THE ICHNOLOGICAL - SEDIMENTOLOGICAL SIGNATURE OF WAVE- AND RIVER-DOMINATED DELTAS: DUNVEGAN AND BASAL BELLY RIVER FORMATIONS, WEST-CENTRAL ALBERTA

Lorraine Coates B.*., McMaster University, 1995

THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE In the Department Of Earth Sciences

O Lorraine Coates 2001 SIMON FRASER UNIVERSITY

May 2001

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The Upper Cretaceous (middle Cenomanian) Dunvegan Formation consists of a series of interbedded marine to non-marine sandstones and shales deposited in an actively subsiding foreland basin setting. It crops out in north- western Alberta and extends into the subsurface of west-central Alberta. It overlies the Shaftesbury Formation and is capped by shales of the Kaskapau Formation. Previous workers subdivided the formation into seven allomembers (A-G), based on detailed analysis of the sedirnentologv and genetic stratigraphy. Allomembers D and E were chosen for this study because they correspond to well-developed wave-dominated and river-dominated deltaic successions, respectively. The Upper Cretaceous (early-mid Campanian) Belly River Formation gradationally overlies the Lea Park Formation. The transition is marked by marine mudstones of the Lea Park passing into deltaic and fluvial sandstones of the Belly River. Previous workers subdivided the formation into eight cycles (A- H), based on detailed analysis of the sedimentology and genetic stratigraphy. Cycles D-G were chosen for this study because they tend to correspond to a rnixed wave/ river deltaic succession. The study area comprises Townships 59 to 64, and Ranges 21W5 to 05W6 for the Dunvegan Formation and Townships 43 to 49 and Ranges 28W5 to 08W5 for the Belly River Formation. Seventy cores, 38 from the Dunvegan Formation and 32 from the Belly River Formation were analysed sedimentologically and ichnologically, in order to compare the ichnologicd characteristics of river- us. wave-dominated and mixed wave/river deltaic successions. The principal differences lie in the prodelta and distal delta front deposits. In the prodelta, the river-dominated succession is characterized by areas largely devoid of bioturbation. Current-generated structures and deformational structures dominate the sandstones, and syneresis cracks are abundant. The facies yield a very Iow abundance but moderately diverse "highly stressed" Cnrzinnn ichnofacies. Burrowing is sporadic, ichnogenera are diminutive in size, and stnictures of trophic generalists domulate. In contrast, the wave-dominated and &ed wave/river successions yield a diverse though low abundance "stressed" Cnrzinnn ichnofacies. Hummocky cross-stratification and storm- induced oscillation ripple laminated tempestites dorninate the sandstones, though deformational structures and syneresis cracks are located throughout. In the wave-dominated succession, bioturbation may cause a graded or rnottled appearance, dismpting the discrete bedded character. This is rarely the case in the rnixed wave/river succession, where bedding contacts are very sharp. Structures of trophic generalists and opportunists dominate these successions. There are two principal differences in the delta front. The first is the comparative abundance of convoluted silty sandstone facies in the river- dominated and mixed wave/river successions of the distal delta front. This facies is typically devoid of burrowing. In contrast, the wave-dominated succession consists of minimal amounts of convolute bedding and other deformational features. Stacked HCS and SC3 beds dominate. Secondly, in the delta front the river-dominated succession yields a very low abundance and very low diversity, "highly stressed" Cnlzinnn ichnofacies, where amalgamated HCÇ beds are intercalated with convoluted and massive sandstone beds. In contrast, the wave- dominated and mixed wave/river successions yield a moderately diverse and locally abundant, mixed Skolithos-Crzrzinnn ichnofacies, where convolute bedding is only locally common. Dwelling/suspension-feeding structures are generally rare in the delta front. Ichnogenera of the proximal Cnrzinnn suite dominate this setting instead. The differentiating factor between the delta front and middle to upper shoreface is the uncornmon occurrence of dwelling/suspension-feeding structures and the dominance of deposit-feeding structures in deltaic settings. In contrast, dwelling/suspension-feeding structures dominate the middle to upper shoreface environment. Organisms inhabiting a substrate are sensitive to environmental conditions and to changes in that environment, responding to both physical and chemical changes in that setting. Variations in salinity, fluctuating oxygenation, an abundance of organic matter, increased turbidity and sedimentation, and unstable/soupy/ shifting substrate affect the resulang ichnofossil morphologies and therefore affect the style of the deltaic successions. First and foremost, 1 would like to thank James MacEachem. In the two years at Simon Fraser, he has dways made hùnself available for questions or discussion. He is a great teacher with a lot to give and should be comrnended for his editing skills! Mostly, 1 would like to thank James for being so patient with me for the past 2 years while 1 worked full time and had a family while finishing my thesis. Then waiting till the end of the semester for the final copy because my family was on vacation! Thanks to the NSERC operating grant 184293, awarded to James MacEachem, which provided the rneans for me to undertake this work. My good friends Paul and Christine McNaughton have to be some of the best. They never thought twice about getting me from the airport, giving me lodge, making me dinners, and driving me to and from ÇFU on my numerous trips to Vancouver. 1would like to thank the most supportive person ever, my husband, Jason. He never complained when 1spent our holidays (Thanksgiving, Christmas, Easter, Sumer) writing and going to Vancouver but gave me the space and support that enabled me to finish. And thanks to my beautiful baby, Elise, for being so good while sitting on my lap, printing out the find copy! TABLE OF CONTENTS PAGE .- APPROVAL PAGE .-.Lf ABSTRACT U1 ACKNOWLEDGEMENTS vi TABLE OF CONTENTS vii LIST OF FIGURES X

CHAPTER 1 INTRODUCTION, SCIENTIFIC PROBLEM, OBJECTIVES, STUDY MA,DATA BASE, METHODS, AND STRATIGICAPflY

1.1 INTRODUCTION 1.2 SCIENTIFIC PROBLEM 1.3 OBJECTIVES 1.4 STUDY AREA, DATA BASE, METHODS 1.5 REGIONAL STRATIGRAPHY

CHAPTER 2 INTRODUCTION, PREVIOUS WORK, AND PALEOGEOGRAJ?HY/ BIOSTRATIGRAPHY

2.2 INTRODUCTION 2.2 PREVIOUS WORK 2.21 Dunvegan Formation 2.22 Belly River Formation 2.3 PALEOGEOGRAPHY

CHAPTER 3 INTRODUCTION, FACIES DESCRIPTIONS 3.1 INTRODUCTION 3.2 FACIES DESCRIPTIONS 3.3 DUNVEGAN FORMATION 3.31 Shingle D3 3.32 Shingle D2 3.33 Shingle Dl 3.34 Shingle E3 3.35 Shingle E2 3.36 Shingle El

vii 3.4 BELLY RIVER FORMATION 3.41 Cycle D 3.42 Cyde E 3.43 Cycle F 3.44 Cycle G 3.45 Cycle H

CHAPTER 4 FACIES ASSOCIATIONS AND INTEICPRETATION OF DEPOSITIONAL ENVIRONMENTS 4.1 INTRODUCTION 4.2 DUNVEGAN FORMATION, ALLOMEMBER D 4.21 Facies Association and Typical Features 4.22 Introduction 4.23 Interpretation

4.3 DUNVEGAN FORMATION, ALLOMEMBER E 4.31 Facies Association and Typical Features 4.32 Introduction 4.33 Interpretation

4.4 BELLY RIVER FORMATION 4.41 Facies Association and Typical Features 4.42 Introduction 4.43 Interpretation

CHAPTER 5 FACIEÇ CRITENA FOR EIFFERENTIATION OF DELTAIC END MEMBERS: RIVER- VS. WAVE-DOMINATED DELTAIC SUCCESSIONS 5.1 INTRODUCTION 0.2 PRODELTA 5.3 DELTA FRONT

CHAMER 6 CHARACTERIçTICS OF RIVER-DOMINATED, WAVE-DOMINATED, AND MIXED WAVE/RIVER DELTAIC SUCCESSIONS: DIFFERENTIATION FROM SHOREFACE DEPOSITS 6.1 INTRODUCION 6.2 PRODELTA 6.21 Prodelta of the River-Dominated delta complexes 6.22 Prodelta of the Wave-Dominated delta complexes 6.23 Prodelta of the Mixed Wave/River Influenced delta complexes 6.24 Prodelta: Comparison of Environmental Controls

6.3 DELTA FRONT 6.31 Delta Front of the River-Dominated delta complexes 6.32 Delta Front of the Wave-Dominated delta complexes 6.33 Delta Front: Relative Transgression of the Wave-Dominated delta complexes 6.34 Delta Front of the Mixed Wave/River Influenced delta complexes 6.35 Delta Front: Comparison of Environmental Controls

6.4 DIFFERENTIATING DELTA FROM SHOREFACE SUCCESSIONS 6.41 Introduction 6.42 Prodelta us. Offshore 6.43 Delta Front us. Lower to Upper Shoreface

CHAPTER 7 CONCLUSIONS

APPENDIX A APPENDIX B APPENDIX C APPENDIX D LIST OF REFERENCES LIST OF FIGURES PAGE

Figure 1-1 Study Area Figure 1-2 Stratigraphie Column

Figure 2-1 Allostratigraphy of the Dunvegan Formation 21 Figure 2-2 Allostratigraphy of the Belly River Formation 22 Figure 2-3 Paleogeography of the Western Interior Çeaway during 23 the late Cretaceous (mid-Cenomanian) Figure 2-4 Paleogeography of the Western Interior Seaway during 24 "Belly River" the(Mid-Campanian) Figure 2-5 Generalized Cross-Section through the Alberta Foreland 25 Basin

CHAPTER 3 3.3 DUNVEGAN FORMATION

3.31 Shingle D3 Figure 3-1 Litholog 13-28-61-02W6 Figure 3-2 Facies Shots of Shingle D3 of the Dunvegan Formation

3.32 Shingle D2 Figure 3-3 Litholog 10-26-63-24W5 Figure 3-4 Litholog 06-11-62-03W6 Figure 3-5 Litholog 07-10-63-01W6 Figure 3-6 Facies Shots of Shingle D2 of the Dunvegan Formation Figure 3-7 Facies Shots of Shingle D2 of the Dunvegan Formation Figure 3-8 Facies Shots of Shingle D2 of the Dunvegan Formation Figure 3-9 Facies Shots of Shingle D2 of the Dunvegan Formation

3.33 Shingle Dl Figure 3-10 Litholog 02-18-64-23W4 Figure 3-11 Litholog 11-16-63-24W5 Figure 3-12 Litholog 10-18-64-23W5 Figure 3-13 Facies Shots of Shingle Dl of the Dunvegan Formation Figure 3-14 Facies Shots of Shingle Dl of the Dunvegan Formation

3.34 Shingle E3 Figure 3-15 Litholog 11-05-63-26W5 Figure 3-16 Litholog 05-27-61-01 W6 Figure 3-17 Litholog 04-08-63-02W6 Figure 3-18 Facies Shots of Shingle E3 of the Dunvegan Formation Figure 3-19 Facies Shots of Shingle E3 of the Dunvegan Formation Figure 3-20 Facies Shots of Shingle E3 of the Dunvegan Formation Figure 3-21 Facies Shots of Shingle E3 of the Dunvegan Formation

3.35 Shingle E2 Figure 3-22 Litholog 10-3461-26W5 Figure 3-23 Litholog 06-35-62-27W5 Figure 3-24 Facies Shots of Shingle E2 of the Dunvegan Formation Figure 3-25 Facies Shots of Shingle E2 of the Dunvegan Formation Figure 3-26 Facies Shots of Shingle E2 of the Dunvegan Formation Figure 3-27 Facies Shots of Shingle E2 of the Dunvegan Formation

3.36 Shingle El Figure 3-28 Litholog 07-11-60-22W5 Figure 3-29 Litholog 14-16-60-21W5 Figure 3-30 Facies Shots of Shingle El of the Dunvegan Formation Figure 3-31 Facies Shots of Shingle El of the Dunvegan Formation Figure 3-32 Facies Shots of Shingle El of the Dunvegan Formation Figure 3-33 Facies Shots of Shingle El of the Dunvegan Formation

3.4 Belly River Formation

3.41 Cycle D Figure 3-34 Lithologl 6-07-49-08W5 Figure 3-35 Litholog 10-23-48-06W5 Figure 3-36 Litholog 08-22-49-07W5 Figure 3-37 Facies Shots of Cvcle D of the Belly River Formation Figure 3-38 Facies Shots of cycle D of the Belly River Formation Figure 3-39 Facies Shots of Cycle D of the Belly River Formation

3.42 Cycle E Figure 3-40 Litholog 06-11-47-05W5 Figure 3-41 Litholog 06-10-43-04W5 Figure 3-42 Facies Shots of Cycle E of the Belly River Formation Figure 3-43 Facies Shots of Cycle E of the Belly River Formation Figure 3-44 Facies Shots of Cycle E of the Belly River Formation Figure 3-45 Facies Shots of Cycle E of the Belly River Formation

3.43 Cycle F Figure 3-46 Litholog 04-22-47-03W5 Figure 3-47 Facies Shots of Cycle F of the Belly River Formation Figure 3-48 Facies Shots of Cycle F of the Belly River Formation Figure 3-49 Facies Shots of Cycle F of the BelIy River Formation

3.44 Cycle G Figure 3-50 Litholog 10-09-47-02W5 Figure 3-51 Litholog 16-13-43-28 W4 Figure 3-52 Facies Shots of Cycle G of the Belly River Formation Figure 3-53 Facies Shots of Cycle G of the Belly River Formation Figure 3-54 Facies Shotç of Cycle G of the BelIy River Formation Figure 3-55 Facies Shots of Cycle G of the Belly River Formation

3.45 Cycle H Figure 3-56 Litholog O8-l9-45-Ol W5 Figure 3-57 Litholog 07-15-47-02W5 Figure 3-58 Facies Shots of Cycle H of the Belly River Formation Figure 3-59 Facies Shots of Cycle H of the Belly River Formation Figure 3-60 Facies Shots of Cycle H of the Belly River Formation

CHAPTER 6

Figure 6-1 Litholog 10-34-61-26W5 Figure 6-2 Litholog 08-12-63-27W5 Figure 6-3 Litholog O7-10-63-Ol W6 Figure 6-4 Litholog 10-26-63-24W5 Figure 6-5 Litholog 02-18-6423E5 Figure 6-6 Litholog 1O-Og-WO2W5 Figure 6-7 Litholog l6-0749-O8W5 Figure 6-8 Litholog 16-13-43-28W4

xii CHAPTER 1 INTRODUCTION, SCIENTIFIC PROBLEM, OBJECTIVES, STUDY AREA, DATA BASE, METHODS AND REGIONAL STRATIGRAPHY

1.1 INTRODUCTION This thesis investigates the ichnological signatures of river- and wave- dominated delta successions, specifically those of the Dunvegan and Basal Belly River Formations. The purpose of the study is to demonstrate that the delta facies mode1 is incomplete without the integration of the ichnology. IchnoIogy (the study of trace fossils) is an important part of the interpretation of a paleoenvironment and should be used in conjunction with sedimentological and stratigraphie data. Ichnofossils (trace fossils) are unique because although they may represent the morphology of the trace-making organisrns in some instances, of greater importance is that they also reflect the ethology (behaviour) of the trace-rnaker and the physical characteristics of the substrate (Seilacher, 1964; Frey, 1975; Ekdale et al., 1984). Organisms inhabiting a substrate are sensitive to environmental conditions and to changes in that environment, and they respond to both physical and chemical changes in that setting. The sarne trace-maker can therefore create different biogenic structures in response to different environmental conditions (Ekdale et ni., 1984; Pemberton et al., 1992). Variations in temperature, salinity, sedimentation rates, amounts of sediment deposited or eroded, oxygenation of water and sediment, and substrate coherence and stabiiity all have profound effects on the resulting ichnofossil suites. These suites cmtherefore be used in determination of onginal biological, ecological and sedimentological conditions (Frey and Seilacher, 1980). Ichnology has become more widely used in aiding environmental interpretations of shoreface, incised valley systerns, and estuarine environments. Deltas need to be added to this growing list, as their ichnological assemblages are unique, though subtle in expression. This thesis, then, also serves as a case study in a larger project with 2 the ultimate aim of establishing integrated ichnolcgical-sedimentoIogicaIfacies models for del taic successions. The working definition of a delta employed in this thesis will be that of Elliott (1986): "discrete shoreline protuberances formed where rivers enter oceans, serni-enclosed seas, lakes or lagoons and supply sediment more rapidly than it can be redistributed by basinal processes". By this definition, d deltas are, to some degree, nver dominated. The sediment in a delta is normdly derived directly from the nver that feeds it. The "discrete shoreline protuberance" has led Walker (1992) to suggest that there are no such things as tide-dcminated deltas. Dalrymple f1999), however, has argued that the "shoreline protuberance" may not always form in tidally dominated settings, and uses the Fly River Delta as an example. He states, instead, that the important part of the delta definition is that the sediments are supplied more rapidly than redistnbuted, creating a prograding system. As tide-dorninated deltas are not dealt with in this thesis, the controversy surrounding "shoreline protuberance" is beyond the scope of this study.

