3).

generally recognized as a sharp decrease on the gamma ray log (Fig 4.1 ) which

corresponds to an increase on the resistivity log. This f o n s a distinct sharp

based coarsening upward signature on the logs, which can be correlated across

al1 sections and it is interpreted as a discontinuity bounding two distinct lithologic

units. In Well A41(Fig 4.2) cuttings show very little change across the surface. In

Well A42, (Fig 4.3) the sample below contains a medium grey siltstone with

traces of quartz and pyrite. Above the hnsA surface the sample contains a

medium grey siltstone speckled with white dolornitic limestone, 5% phosphatic

material and 5% coarse to very warse quark grains, as well as trace amounts of

pyrite and calcite grains. In Well A46 (Fig 4.4) the sample below MSA at 320 m is

composed of a medium grey siltstone. The sample above (317 m) contains the

same medium grey siltstone and traces of phosphatics, as well as about 10%

very fine, well consolidated light tan sandstone.

MARKER SURFACE B (MsB) can be seen only in the western end of Section

1-1' (Plate 1 .) In Well A l it is recognized as an increase on the gamma ray and

a decrease on the resistivity log. The MSB (Fig.4.1) can be correlated through to

about Weli A33, where it bewmes unidentifiable.

MARKER SURFACE C (MsC) is reçognized on logs by a characteristic

decrease on the gamma ray log and a wrresponding increase on the resistivity

log signal (Fig. 4.1 ). In Well A41 (Fig 4.2), there is a change across this surface

from a medium grey shaly siltstone with traces of quartz below, to a grey shaley

siltstone above mixed with: 10% gamet coloured siltstone; 4% quartz grains; and

traces of pyrite. In Well A42 (Fig. 4.3) MsC is bracketed by a medium grey

BFS

MSC

VE4

215m, it grey :

220m, lt grey :

265m, R grey

Rg- 442 Paired log signatures for Well A41, with descriptions for -

individual. sample depths. For complete d b p t i o n s see Apbndix II.

j 215m. lt grey shaly silt bace pyrite

' 220rn. lt grey shaly silt trace of pyrite 8 phos

t

- 250m, it grey shah s i i trace pyrite

255m # grey shaly sa 20% gamet col sltsf 4%

260m. It gray shaty sin. 10% gamet cd SM, 4%

265111, k grey shaty SR mdsf trace quartz

~g signatures A41, with ions for - d sample For complete ions see k II .

BFS

MSA

MSC

VE4

MSD

Fig.4.3 Pairedlog signatures for Well A42. wiVi descriptions for individual sample depths. For complete descriptions see Appendk II.

i80m. med grey shaly Olt, bace pyrite. trace

phos

l85m. med grey SM, pyrite; 34% phos. trace lighi R quark.

190n meâ grey sbt, 10% phos, trace CaC03

225m med grey %5% phos. trace pyrite.

230m. med grey dbt, 203% red s%. 29% phos.

trace pyrite.

235rn, rned grey SM, 34% brn and indian red

SM, 3% phos, trace pyrite

240m. med grey sltst, 5.10% phos,

245m missing

250m. 25% CU to vcU qz, tmcë phos. med grey

sttst

Paired log signatures for Well A42, with descriptions for individual sample depthç. For mmplete desaiptions see Appendii II.

281m. med gm

, 2Wm. med gn

, 287m, rned gn

290m, medium

BFS

MSA

MSC

VE4

MSD

Fig. 4.4 Paired log signatures for Weil A46. with 'descriptions for individual sample depths. For complete

S, descriptions see Appendix II . -

338m1 CU to vcL quartz, rned grey sltst, trace

d log signatures Vell A46, with riptions for idual sample hs. For complete riptions see mdbc II.

3411~1, CU to v c l quariz, med grey sltst. trace

siltstone with 5-1 0% phosphatic material below and a similar siltstone above,

containing brown and red siltstone and trace amounts of phosphatic debris and

pyrite. In Well A46 (Fig 4.4) the change on the log does not correspond well to

the samples. At 329 and 332 m, samples wntain medium grey siltstone with

traces of phosphatic material, while at 335 m the sample is mostly quartz with

some phosphatic and grey siltstone. The MSC is identified on the well log at

330 m.

The Viking Erosion 4 surface (VE4) is recognised as a sharp increase on

the gamma ray log and a corresponding sharp decrease on the resistivity log.

Cutting samples were not examined for VE4 in well A41 (Fig 4.2). and the

sample directly above VE4 in well A42 (Fig 4.3) had been misplaced. The

sample below VE4 contained 25% quartz, some trace phosphatic material and a

medium grey siltstone. There were no changes evident in samples for well A46,

(Fig 4.4.) Samples are composed of warse to very warse quartz, with srnaIl

arnounts of medium grey siltstone and traces of phosphatic material.

MARKER SURFACE D (MsD) is recognized as a sharp increase on the

gamma ray log which corresponds to a decrease on the resistivity log. This

surface separates two units; a somewhat coarsening upward unit below from an

upper unit which contains a series of either blocky or coarsening upward cycles.

As discussed above, MSD was not documented in cutting samples.

4.3 Marker-Lithostratigaphic Unit Relationships

The bounding surfaces described above subdivide the section between

the top of the Joli Fou Formation and BFS into three stratigraphie packages:

BFS to MSA, MSA to VE4; and VE4 and MSD. The package between BFS and

MSA contains the St. Walburg Sandstone and correlates to the upper portion of

the Westgate Formation. The package between MSA and VE4 is a muddier

interval above the Viking Sandstone, and correlates with the lower part of the

Westgate Formation. It is the depositional result of the maximum flooding of the

sea during late Viking time and contains the finest sediments. These WO

packages are mapped in more detail for a smaller area of Saskatchewan in

Chapter 5. The package between VE4 and MSD correlates to the bulk of the

Viking deposits in Alberta. The bounding discontinuities - or their correlative

conformities-described previously and summarized for Alberta by Boreen and

Walker (1 991) are contained between these two boundaries.

5. Regional Allo-Stratigraphie Correlations

Five cross-sections were constnicted for the Viking interval across east

central Alberta and west central Saskatchewan (Plates 1 to 5). Cross-sections

1-1' through 3-3' are parallei to depositional dip (Fig. 1.3)' trending southwest to

northeast, and cross-sections 4-4' and 5-5' are parallel to depositional strike and

trend northwest to southeast. Cross-sections were constructed using paired

gamma ray and resistivity log signatures and BFS was used as a daturn. At the

west end of cross-sections 1 - A ' , 2-2', and 3-3', BFS has a very distinct signature

on the logs, however, it becomes increasingly more difffcult to identify toward the

eastern margin as discussed previously.