1.2 SCIENTIFIC PROBLEM The sedimentology and stratigraphy of the Dunvegan Formation and the Belly River Formation have both been studied in detail (Bhattacharya, 1988, 1989a,b, 1993,1999; Bhattacharya and WaIker, 1991,1992; Power, 1993; Power and Walker, 1996) and the question arises "why should these formations be looked at again?" Some trace fossils and abbreviated trace fossil assemblages were breitly mentioned in the description of the facies associations, but were not fully described or integrated with the sedirnentology. One of the main objectives of this thesis was to ensure that al1 the traces were identified, as the main focus of previous studies was primarily the sedimentology and stratigraphy. The trace fossil assemblages recorded previously were anticipated to be incomplete or inaccurate. Further, there was no attempt to integrate ichnology with sedimentology, which markedly limited details of the depositional environment. 3 This, in tum,limits the effectiveness of the resulting "deltaic" facies models proposed. The problem pertaining to the lack of use (or exclusion) of trace fossils is not unique to these previous studies. Many studies of deltas completely ignore the fact that trace fossils are present or add them in their descriptions as an afterthought but with no explmation. Others use them only under circurnstances where they support an interpretation already arrïved at on the basis of sedimentology and stratigraphy done.

1.3 OBJECTIVES There are five main objectives of this study, each one leading to the next. The study commenced with the identification of sirnilarities and differences in the trace fossil suites of the comparable subenvironments of river- and wave- dominated delta deposits. These trace fossil suites were then categorized into ichnological assemblages. It was important to integrate ichnology with sedimentology to interpret the various subenvironments. Once accomplished, the next goal was to distinguish the likely paleoenvironmental factors that generated the differences in the trace fossils found in river- and wave-dominated deltas. These paleoenvironmental factors are crucial, as they affect the behaviour of infaunal organisms in the different subenvironments of river- and wave- dominated deltas. The ultimate goal of this thesis is to act as a major case study in the development of intg*~atedichnological-sedimentological facies models for del tas.

1.4 STUDY AREA/ DATA BASE/ METHODS Two formations were studied from subsurface data: the Basal Belly River Formation of central Alberta and the Dunvegan Formation of west-central Alberta (Figure 1-1). The study area comprises Townships 59-64 and Ranges UW5-04W6 for the Dunvegan Formation; and Township 43-49 and Ranges 28W408W5 for the Belly River Formation. AU the data in this study were collected through detaiied sedimentological and ichnologicd analyse of 70 cored 4 intervals; 32 cores from the Belly River Formation, that averaged of 20.1 m in length, and 38 cores from the Dunvegan Formation, that averaged of 23.4 m in length. A list of well locations, cored intervals and core lengths that were utilized in this thesis is located in Appendix B. Dr. Mike Ranger's core logging software was used to create ail lithologs in this thesis. Sedimentological analysis focused on characteristics such as grain size, sorting, bed thickness, bed contacts, and physical sedimentary structures including deformation structures. Ichnological analysis focused on identification of ichnogenera, relative abundances, diversity and size of each ichnogenera, uniformity of bioturbation and intensity of bioturbation. The individual trace fossils in each deltaic sub-environment were identified and categorised into trace fossil associations using an ethological classification. One of the main objectives was to integrate ichnology with sedimentology to interpret the various subenvironments. These relationships helped identify how factors such as changes in oxygenation, salinity, temperature, subskate consistency/stability, water turbidity, sedimentation rate, and organic detritus concentrations affect the behaviour of organisms, and consequently, their resulting bace fossils. These relationships were analysed in both wave- and river-dorninated delta complexes. Since these paleoenvironmental factors or their relative sigruficance differ in each setting, one hypothesis of the thesis was that markedly different trace fossil assemblages were anticipated. The stratigraphy of the Belly River and Dunvegan formations interpreted by Power (1993) and Bhattacharya (1989), respectively, was employed in this thesis. These previous studies encompassed detailed sedhentological and stratigraphic analyses. These studies attempted to identify the prodelta, delta front, and delta plain/channel subenvironrnents, as well as the dominant physical process operating (i.e., river- or wave-dominated/influenced). Bot. projects employed an alloshatigraphic framework, the only approved genetic stratigraphy of the NACSN (1983) and identified the stratigraphic positions of cycles or allomembers. 1.5 REGIONAL STRATRIGRAPHY The Dunvegan Formation is situated in northwestem Aiberta, and is Upper Cretaceous (middle Cenomanian) in age. It consists of a series of interbedded marine to non-marine sandstones and shales deposited in an actively subsiding foreland basin, the Western Interior eperic seaway of North America (Stott, 1984). The Dunvegan Formation overlies the shales of the Shaftesbury Formation and is terminated by the shdes of the overlying Kaskapau Formation (Singh, 1993; Bhattachawa, 1988,1989a,b31993,1999) (Figure 1-2) The basal Belly River Formation is situated in central Alberta and is Upper Cretaceous (early-mid Campanian) in age. The Belly River Formation lies above the Lea Park Formation and is succeeded by the Bearpaw Formation (Figure 1-2). The transition is marked by marine mudstones of the Lea Park Formation giving way to sandstoneç of deltaic and fluvial origin of the Belly River Formation. The transition contains a series of interbedded marine and non-marine sandstones, siltstones and muds tones (Power and Walker, 1996). Coasta1 and non-marine sediments of the Belly River Formation intertongue northeastward with marine sediments of the Lea Park Formation. This marks the passage from an open marine shelf to a non-marine alluvial environment, as the Belly River "wedge" of sediment prograded eastward and infilled the basin. Wilon Creek

- -. ... .r

Ferrier-Wiltesden

Figure 1-1 : Location map of the Dunvegan and Belly River formations of central Al berta (modified from B hattacharya, 1993; and Power and Walker, 1996). Alberta Alberta Alberta Central Plains NW Plains NE Plains

Paleocene Paskapoo 1 1 I Maastrichtian Scollard

Wapiti p. Campanian E 1 Belly River \ Santonian Puskwaskau 1 Coniacian "Colorado shale" Badheart Mus kiki Camtum 1 Turonian .------

- --

Doe Creek Cenomanian Dunvagrn Shaiîes -bury Fish Scale Zone FÏsh Scaie Zone

Peace Joli Fou River Cadotîe Colon Harmon Mclaren Albian Notikewin Mannville River Pelroleum Clearwater ciearwate: . uo$i,mer Glauconitic Blues Wabiskaw Curnminqs

Aptian Ellerslie Barremian

Figure 1-2 Stratigraphic chart of Cretaceous intervals in the Western Canada Sedimentary Basin, Alberta, Canada (modified after Pemberton and MacEachern, 1995). INTRODUCTION, PREVIOUS WORK, AND PALEOGEOGRAPHY/BIOSTRATIGRAPm

2.1 INTRODUCTION The first part of this chapter focuses on the previous work of Janok Bhattacharya (cf., Bhattacharya, 1988,1989a,b, 1993,1999; Bhattacharya and Waker, 1991,1992) and Murray Gingras (cf ., Gingras et al., 1998) on the Dunvegan Formation, and by Bruce Power (cf., Power, 1993; Power and Wallcer, 1996) on the Belly River Formation. These works provide the most complete and comprehensive assessrnent of the regional and physical sedimentological analysis of these two units. The focus of this thesis is not to re-interpret the stratigraphy, but rather to refine and elaborate upon the ichnological elements of these units, and to integrate this with the excellent sedimentological and stratigraphic analysis already published. For this reason, the stratigraphic frameworks of Bhattacharya and Power are employed for the Dunvegan and Belly River, respectively. AUomernbers E and D of the Dunvegan Formation and cycles D, E, F, G, and H of the Belly River Formation were the intervals that were focused upon in this thesis. The second part of this chapter provides a synopsis of the paleogeography and bioshatigraphy of the Western Interior Basin during the Cretaceous, specifically dealing with the Cenomanian and Campanian. This places these two stratigraphic uni& into their regional contexts.