Cross-section 1-1' (Plate 1) contains 46 wells and extends from Well 7-

12-51 -1 6w3 (Al ) in the west to Well 16-1 865-22w3 (A46) in the east. Cross-

section 2-2' (Plate 2) contains 43 wells and extends from Well 8-4-44-8w4 (BI )

in the west to Well 12-4-57-1 8w3 (843) in the east. Cross-section 3-3' (Plate 3)

contains 32 wells, and extends from Well 4-1 7 4 0 28w3 ( C l ) to Well 6-1 2-52-

14w3 (C32). Cross-section 4-4' (Plate 4) contains 38 wells, and extends from

Well 10-3080-24w3 (Dl ) in the north to Well4-1145-16w3 (D38) in the south.

Cross-section 5-5' (Plate 5) contains 35 wells, and extends from Well4-24-58-

9w4 (El) in the north to Well 13-23-44-24w3 (E35) in the south. Well density on

al1 sections averages about two per township. Land locations for the wells used

on the cross-sections are listed in Appendix 1.

5.1 Correlation of Markers

All rnarkers, with the exception of MSB, were correlated along each of the

five cross-sections. The results of these correlations are discussed below.

MARKER SURFACE A (MsA) forms the base of a distinct coarsening upward

signature which c m be traced the length of ail cross-sections. Each of the dip

sections (Plates 1, 2, 8 3) show a significant amount of vertical relief along MSA

toward the basin margin (east). This is particularly prevalent in cross-section 2-

2' (Plate 2), where MSA shows at least 20 rn total vertical relief between Well B I

and Well 837. The surface has a significant amount of topographic relief, as it

retums (approximately) to its original height in several places between the two

wells (Le. B I 1, 825, 830). MSA truncates a horizontal marker (Plate 1, Wells

A39 and A40), suggesting it is erosional in nature. MSA also shows as much as

10 m of vertical relief between individual wells along the cross-section (Plate 1,

Wells A30 and A31 ). In cross-section 44 ' (Plate 4), a strike section along the

eastern margin, there is a progressive increase in relief between MSA and BFS

(MSA drops relatively) toward the middle of the section (Well D23) after which

there is an abrupt decrease (Well D27) and the surface flattens. In cross-

section 5-5' (Plate 5) MSA shows no significant topographic changes the length

of the section.

The package bounded by BFS and MsA shows a general thickening trend

toward the northeast. This does not appear to occur at the expense of the lower

package, contained between MSA and MSC.

The MSB is shown only on cross-section 1-1 ', where it can be traced from

Well A l to Well A33. It is recognized as an increase on the gamma ray which

corresponds to a decrease on the resistivity log signature. Because it could not

be traced across the sections, it will not be discussed in detail.

The MSC surface can be correlated along the length of each cross-

section. It is recognized on the basis of it's strong resistivity increase, and

corresponding but lesser gamma ray signal decrease. This surface is seldom

separated from VE4 by more than 5 ml and in several places appean to truncate

VE4 (e.g. Plate 4, Well D l 1 ) on each of the cross-sections (See Table 1). In

several of these occurences, VE4 is removed in only one well (Wells B I 8. 826,

835, Plaste 2; Wells D l 1, D30, Plate 4). In cross-sections 1 -1 ', 4-4, and 5-5',

however, MSC removes VE4 in multiple wells, giving it a significant areal extent

(Plate 1 : A8-A16, Plate 4: D34end, and Plate 5: E24-E28). MSC removes as

much as 15 m of the underlying lithology in cross-section 5-5' (Wells E4 to €7)

and at least 10 m in cross-section 1-1 ' (Wells A8 to A l 1 ). The MSC remains an

almost constant distance above the VE4 surface from the western edge to Well

A9 and from Well A26 to Well A41. MSC drops stratigraphically and removes

the VE4 surface between Wells A1 0 and A1 6, and between Wells A1 7 and A25

it has a variable stratigraphie position above the VE4 surface. MSC removes

markers along the length of the sections. In all three dip sections, (Plates 1, 2,

and 3) it rises stratigraphically above the VE4 surface as it approaches the

eastem margin. In Section 3 (Plate 3) MSC correlates to the middle of a shale

Table I -

Cross Section (Plate)

1 2 2 2 2 3 4 4 4 5 5 5

Bel - Location

A8 814 817 825 834 Cl8 010 029 034 €4 El3 €24

teen Location

Af 6 817 b19 827 836 C22 d12 031 End €8 - €16 €28

Table 1. Locationofoccurences where MSC truncates VE4,

in Weil C32. In Cross-section 2 (Plate 2) MSC correlates just undemeath the

Flotten Lake Sandstone, and in Cross-section 1 (Plate 1 ) MSC correlates

behveen two of the sands of the Flotten Lake. Toward the south, in Cross-

section 4, (Wells D35 through D38) MsC appears to be dropping

stratigraphically, removing an increasing amount of the lower interval, while in

Cross-section 5 (Plate 5) MSC appears to be relatively Rat.

VE4 remains at a relatively consistent stratigraphic position above MSD

across the cross-sections until it reaches the eastem margin. In the eastem end

of cross-sections 1-1 ' and 2-2', (Plates 1 and 2) VE4 correlates below Flotten

Lake Sandstone., and in 3-3', VE4 and MSC correlate through what appear to be

basin shales. At the south end of cross-section 44' , MSC removes VE4.

According to Simpson (1982) the basin margin retreats to the east at about the

middle of the study area (Fig. 2.2), placing the southern end of cross-section 4-4'

and the eastem end of cross-section 3-3' in the deeper basin.

MSD is the base of the Viking allofonation, separating the Viking

Formation from the Joli Fou Formation. This surface is recognized cn the log

signatures as a decrease in the resistivity signal which may or may not

correspond to an increase in the gamma ray signature. The gamma ray

signature varies greatly along the length of the cross-sections, but MSD is

always picked at the transition between the upward coarsening Joli Fou and the

blocky, sornewhat upward coanening units of the regional Viking Formation.

This marker surface shows very little topographic relief with respect to BFS

datum.

6. Mapped Structural and Stratigaphic Trends

6.1 Data Base and Cornputer Mapping

Within the larger scope of the study area described in chapter 1, a

smaller area was mapped in more detail: Townships 45 to 62, Ranges 18W3 to

W4 (Fig. 6.1 ). In this area, approximately five wells were chosen from each

township, except in the east-central and northeast area of the map, where there

is limited well data, and al1 available wells were used. Preference was given to

wells with a metric scale, because these wek were drilled more recently. In

total 785 wells were examined (Fig. 6.2).