2.2 PREVIOUS WORK 2.21 Dunvegan Formation The Dunvegan Formation was previously interpreted as "deltaic" by McLearn (1919), Stelck et RI. (1958), Tater (1964), Burk (1982), Stott (1982). Large- scale studies of the Dunvegan Formation was completed by Burk (1963) and Stott (1982). Burk (1963) completed a large subsurface study of the Dunvegan, and 9 created an isolith map for all of the sandstones. This study unfortunately did no include core descriptions, sedimentological details, or any stratigraphie subdivisions. In the isolithmap, a general thinning of the sandstone in a southeast direction was identified. Stott (1982) dso identified the Dunvegan Formation as deltaic usïng outcrop data to the north and northeast. This interpretation was based on the identification of a marine to fluvial transition. Plint (2000) studied the upper Shaftesbury, Dunvegan, and lower Kaskapau formations and provided a set of detailed regional subsurface well-log correlations. He has reconstructed the paleogeography of the Dunvegan Delta complex for another 220 km further north and up to 150 kxn further west of Bhattacharya's (1989) original study area. Paleogeographic maps reveal a series of lobate to cuspate deltas indicating sigruficant fluvial influence, but with local facies successions dominated by wave-formed structures. Bhattacharya addressed the sedimentology and stratigraphy of the Dunvegan Formation for his PhD thesis (Bhattacharya, 1989). Bhattacharya interpreted the Dunvegan Formation not as a single delta, but as a stacked series of different types of deltaic depositional systems. Nineteen facies were grouped into 7 distinct successions. These facies were then linked to lithofacies assemblages. These assemblages defined distinct, large-scale depositional systems. The seven distinct successions follow thcee basic patterns: 1) coarsening upward (or sandier upward) successions; 2) erosionally based finùig-upward successions; and 3) irregular successions, which comody contain nonmarine indicators. Bhattacharya (1989) divided the Dunvegan Formation into seven domembers, A to G, from youngest to oldest (Figure 2-1). These cycles prograded to the southeast, with shorelines trending approximately northeast- southwest Non-marine deposits increase toward the northwest, and marine deposits dominate in the southeast. Bounding discontinuities, in the form of major marine flooding surfaces, were used to define each allomember, sidar to the approach of Galloway (1989a,b). Each allomember is described as heterolithic 10 and contains sets of offlapping (regressive) uits that are separated by thin transgressive units. Bhattacharya (1989), and Bhattacharya and Wallcer (1991) interpreted AUomember E as a largely river-dominated deltaic depositional system. It is roughly pod-shaped, and ranges in thickness, from about 20 m in the far southeast, to a maximum of 65 m in the east-central portion of his study area. It consists of four, offlapping shingles, labeled Shinges El-E4, (Figure 2-1) that downlap to the southeast ont0 the top of the underlying Allomember F. Shingle E4, the oIder of the four shingles, is interpreted to represent progradation of two sandy delta lobes with a high degree of reworking by basinal processes in the form of waves and storms, suggesting that this part of the delta was wave- influenced. This lobe was subsequently transgressed and "abandoned".A basinward shift in deposition aLlowed the deposits of shingle E3 to overlie and offlap shuigle E4. Shingle E3 is interpreted to be composed to two overlapping river-dominated delta lobes. This shingle forms an elongate birds-foot shaped sandy delta lobe (Bhattacharya and Walker, 1991). Like shùigle E4, E3 was subsequently abandoned. Another basinward shift in the locus of deposition permitted the sediments of shingle E2 to prograde over shingle E3. Shingle E2 was interpreted as a prograding river-dominated delta, representing a highstand system tract relative to El. Shingle El was interpreted as a lowstand river-dorninated delta lobe (Bhattacharya, 1989). The main distributary of El, the "Simonette channel", splits into a distributary network that feeds a lowstand delta in the Bigstone area to the southeast. The erosive base of the Simonette channel was interpreted as a regressive surface of erosion (RSE) related to a relative fa11 of sea level, though it could also have been the result of autocyclic processes (Bhattacharya, 1989).The base of the Simonette channel also truncates portions of shgles E2 and E3. This RSE passes seaward into a correlative conformity. A widespread subaerial exposure surface, characterized by in sifri root traces, was interpreted to correlate 11 with the sequence boundary at the base of the Simonette channel (Figure 2-1). The Sirnonette channel also marks the lower boundary of shingle El. Çeveral surfaces contain a thin transgressive unit overlying AUomember E. This surface consists of an erosional base, and is therefore interpreted to constitute a transgressive surface of erosion (TSE), and marks the base of the transgressive systerns tract. A sharp contact behveen sandstones and mudstones is interpreted to indicate abrupt deeperiing, temiinating AUomember E. Further deepening is thought to be marked by a sharp contact between bioturbated sandy mudstones and the overlying shatified silty marine mudstones. Better stratified mudstones are interpreted to be associated with the next progradational deposits of the overlying Allomember D. Bhattacharya (1989) interpreted the deposits of Allomember D as wave- dominated delta lobes that grade upward into barrier islands. These deposits are irregular to pod-shaped, and range from 8 to 35 m in thickness. Allomember D consists of three shingles that offlap to the southeast, and downlap ont0 Allomember E (Figure 2-1). In the northwest, shingle Dl lies erosionally upon D2. D2 lies erosionally on D3, and all three become conformable toward the basin. Shingle D3 is poorly preserved and is mainly tTuncated by an erosional surface. D3 represents a deltaic lobe, truncated by a possible TSE. Deposits of shingle D2 are interpreted to represent a wave-dominated delta that grades upward into a barrier island succession, created during a relative highstand of sea level. D2 has a linear shape, oriented parallel to paleo-shoreline trends (NE- SW), with about a 10 m thickness of sandstone (compared to about 18m in river- dominated delta systems of Allomember E). ShingIe Dl was created due to an allocyclic seaward shift in the position of shoreline, which was accompanied by channelling in the Waskahigan area (i.e. the Waskahigan channel). This is interpreted as part of a lowstand systems tract. Deposits of Dl create a cuspate- shaped lobe overlying an RÇE, and is interpreted as the lowstand delta. The RSE associated with shingle DI is thought to correlate wifhrooted horizons capping the lagoonal deposits in shingle D2. Shingle Dl was terminated due to a 13 transgression. Concornitantly, the Waskahigan channel was back-filled with a thick succession of estuarine deposits. Bhattacharya (1989) states "without art accompanying sandstone distribution map, the delta front facies succession would be practicdy indistinguishable from sandy wave- and storm-dominated shand plain deposits not associated with deltaic outbuilding". A preliminary assessrnent of the ichnology in the Dunvegan formation was undertaken by Gingras et al. (1998). This study fucused on the sedimentological and ichnological aspects of allomembers E and D of the Dunvegan Formation. Gingras et al. (1998) evaluated the ichnology and sedimentology in the context of the subenvironrnents of the delta, which were divided into the offshore transition, prodelta, subaqueous delta front and the proximal delta front/distributary mouth bar. They concluded that the main difference between allomembers E and D was the intensity and overall diversity of ichnogenera. In the proximal facies of Allomember E, the overall intensity of bioturbation and diversity of ichnogenera were found to be reduced, with a general suppression of the Skolithos ichnofacies. This differs from AUomernber D, where the intensity of burrowing is greater, there is a higher diversity of ichnogenera, and a comparatively more diverse Skolitlios ichnofacies. Gingras et nl. (1998) stated that this type of ichnological study cm provide insights into the ethology exhibited by infauna in the different depositional settings. They also stressed that these differences emphasize the influences that the different environmental parameters (e.g. such as variability in salinity, temperature, sedimentation rates, water turbidity, and substrate consistency) play in an organism's selection of an ethological sumival strategy. 2.22 Belly River Formation The most comprehensive allostratigraphic anaiysis of the subsurface part of basal Belly River Formation was undertaken by Power (1993) as a PhD project at McMaster University. The Belly River Formation was interpreted as a stacked series of depositional systems. Eight different cycles were distinguished, labeled A-H, from oldest to youngest (Figure 2-2). A sedimentological analysis was completed on each cycle. The cycles are defined by bounding discontinuities, such as marine regressive surfaces of erosion and non-marine subaerial unconformities, which are genetically linked. Regressive surfaces of erosion (RSE were formed by forced regressions, caused by high frequency allocyclic base level falls that rapidly displaced the shoreline basinward before deposition of the shoreline cycle. The six youngest cycles, C-H, are interpreted to reflect high frequency fluctuations in base level, and were believed to be fulIy deveioped within the study area. Within cycles C-H, the older allomembers (C-E) form a shongly progradational stacking pattern, and are interpreted to have been deposited during a period of reduced rates of long term rise in base level (i.e. highstand systems tract). The youngest cycles (F-H) form a progradational/ aggradational stacking pattern, which reflects a period of increased rates of long term base level rise. Cycle G was deposited when the rate of long term rise reached a maximum. This allowed for extensive transgressive sedimentation. Cycles D, E, F, G, and H were focused upon in this thesis. All five cycles were interpreted as prograding, river-dominated deltaic "shorefaces"(Power, 1993). Cycle F was interpreted to represent the most proximal position relative to the fluvial input, whereas cycles D and E were interpreted to be more distally positioned. Cycles G and H are different from the others, as they lack channels cutting into " shoreface" deposits. In Cycle G, there is an elongate sandstone tongue at least 60-70 km in length, and Cycle H is believed to indicate little reworking of the proximal sediments by basinal processes (Power and Wallcer, 1996). 14 Al-Rawahi (1993) studied the transition from the Lea Park Formation to the continental Belly River Formation. This study involved analysis of 78 cored intervals and correlation of over 500 electrical well logs. The study area encompassed 1500 km2 of the plains of central Alberta. The sediments studied comprise a 50 m thick section and were divided into three domernbers. These allomembers are bounded by erosional discontinuities, which formed due to relative sea level changes. Ailomember 1is interpreted as a prograding fluvial- and wave-dominated delta. These sediments were tnincated by Allomember 2, which consist of non-marine channel fiIl, mudstones with root traces, and coal beds. Allomember 3 is composed of both transgressive and regressive sediments. The regressive sediments include fluvial- and wave-dominated lobate delta front sandstones. These allomembers are interpreted to define a fourth-order cycle of relative sea level change, estirnated at about 190,000 ka. Jerzykiewicz and Norris (1994) interpreted the "Belly River" clastic wedge in the Southern Foothills, and is intemally subdivided by the Pakowki marine shale into two deltaic successions. The lower delta is situated in the "Lees Lake Formation" (previously called the Chungo Member of the Belly River Formation by Stott, 1963) and is interpreted as prodelta turbidites. This is overlain by wave- and tidally-influenced deltaic sandstones of the "Burmis Formation" (previously called the "basal Belly River sandstone").The Burmis Formation is capped by the Pakowki Formation. The depositional environment that created a distal to subproxirnal succession in the "Belly River" cIastic wedge was interpreted in temis of a compressional and northeasterly migrating, Laramide deformational front (Jerzykiewicz and Norris, 1994). This migration was not steady and was interrupted by a short transgression of the Pakowki Sea, subdividing the "Belly River" ciastic wedge into two, shallowing-upward, deltaic successions that reflect two phases of Laramide tectonism in the source area. This mode1 is not widely accepted. When the Laramide tectonic activity reactivated, it resulted in the development of the fluvially dominated Connelly Geek/Lundbreck (Foremost 15 Member) delta, coinciding with the Pakowki regression at ap proximately 80 Ma. Jerzykiewicz and Noms (1994) correlated the Comelly Creek in the Southem Foothills with the Foremost Member of the Belly River Formation in southwest and southeast Alberta. Harnblin and Abrahamson (1996) divided the basal Belly River Formation hto a senes of at least seven stacked, composite, primarily regressive cycles. These cycles comprise oftlapping progradational uni6 dorninated by shoreline sediments. Each cycle includes several to many individual subunits bounded by localized transgressive surfaces. These authors did not discuss the sedimentology in detail. Story (1982) studies Belly River deposits in the Keystone-Pembina area. The subsurface sedirnents were interpreted to represent deposition in a shallow lobate deltaic system. Unfortunately, little to no data on the deposits were given in this study. Wasser (1988), and Hartling and Wasser (1989) also studied the Keystone- Pembina and Ferrybank areas. They interpreted the sediments to represent a series of overlapping deltaic lobes. Again, unfortunately, no detailed facies analysis of the sediments was provided. Sabry (1990) studied the lithology of subsurface sediments of the Belly River Formation. Little detail was presented. The area of study was large (about 18,000 km2) and 50 cores were examined. Sabry interpreted the sandstones to have been deposited in many types of environments, including deltaic, estuarine, tidal channels, tidal flats, tidal sand ridges, and fluvial environments. 2.3 PALEOGEOGRAPHY The foLlowing section is a synopsis of the evolution of the Cretaceous seaway of Western Interior North America, with specifics during the Cenomanian and Campanian during deposition of the Dunvegan and Belly River formations, respectively. The Westem Interior of North America during the Cretaceous was flooded and a seaway was created. At peak flooding, the seaway extended from the Canadian Arctic and Alaska to the Gulf of Mexico, perhaps with intermittent connections to the Hudson's Bay region (Figure 2-3, Figure 2-4). The shape and size of the seaway changed in response to tectono-eustatic, tectonic, and sedimentologic processes (e.g., delta building, shoreline progradation). This seaway occupied a tectonically active Andean-type foreland basin (Eberth, 1998). West of the seaway, lay the Cordilleran thrust belt, intrusive bodies and volcanic centres. East of the seaway sat a broad, erosionally planed, stable cratonic platform. The basin was asymmetrical, with a greater rate of subsidence dong its western margin and a corresponding thickened sedimentary succession (Figure 2-5) (Kauffman, 1984; Ra yc haudhuri, 1994). It was in the Aptian Stage that the seaway was initially flooded from the north. During the early to late Aptian time, an extensive northern arm and a minor southem arm from the Gulf of Mexico encroached slowly and irregularly into the basin. They met in the middle Late Aptian time in central and southern Colorado. In the late Aptian, there was a brief and partial retreat, but the sea joined again in the latest Albian - earliest Cenomanian tirne. The marine system rernained continuous between the proto-Gulf of Mexico and the Circum-Boreal Seaway, for nearly 35 Ma (Kauffrnan, 1984; Raychaudhuri, 1994). It drained from the interior of North America for the last tirne in the Middle Maastrichtian, but wîth a remnant arm persisting into the Middle Paleocene. Sea Ievel fluctuations and related tectonic modification of the foreIand basin are believed to be the main conhols on clirnate and biogeographic 17 distribution in the Westem Intenor Seaway through time (Kauffman, 1984). During latest Albian to Middle Maastrichtian tirne, there were five major third- order tectono-eustatic cycles and numerous fourth-order transgressive-regressive cycles. These cycles altered the shape, bathyrnetry, and sedimentological patterns of the basin and can be linked to global tectono-eustatic sea-level changes (Kauffman, 1984). Peak rises of relative sea-level, recording third-order cycles, occurred in the middle Late Albian, the midde Early Turonian, the Lower Coniacian-Late Santonian, the late Early Campanian, and the middle Late Campanian stages (Kauffman, 1984). Peak flooding occurred during Early Turonian and Coniacian-Santonian times. The fourth-order cycles are thought to be related to smaller sea-level changes or stillstand events, and are expressed as regional strandplain fluctuations, progradational events, and/ or regional disconformities (Kauffman, 1984). Two major episodes of the Columbian Orogeny are recorded. The first episode occuned during the Late Jurassic to the earliest Cretaceous (Berriasian- Valanginian) and the second occurred during the late earIy Cretaceous (Barremian-Aptian to Cenomanian, cfi, Stott, 1984). The Dunvegan Formation was deposited during the second phase of the Columbian Orogeny. Stott (1984) recognized that the sedirnents deposited during this time consist of series of transgressive-regressive cycles. During the early Cenomanian, the Westem Interior temperate biota were still largely isolated from the Gulf Coast seas by a shallow clastic sedimentary si11 in the south. The biota werw predominantly cool to mild temperate (Kauffman, 1984).The early Cenomanian eustatic rise caused buildup of tropical to subtropical Tethyan biotas in the Gulf Coast, and the transgression initiated a widespread invasion of the Interior Szaway. The subtropical ocean is referred to as the Tethys, and the Polar ocean is referred to as the Boreal (Hay et al., 1993). The reshicted southem aperture of the basin remained an effective barrier to northward migration of warm-water taxa. The slightly brackish, oxygen- reshicted chemistry of the Interior Çeaway at this tirne also created a barrier 18 againçt tropical to subtropical Tethyan biotas. It was during this tirne (latest Albian to earliest Cenomanian, cc, Stott, 1984) in the Canadian Rocky Mountains that a major sea-level still-stand occurred, recorded by the Fish %ale Marker Horizon. In rniddle Cenomanian the, the barrier at the southem aperture of the Western interior basin waç breached by continued eustatic sea level rise (third order). An intermixing of the northem and southem temperate biotas reached the southem one-third of the Western Intenor and Texas. Rare sub-tropical biotas reached southem Colorado. Temperate zone biotas predominated throughout the Cenomanian, but it is believed that warmer water temperatures were expanding northward from the southern interior subprovince (Kauffman, 1984). During the early to mid-Cenomanian in the Canadian Rocky Mountains, a regression of the Dunvegan delta occurred (fourth order, cc, Kauffman, 1984). The Dunvegan is characterized in northeastem British Columbia by alluvial and floodplain deposits, and in west-central and central Alberta by marine sandstones and shales (delta front and prodeltaic sediments). The Dunvegan Formation belongs to the Acnntlzocerns nfhabnscerzse ammonite zone (Jeletzky, 1968). This has been subdivided on the basis of inoceramid pelecypods into the Inocernmus nltherfordi and Inocermnus dzmuegnnensis subzones. The Kaskapau Formation, which overlies the Dunvegan Formation, belongs to the upper Cenomanian Dunvegmocerns Zone. The Base of Fish Scales (BFS) marker, located below the Dunvegan Formation, belongs, in part, to the Bec~ttonocernsbeatfonense Zone, but ammonites have not been recovered from the upper part of the Shaftesbury Formation in outcrop (Bhattacharya and Walker, 1991). The upper Shaftesbury and lower Dunvegan formations have been assigned to early Cenomanian Textularia alcesensis Zone, based on foraminiferal assemblages which encompasses the Beattonocerns beaftonense ammonite Zone. These zones refer to the northwest, Peace River and Fort St. John areas, but is not recognized in the southeast or the plains, where the 19 Shaftesbury is allocated to the V. perplexlis Zone (Caldwell et al., 1978). The middle Cenomanian probably represents 1.5 Ma (Haq et nl., 1988). During late Cenomanian tirne, warm-water cosmopolitan and marginal- Tethyan (subtropical) taxa first appeared into the southern half of the Western Interior Seaway. This began with a few specialized (stenothermal), planktonic foraminifera and calcareous namoplankton which gradually diversified forrning widespread pelagic carbonates (Greenhorn cycle in Montana/Colorado). This kvas abruptly alteïed during the Late Cenomanian and Early Turonian (Kauffman, 1984). The near-peak h-ansgression created a sharp rise in water temperature and salinity levels throughout the central and southem part of the seaway. This is indicated through stable isotope, sedimentologic, and biologic data. The flooding of the Gulf and Caribbean water masses into the Western Interior Seaway was a result of rapid eustatic sea level rise and/or sudden breaching of barriers to the encroaching ocean in less than 0.5 Ma (Kauffman, 1984). During the Late Cretaceous, the interior of North America was extensively flooded. Two peak transgressive events during Turonian and Santonian time were interrupted by a regressive phase during w-hich the Cardium Formation was deposited (Stott, 1988). The succeeding coarse clastic sediments that were deposited include the Belly River Formation, the Brazeau Formation, and Wapiti Formation. These sedirnents were deposited in the Mid-Campanian, during the early phase of the Laramide Orogeny (Stott, 1984). The Laramide Orogeny provided thsting and mountain building in the west which resulted in the southward retreat of the Lea Park Sea (Stott, 1984). This regression is interpreted to be coincident with a Haq et nl. (1988) third-order eustatic sea level fall. A northern migration of subtropical biotas during the Coniacian- Santonian transgressive event occurred during the Iatest Santonian and earliest Campanian time (Le., the Scnplzifes Izippocrepis Zone). This event is represented by a northem spread of pelagic chalks and limestones, and by a smdincrease in planktonic foraminiferal nurnbers and diversity, including an increase in 20 divers* of keeled species (Kauffman, 1984). The subtropical-warm temperate boundary reached southem Wyoming. The Santonian and earliest Campanian is interpreted as a less extensive transgressive event compared to the previous transgressive incursions. This transgressive peak was characterized by fluctüating level of subtropical Tethyan biotic influence throughout the 5 Ma it existed. A moderately extensive and rapid (2.5 Ma) marine regression followed this incursion. At some point during this regression the Belly River Formation was deposited. The regression was temiinated during the rniddle Early Campanian (Kauffman, 1984). Detailed biostratigraphic resolution of the interval containing the Lea Park-Belly River transitional sediments is uncertain due to the scarcity of fauna within the non-marine section, and the sbongly diachronous character of the sediments. In central Alberta, the Lea Park and lower Belly River formations are assigned to the molluscan Scnplzifes Iiippocrepis Zone. A number of smaller transgressions Çollowed Belly River deposition during Campanian-~Maastrichtianthe, but within the Westem Interior basin, none were of comparable magnitude to any of the previous events. The Westem Interior basin remained characterized by a northward incursion of subtropical and warm temperate biotas (Kauffman, 1984). The last major transgression peaked during the middle Late Campanian. With this came a major incursion of subtropicd biotas, reaching into central Canada. A major regression followed, and al1 subtropical biotas disappeared from the Western Interior Seaway (Kauffman, 1984).The Early and Middle Maastrichtian marks the major regression of the epicontinental Westem Interior Seaway, though minor transgressions intermpted this overall regressive event. Allomember Roundins Discontinuities .-' nieters / ' (Major Flooding surface) FSU ' - Shingle Bounding Discontinuities Erosion Surfaces

Sandstone

h Roots Figure 2-2. Allostratigraphy of the Lea Park-Belly River Formation. Letters refer to cycles (modified from Power and Walker, 1996). Figure 2-3: The Palaeogeography of the Western lnterior seaway during the late Cretaceous (mid-Cenomanian). (modified from Bhattacharya, 1993) Figure 2-4: Palaeogeography of the Western Interior Seaway in the "Belly River" time, Mid-Campanian (H. nodosus time) (modified from Eberth, 1 998). 1 I I i Stable Eastern Platforrn Zone: Zone of maximum subsidence,, Zone of hige subsidence and I "Hinge Zone" sedlmentation Rate: sedimentation rate: I Moderate subsidence and 4 low sihsidence and sedimentatlon Shallow Water I Oeepest Water in west I water depths 1 rate; shelf depths; many disconformities I central troughs I

I I I Stable Craton Maximum Water -

Sedirnentary Basin Fill Thrust Belt, Plutonisrn, Vulcanism lsostatic Rebound in Hinge Zone: Basin-Swell Structures

Basin: Loading Axial Basin: Subs~dence Subduction-lnduced Subsidence CHmR3 FACIES DESCRIPTIONS AND FACIES SUCCESSIONS

3.1 INTRODUCTION Facies analysis was necessary in order to interpret and integrate the sedirnentology and ichnology of the rocks. This chapter presents these detailed descriptions of facies. This includes sedimentological analysis that focused on characteristics such as grain size, sorting, bed thickness, bedding contacts, and physical sedimentary structures including penecontemporaneous deformation structures. The ichnological analysis focused on identification of ichnogenera, their relative abundances, diversities and sizes, as well as the intensity and uniformity of bioturbation. In Allomember D of the Dunvegan Formation, each facies within shingle Dl, D2, and D3 were separately described. For each shingle, these facies were categorized into the typical facies succession. This process was repeated for shùigle El, E2, and E3 of Allomember E. Within the Belly River Formation, each facies within cycles D, E, F, G, and H were separately described and subsequently categorized into the typicd facies successions for each cycle. A facies is defined as, "a body of rock characterized by a particular combination of lithology, and physical and biological stnictures that bestow an aspect different from the bodies of rock above, below and laterally adjacent" (Walker, 1992). Facies successions are defined as, " a vertical succession of facies characterized by a progressive change in one or more parameters" (Walker, 1992). In Chapter 4, the facies descriptions and facies successions are packaged into facies associations and the depositional environments will be interpreted. In the Dunvegan Formation, the facies for shingles Dl, D2, and D3 are packaged into a facies association for Allomember D. The facies for shingles El, E2, and E3 are also packaged into a facies association that accounts for aLl of Allomember E. In the Belly River Formation, cycles D, E, F, G, and H are packaged into a " typical" facies association. 3.2 FACIES DESCRIPTIONS Chapter 3 is subdivided into two sections. The first deds with the Dunvegan Formation and the second deds with the Belly River Formation. Each shingle (Dunvegan Formation) within domembers D and E, and each cycle (Belly River Formation) is separately described. The layout for each shingle/cycle description is as follows. The typical facies succession associated with the shingle/cycle is described. Lithologs that exhibit these successions are included at the end of the shingle/cycle description. Each facies within the succession is described, with photos of core that help illustrate the facies' characteristics. A legend with the abbreviations found on the lithologs is given in Appendix A. The cored intervals that contain specific shingles/cycles are surnrnarized in Appendix C. Descriptions of al1 the trace fossils found in the Dunvegan and Belly River Formations are summarized in Appendix D. The trace fossils throughout this thesis are referred, in abundance, as very rare (vr), rare (r), moderate (m), common (c), and abundant (a).

3.3 DUNVEGAN FORMATION 3.31 Shingle D3 The succession exhibited in shingle D3 of allomember D is characterized by four facies. The basal facies consists of shale, which is overlain by an interstratified sandstone, silty mudstone and shale facies. This interstratified facies grades upward into a larninated sandstone facies. In three cores, the larninated sandstone facies is not present, and is replaced by an interbedded sandstone and mudstone facies (Figure 3-1).

Sha le Facies The shale facies comprises intervals rangmg from 0.4 to 3.3 m in thickness, averaguig 2 m thick. The shale is mainly fissile and contains rare thin beds and 28 layers of sandstone. Interstitial silt is intermittently distributed, creating a blocky appearance. There is an abundance of carbonaceous detritus, rare siderite- cemented beds and very rare pyrite nodules are also present. The sandstone beds contain oscillation ripples, wavy parallel lamination, and combined flow ripples. Bioturbation intensity is very low and the bulk of the facies is devoid of ichnogenera. Trace fossil diversity is also low. The ichnoIogical suite reflects a "distal" Cnrzinnn ichnofacies, including Zooplzycos (vr), Lockein (r), Plnnolifes (r), Teidziclznzrs (r), Siplzonichnzrs (vr), Skolitlzos (vr) and fugichnia (r). These ichnogenera are generally diminutive u? size.

Interstratifed Sandstone, Silty Mudstone, and Shale facies The interstratified sandstone, silty mudstone, and shale facies is characterized by thin beds and layers amalgamated into composite bedsets (Figure 3-2 A). The beds range in thickness from 1 to 10 cm, averaging 2-3 cm thick. The composite bedsets Vary from 0.3 to 6.6 m in thickness, averaging 3 rn thick. This facies constitutes the majority of the preserved section of shingle D3. The bedding contacts are generally sharp, but sporadically disrupted by bioturbation. Sandstone beds thicken upward and tend to dorninate the facies. The sand is well sorted, and grain size grades upward from lower fine to upper fine. Mudstone rip-up clasts are rare and found only at the bases of thicker (approximately 10 cm), amalgarnated sandstone beds. The silty mudstone beds average 2-3 cm in thickness. These beds are massive and blocky in appearance, and are devoid of bioturbation. The shale beds are typically very dark, and contain rare to moderate numbers of sand-filled syneresis cracks (Figure 3-2 B), as well as rare pelecypod molds. Carbonaceous detritus is common throughout the facies. Siderite- cemented beds are present though variable and range from absent to abundant. Shell fragments are rare. The dominant physical structures include abundant oscillation ripples, with moderate wavy parallel lamination (Ha,hummocky 29 cross stratification), and rarer low angle planar parallel lamination and combined flow ripples. Convolute bedding and load casts are also present but are not characteristic. Bioturbation is mainly associated with the sandstone beds. Traces are present in the mudstone beds only where they suttend from the overlying sandstone beds (Figure 3-2 A, Cf and D). Bioturbation intensities range from absent to !ow. There is a low abundance of ichnogenera, and diversity is high. The ichnological suite reflects a "stressed" Cnrzinnn ichnofacies, including Zooplzycos (c), Helminthopsis (c), Anconicltnzrs (c), Terebellinn (r-c), Clionrirites (r), Plnnolites (c), Teichiclzniis (c), Rhizocornllitirn (r), Sipkonichnus (vr-r), Rosselin (r), As terosorna (r), Cyl inrlriclznus (r), Pnlneopliynrs (r), Skol ihs(r) and higichnia (r-c). Tube diarneters of Teidziclznrrs range from 0.5 cm to 1cm. Rosselin are diminutive, with a tube diameter averaging 0.5 cm, and the bulb averagmg 1.5 cm in diameter.

Interbedded Sandstone and Mudstone Facies The interbedded sandstone and mudstone facies is present in only three cores, and comprises composite beds ranging from 5 -15 cm in thickness. These beds are amalgamated into composite bedsets ranging from 0.5 to 1.5 m in tluckness. The mudstone beds are dishibuted sporadically throughout the sandstone and are generally less than 5 cm thick (Figure 3-2 E). They also contain rare sand-filled syneresis cracks. The sandstone beds are generally 8 - 15 cm thick. The sand is very weil sorted and upper fine in grain size. Carbonaceous detritus and siderite-cemented beds are present but rare. Physical structures are dominated by low angle wavy pardel lamination (HCS), low angle planar parallel Lamination, and planar paralle1 lamination, in addition to rarer oscillation ripples, combined flow ripples, and convolute bedding. Bioturbation is concentrated in the mudstone beds, with few traces extending into the sandstone beds. The bioturbation intensities range from absent to low. Ichnogenera abundance and diversity is very low. The 30 ichnological suite reflects a Crz

Laminateif Sandstone Facies The Iaminated sandstone facies comprises thick packages of sandstone beds ranging from 15-40 cm in thickness (Figure 3-2 F). These beds are amalgamated into simple bedsets ranging from 1m to 1.8 m thick. Sand is well sorted and grain size varies from upper fine to lower medium. Carbonaceous dehitus is common and typically marks the lamination. Mudstone rip-up clasts are rare and located at the bases of individual sandstone beds. Physical structures are dominated by low angle planar parallel lamination, low angle wavy parallel lamination (Ha),and rarer oscillation ripples and current ripples. This laminated sandstone facies is devoid of bioturbation, with the exception of rare Lockein found in a single core. 3 1 Figue 3-1. Litholog of weU13-28-61-02W6, exhibiting shingles D3 and D2 of the Dunvegan Formation. In this location, the basal portion of D3 consists of an interstratified sandstone, silty mudstone, and shale facies. The silty mudstone dominates in the Iower portion of this facies. This is overlain by an interbedded sandstone and mudstone facies. D3 is erosively overlain by D2, separated by a regressive surface of erosion. The base of D2 consists of a bioturbated sandy mudstone/muddy sandstone facies. This is overlain by a trough cross-stratified sandstone facies, passing upward and interfingering with a laminated to bioturbated sandstone facies. PCP Et Al. Lator 13-28-61-02~6 GRAIN SlZE cobble pebble

Trough cross-stratified Sandstone Facies (Proximal Delta Front)

Allomember Laminated to Bioturbated D2 Sandstone Facies (ProximalDelta Front)

Bioturbated Sandy Mudstone; Muddy Sandstone Facies (Distal Delta Front)

Sandstone lnterbedded with Mudstone Beds Facies (Distal Delta Frorit)

Allomernber D3

Interstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 32 Figure 3-2. Facies of shgle D3 of the Dunvegan Formation. (A) A weakly bioturbated interstratified sandstone, silty mudstone, and shale facies. Physicd structures are dominated by wavy parallel lamination and osciüation ripples. Trace fossils include Helnrintliopsis (H), Plnnolites (Pl), Teiclriclzni~s(Te), and Terebellim (Tb). Well10-33-60-05W6, depth 2835.9 m. (B) Interstratified sandstone, silty mudstone, and shale facies. Sand-fililled syneresis cracks subtend downward into the shde beds. Sandstone beds contain wavy parallel lamination. Plnnolites (Pl) are srnall and rare in numbers. Well13-28-61-02W6, depth 2431.5 m. (C) Interstratified sandstone, silty mudstone, and shale facies. The sandstone contains Rosselin (Ro). The shale contains Plnnolites (Pl). Well10-03-52-26W5, depth 2086.1 m. (D) Interstratified sandstone, silty rnudstone, and shale facies. Trace fossils include Teicliiclrntls (Te) and Plnnolites (PI). Well09-04-62-MW6, depth 2358.9 m. (E) Sandstone interstratified with mudstone facies. Physical structures include wavy parallel lamination and combined flow ripples. Sandstone contains Skolitllos (Sk). Shale contains Plnnolites (PI). Well04-08-63- 02W6, depth 2165.7 m. (F) Laminated sandstone facies, containing arnalgamated beds of low angle planar parallel lamination. Well10-33-60-05W6, depth 2833.9 JLU The succession exhibited by shingle D? of Allomember D is characterized by seven facies. The base of the succession consists of an interstratified sandstone, silty mudstone, and shale facies (Figure 3-3). Along the strike of the interpreted shoreline in both a northeast and southwest direction, the interstratified facies is replaced by a bioturbated sandy mudstone/muddy sandstone facies (Figure 34). These two facies are believed to have been deposited sirnultaneously, but the interstratified facies is interpreted to have been deposited in a closer proxirnity to major distributary channels, and therefore more affected by river influences. Both basal facies are overlain by a laminated to bioturbated sandstone facies (Figure 3-5). This grades into larninated to apparently stnictureless sandstones, passing upward and interfingering with a trough cross-stratified sandstone facies (Figure 3-5). The cross-stratified sandstones are capped by either a coal facies, or an interstratified sandstone and shale facies (Figure 3-4).

Interstratified Sandstone, Silt-y Mudstone and Shale Facies The interstratified sandstone, silty mudstone and shale facies is characterized by thin beds and layers arnalgarnated into composite bedsets that range from 2 to 10 m in thickness. Bed thicknesses vary from 1 cm to 10 cm, but are typically 1-2 cm thick. These beds typically have sharp upper and lower contacts (Figure 3-6 A), with sporadic disnipion from bioturbation (Figure 3-6 B). Sandstone bed thickness averages 1-2 cm. The sand is well sorted and grain size coarsens upward from lower fine to upper fine. The silty mudstone beds are massive and blocky in appearance, and are devoid of bioturbation. Bed thicknesses are generally 1-2 cm, but reach up to 10 cm thick. Shale beds and layers are dark and carbonaceous. These beds contain rare sand-filIed syneresis cracks. Carbonaceous dekitus is common throughout the interstratified facies, with moderate mmbers of siderite-cemented beds, as well as rare amounts of pyrite nodules and shell fragments. Physical structures are dominated by 34 oscillation ripples, wavy pardel lamination, convolute bedding and rarer low angle planar paralle1 lamination, combined flow npples and current ripples. Micro-faults and gutter casts 2 cm to 113 cm deep are also common. The majority of bioturbation occurs in and around the sandstone beds, dismpting the contacts. Bioturbation intensity is low (Figure 3-6 A and B) but diversity of ichnogenera is high. This ichnologicd suite reflects a Cnrzinnn ichnofacies, uicluding A nconiclzn ils (c),Zoophjcos (r-m), Helmin tlzopsis (r), Lockein (vr), Clzondrifes (r), Terebellinn (r-c), PInnolites (a), Teichiclzntis (r), Siplzonidznzls (r), Asferosornn (r), Rosselin (vr), Cylindndintrs (vr), Pdneoplzyars (r), Skolitlzos (r), Mncnroniclinirs (r) and fugichnia (vr). Ichnogenera are typically diminutive in size. For example, Teiclzidznus are generally millirnetre scale, consisting of 3-5 spreiten, and appear round or "ball-like" in shape. Few reach 5 cm in length. Plnnolites diameters range from 0.2 cm to 0.5 cm, but the majority are less than 0.5 cm. Skolitlzos are generalIy less than 1cm in length.