All values are plotted using latitude and longitude. The depths to three

surfaces (BFS, MSA, and VE4) were recorded for each well in an ExcelTM

Spreadsheet, and checked against related cross sections (Fig. 6.1, Appendix

III). A structure contour map for each horizon and isopach maps for three

intervals were produced using Geographix TM (Figures 6.3 to 6.8). The purpose

of this part of the project was to detemine the structure associated with VE4,

similar to the study of Walker (1 995) for Alberta. However, as discussed in

Chapter 5 the MSC surface truncates the VE4 surface and underlying lithologies

in some areas (Table 1). Therefore, the VE4 mapped surface is a combination

VE~/MSC surface.

All well data were entered into a ~ indows" €xcelTM Version 5.0

spreadsheet on an IBM Pentium 166MHz. The data file was then imported into

~ e o ~ r a p h i x ~ (version 7.7) '. A kriging algorithm was used to produce a grid

1 GeoGraphix is a cornputer software rnapping package pmduced by GeoGraphix.

Fig. 6.1 Diagram showing the area (darkened) of more detailed regional mapping. Townships 45 to 62, Ranges 18W3 to W4.

Data Points

Fig. 6.2 Diagram showing the data points used for regional mapping. 786 wells were used, averaging 5 wells per township. except to the northeast, where al1 available data was used.

from which the structure contour and isopach maps were generated. Grid size

was modified somewhat in order to remove artifacts of the gridding algorithm

from the maps. The data file has been included as Appendix III.

6.2 Structure Contour Maps

Structure contour maps were created for each of BFS, MSA and VE4

(respectively, Figures 6.3, 6.4, and 6.5). Each will be described in detail and

then compared.

The structure contour rnap of BFS (Fig. 6.3) shows a relatively gentle dip

(0.204' at the indigo arrow, rnap center) toward the southwest of the rnap area.

The structurally highest area of the map is in the northeast and the overall

structural trend is northwest to southeast, parallel to the subcrop edge of Lower

Colorado strata. At the southeastem corner of the rnap area there is a linear

depression, (marked by the light blue arrow) which rises structurally along its

length as it trends to the northwest. This feature will be discussed in more detail

after al1 three structure contour maps have been described.

The structure contour rnap of the MSA surface (Fig. 6.4) shows

characteristics very similar to that of BFS. It shows a high in the northeast and

an overall structural deepening to the southwest, with a relatively gentle dip

(0.245' at the indigo arrow, rnap center). This rnap also shows a linear

depression which fises structurally as it trends to the northwest. It is also marked

by a blue arrow at the southeast corner and extends to the northwest.

The structure contour rnap of the VE4 surface, (Fig. 6.5) shows

characteristics similar to the two previous maps: a gentle overall structural

Structure Contour Map: Base of Fish Scales (BFS) C.I.: 25 m.

Fig. 6.3

25 W3

Structure Contour Map: Base of Fish Scales.

Structure Contour Map: Marker Surface A (MSA) C.I.: 25 m.

25 W3

Fig. 6.4 StrUcture Contour Mûp: MARKER SURFACE A.

deepening trend to the southwest (0.251' at the indigo arrow, rnap center), with a

structural high to the northeast, and a low to the southwest. It also shows a

similar linear depression rising strudurally from the southeastern corner toward

the northwest, which has been marked with a blue arrow.

6.3 lsopach Maps

The isopach maps show the thicknesses of the three intervals BFS to

MSA, MSA to Ve4, and BFS to VE4 (respectively Figures 6.6, 6.7, 8 6.8). Each

interval is disscussed separately and then al1 are wmpared.

The isopach rnap of the interval from BFS to MSA (Fig. 6.6) shows a

thickness change from ~ 3 0 to +50 m. There is a prominent thickening of the

interval in the central portion of the rnap area, centered on 53-21W3. The interval

thins in al1 directions from this thickest area.

The isopach rnap of the of the lower interval, MSA to Ve4 (Fig. 6.7) shows

a thickness change from about 10 to 25 m. The interval averages about 21

meters thick, and no obvious trends were observed on the map.

The isopach rnap of the whole interval, BFS to VE4 (Fig. 6.8) has a

contour interval of 10 m, and shows a thickness change from about 50 to 80 m.

It shows an overall thick in the central portion of the rnap area, centered at about

township 53-21 w3. It has characteristics very similar to the upper interval (Fig.

6.6).

6.4 Discussion

Several conclusions can be drawn from the structure contour and isopach

maps. The structure contour maps (Figures 6.3, 6.4, and 6.5) show similarities.

Fig. 6.5

Structure Contour Map: Viking Erosion 4 (VE4) C.I.: 25 m.

25 W3 Structure Contour Map: Viking Erosion 4 Surface.

Isopach Map: BFS to MSA C.I.: 10 m.

Fig . 6.6 lsopach Map: Base of Fish Scales t0 MARKER SURFACE A.

Isopach Map: MSA to VE4 C.I.: 5 m.

Fig. 6.7 lsopach Map: MARKER SURFACE A to Viking Erosion 4 Surface.

Isopach Map: BFS to VE4 C.I.: 10 m.

Fig. 6.8 isopach Map: Base of Fish Scales to Viking Erosion 4 Surface.

Each drops structurally towards the southwest, and each contains a linear

feature trending southeast to northwest through the approximate center of the

map. The structural dip is controlled by the dope of the Foreland Basin margin,

which dips to the southwest in this area. The linear feature which trends tom

southeast to northwest on each map has the approximate morphology of a

valley, a long narmw depression gradually thinning and rising to the northeast.

However, structure contour maps of each of the successive surfaces are almost

rnirror images, suggesting that the depression foned in either of WO ways: 1 ) it

existed before the regional Viking was deposited and remained a depression

throughout Viking, Westgate and BFS deposition; or 2) al1 affected formations

were deposited and then the depression was formed aftewards. It is vefy

unlikely that this depression could have been maintained as a depositional

feature during Lower Colorado time, as any erosion would have removed

evidence of it. The fact that this depression feature is recognized on al1 three

surfaces suggests that it must have been fomed on al1 of them at the same time,

and is most likely controlled by some mechanism other than deposition.