Bioturbated Sandy Mudston&uddy Sandstone Facies The bioturbated sandy mudstone/ muddy sandstone facies ranges frorn 0.5 to 2.5 m in thickness, averaging 2.5 m thick. The basal portion consists of sandy mudstone (Figure 3-6 C), and passes upward into muddy sandstone (Figure 3-6 D). Sand is well sorted and grain size varies from lower fine near the base to upper fine near the top. Carbonaceous detritus is cornrnon throughout, as well as rare syneresis cracks and siderite-cemented beds. Most physical structures have been destroyed by bioturbation. Those that remain identifiable include oscillation ripples and rarer wavy parallel lamuiae. This facies displays high bioturbation intensity. Trace fossils are abundant throughout (Figure 3-6 C and D) and the ichnological suite is diverse. The trace fossil assemblage reflects a mixed Skolitlzos-Cmzinnn ichnofacies. Ichnogenera include Zooplzycos (a), Anconiclinzrs (m), Helrninflzopsis (r-m), Clionclrites (r), Terebellinn (r),Plnnolites (m), Teiclzicltnus (m), RIzizocornlliurn (r), Sip~zonic~znus(r), Asferosomn (r-m), Cylindricltnus (m-a), P~lneoplzyais(vr), ~znlnssinoides(vr), Arenicolites (vr), Diplocrnterion (rn), Skolitlios (r), and fugichnia (vr). These ichnogenera are found in a variety of sizes suggestirig that structures of both juvenile and adult trace makers are present. For example, Teichiclzntïs ranges from less than 1cm in length with few spreiten to robust burrows with abundant spreiten. Cylindrichrts are mainly less than 1cm in diameter, Diplocrnterion Vary from a few centimetres to 10 cm in Iength, and Skolithos ranges in length from 1.5 cm up to 12 cm.

Larninated to Biotztrbated Sandstone Facies The lamuiated to bioturbated facies consists of beds ranging from 5 cm to 60 cm in thickness. These are amalgarnated into composite bedsets varying in thickness from 1m to 6.5 m, and averaging 4.5 m. Many of the laminated sandstone beds are capped by biogenically mottled tops (Figure 3.7 B; Figure 3-8 A, B, and D). Sands are well sorted, and grain size varies from upper fine to upper medium. Carbonaceous detritus is common throughout, as well as rare siderite-cernented beds and very rare mudstone beds rich in organic matter (Figure 3-7 C). Syneresis cracks are present within the mudstone beds. Rare to moderate numbers of mudstone rip-up clasts are present, and many resemble remnants of Asterosontn (Figure 3-8 C). Physical structures are dominated by wavy parallel laminae (reflecting HCS beds) and low angle planar parallel lamùiae, with rarer oscillation ripples, trough cross-stratification, combined flow ripples, current ripples, and convolute bedding. Bioturbation intensities range from moderate to abundant (Figure 3-7 A) but burrowing is sporadic and mainly located near the tops of laminated sandstone beds. The ichnological suite is diverse and reflects a mixed Skolitlios- Cnizinnn ichnofacies. Ichnogenera include Zoophycos (r), Helrninfhopsis (vr), Lockeia (r), Terebellinn (vr), Plnnolites (r-m), Teichiclimls (r-m), Rltizocornlliurn (vr), Sipl~oniclznzts(vr-r), Cylind?ichnzts (a), Rosselin (r), Asferosomn (vr), ninlnssinoides (r), Pnlneoplzyaïs (r), Arenicolifes (vr), Diplocraterion (vr-c), Skolithos (r), 36 Mncnroniclrnus (r-m), Conichnris (vr), enigrnatic traces (upside-down Teidiiclznns) (r), and fugichnia (r-a). Diplocmterion may reach Iengths of up to 20 cm (Figure 3- 8 A). Cyli~rdncltnitsare generally diminutive, with tube diameters varying from 0.3 cm to 0.5 cm and Iengths varying from 1cm to 6 cm (Figure 3-7 A and 8; Figure 3-8 B). Mncnronidrntrs are also diminutive, vwgfrom 0.3 cm to 1cm in diarneter (Figure 3-8 D). Teiclziclznils range from 0.3 cm to 0.5 cm in diarneter (Figure 3-7 C).

Laminated to Shrrctureless Sandstone Facies The laminated to apparently sbxctureless sandstone facies is characterized by thick sandstone packages, varying from 10 cm to 60 cm in thickness. These beds are erosionally amalgarnated into composite bedsets 1m to 5 m thick. Sand is well sorted and grain sizes range from upper fine to lower medium. Carbonaceous detritus is common throughout, as well as very rare shell fragments. Root traces are present at the top of this facies. Dominant physical structures inciude low angle planar parallel lamination (Figure 3-9 A) and wavy parallel larnination, with rarer convolute bedding, swaley cross-stratification and trough cross-stratification. This facies is devoid of bioturbation.

Trough Cross-Stratified and Current Rippled Sandstone Facies The trough cross-stratified sandstone facies comprises beds from 10 cm to 30 cm in thickness, but they are erosionally amalgamated into bedsets ranging in thickness from 1.0 m to 1.5 m. The sand is moderately well sorted, with grain sizes varying from upper fine to upper medium. Rare siderite-cemented beds, mudstone rip-up clasts, mudstone beds, very rare shell fragments, and pelecypod and gastropod shell molds are present throughout. The physical structures are dorninated by trough cross-stratification (Figure 3-9 B) and current ripples, highlighted by carbonaceous detritus. Rare low angle planar parallel larnination and wavy parallel lamination are also present. Root traces may be present at the top of the facies. 37 Bioturbation intensity is very low and sporadicdlv dishibuted. Skolitlios are very rare and occur within the current nppled sandstone. Teiclzichn~isand enigmatic (unidentified) burrows are also very rare, and restricted to the trough cross-stratified sandstones.

Cod Facies The coal facies is oniy found in one core, 07-10-63-01W6. The facies is 10 cm thick. It consists of very du11 coal that presumably contains abundant interstitial clastics.

Interstratifiecl Sandstone and Shale Facies The interstratified sandstone and shde facies consists of thin beds (averaging 1- 2 cm) and layers (0.2 - 1cm) amalgamated into composite bedsets that range from 2 to 4 m in thickness (Figure 3-9 C). Bed contacts are generdly sharp but disrupted by sporadic burrowing (Figure 3-9 D). Sand is well sorted with grain sizes varying from lower fine to upper fine. Shale beds are very dark, carbonaceous, and contain sand-filled syneresis cracks. Carbonaceous detritus is common throughout the facies, with rare numbers of siderite-cemented beds. The dominant physicd structures include oscillation ripples, wavy parallel lamination, with rarer combined flow ripples and convolute bedding. The majority of the bioturbation is sporadicdly distributed and associated with the sandstone beds. The intensity of bioturbation is generally low to moderate. Ichnogenera diversity is high, although the assemblage reflects a somewhat rnixed "stressed" Skolithos-Cnrziann ichnofacies. Trace fossils include Anconicltnils (r-m), Zooplycos (r),Helrninthopsis (r), Clzondrites (r), Plnnolites (m-a),

Teichiclrnz~s(m), Lockein (19, Cylindriclznus (r),Rosselin (m-a), Arenicolifes (r), Pnlneoplzynls (r), Skolitlios (c),and fugichnia (r). Not al1 traces are located in one settins many cores need to be examined to find the full range of ichnogenera mentioned. The trace fossils are generally diminutive in size. For example, 38 Cylindriclznzcs are generally 0.2 cm in diameter, with lengths averaging 1 cm. Pl~nolitesrange from 0.2 to 0.4 cm in diameter. 39 Figure 3-3. Litholog of well10-26-63-24W5, exhibiting the succession of shingles D2, Dl, and C of the Dunvegan Formation. D2 comprises an interstratified sandstone, silt-y mudstone, and shale facies, overlaïn by a lamuiated to structureless sandstone facies. D2 is erosively overIaùi by Dl, and they are separated by a regressive surface of erosion. Dl was terminated by a marine flooding surface, followed by progradation of shingle C. Amoco Waskahigan 1O-2H3-24~5 GRAIN SlZE cobble pebble

Shingle c

MjFS ...... S. -lm m.#. --m.-* .SidS ...... ---< ...... mm# -----Wd - - Laminated Sandstone Facies ...... -:.-.-:--??- Shingle :::a.3a-*-.-. (Delta Front) ...... -*. Dl ...... --. ---- .. -160 ...... -.-a------. . -*. ' A,. 393. - " ..... side.. - ...... RSE . . -.Gd-.-. . . -3.33. .- S. a.. Larninated to Structureless ..-..- .o..-- ...... ------.-.+. -la Sandstone Facies ....--., (Distal Delta Front)

Shingle 02 Interstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 40 Figure 3-4. Litholog of well06-11-62-03W6, exhibiting the succession of shingles E2, D3, D2, and C of the Durivegan Formation. E2 consists of an interstratified sandstone, silty mudstone, and sMefacies, overlain by a laminated to structureless sandstme. This is overlain by a bioturbated sandstone facies. E2 is capped by a major flooding surface. D3 overlies E2, and largely consists of shale that is weakly interstratified with sandstone and silty mudstone. D3 is overlain by D2. D2 comprises thoroughly bioturbated sandy mudstone that grades upward into a muddy sandstone facies. This is overlain by a laminated to biohirbated facies with root structures at the top. D2 is capped by an interstratified sandstone and shale facies. D2 is capped by a major flooding surface and overlain by a shale facies of C. Shingle C

lnterstratified Sandstone and Shale Facies (Distal Delta Front)

Laminated to Bioturbated Sandstone Facies (Distal Delta Front)

Shingle 02

Bioturbated Sandy Mudstone/ Muddv Sandstone Facies (Proximal Prodelta to Distal Delta Front)

Shingle Interstratified Sandstone. Silty D 3 Mudstone and Shale Facies (Proximal Prodelta)

Laminated to Bioturbated Sandstone Facies (Distal Delta Front)

Shingle E2 Larninated to Struztureless Sandstone Facies (Distai Delta Front)

Interstratified Sandstone. Silty Mudstone. and Shale Facies (Proximal Prodelta) 41 Figure 3-5. Litholog of well07-10-63-01W6, showing the succession exhibited in shingles D3 and D2. D3 comprises an interstratified sandstone, silty mudstone, and shale facies. The siltstone is dominant in the lower portion, and sandstone beds thicken and become more dominant upwards. This is overlain by a laminated sandstone facies. D3 is erosively overlain by D2, separated by a regressive surface of erosion. D2 comprises a thoroughly bioturbated muddy sandstone facies, grading upward into a larninated to bioturbated sandstone facies. This is overlain by a trough cross-stratified sandstone facies with root structures near the top and capped by a coal bed. Esso Simonette 7-10

GRAIN SlZE . ,

Shingle C

Trough Cross-Stratified Sandstone Facies (Proximal Delta Front to Foreshore)

Shingle D2

Larninated to Bioturbated Sandstone Facies (Delta Front)

Bioturba ted Sandy Muds Muddy Sandstone Facies (Distal Delta Front)

- - Laminated Sandstone Facies (Distal Delta Front)

Shingle 03 Interstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 42 Figure 3-6. Facies of shïngle D2 of the Dunvegan Formation. (A) Very weakly bioturbated, interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by oscillation ripples and wavy paralie1 lamination, with a rare cornbined flow at the base of the photo. Trace fossils include Helrnintlzopsis (H), Chondrites (Ch), Plnnolites (Pl), and Siphonichnzis (Si). Well05- 27-61-01W6, depth 2410.9 m. (B) Interstratified sandstone, silty mudstone, and shale facies. Sandstone beds contain wavy parallel lamination. Trace fossils include Helrnintlzopsis (H), Zwpltycos (Z),Chondrites (Ch), Plnnolites (Pl), Teichiclznz~s(Te), and Skolitlzos (Sk).Well09-04-62-04W6, depth 2356.9 m. (C) Bioturbated sandy mudstone facies. Physical structures are destroyed by biotubation. Trace fossils include Zooplzycos (Z), Hehninthopsis 0,Anconicllnus (An), Clzondrites (Ch), Plnnolites (Pl), Teidziclznus (Te), and Asterosornn (As). WeU 06-11-62-03W6, depth 2537.4 m. (D) Thoroughly bioturbated muddy sandstone facies. Trace fossils include Helrninthopsis (H), Chondrites (Ch), Nzizocornlli~rrn (Rh), Pnlneophynis (Pa),and Skolitlzos (Sk). WeU12-24-61-03W6, depth 2567.4 m.

43 Figure 3-7. Facies of shgleD2 of the Dunvegan Formation. (A) Thoroughly bioturbated section of the laminated to bioturbated sandstone facies. Trace fossils include Cylind?iclznxs (Cy), Palneophynts (Pa), and Mncnronichms (Ma). Well06- 11-62-03W6, depth 2535.6 m. (B) Larninated to bioturbated sandstone facies. The majority of the physical structures are destroyed by bioturbation, except for a thin, wavy parallel laminated sandstone bed. Trace fossils include Cylindriclznus (Cy), Mncizronichntis (Ma) and fugichnia (fu). WeU 07-10-63-01W6, depth 1976.3 m. (C) Gradation of the interstratified sandstone, silty mudstone, and shale facies into the laminated to bioturbated sandstone facies. Physical structures include oscillation ripples and wavy parallel lamination. Trace fossils include Helrninthopsis O-I), Terebellinn (Tb), Lockeia (Lo), Chondrites (Ch), Plnnolifes (Pl), Teichichnzis (Te), Pnlneophjms (Pa), and Diplocrderion (D). Well07-10-63-01W6, depth 1977.1 m.

44 Figure 3-8. Facies of shingie D2 of the Dunvegan Formation. (A) Laminated to bioturbated sandstone facies. The sandstone contains wavy parallel lamination and Diplomntenon (D). Weli 07-17-61-03W6, depth 2762.6 m. (B) Laminated to bioturbated sandstone facies. Trace fossik include Cylindnctrnrrs (Cy), and Mncnroriichnus (M). Well13-28-61-02W6, depth 2425.6 m. (C) Mudstone np-up clasts resembling remnants of Asterosorna burrows. These mudstone rip-up clasts are located in the laminated to bioturbated facies. Well06-11-62-03W6, depth 2532.4 m. (D) Laminated to bioturbated sandstone. Physicd stnictures include wavy pardel lamination. Trace fossils include Cylindnclznzrs (Cy), Pnlneop?ryczrs (Pa), Mncnronichnus (Ma), and fugichnia (fu). Wel113-28-61-02W6, depth 2425.3 m.

45 Figure 3-9. Facies of shingle D2 of the Dunvegan Formation. (A) Low angle planar pardel lamhated sandstone of the Iaminated to stnictureless sandstone facies. Well07-10-63-01W6, depth 1973.5 m. (B) Trough cross-stratification and wavy parallel lamination of the trough cross-stratified sandstone facies. Well 07- 10-63-01W6, depth 1972.1 m. (C) Interstratified sandstone and shale facies. Physical stnictures include wavy pardel laminae, oscillation ripples, and combined flow ripples. Sand-filled syneresis cracks (syn) subtend into the shale. Trace fossils include Lockein (Lo) and Planolites (Pl). Weil 06-11-62-03W6, depth 2528.1 m. (D) Interstratified sandstone and shale. Physical structures include oscillation ripples and wavy pardel laminae. Trace fossils include Helminthopsis (H), Chondrites (Ch), Plnnolites (Pl), Cylindrichnus (Cy), ?Arenicolites (Ar), and Pnlneop~zyms(Pa). Well09-04-62-04W6, depth 2349.9 m.

The succession exhibited in shingle Dl of AUomember D of the Dunvegan Formation is characterized by three facies (Figure 3-10; 3-11). The basal facies consists of laminated sandstone (Figure 3-12), which is interbedded with an overlying interstratified sandstone, silty mudstone and shale facies. This grades upward into a bioturbated sandy mudstone facies. In some cores, the laminated sandstone facies is absent and the basal facies consists of the interstratified sandstone, silty mudstone, and shale, overlain by the biohirbated sandy mudstone facies.

Larninated Savtdstone Facies The laminated sandstone facies comprises beds 15 - 75 cm in thickness, but are erosionaliy amalgarnated in units up to 13 m thick (Figure 3-12). These larninated sandstones are interspersed with bioturbated intervals (Figure 3-13 A). The sand is well sorted and varies in grain size from lower medium to upper medium. Carbonaceous detritus is common and typically marks lamination. Mudstone np-up clasts (Figure 3-13 B), abundant siderite-cemented beds, and rare coal laminae/wood fragments are present throughout. Mudstone beds are also common and typically contain syneresis cracks. Rip-up clasts range from rare to very abundant, and are characterized by (1)long, thin mudstone fragments with sand interlaminations; (2) possible remnants of Asterosorna structures (Figure 3-13 B and C); (3) millimetre- to centimetre-sized angular to sub-angular clasts; and (4) rounded sideritized nodules (Figure 3-13 8). These rip-up clasts may be concentrated into stringers that are aligned parallel to lamination or are distributed randomly. The larninated sandstone is dominated by fow angle planar parallel larnination, wavy parallel lamination, trough cross-stratification (Figure 3-13 D), and current npples (Figure 3-13 E). These structures are typically intermingled with the trough cross-stratification and current ripples very generally associated witl~the upper part of the facies. Other structures include rare oscillation ripples, 47 combined £low ripples, agg-radational ripples, apparently stnictureless beds, and very rare convolute bedding. Bioturbation intensiv is typically low and sporadic in distribution. The ichnogenera diversity is moderate. The ichnological suite is a rnixed Skolithos- Cnrzicznn ichnofacies, and consists mainly of Plnnolites (r-m), Teicliicltniw (r), Cylbidriclinzrs (r), ~znlnssinoides(vr), Pnlneopltyars (r), Skolitlios (r), Ophioniorplm (r), enigmatic traces (m), and fugichnia (r). Plnnolites are mainly located in the mudstone beds, whereas the remaining ichnogenera are associated with the sandstone beds.

Interstratified Sandstone, Silty Mudstone, and Shale Facies The interstratified sandstone, silty mudstone, and shale facies is characterized by thin beds and layers arnalgamated into composite bedsets, corresponding to "wavy bedding". The beds range from 1-5 cm in thickness, averaging 2 cm. The facies is typically 1-4 m in thickness. Sandstone beds are typically 2-3 cm thick, with sharp bases and tops that are sporadically dismpted by burrows (Figure 3-14 A and B). Sand is well sorted, and grain size varies from lower fine to upper fine. The silty mudstone beds are apparently structureless in appearance and devoid of bioturbation. Shale beds are typically dark and carbonaceous. Burrows are present in the shale beds only where they subtend from the overlying sandstone beds. The shale beds contain rare, sand-filled syneresis cracks. Carbonaceous detritus is cornmon throughout, with rare siderite-cemented beds, shell fragments, and gutter casts locally present. Physical structures are dominated by oscillation ripples, and wavy parallel lamination, with rarer low angle planar parallel laminae, combined flow ripples, convolute bedding, and very rare current ripples. Burrowing is concentrated in and around the sandstone beds. The bioturbation intensity of the interstratified facies is low, but the diversity of ichnogenera is high. The ichnological suite represents a Cnrzicznn ichnofacies (Figure 3-14 A and B) with rare elements of the Skolithos ichnofacies. The suite 48 consists of Anconicllnus (r), Helntinthopsis (r), Zoopliycgs (vr), Chondrites (vr), TerebelIinn (r), Plnnolites (m-a), Teidzidrnrcs (m-a), Siplzoniclinns (vr), Cylindriclinzis (vr), Pnlneopliynis (vr), Skolitlios (vr), and fugichnia (r). Individual traces range markedly in size. For example, Teidlicltntls may be characterized by horizontal tubes with only a few spreiten or by more robust structures (dwelling tubes are 1 cm wide and 0.5 cm in length) with abundant spreiten.

Bioturbated Sandy Mudstone Facies The bioturbated sandy mudstone facies ranges from 0.2 - 6.3 m in thickness (Figure 3-10). The base is typically less burrowed than the top, and is sandier, more intensely bioturbated and coarser grained upward. Sand grain size varies from upper fine to lower medium. Carbonaceous detritus is present throughout, with rare siderite-cemented beds and sideritized mudstone rip-up clasts. Bioturbation has destroyed most physical shvctures (Figure 3-14 C). Remaining identifiable structures include oscillation ripples, combined flow ripples and wavy parallel lamination (Figure 3-14 D). The facies displays a common to abundant bioturbation intensity, increasing upward. The trace fossils are uniforrnly distributed and reflects a high diversity assemblage. The ichnological suite is a Cnczinnn ichnofacies, with the introduction of rare elements of the Skolitlros ichnofacies. Trace fossils include Helniin thopsis (r-c), Zoopliycos (r-c), A nconiclinus (r), Cltondrites (r), Terebellinn (r- m), Plnnol ites (c),Teidziclrnzrs (m-c), Siphoniclmrrs (r-m), Asterosomn (r-c), Cylindriclinzis (r), ~inlnssinoides(vr-r), Pnlneophynrs (vr-r), Skoliflios (r), Ophiornorplzn (vr-r), and fugichnia (r). Trace fossils are generally diminutive. For exarnple, the tube diameter of Teiclziclinzis varies from 0.5 cm to 1.0 cm. The thickness of Zooplycos lobes average 0.5 cm. 49 Figure 3-10. Litholog of well02-18-64-23W5, exhibiting the succession of shingles D2 and Dl. D2 comprises an interstratified sandstone, silty mudstone and sMefacies, and is erosivelv overlain by Dl. They are separated by a regressive surface of erosion. Dl comists of a laminated sandstone facies, that grades upward into an interstratified sandstone, silty mudstone, and shale facies. This is overlain by a thoroughIy bioturbated sandy mudstone facies. Dl is capped by a major flooding surface and overlain by C. Amoco Mobile Waskahigan 02-1 864-23~5

GRAIN SlZE

2 granule ; 5 E 5 2

Bioturbated Sandy Mudstone Facies (Proximal Prodelta to Distal Delta Front)

Shingle Dl

lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta)

Laminated Sandstone Facies (Channel Fill)

Shingle lnterstratified Sandstone, Silty 02 Mudstone,and Shate Facies (Proximal Prodelta) 50 Figure 3-11. Litholog of weU 11-16-63-24W5, exhibithg the sriccession of shingles D2 and Dl. D2 comprises an interstratified sandstone, siky mudstone and shale facies. D2 is erosively overlain by Dl. They are separated by a regressive surface of erosion. Dl consists of a Iaminated sandstone facies that grades apward into an interstratified sandstone, silty mudstone, and shale facies. Dl is capped by a major flooding surface and overlain by C. Pan Am D-2 Waskahigan 11-1 6-63-24~5 GRAIN SlZE cobble pebble

Shingle C

lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta)

Shingle Dl

Larninated Sandstone Facies (Channel Fill)

Shingle Interstratified Sandstone, Silty D2 Mudstone, and Shale Facies (Proximal Prodelta) 51 Figure 3-12. Litholog of well10-18-6423W5, exhibiting the succession comisting of Dl that erosively overlies D2. These are separated by a regressive surface of erosion. Dl consists of a laminated sandstone facies, with abundant mudstone beds and mudstone rip-up clasts. Dl is capped by a major flooding surface and is overlain by C. Mobil Pan Am Waskahigan 10-18-64-23w5 GRAIN SIE

Shingle C

Shingle Larninated Sandstone Facies Dl (Channel Fill)

lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 52 Figure 3-13. Facies of shingle Dl of the Dunvegan Formation. (A) Laminated sandstone facies. The sandstone contains Cylind~cli~zzis(Cy). Well10-18-64-23W5, depth 1536.7 m. (B) Mudsione rip-up cIasts either as wispy mudstone that resemble remnants of Asterosorna (As) or as siderite-cemented nodules. The mudstone rip-up clasts are located within the Iaminated sandstone facies. Well 10-18-6423W5, depth 1541.8 m. (C) Mudstone rip-up clasts resembling remnants of Asterosorrzn (As). These are located within the larninated sandstone facies. Well06-20-64-23W5, depth 1533.5 m. (D) Trough cross-stratified sandstone located withiri the laminated sandstone facies. The sandstone contains Skolithos (Sk). WeIl11-19-59-03W6, depth 3029.9 m. (E) Current nppled sandstone in the laminated sandstone facies. Well11-19-59-03W6, depth 3024.8

53 Figure 3-14. Facies of shingle Dl of the Dunvegan Formation. (A) Interstratified sandstone, silty mudstone, and shale facies. Sandstones contain wavy paralle1 laminae, oscillation rïpples, and rare cornbined flow ripples. Trace fossils include Chondrites (Ch), Plnnolites (Pl), Teic~zichntis(Te), and fugichnia (fu). Well 11-16-63- 24W5, depth 1706.8 m. (B) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by wavy parallel lamination. Trace fossils include Zooplzycos (Z), Helminthopsis 0,Anconichmls (An), Chondrites (Ch), Terebel linn (Tb),Teichichnzis (Te), and Cylindriclznus (Cy) . Well10-03-62- 26W5, depth 2075.9 m. (C) Thoroughly bioturbated sandy mudstone facies. Trace fossils include Helrninthopsis (H), Plnnolites (Pl), Cltonchifes (Ch),TeicJziclznzw (Te),and Pnlneoplzyacs (Pa). We1102-18-64-23 W5, depth 1543.9 m. (D) Bioturbated sandy rnudstone, with a rare wavy parallel laminated sandstone layer. Trace fossils include Helrnintlzopsis (H), Zoopltycos (Z),Plnnolifes (Pl), Teichichnzis (Te),and higichnia (fu). Well02-18-64-23W5, depth 1542.7 m.

The succession exhibited in shingle E3 of Allomember E of the Dunvegan Formation is characterized by four facies. The basal facies is only present in one- third of the cores, and consists of an interbedded sandstone and mudstone (Figure 3-15). This is overlain by a shale facies that is present in about one- quarter of the cores. The shale facies grades upward into an interstratified sandstone, silty mudstone, and shale facies. This interstratified facies dominates the succession, and cons titutes the basal facies where both the shale facies and the laminated sandstone are absent (Figure 3-16; 3-17). The Allomember E3 succession is capped by a laminated to bioturbated sandstone facies, which is present in half of the cores.

Interbedded Sancistone and Mzrdstone Facies The interbedded sandstone and mudstone facies comprises beds ranging from 2 to 20 cm in thickness. These beds are amalgarnated into composite bedsets ranging from 1to 2.3 m thick. The mudstone varies in thickness from layers less than 1cm thick (Figure 3-18 A), to thin beds about 1cm thick. The mudstones are very dark and contain sand-filled syneresis cracks (Figure 3-18 B). The sandstone beds average 2 to 3 cm in thickness. The sand is well sorted and grain size ranges from lower fine to upper fine. Carbonaceous detritus is moderate and typically dernarcates the lamination. Rare siderite-cemented beds, pp-ite nodules and shell fragments are present throughout the facies. Physical structures are dominated by wavy parallel lamination (Ha)and oscillation ripples, with rarer low angle planar parallel lamination, and combined flow ripples, as well as very rare current ripples. The intensity of bioturbation is weak to absent, with a rare abundance of ichnogenera distributed sporadically throughout the facies. Trace fossil diversity is hi& and the ichnological suite reflects a Cmzinnn ichnofacies, with inclusion of rare elements of the Skolithos ichnofacies. The mudstone interbeds contain rare numbers of trace fossils that typically include Zoopliycos (vr), Helrnintlzopsis (vr), 55 Clrondrites (vr), Terebellinn (vr), Plrrnolifes (r-a), Teichiclznits (r-a), Siplionicltnzrs (vr), and Rliizocorrrlliitrn (vr). The sandstone beds typically contain Lockeirr (vr), Teidiiclznzrs (r-a), Asterosornn (vr-m), Cylindn'clintrs (r) (Figure 3-18 C), T7uilnssinoides (vr-r), Palneopliyctrs (vr), Skoliflros (vr-m), Opliiornorplin (vr), Mncnronicltnzu (vr), and fugichnia (r-m). Trace fossils in the mudstone beds are generally diminutive in size, typically less than 0.5 cm in diameter.

S ha le Facies The shale facies comprises intervals ranging from 1.5 m to 2.5 m in thickness. The shale is dark, fissile and contains moderate amounts of carbonaceous detritus. Sidente-cemented beds are present but rare. Sandstone beds are rare and characterized by oscillation ripples and wavy pardel lamination. The shale facies is devoid of bioturbation.

Interstratified Sandstone, Silty Mudstone, atrd Shale Facies The interstratified sandstone, silty mudstone, and shale facies comprises beds and thinner layers, amalgamated into composite bedsets ranging from 1.5 m to 8 m in thickness. The beds range in thickness from 1cm to 40 cm, averaging 2 to 3 cm. The basal contacts of the beds are typically sharp (Figure 3-19 A). The sandstone beds commonly grade upward into silty mudstone (Figure 3-19 B) or may be locally dismpted by bioturbation (Figure 3-19 A and C) or convolute bedding (Figure 3-20 A and B). The sand is well sorted and varies from lower fine to upper fine in grain size. The silty mudstone is massive and apparently stnictureless in appearance and devoid of burrowing. The shale beds are very dark, fissile, and contain abundant sand-filled syneresis cracks (Figure 3-19 D). Carbonaceous detritus is abundant throughout the interstratified facies, and siderite-cemented beds are rare to moderate. Physical structures are dominated by wavy parallel lamination, oscillation ripples, and combined flow ripples, commonly with convoluted beds (Figure 3-19 B; Figure 3-20 A and B), loading 56 structures, micro-faults and gutter casts, and rarer low angle planar pardel lamination, current ripples, and aggradational ripples. Bioturbation intensities range from absent to weak, with a rare abundance of ichnogenera mainly associated with the sandstone beds. Trace fossil diversity is high and the ichnological suite comprises a "stressed" Cnrzinnn ichnofacies (Figure 3-19 A to C). Trace fossils include Anconichnrrs (r-c), Helrninflropsis (m), Zoophycos (m), Lockein (r), Chondrites (vr), Terebellinn (r-c), Plnnolites (a), Teichichnus (a), Siplioniclrnr~s(vr), Rosselin (vr), Cy!indriclin tr s (vr), l7inlnssinoides (vr), Pnlneophycus (vr), Skolithos (r-m), Opliioniorplut (vr), and fugichnia (m). The trace fossils are generally diminutive in size. For example, Teichicltnus ranges from 0.2 cm to approximately 0.7 cm in diameter.