The Devonian Prairie Evapon'te is interpreted by Holter (1 969) to have

undergone extensive ieaching and dissolution during the Late Cretaceous and

Tertiary. Several penods of dissolution -and related wliapse- have occurred

(Holter, 1969), one during Mannville time, and another significant period just after

deposition of the Second White Speckled Shale. This resulted in brecciation and

collapse of overlying strata, and affected structure as high as the First White

Speckled Shales. Holter (1 969) documented a series of long linear valley-like

trends of salt-solutioning, with collapse structures that affect apparent thickness

and structure. Van Hulten (1 984) deswibed the structure of a Mannville field at

Pikes Peak, (T. 50, R. 23w3) where oil is trapped in a northwest-southeast

trending anticline. Dissolution of the Prairie Evaporite, caused the formations

above to collapse into the void, creating the anticlinal trap. Haidl (1984) also

interpreted solution controlled structures in the northeastem Lloydminster area,

with solution occumng shortly after deposition of the Second White Speckled

Shales.

Structural contour maps produced by Wilson and Bennett, (1 985) in the

area of this study show a structure almost identical for the Mannville, Sparky and

Pre-Mannville unconforrnity (Maps H16a, H17a, and H18a.) Each shows a linear

depression in the same location having the characteristic valley like morphology

and a northwest to southeast trend. They attnbuted the structure on each of

these surfaces to have fonned due to the dissolution of the Prairie Evaporite.

This linear depression (marked by the blue arrow) through the regionally mapped

area is evident throughout the vertical section from the Pre-Mannville

unconformity up through the BFS. In this area, the complete vertical section must

have been altered during one interval of dissolution of the Prairie Evaporite,

perhaps during Second White Speckled Shale time.

The isopadi of the upper interval (BFS to M A , Fig. 6.6) is thickest in

Township 53, Range 21 W3. This interval contains the St. Walburg Sandstone

(Fig. 1.1 ), and the thick in 53-21\1113 corresponds very closely to Simpson's

(1 982) isopach of the St. Walburg Sandstone (Fig. 6.9) which shows the thickest

portion of the sand centered at about 54-21 w3. Both Simpson's isopach (Fig.

6.9) and the ispoach of BFS to MSA (Fig. 6.6) show the same thickening trend,

aven though the intervals are slightly different.

The isopach map of MSA to VEJ (Fig. 6.7) shows very little change in

overall thickness despite the changes in structural relief shown on the structure

maps (Figs. 6.4 and 6.5). The VE4 surface in Alberta has been interpreted as a

Transgressive Surface of Erosion (TSE) created by a rise in relative sea level

(Walker, 1995), and is covered by deep water shales. This interval represents

deposition during the latest Albian after VE4 was formed, when the basin was

deepest and marine sedimentation simply blanketed the topography with an

approximately equal layer of deep water shales without preference for

topography. Because the lower interval is so consistent, the isopach of the entire

interval (Fig. 6.8) shows characteristics overprinted by the upper interval.

Fig. 6.9 lsopach Map: St. Walburg Sandstone (modified from Simpson. 1982). Note the thick is centered cver about 54-21 W3.

7. Discussion

There are several conclusions which can be drawn from this regional

study of the Viking Formation. A diagram summarizing these interpretations is

presented in Figure 7.1, and a revised stratigraphy (Fig. 7.2) is proposed for the

eastern margin of the Foreland Basin. Five bounding surfaces or discontinuities

are postulated to occur across the entire study area. The significanœ of these

are discussed below. A workable framework has been developed which can be

used to interpret the Viking Formation of Saskatchewan in context with the rest of

the Foreland Basin.

The BFS was originally interpreted by Simpson (1 982) to disappear to the

north within the Saskatchewan portion of the basin, (Fig 2.1 ). However, in this

study, it is proposed that BFS can be traced from the center to the eastern

rnargin of the Foreland Basin (Fig. 7.1 ). This is significant because BFS is used

as a datum in Viking studies in Alberta. Conelation of BFS to the eastem margin

allows Viking studies in Saskatchewan to be readily conelated with the existing

Alberta stratigraphy. This enables cornparison of findings and delineation of the

regional extent and geometry of the discontinuities, thus allowing the

relationships between Saskatchewan and Alberta Viking oil fields to be defined.

In a study of the Flotten Lake Sandstone in northwestern Saskatchewan, Webber

(1 995) had difficulty relating his findings to the time equivalent Viking Formation

(Simpson, 1982). The daturn used for the Flotten Lake was a marker just below

the St. Walburg Sandstone, and no argument wuld he made about whether it

Southwest

Summary of Eastern Margin Late Albian Stratigraphy Northeast

I BFS

+ - - - - - - - - - O

MSA 4,-,, st w!kd!urg, - -

Viking

Joli FOU ( ~ o t TO Scale) Fiy 7.1 Suiiimary of the stratigraphie relationships

of Late Albian deposits on the eastern margin of the Foreland Basin.

Revised Regional Stratigraphy of the Lower Colorado Group

Eas t-central West-central Biozones Alberta Saskatchewan

Fish Scales @ne

Base of Fish Scales 1 "Miliamm ina

Westgate Walburg mmitobensis "zone Formation n d s to ne Piacenticeras [iarchse

Diploceras cf. fredericksburgense

A t t e n Lake

Formation

Pense Formation

Fig. 7.2 Diagram showing the revised stratigraphy of the Lower Colorado Group along the eastem margin of the Foreland Basin. Note the Base of Fish Scales now extends across the basin, and the Flotten Lake Çandstone is sornewhat younger than the Viking Formation.

was truly horizontal, nor could the stratigraphic relationship between the Flotten

Lake Sandstone and the Viking Formation be resolved.

Some recent discussons have suggested the possibility that along the

eastern margin of the Foreland Basin, BFS is actually a stacked series of

surfaces which become amalgamated into one upon reaching the central part of

the basin (G. Reinson, pers.comm. June, 1997). This could occur as a function

of the very shallow gradient of the eastern margin slope. Any relative sea level

change would move the shoreline into or away from the center of the basin very

rapidly. Because BFS is a maximum flooding surface. relative sea level

fluctuations may not be recognized in the basin center, but could be represented

along the Foreland Basin margin in the f o n of several linked surfaces. More

detailed study is needed to evaluate this .

The MSA is a bounding discontinuity which c m be traced across the entire

study area (Fig.7.1), and correlates with the base of the St. Walburg Sandstone.