Laminated to Biotzrrbated Sandstone Facies The laminated to bioturbated sandstone facies is characterized by intervals of differing stratification. The facies includes lamuiated apparently stnictureless sandstone, rare silty convoluted sandstone, and laminated to bioturbated intervals (Figure 3-20 C and D). The beds are amalgamated into bedsets ranging from 0.7 m to 2.0 m thick. The individual larninated sandstone beds ranges in thickness from 5 cm to 45 cm. The sand is moderately well sorted, and grain size ranges from lower fine to lower medium. The silty convoluted sandstone is devoid of bioturbation, but contains abundant carbonaceous detritus demarcating the deformed stratification. Loading structures and rare micro-faults are also present. The mudstone layers are rare and are generally less than 1cm thick (Figure 3-21 A). The mudstone is dark, and consists of sand-filled syneresis cracks. The laminated sandstones are interspersed with intervals of bioturbated mudstone layers or beds. Carbonaceous detritus typically marks lamination. Siderite-cemented beds are rare. Primary physical structures include wavy parallel lamination (HCS) (Figure 3-21 B), apparently stnictureless units, and oscillation ripples, with rarer low angle planar parallel lamination (Figure 3- 57 21 C). There is only a single occurrence of trough cross-stratification, which contains spherulitic siderite aligned paralle1 to the lamination (Figure 3-21 D). Bioturbation intensities range from absent to moderate. There is a moderate abundance of ichnogenera, although the diversitv is high. The ichnological suite reflects a Cnlzimzn ichnofacies with rare elements from the Skolitlzos ichnofacies. In the muddier sandstone beds (Figure 3-20 C), ichnogenera include Zoopltycos (m-c), Helmintlzopsis (m-c),Anconicltn tis (r), Chonhites (r), Terebellinn (r), Plnnolifes (m-c), Teicllid~ntis(m-c), Rl~izocornllitirn(vr- r), Siplzoniclznzis (vr-r), and Asterosornn (r). The sandstone beds (Figure 3-20 D; Figure 3-21 B) typically contain Cylindricltnus (r), P~lneopkycus(vr), Diplocr~te~ion (vr), Skolifltos (vr), Ophionzorplzn (vr), and hgichnia (vr). 58 Figure 3-15. Litholog of well11-05-63-26W5, exhibithg a succession consisting of shingles E3, E2, and El of the Dunvegan Formation. E3 comprises interbedded sandstone and mudstone facies near the base of the succession. This facies is overlain by an interstratified sandstone, silty mudstone, and shale facies that grades upward into a larninated to bioturbated sandstone facies. E2 overlies E3 and comprises a silfymudstone facies. E2 is erosively overlain by El. El consists of a laminated sandstone facies. Mertand et al. Simonette 1 1-0563-26~5

GRAIN SiZE II 1

Shingle Laminated Sandstone and El Mudstone Rip-up Facies (Channel Filt)

Shingle E2 Silty Mudstone Facies (Distal Prodelta)

Laminated to Bioturbated Sandstone Facies (Distal Delta Front)

Shingle E3 Interstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta)

Sandstone lnterbedded with Mudstone Facies (Distal Delta Front) 59 Figure 3-16. Litholog of well05-27-61-01W6, exhibiting a succession consisting of shingles W,E2, and D3. E3 comprises interstratified sandstone, silty mudstone, and shale facies. E3 is overlain by E2, and separated by a minor flooding surface. E2 consists of an interstratified sandstone, silty mudstone, and shale facies, that grades upward into a laminated to bioturbated sandstone facies. This is capped by a major flooding surface and overlain by D3. Dome et. al. Lator

Shingle D3 Laminated to Bioturbated Sandstone Facies (Distai Delta Front)

Shingle E2 lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta)

MnFS

Shingle lnterstraiified Sandstone, Silty E3 Mudstone, and Shale Facies (Proximal Prodelta) 60 Figure 3-17. Litholog of weU04-08-63-02W6, exhibiting a succession consisting of shingles E3 and E2. E3 comprises interstratified sandstone, silty mudstone, and shale facies. The sandstone bed thicknesses vaxy throughout the facies. This facies is overlain bv a thoroughly bioturbated laminated to bioturbated facies. E3 is overlain by E2, separated by a rninor flooding surface. E2 conçists of a thoroughly bioturbated, laminated to bioturbated facies. Arco Sincl. Lator

GRAIN SlZE cobble pebble

Shingle D MjFS Laminated to Bloturbated Shingle Sandstone Facies E2 (Delta Front)

MnFS Larninated to Bioturbated Sandstone Facies (Distal Delta Front)

Shingle Interstratified Sandstone, Silty E3 Mudstone, and Shale Facies (Proximal Prodelta) 61 Figure 3-18. Facies of shingle E3 of the Dunvegan Formation. (A) Interbedded laminated sandstone and mudstone facies. Physical stnictures are dominated by wavy pardel lamination, oscillation npples and rarer combined flow ripples. The mudstone contains Plnnolites (PI) and syneresis cracks (syn). Well07-06-63- 26W5, depth 1991.5 m. (B) Interbedded laminated sandstone and mudstone facies. Physical structures are dominated by wavy parallel lamination, oscillation ripples, and rarer combined flow ripples. The mudstone contains Pl~nolites(Pl), Skolith (Sk), fugichnia (fu), and syneresis cracks (syn). Wel108-12-63-27W5, depth 1980.5 m. (C) Wavy parallel laminated sandstone bed, located in the interbedded laminated sandstone and mudstone facies. Sandstone contains Cylindriclinzis (Cy). Well07-05-63-36W5, depth 1955.1 m.

62 Figure 3-19. Facies of shingle E3 of the Dunvegan Formation. (A) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dorninated by wavy parallel Iaminae and combined fiow ripples. Trace fossils include Helrninthopsis (H), Plnnolites (Pl), Teichichnus (Te),Terebellinn (Tb), Skolithos (Sk), and fugichnia (fu). Well11-05-63-26W5, depth 1961.9 m. (B) Convolute beds of the interstratified sandstone, silty mudstone, and shde facies. Discernible physical structures include wavy paraIlel Laminae, oscillation npples, and combined fi ow ripples. Trace fossils include Plmolifes (Pl), Teiclzic~znus(Te), Dnlneophyczlclrs (Pa). Syneresis cracks (syn) are located in the shale beds. Well11-19- 59-03W6, depth 3051.9 m. (C) Interstratified sandstone, silty mudstone, and shale facies. Physical stnictures include combined flow npples and wavy pardlel lamination. Trace fossils include Helrninthopsis (H), Plnnolites (Pl), Teichiclznus (Te), and Skolit110s (Sk). Syneresis cracks (syn) are located in the shale and silty rnudstone beds. Weil 06-11-62-03W6, depth 2356.4 m. (D) Interstratified sandstone, silty mudstone, and shale facies, devoid of bioturbation. Physical structures are dominated by oscillation ripples and combined flow ripples. Trace fossils include Plnnolites (Pl). Syneresis cracks (syn) are located in the shale and silty mudstone beds. Well05-27-61-01W5, depth 2432.4 m.

63 Figure 3-20. Facies of shïngle E3 of the Dunvegan Formation. (A) Interswatified sandstone, silty mudstone, and shale facies. Physical structures include wavy pardel lamination, combined flow ripples, and convolute bedding. Shell fragments (shell) are also located in a sandstone bed. Trace fossils include Plnnoiites (Pl) and fugichnia (hi). WeU 08-12-63-27W5, depth 1979.4 m. (B) Convolute bedded, interstratified sandstone, silty mudstone, and shale facies. Well06-35-62-27W5, depth 2074.9 m. (C) Laminated to biohirbated facies, containing rare mudstone beds and wavy pxailel laminated sandstone. Trace fossils include Helrninthopsis (H), Plnnolites (Pl), Teiciticltnus (Te),Terebellinn (Tb), Asterosomn (As), and Cylindrichnus (Cy).Well01-08-63-26W5, depth 1899.9 m. (D) Thoroughly bioturbated, laminated to bioturbated sandstone facies. Physical structures are destroyed by bioturbation. Trace fossils include Helrnintlzopsis (H), Teichichnus (Te),and Diplocrnterion (D). WeU 0408-63-26W6, depth 2174.3 m.

64 Figure 3-21. Facies of shingle E3 of the Dunvegan Formation. (A) Laminated to bioturbated sandstone facies that contains rare mudstone beds. Physical structures include oscillation ripples and wavy parallel lamination. Plnnolites (Pl) are Iocated in the mudstone beds. A syneresis crack (syn) is located in the shde bed. WeU 06-11-62-03W6, depth 2552.8 m. (B) Laminated to biohirbated sandstone facies. Wavy parallel laminated sandstone dominates. Trace fossils include PZnnolites (Pl), Asterosomn (As), PnZneophyals (Pa), Skolithos (Sk), Ophiomorplzn (0)and an enigmatic (unidentified) trace. Well01-08-63-26W5, depth 1899.7 m. (C) Laminated to bioturbated sandstone facies. Well06-35-62- 27W5, depth 2073.0 m. (D) Trough cross-sbatified sandstone, located in a thick sandstone bed of the interstratified sandstone, silty mudstone, and shale facies. Shell fragments (shell), carbonaceous detritus, and spherulitic siderite (orange spots) aligned to stratification are present. Well04-08-63-02W6, depth 2181 -9m.

The succession exhibited in shingle E2 of AUomember E of the Dunvegan Formation is characterized by six facies. The basal unit consists of a shale facies that is very rare and present in only three cores. In the majority of cored intervals, the basal unit is characterized by an interstratified sandstone, silty mudstone and shale facies. In four cores, the silty mudstone of the interstratified facies is so predominant that it has been assigned its own facies; namely, the silty mudstone facies. In these localities, the interstratified sandstone, silty mudstone, and shale facies is replaced by the silty mudstone facies. The silty mudstone facies is interpreted to have been deposited in closer proximity to major distributarv channels. Both facies grade upward into a convoluted silty sandstone facies. This is overlain by a laminated to siructureless sandstone facies, although it is not present in all cores (Figure 3-22). A laminated to bioturbated sandstone facies (Figure 3-23) may be found replacing or overlying the laminated to structureless facies. In the majority of cores the shde facies of D3 is found overlying the laminated to bioturbated facies (exarnphs: 08-12-63-27W5,06-11- 62-03W6 (Figure 3-4), O5-27-61-01 W6). In these three cases, the laminated to bioturbated facies overlies the laminated to structureless facies, and is abruptly overlain by shales of Allomember D.

S ha le Facies The shale facies comprises intervals ranging from 1-5 to 2 m in thickness. Carbonaceous detritus and siderite-cemented beds are present, but are rare to moderate in number. Sandstone and siltstone layers are rare, and are typically around 5 mm thick. The sandstone beds contain oscillation ripples, combined flow ripples and very rare current ripples. The shale facies is mainly devoid of bioturbation, with less than 5 % of the interval dismpted by biogenic activity. Ichnogenera diversity and abundance is very low. The ichnological suite reflects a "distal" Cnizinnn ichnofacies, including Helmintlzopsis (vr), Plnnolites (vr), and fugichnia (vr). The trace fossils are diminutive in size. 66 Interstra tified Sandstone, Silty Mudstone, and Shale Facies The interstratified sandstone, silty mudstone, and shale facies comprises beds amalgamated into composite bedsets rangmg from 1.5 m to 14 m in thickness, averaging 4.0 m. Bed thicknesses vary from 1cm to 50 cm, with the majority ranging from 2 - 3 cm thick. The basal contacts of the beds are generally sharp. The upper contact of the sandstone beds may be sharp (Figure 3-24 A), or may grade upward into silty mudstone, or may be disnipted by bioturbation. The sandstone beds generally thicken upward. Rare, thicker sandstone beds range from 10 cm to 50 cm in thickness (Figure 3-24 C). Sands are well sorted, and grain size coarsens upward from lower fine to upper fine, coïncident with increasing bed thicknesses. Mudstone rip-up clasts are rare and are typically present at the bases of the thicker sandstone beds. The silty mudstone is relatively dominant and is characterized by massive and apparently structureless beds, and devoid of bioturbation. The shale is very dark and may be massive to fissile in appearance (Figure 3-24 A). Sand-filled syneresis cracks are abundant in the shale beds. Carbonaceous detritus is common throughout the facies, and siderite-cemented beds, though present are rare. Dominant physical structures include oscillation ripples, wavy parallel lamination (HG), and combined flow ripples (Figure 3-24 D). Current ripples, convolute bedding (Figure 3-24 E; 3-25 A) and loading structures are also comrnon but subordinate. The majority of the bioturbation is associated with the sandstone beds. Trace fossils are rare in the mudstone beds and occur only where they subtenci frorn the overlying sandstone beds. Bioturbation intensities vary from absent to rare. There is a very low abundance of ichnogenera, with only about 5% to 10% of the interval biogenically disnipted, although diversity may be high overall (Figure 3-24 A, Cf and E). Though, the overall diversity is high, aU the traces mentioned below are never found in one cored interval, many cores must be examuied to complete the full spectrum of the assemblage. The ichnological suite reflects a Cntzinnn ichnofacies, and includes Anconiclinrcs (m), Helrnintlzopszs (m), Zmphycos (r), Lockein (vr), Plnnolifes (m), Teichidintrs (rn), Cylind~clznus(r), 67 Chondrites (vr), Asterosonzn (vr), Rossel in (vr), Siplmnichnus (vr), Thnlnssinoides (vr), Pd-ieopliynis (vr), Skoliflios (vr-r), and fugichnia (r). Trace fossils are generally diminutive in size. For exarnple, Teichiclznzrs are less than 1cm in diameter, and average 0.5 cm.

Silty Mudstone Facies The silty mudstone facies ranges in thickness from 1.2 to 5.5 m. The silty mudstone is generally massive and apparently structureless in appearance and tan in colour (Figure 3-24 F). Carbonaceous detritus and siderite-cemented beds are common. Sandstone is common throughout, and typicaIly demarcates convolute bedding and loading structures. Sand grain size varies from lower fine to upper fine. This facies is typically devoid of bioturbation. Where trace fossils are present, they are very rare and found toward the base of the facies. It is interpreted that these traces reflect organisms that originally resided in the underlying facies and were subsequently buried by the silty mudstone facies. Ichnogenera include Cylindric~znzrs(vr) and Plnnolifes (vr).