It is interpreted as an erosional surface, removing at least one marker horizon

(marker x, Fig. 3.6). This is further supported by the isopached interval of BFS to

MSA (Fig. 6.6). This isopach map shows a consistent increasing thickness trend

toward the northeast. The same trend is repeated on the isopach for the interval

BFS to VE4. If the thickening was caused by a change in accommodation space,

then underlying markers should be approximateiy parallel under this surface, and

would not be tnincated (Le. marker x: Fig. 3.6). BFS is interpreted to be

horizontal (Walker, 1995; Fig. 6.3), so these two ispoachs show the structure on

their respective lower surfaces. This also supports the interpretation that both

MSA and VE4 truncate underlying strata. The interval between BFS and MSA

contains the St. Walburg Sandstone. This interval thins to the southwest of the

study area as the St Walburg thins. Although this portion of the vertical section

was not exarnined in detail, section 1-1' illustrates at least two separate phases

of sedimentation occurred, separated by a discontinuity. This will also need more

detailed study.

The MSB is only traceable in the western portion of section 1, and can not

be correlated to the eastem margin (Fig. 7.1). This suggests it is a function of

western margin or central basin processes. It may have been removed by

another discontinuity in the same way that MsA removes marker x, or rnay simply

pass basinward into a correlative conformity.

The MSC correlates very closely to the VE4 surface along the length of the

cross sections (Fig. 7.1). It varies from a maximum of 5 m above VE4 in the

basin center to removal of what appears to be about 15 m of sediment below

VE4 from Well A8 to A1 2 (Plate 1 ). MSC correlates between two of the Flotten

Lake sand bodies on Sections 1 and 2 (Plates 1 and 2). This suggests that the

Flotten Lake is younger than the Viking Formation (Fig 7.2). The MSC surface is

significant because it is evidence of the continued dynamic nature of relative sea

level in the basin during Flotten Lake time. Closer examination of MSC may show

it to be a transgression O C C U ~ ~ ~ subsequent to VE4, or it may simply be a saur

surface associated with eastem margin currents. More study is needed to

properly define it.

The VE4 in Alberta is interpreted as a transgressive surface of erosion

(TSE) and can be correlated from Alberta across the Foreland Basin into

Saskatchewan (Fig.7.1). It does not remain a TSE al1 the way across, there must

be a point in the central basin where it becomes a correlative conformity, but a

change in relative sea level would affect the eastern margin as well, so it must

become a TSE there as well. VE4 is correlated below the Flotten Lake

Sandstone in western Saskatchewan on both Sections 1-1' and 2-2' (Plates 1

and 2). This evidence suggests that the Flotten Lake Sandstone is not time

equivalent to the Viking, but somewhat younger. Walker (1 995) defines the VE4

as the final transgression in Viking time, and Boreen and Walker (1 991) postulate

that Caroline and Garrington fields were lag deposits created during punctuations

in that transgression. The Flotten Lake Sandstone may be equivalent to these

punctuations. but in the overall transgression it is more likely associated with the

slightly later highstand phase of deposition along the eastem margin.

The MSD is the bounding discontinuity separating the Viking Fomlation

and the Joli Fou Formation. In the middle of the basin, the logs record a shale-

on-shale contact. At the eastem end of Section 3 (Plate 3) the log signatures

underlying MSD suggest t i e lithologies becoming increasingly sandier upward.

These correspond roughly to the Spinney Hill Sandstone, recently interpreted by

Sandy (1997) as a series of backstepping shorefaces incised during a

punctuated transgression at the end of Joli Fou time.

Simpson interpreted the Flotten Lake Sandstone in Saskatchewan to be

time equivalent to the Viking Formation, separated by a narmw area of no sand,

which he interpreted to be the result of non-deposition. This study documents

surfaces in the Viking that can be traced across the basin to the eastern margin.

Therefore the area of nondeposition that Simpson defined can not be a

depositional phenomenon. There is evidence that it may rather have been

created by erosion. The erosion of VE4 by MSC can be traced through a band of

about 4 townships wide, which trends approximately east-southeast to west-

northwest across this study area (Fig. 7.3). Within this area, the erosion that

creates MSC removes sediments, and in many areas VE4 is removed as well.

Since MSC can be traced to the middle of the Flotten Lake Sandstone, there is

evidence that the erosion surface was created in sorne way by the deposition of

the Flotten Lake Sandstone on the eastern margin of the Foreland Basin.

VE4 Lowstand

In his discussion of the VE4 surface, Walker (1995) predicted that there

must be a lowstand shoreface associated with VE4, possibly northeast of his

study area (Fig. 3.2) in eastem Alberta or western Saskatchewan. The results of

this study suggest a VE4 lowstand shoreface on Section 1-1 ' between 1 a and 1

(Plate 1; and isolated in Fig. 7.4) It is delineated by rnarkers Al BI and C (Fig 7.4

8 7.1 ). The relationship is complicated by subsequent erosion associated with

the MSC marker. In this area MSC has rernoved the VE4 surface and parts of the

two uppermost coarsening upward successions.

From west to east: MSC erodes down through the VE4 surface at Well Ag.

In Well A13 the two marken A and B appear, each of which define the base of a

progradational unit. In Well A l 6, (Fig. 7.4 ) VE4 reappears above Marker B as

Area of

Fig 7.3

VE4 Erosion.

SW4

. . . , - . .. .- L- e!: . . e- ..O--*.. - --La\* - --. \ q : : ! O*' ; .. S. &!,!rj

a . -

Diagram showing the area in which VE4 is variably removed by MSC.

Fig 7.4 Cross Section la-1 showing threc relationships to the MSC and VEd text.

g three markers: A, 6, and C and their id VE4 surfaces. For explanation see

From west to east: MSC erodes down through the VE4 surface at Weil Ag.

In Well A l 3 the two markers A and B appear, each of which define the base of a

progradational unit. In Well A16, (Fig. 7.4 ) VE4 reappears above Marker 6 as

MSC clirnbs out of the shoreface. Marker C appean in Well A18 and erodes

through Marker 8 in Well A20 (Fig. 5.1). This area is complex and needs more

detailed work to unravel the stratigraphic relationships and depositional history.

However, marken A, B, and C are bounding surfaces, and suggest individual

episodes of progradation within this portion of the study area. These may

represent initial and resumed transgressive surfaces of erosion.

8. Summary

Eight major conclusions can be drawn from this study of the Viking

Formation in east-central Alberta and west-central Saskatchewan:

1) The Base of the Fish Scales zone (BFS) can be correlated from the

central portion of the WCSB through to the eastern rnargin. In order to do sol

drill cutting samples must be examined, because the characteristic well log

marker becomes increasingly cryptic as it is traced basinward.

2) The VE4 surface (Walker, 1995) can be traced into Saskatchewan and

across to the eastem margin. VE4 is removed in the west central portion of

Saskatchewan by subsequent erosion associated with MSC, but is preserved

further east.

3) MARKER SURFACE C (MsC) parallels the VE4 through most of the basin.

Within a broad swath across the center of the study area, VE4 is variably

removed by MSC. This broad swath corresponds very well to the gap between

the Viking and the Flotten Lake Sandstone which Simpson (1982) interpreted as

non depositional.

4) The Flotten Lake Sandstone was interpreted by Simpson (1982) to be

time equivalent to the Viking Formation. In this study, the Flotten Lake

Sandstone is correlated above the VE4 and is associated with the MSC surface.

This impl ies that the Flotten Lake Sandstone is stratigraphical l y younger than

the Viking Formation.

5) A potential candidate for a lowstand shoreface associated with VE4 is

correlated in the north central portion of the study area, and contains three

coarsening-upward successions. More detailed evaluation is needed but there

is evidence suggesting fluctuation of relative sea level, and these may define

minor initial and resumed transgressions. The surrounding area has been

affected by ravinement associated with the creation of the MsC surface.

6) The overall structure of the Viking within the study area is controlled by

the solution of the Prairie Evaporite. The long linear depression trending

northwest through the Saskatchewan portion of the study area is present

throughout al1 Lower Colorado strata.

7) The narrow area between the Flotten Lake Sandstone and the Viking

Formation. which Simpson interpreted as non-depositional is reinterpreted to be

erosional in nature. In this area, MSC erodes through the VE4 during the

deposition of the Flotten Lake Sandstone.

8) The stratigraphy developed in this study forms a regional stratigraphie

framework for the Viking and associated formations in Saskatchewan. Using this

framework, more detailed studies of the Viking in Saskatchewan can be

interpreted in context with events affecting the entire Foreland Basin.

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- , 1980b, Low Permeability Gas Reservoirs in Marine Cretaceous Sandstones of Saskatchewan: 7. Viking-Newcastle (Middle to Upper Albian) Correlations in Southeastern Saskatchewan, Southwestern Manitoba, Northwestern Montana, and North Dakota. in: Christopher, J. E., and Macdonald, R., (eds) Summary of lnvestigations 1 980, Saskatchewan Geological Survey, p. 133-1 38.

-, 1980c, Low Permeability Gas Reservoirs in Marine Cretaœous Sandstones of Saskatchewan: 8. Viking Formation (Upper Albian) of East central Saskatchewan, in: Christopher, J E , and Macdonald, R., (eds) Summary of lnvestigations 1980, Saskatchewan Geological Survey, p l 39-142.

-, 1979a, Lithologic Descriptions of Selected Cored Sections from Lower Colorado Group (Cretaceous) of West-Central Saskatchewan, Saskatchewan Geological Survey, Report 160, 124p.

-, 197913, Low Permeability Gas Reservoirs in Marine Cretaceous Sandstones of Saskatchewan: 3. Lower Colorado (middle Albian to Cenomanian) Strata of East-Central Saskatchewan, in Christopher, J.E.,and MacDonald, R., (eds), Saskatchewan Geological Survey, Sumrnary of lnvestigations 1979, p l 86-1 90.

-, 1975, Manne Lithofacies and Biofacies of the Colorado Group (Middle Albian to Santonian) in Saskatchewan, in: Caldwell, W.G.E., (ed), The

Cretaceous System in The Western lnterior of North America, Geological Association of Canada, Special Paper #13, p 553-587.

-, and O'Connell, S.C., 1979, Low Peneability Gas Resewoirs in Marine Cretaceous Sandstones of Saskatchewan: 2. Lower Colorado (middle Albian to Cenomanian) Strata of Southern Saskatchewan, in Christopher, J.E., and MacDonald, R. (eds), Saskatchewan Geological Suwey, Summary of Investigations 1 979, p l 81 -1 85.

Slipper, S.E., 1917, Viking Gas Field. Structure of Area., Canada Department of Mines, Geological Survey, Summary Report, 1 91 7, Part C, p 6c-9c.

Stansberry, G. F., 1957, The Viking Fomation, Central Alberta, Bulletin of Canadian Petroleurn Geology, 12, p 773.

Staubo, J. P., 1970, Viking Fomation in Southeastern Saskatchewan, A Tidal Current Deposit. unpublished Masters Thesis, University of Manitoba, 75p.

Stelck, C. R., 1 958, Stratigraphic Position of the Viking Sand. Al berta Society of Petroleum Geologists Joumal, 6, p.2-7.

Tizzard, P.G. and Lerbekmo, J.F., 1 975, Depositional History of the Viking Formation, Sufield Area, Alberta, Canada. Bulletin of Canadian Petroleurn Geology 23, (4) p.715-752.

van Hulten, F. F. N., 1984, Petroleum geology of the Pikes Peak oil field Waseca Format ion, Lower Cretaceous, Saskatchewan, in: Stott, D. F., and Glass, D. J., (eds) The Mesozoic of Middle North America, Canadian Society of Petroleum Geologists, Memoir 9, p. 441 -454.

Walker, R.G., 1995, Sedimentary and Tectonic Origin of a Transgressive Surface of Erosion: Viking Fomation, Alberta, Canada, Joumal of Sedimentary Research, 865, 209-221.

-, and Wiseman, T.R., 1995, Lowstand Shorefaœs, Transgressive lncised Shorefaces, and Forced Regressions: Exarnples From the Viking Formation, Joarcam Area, Alberta, Joumal of Sedimentary Research, 865, #Il p. 132-141.

Webber, J. D., 1995, High Resolution Stratigraphic Analysis of the Lower Cretaceous (Albian) Flotten Lake Sandstone, West-Central Saskatchewan, unpublished honoun thesis, University of Regina, Regina. Saskatchewan, 63p.

Weimer, R. J., 1988, Record of Relative Sea-level Changes, Cretaceous of Western lntetior USA, in: Wilgus, C. K., Hastings, B. S., Kendall, CG. St. C.,

Posamentier, H.W., Ross, C.A.. and Van Wagoner, J.C., (eds ) Sea Level Changes-An lntegrated approach, SEPM Special Publication 42, p. 285- 288.

Young, H.R., 1 965, Heavy Minerals from the Viking Fonation, West Central Alberta, Bulletin of Canadian Petroleum Geology, 13, p 397-404.

-, 1964. Petrology and Heavy Minerals of the Viking Fonation, West Central Alberta, Bulletin of Canadian Petroleum Geology, 12 p 923.

Amendix 1

Cross-section Weil Locations

Amendix II

Drill Cuttina Sample Descriptions

Cavings: quartz sands are found in each sample through to the base of the

weII:

well rounded CU to fine pebble size quartz, feldspar, dolostone and

lirnestone clasts, quartz and volc fragments of CL to CU size, carbonate

fragments

140-160m, grey silty shales, a fine grit covers the chips, which can be blown - off.

165m, medium grey silty shales, with traces of a light colcured fL sand

speckled with black, and a medium brown silty shale.

170m1 medium grey silty shales, with particles of light coloured R sand, and 10

% indian red wlour (oxidized) shales and silts, 45% well rounded

phosphatics.

175m, medium grey silty shales, with particles of light coloured fL sand, and 10

% indian red colour (oxidized) shales and silts, 2-356 well rounded

p hosphatics.

1 80m1 medium grey shaly silts, with pynte traces, traces of phosphatics.

1 85m, medium grey siltstone, several concretions of pyrite; 3-5% phosphatics,

both within silts and as solitary grains, traces of the light fL sand.

190m, medium grey siltstone, with 10% spines, teeth and other phosphatics

mixed in, as well as small amounts of carbonate fragments.

195m, medium grey siltstone, with 8% phosphatics, as well as small amounts

of carbonate fragments, very well rounded fi quartz grains.

200m. medium grey siltstone, traces of phosphatics and fL quartz grains.

205m, medium grey siltstone, 25% clear quartz angular and low sphencity;

clumps of pyrite that appear to have been oxidized; 5% small black and

brown phosphatics, some rounded; at least three separate siltstones

defined by varying colour from medium grey to light grey and light tan;

carbonate minerals are in evidence as well but not large quantities.

21 Om, medium grey siltstone wntaining white grains which react very slowly to

acid, and turn greenish when wet; 3-51 phosphatics and teeth.

21 Sm, medium grey siltstone containing white grains which react very slowly to

acid, and turn greenish when wet 2-31 of phosphatics and teeth.

220m, medium grey siltstone, some rernnants of the speckled siltstone from

above; 45% of phosphatics and teeth, traces of pyrite.

225m, medium grey siltstone; 3-536 phosphatics, traces of pyrite.

230m, medium grey siltstone, 23% red silts, 23% phosphatics, traces of

pyrite. -

235m, medium grey siltstone, with 3-5% brown and indian red siltstone.

phosphatics make up to 3 % of sample. traces of pyrite.

240m. medium grey siltstone, 5-1 0% phosphatics, spines, possibly teeth.

chalcopyrite silts? (looks brassy brown like chalcopyrite, may also be

gamets, very small xls in a silt matrix)

245m rnissing

250m, qz and volc frags make up 25% CU to vcU, traces of phosphatics,

medium grey siltstone, more chalcopyrite silts.

255m, qz and volc frags make up 15% CU to vcU, traces of phosphatics,

medium grey silts, more chalcopyrite silts.

260m, medium grey siltstone, traces of phosphatics

265m, medium grey siltstone, traces of phosphatics

270m, medium grey siltstone, traces of phosphatiu

150m-175m dark grey calcareous speckled shales, speckles can be blown off

the shales, fragments of calcite (elongate crystal habit) appear to be

shell fragments.

180m, medium grey shales contain 10% indian red mudstone (oxidized),

rounded particles of light yellow siltstone, and some few quartz grains.

185m, dark grey shales and 5% shell fragments,

1 gOm, dark grey shales and 5% shell fragments,

1 95m, dark grey shales and 5% shell fragments , silt content increasing

200m, dark grey shales, 4% pyritized siltstones, indian red (oxidized) and

rounded light yellow siltstone particies, 3-5% phosphatic particles -tooth.

205m1 dark grey shales, 2-3% pyritized siltstones, indian red (oxidized) and

rounded light yellow siltstone particles, 34% phosphatic particles

210m, light grey shaly silts traces pyrite

21 5m, light grey shaly silts traces pyrite and phosphatics

220m, light grey shaly silts traces of pyrite. traces of phosphatics.

225m medium grey shaly silts as above, now 3% quartz mu in size, medium to

high sphericity, subangular to subrounded. traces of pyrite and

phosphatics.

230m, medium grey shaly silts as above, 25% woody material, black, bent, 3%

quartz as above, traces of phosphatics

235m, 50% siltstones of a beer bottle brown -gamet?- mixed with light tan

wlour. 3% phosphatics, 5% quartz grains as above, rest grey shales as

above. traces of pyrite.

240m, dark grey shaly silts similar to above, 35% black, bent woody material,

3-456 quartz as above, traces of phosphatics. looks coaly

245m1 medium and dark grey shaly silts, dasts of darker chocolate brown

siltstone as in 235m, 4-5% quartz grains as above, traces of phosphatics

250m, shaly silts light grey in colour, only traces of pyrite.

255m, light grey shaly silts, 20% (gamet brown) siltstone sppears oxidized

under low magnification. 45% quartz grains as above. traces of pyrite.

260m, light grey shaly silts, 1 01 (gamet brown) siltstone as above, 45%

quartz grains as above. traces of pyrite.

265rn, light grey shaly silts and mudstones, traces of quartz and wood as

above

Well 1 6-1 8-65-22w3 3 meter intervals

Cavings of quartz and felspar clasts ranging from 5-1 0% in al1 samples. the

fragments while consistantly being present, are different in each well,

most include angular cloudy quartz and pink orthoclase, and granite

containing heavy minerals and changing size rapidly

230-278m, medium grey silts with carbonate fragments, rounded and angular

pebbles of quartz and feldspars, desp red micas (wafer thin, may be

phosphatics, found in shales, ) phosphatics variable . traces of pyrite.

minor shell fragments in the lower portion.

281 m, medium grey siltstone, no phosphatics observed,

284m, medium grey siltstone, deep red micas, 2-31 phosphatics observed

nune recognizable.

287m, medium grey siltstone, some of the shale contains phosphatics, scales,

spines etc.,

290m, medium grey siltstone,

293-299m, medium grey siltstone,

302m, medium grey siltstone, few small cuttings of vfU sized sandstone, well

consolidated, light tan colour, as well transparent brown micas

observed.

305m, 30% rounded chunks of vfü sized sandstone, well consolidated, light tan

colour, medium grey siltstone, fragments of micas observed too.

308m, 30% rounded smaller chunks of vfü sized sandstone, well consolidated,

light tan colour, medium grey siltstone, fragments of micas and 34%

phosphatics observed. spines and scales as well as undetemined and

range in size from vcL to vfü and as fragments within the siltstones.

31 1 m, 30% rounded smaller chunks of vfü sized sandstone, well consolidated,

light tan colour, medium grey siltstone, fragments of micas and 34%

phosphatics observed; spines scales and undeterrnined, range in size

from vcL to vfü and as fragments within the siltstones.

314111, 25% rounded smaller rhunks of vfU sized sandstone, well consolidated,

lisht tan colour, medium grey siltstone, fragments of micas and 3-4%

phosphatics observed; spines scales and undetenined, range in size

from vcL to vfU and as fragments within the siltstones.

31 7m, 10% rounded smaller chunks of v fü sized sandstone, well consolidated,

lig ht tan colour, medium grey siltstone, 34% phos phatics observed.

undetermined, range in size from vcL to vfü and as fragments within the

siltstones.

320m, medium grey siltstone,

323m, medium grey siltstone,

326m, medium grey siltstone, 2 phosphatic dasts observed

329m, medium grey siltstone,

332rn, medium grey siltstone, few large sized phosphatics observed.

335m, clean quartz sand CU to vcL size, almost al1 quartz, some phosphatic

spines and teeth, -10% grey siltstone, as well as cavings

338m, clean quartz sand CU to vcL size, almost al1 quartz, grey siltstone, one

chunk finer light wloured sandstone. traœs phosphatics.

341rn, clean quartz sand CU to vcL size, alrnost al1 quartz, grey siltstone, one

chunk finer light wloured sandstone. traœs phosphatics.

344m, 50% drill rnud, 15 quartz sand as above, trace phosphatics.

ail samples down to 386 contain large amounts of drill rnud, and so were not

examined closely.

Amendix III

Mappina Database

--

ibn I P

28 61 24 - - Si ' 2 61

- -

24 6 , - - . - . a

E ci? O O

lo + IV)

- '* IV, 1- 1 0 0 ! * !g

i n ! V ) I ( O ' * l Q ) ~ V I Q ) ( D l 0 N FI^ Q ) I Q O I - ~ O I ~ I ~ ~ ( D I ~ I C ~ - a a > a ) l W (3 iN Ol t lmlW Cr, Cui* U, tq*lCYi(31* NI-,C31VIi(DIhib a ) i C û t Q ) Q).Q> * i 0 1 W 1 N N ; N I N ( N ( N ( N ~ N I N NINININININ t C V I N I C V I N I N t C Y ~ N N ~

N rirr)iQOlVI N t/.?'b r 0Ib a b ! m rn * l *

~ \ ~ O & i a mlmia , 1 0 I i n miU3 in'

, . . . ' u i w * - ~ a . a ~ - l ~ i r c t c ~ ) ~ ~ O > I ~ > I ~ ~ I C ~ I ~ I Q ~ ~ * ) ~ + I N W I O ~ ~ ~ O I ~ ~ ~ ~ ~ ~ ~ ~ ~ I ~ ~ I V I V ) w r-

Cl F N I CUINI-/-/ m I N N N r r r i - N r N r I I

, a g l ~ : ô ; s $ 1 0 i - ~ : ~ i ~ : ~ ! ~ ! ~ i ~ ' S ~ ~ l ~ ' ~ ! ~ ! ~ [ f i ~ ~ j ~ ; ~ R ; ~ ! ~ ! R i 2 j ~ : # ~ ; $ - 1 N/ N I N : N { N N NI N;Nf N I N I N / & 61 N I N I N I N ' N ~ NI NIN. Ni NI CVl N!NI NiNIN: N: C I . N

b I 1

at neg long KB Stru-C < Stru-VE4 - ---, BFS -.

236 217 - - - - - , 284 257 -- - -

265" - -- 242 256' --- .. 237' 261' , - 243' - - ,

-

- --

305 -- - -- 278 - ,

303 -A - - -- 282 - -

389' ai' 382 417 404 442 3*9 iis

' 348 384

- rC3 (O

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1i9 Q > 'O

- ri) ia 1 % !rn

- i v ) aa Ir- ;?

i h io IV)

;? :m I V )

Li, I I I

~ ~ ( D ~ - D N I ~ ~ N ~ ~ > ~ O ~ - ~ V ) ~ ~ I ~ I O O I ~ m i o ; o ; ~ ~ ~ O I N I Q D ~ Q D ~ ~ ~ ; ~ ) ~ C V ) C U ~ ~ ~ N N O hi@ C V ~ * V ) , O F- CD ~ * I ( C ) ~ ~ Q O ~ O I ~ O O ~ O Q ) O ~ O I - - ~ - I N I P - - ' N O ~ C ~ * O

a N c3 n c3 C ~ ~ D I D m m i m m ~ ~ ~ ~ m ~ m l r n ~ ~ y m m 1 m 1 m m # m ci o o c3 o cv o rn -

-q (Y 1

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1 !

W I N C3tOIQ) lCc1(D m i m I r ' ) ~ w i w ~ i m

- - 1 - m lu3 -10 *i tL> .!in e3 lm VI IV)

r i - r 1 C 3 mi* si? f i lm V)im

l 1

-10 - ~ B ~ ~ ~ V ) ~ ~ ~ [ D I ~ ~ ~ ~ ( D ' C U ~ - ~ ~ Q > ~ V ) I C D ~ ~ C > ~ O ' ~ ~ F ~ ( D ~ ~ I C I ~ ~ W ~ Q D ~ C V I Q ) ! V ~ Q) , * wjV)'(DIN WihF-ill>.wi<DiV>V>IV> > V > I V > ~ < O V > ~ t l t i < D t i ~ i V > i t ! m ~ V > V > I ~ I Y > ~ w 1 U > i m i V > i 1 l > V>m wiV>t<O

, (Y '

1 % l * ' r- i CU. le3 IV)

1

~ l C U i ( D 1 N t 1 N i I l ) -lQ)IV> O l Q I N tOiO~~iO1tO1+~O CU QO N tû !Il%* NIN r -lNINt-e- 0 ~ 0 I N ~ N I N j O ! N I N I - ~ r / r ' ~ ~ N ~ N [ t ~ * ~ t ~ % ~ ~ ~ = ~ ~ / k ~ ~ I ~ ' N 1 I

i S i --

142 . - -- 188 iss A-.-

1 O4 177 187 i8i iss' -- --, 202 -- - 212 -- 190 --

le7 1 82

'il 177

Ineplonp IKB lbfs Ic ve4 Sh-BFS Stru-C Stni-VE4 BFS 2 C BFS 2 VE4 C 2 VE4 - - - - -- - - - - - - - - - - - - - -- - 4gi: 515 183, 1.57 1s --- 4- - 22 504 525 197 i67 146 30

- - -, . . - - -- 2 1 - 526" 547' 202' - 170 149 32 2 1

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(Y ' I

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