Convoluted Silty Sandstone Facies The convoluted silty sandstone facies ranges from 3 to 4 m in thickness. The sandstone is poorly sorted, although sand sizes are mainly upper fine with rare arnounts of lower fine. Carbonaceous detritus is common throughout the facies, as well as moderate numbers of siderite-cemented beds, rare coal fragments, and mudstone rip-up clasts. Convolute bedding is the dominant physical structure (Figure 3-25 B), but oversteepened beds, loading structures and massive (apparentiy shuctureless) intervals are also comrnon. There are also very rare wavy parallel lamùiae, combined flow ripples and oscillation ripples. This facies is virtually devoid of bioturbation, but Iocally contains Helrnintliopsis (vr) and Anconicltnus (vr). These traces are present in a single core, within a rare mud bed. 68 Lamittated to Sfructureless Sandstone Facies The sandstone facies comprises beds ranging in thickness from 10 cm to 2.3 m. These beds are erosionally arnalgamated into composite bedsets ranging from 1.0 to 5.0 m thick. The facies is characterized by three main components: laminated sandstone beds (Figure 3-25 C), apparently sfructureless beds, and trough cross-stratified sandstone beds. These components are regularly interbedded with one other. The laminated sandstone beds range in thickness from 10 to 75 cm. Sands are well sorted, and grain size varies from lower fine to upper fine. Physical structures are dorninated by wavy parallel lamination and low angle planar parallel lamination, with rarer oscillation ripples, planar lamination, current ripples and convolute bedding. Very rare combined flow ripples are locally preserved. silhtone laminae may be associated with the convolute bedding. The structureless sandstone beds range from 15 cm to 2.3 m in thickness. The sand is well sorted and grain size varies from lower fine to upper fine. Siltstone layers are also sporadically distributed throughout. The trough cross-stratified sandstone beds are rarer and are only found in 4 cored intervals. The beds range from 3 cm to 20 cm in thickness. These trough cross-stratified beds are locally found capping the facies, but are also found interbedded with the laminated and apparently structureless sandstone beds. The sand is well sorted but coarser, with grain sizes ranging from upper fine to lower medium. Physical structures are dorninated by bough cross-stratification and current ripples (Figure 3-25 D). In a single cored location, 15-31-62-26W5, root traces are present at the top of the facies. Carbonaceous detritus is common throughout the facies and typically demarcates the lamination (Figure 3-25 C and D). Mudstone beds and siderite-cernented beds are also present but rare. With the exception of the very rare burrows in the mudstone beds, the sandstone facies is devoid of bioturbation. Trace fossils associated with the mudstones include Plnnolites (vr) and Teicliiclzizus (vr). 69 Laminated to Biofitrbated Sandstone Facies The laminated to bioturbated sandstone facies consists of beds ranging from 2 to 10 cm in thickness. These are amalgarnated into composite bedsets varying from 0.5 to 3 m thick. The laminated sandstone beds are either capped by thin bioturbated intervals (Figure 3-26 A, B, and C) or are moderately to thoroughly mottled due to biogenic reworking (Figure 3-26 D; Figure 3-27 A and B). In the bioturbated intervals, mudstone beds are present and contai.rare sand-filled syneresis cracks. The sandstone is well sorted, with grain sizes ranging from lower fine to upper fine. Physical structures are dorninated by wavy parallel lamination, oscillation ripples, and combined flow ripples, with rarer current ripples, low angle planar pardlel lamination, and convolute bedding. These structures are marked by moderate amounts of carbonaceous dehitus (Figure 3-26 B). Siderite-cemented beds and shell fragments are also present, though rare. Bioturbation intensities Vary from moderate to common. Trace fossils are locally abundant and diveeity of ichnogenera is high. The ichnological suite reflects a Cnlzinnn ichnofacies with rare elements from the Skolitkos ichnofacies (Figure 3-248). Trace fossils include Helnzintlzopsis (m), Zoopl~cos(r), Anconiclznus (m), C/toncirites (vr), Terebellinn (r), Plnnolites (m), Teicliidin~rs(m), Siphoniclz~ttcs (vr-m), Rlrizocornlliturl (vr), Cylindridlnzrs (m), Asterosorrin (r-m), Rosselin (vr), l7mlnssinoides (vr), Pnlneoplzyczrs (r), Arenicolites (vr), Diplocrnterion (r), Skolithos (vr), Opliiomorplm (r),Mncnro~zicltnlis (r), and fugichnia (vr-r) (Figure 3-26 A to D; Figure 3-27 A and B). 70 Figure 3-22. Litholog of weU 10-34-61-26W5, exhibiting a succession comprising shingle E2 of the Dunvegan Formation. E2 consists of an interstratified sandstone, silty mudstone, and shale facies, overlain by a convoluted silty sandstone facies. This grades upward into and is intercalated with a laminated to structureless sandstone facies. OiI et al Sirnonette 10-34-61 -26~5

GRAIN SlZE II 1

2148. Laminated to Structureless Sandstone Facies (Delta Front)

Shingle €2

Convoluted Silty Sandstone Facies (Distal Delta Front)

lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 71 Figure 3-23. Litholog of well06-35-62-2TW5, exhibiting a succession consisting of shuigles E3, E2, and El. E3 comprises a laminated to bioturbated sandstone facies and is capped by a minor flooding surface. E2 overlies E3, and consists of interstratified sandstone, silty mudstone, and çhde facies. This is overlain by a convoluted silty mudstone facies, that grades upward into a laminated to bioturbated sandstone facies. El erosively overlies E2, separated by a regressive surface of erosion. El consists of a laminated to skuctureless sandstone facies that is overlain by a shale facies, and capped by a major fi ooding surface. This surface marks the basal contact of allomember D. H.B. et al Simonette

GRAIN SlZE I I

MjFS Shale Facies (Transgressive Deposits) ITS 1 Shingle Larninated to Structureless El Sandstone Facies (Delta Front)

Laminated to Bioturbated Sandstone Facies (Delta Front)

Shingle E2 Convoluted Silty Sandstone Facies (Distal Delta Front)

lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal P rodelta)

MnFS

Laminated to Bioturbated Shingle Sandstone Facies E3 (Distal Delta Front) 72 Figure 3-24. Facies of shingle E2 of the Dunvegan Formation. (A) Interstraafied sandstone, silty mudstone and shale facies. Physical structures include wavy parallel laminae, oscillation ripples, and combined flow ripples. Silty mudstone beds contain sand-fiued syneresis cracks (syn). Well06-11-62-03W6, depth 2547.9 m. (B) Laminated to bioturbated facies. Discemible physical sb-uctures are dorninated by combined flow ripples. Trace fossils include Zoophycos (Zo), Anconiclrnzis (An), Pl~nolifespl), Seichiclzniis (Te), Choncirites (Ch), Asterosolnn (As), Pdneophjcus (Pa), and Skolithos (Sk). Well 06-11-62-03W6, depth 2543.2 m. (C) A thick sandstone bed Iocated in the interstratified sandstone, silty mudstone and shde facies. The sandstone bed contains low angle planar lamination. Abundant Anconichnus (An) occurs throughout. Well16-01-61-22W5, depth 1899.7 m. (D) Interstratified sandstone, silty mudstone, and shale facies. Physical siructures are dorninated by combined fl ow ripples. The shale and silty mudstone beds contain sand-filled syneresis cracks (syn). Trace fossils include fugichnia (fu). Well05-27-61-01W6, depth 2425.2 m. (E) Convoluted, interstratified sandstone, silty mudstone, and shale facies. The sandstone contains Anconicltntis (An), Plmolifes (FI), and Teichiclzntis (Te). Well 16-01-61- 22W5, depth 1893.3 m (F) The silty mudstone facies is devoid of physical shuctures and bioturbation. Well07-06-63-26W5, depth 1983.7 m.

73 Figure 3-25. Facies of shingle E2 of the Dunvegan Formation. (A) Convoluted siky sandstone within the interstratified sandstone, silty mudstone, and shale facies. Well05-27-61-01W6, depth 2427.2 m. (B) Convoluted silty sandstone. Well10-34-61-26W5, depth 2149.7 m. (C) Amalgamated Ha,located in the laminated to structureless sandstone facies. Carbonaceous detritus demarcates shatification. Well10-34-61-26W5, depth 2149.1 m. (D) Current rippled sandstone, located in the laminated to stnictureless sandstone facies. Well07-05- 63-26W5, depth 1938.4 m.

74 Figure 3-26. Facies of shingle E2 of the Dunvegan Formation. (A) Laminated to bioturbated sandstone facies. Physical structures are dominated by wavy parallel lamination. Mudstone beds are rare. Trace fossils include Helminthopsis (H), Anconichnz

75 Figure 3-27. Facies of shingle E2 of the Dunvegan Formation. (A) Thoroughly bioturbated, larninated to bioturbated sandstone facies. Physical structures have been destroyed by bioturbation. Trace fossils include Helrninthopsis (H), Anconichnris (An), Terebellinn (Tb),PLznolites (PI), Teichichnzls (Te),Siphonichnus (Si), and Cylindriclznus (Cy). Weil 05-27-61-01 W6, depth 2423.4 m. (B) Laminated tu bioturbated sandstone facies. Physical structures destroyed by bioturbation. Trace fossils include Plmolites (Pl), Teiclziclznus (Te), Asterosomn (As), and Pnlneophyais (Pa). Well08-12-63-27W54, depth 1967.0 m.

The succession exhibited in shingle El of AUomember E of the Dunvegan Formation is charactenzed by five facies. The basal facies consists of an interstratified sandstone, silty mudstone, and shde facies. This is overlain by a convoluted silty sandstone facies which interfingers and grades upward into a laminated to structureless sandstone facies (Figure 3-28). Intervals of the interstratified sandstone, silty mudstone, and shde facies may be found intercalated within the laminated to structureless sandstone facies (Figure 3-29). The succession is capped by a shale facies grading upward into a silty mudstone facies. El also contains a laminated sandstone and mud rip-up clast facies that is locally lccated abruptly overlying prodelta and delta front deposits of shingles E2 and E3 (Figure 3-15).

Intersharifien Sandstone, Silty Mudstone, and SItale Facies The interstratified sandstone, silty mudstone, and shale facies is characterized by thin beds and layers arnalgamated into composite bedsets that range in thickness from 1.5 m to 5.5 m (Figure 3-30 A to D). Beds vary from 2 - 3 cm in thickness, with rare, thicker beds from 10 cm up to 50 cm. The basal contacts are typically sharp. The upper contacts of the sandstone beds are sharp, or are sporadically disrupted by burrows (Figure 3-30 B) but locally, they also grade upward into silty mudstone (Figure 3-30 A and D). The sands are moderately sorted and grain size ranges frorn lower fine to lower medium. The silty mudstone is devoid of al1 primary physical and biogenic structures. The shale is typically very black in colour and the beds contain sand-filled syneresis cracks. Carbonaceous detritus is cornmon throughout, with rarer mudstone rip- up clasts and coal fragments. Sandstones have physical structures that are dorninated by wa17yparallel lamination and combined flow ripples, with common numbers of current ripples, convolute bedding (Figure 3-31 A and B) and rare micro-faults (Figure 3-31 A). Rarer low angle planar parallel larnination, 77 and oscillation ripples are locdy developed. Arnalgamated HCS are associated with thicker sandstone beds. The majority of the bioturbation is located in and around the sandstone beds (Figure 3-30 B and D). Bioturbation intensity is variable, ranging from absent to moderate, and trace fossils are sporadicalIy distributed. Ichnogenera diversity is high. The ichnological suite reflects a Cnlzinnn ichnofacies, with rare elements of the Skolitltos ichnofacies. Trace fossils include Anconiclznzls (m), Helnzinfizopsis (vr), Zoopliycos (vr), Terebellinn (vr), Chonhites (vr), Lockein (vr), Plnnolifes (a), Teiclziclznzls (a), Cylindnchritis (m), Asferosornn (r), Rosselin (vr), Thcdnssinoides (vr), Pnlneopltynis (vr), Arenicolites (vr), Skolithos (vr), Ophiornorplin (vr), and fugichnia (c) (Figure 3-30 A to D). Trace fossils are generdy diminutive, with rare robust trace fossils. For example, Teiclzicltntls are generally less than 1cm in length and tube diameters range from 0.5 cm to 1cm. Very rare traces that are approximately 5 cm in length are also present (Figure 3-30 A). Cylindriclzntis are generally diminutive, less then 2 cm in length with tubes less than 0.5 cm in diameter.

Conuoluted Silty Sandstone Facies The convoluted silty sandstone facies is characterized by thick sandstone packages, varying from 1.5 m to 4 m in thickness. The sands are well sorted, and grain size varies from lower fine to upper fine. Carbonaceous detritus is abundant throughout, with rarer coal fragments and sidente-cemented beds. Mudstone beds are very rare, black in colour, and contain sand-filled syneresis cracks, as well as very rare burrows. Physical structures are dominated by oversteepened beds, dewatering structures (Figure 3-31 C),convoluted beds, and gravity micro-faults. Rare low angle planar parallel lamination and low angle wavy parallel lamination may also be present. The silty convoluted facies is typically devoid of bioturbation, with the exception of very rare trace fossils in the mudstone beds. Ichnogenera include 78 Plnnolifes (vr) and Teichichnzts (vr). These trace fossils are generally diminutive in size.

Laminated to Structureless Sandstone Facies The laminated to structureless sandstone facies comprises beds varying from 5 cm to 2.5 m in thickness. These beds are amalgamated into composite bedsets ranging from 0.3 m to 10 m. This facies is characterized by three components, namely, laminated sandstone, structureless sandstone, and trough cross-stratified sandstone. The three components are arnalgamated into a single facies because they al1 appear randornly interbedded with one another. The majority of the lKNnated sandstones are found at the base of the facies, while the trough cross-stratified sandstone is generally located toward the top of the facies. The structureless sandstone is found intercalated throughout (Figure 3-31 D). The convoluted silty sandstone facies and rare occurrences of the interstratified sandstone, silty mudstone, and shale facies are intercalated from the underlying facies (Figure 3-28,3-29). The laminated sandstone beds Vary from 5 cm to 1.5 m in thickness. The sands are moderately sorted, with grain size ranging from lower fine to lower medium. Physical structures are dorninated by low angle planar parallel lamination (Figure 3-32 A), with rarer wavy parallel lamination (HCS), oscillation rippIes, planar lamination, and combined flow ripples. Carbonaceous detritus commonly demarcates these structures (Figure 3-32 A and B). Syneresis cracks are rare and located in rare mudstone beds. Mudstone rip-up clasts Vary from rare to mollerate in number, and are found throughout the facies. The mudstone rip-up clasts are rounded (some sidentized), to oval, and irregular to wispy in shape. The structureless sandstone beds range from 15 cm to 2.5 m in thickness. The beds are poorly sorted, and grain size ranges from lower very fine with abundant silt to upper medium sand. The stnichueless sandstones are typically massive in appearance and devoid of bioturbation. 79 The trough cross-stratified sandstones account for the smallest portion of this facies (Figure 3-33 A). Bed thicknesses range from 5 cm to 60 cm. Trough cross-stratification is typically found toward the top of the facies, although current ripple lamination is present throughout the facies. The trough cross- stratified sandstones are devoid of bioturbation. The lamirtated to shuctureless sandstone facies is generally devoid of biotubation. Bioturbation intensities ace very weak and the distribution of trace fossils is very sporadic. The diversity of ichnogenera is low and the ichnological suite refl ects a "stressed" Cnrzinnn ichnofacies. Trace fossils include Teic?ziclznris (vr), hgichnia (vr), and some enigmatic traces. Plnnolites (vr), Teiclzic/znz

S ha le Facies The shale facies ranges from 2 m to 5 m in thickness. The shale is typically very black and fissile. Carbonaceous dehitus is common, though siderite- cemented beds are rare. This facies contains rare intercalated sandstone and siltstone beds and layers. Bioturbation intensities range from low to absent. Biogenic dismption is sporadically distributed and concentrated around the sandstone beds and layers. The bioturbation is concentrated in the basal 20 cm of the facies. Ichnogenera diversity is very low. The ichnologcial suite reflects a "stressed" Crzizinnn ichnofacies, comprising Anconiclznirs (vr), Plnnolites (vr), Zoopliycos (vr), and Cylindn'dtnirs (vr). The trace fossils are diminutive in size.

Silty Mudstone Facies The silty shale facies ranges from 2 m to 8.5 m in thickness. The facies is massive (stmctureless) in appearance and contains rare sandstone beds. Carbonaceous detritus is cornmon. The sandstone beds contain rare convolute bedding and very rare combined flow ripples. This facies is devoid of bioturbation.

Laminated and Mudstone Rip-up Clast Sandstone Facies The laminated and mudstone rip-up clast sandstone facies comprises beds varying from 10 cm to 2 m in thicknesses. These beds are amalgamated into composite bedsets ranging hom 1 m to 13 m thick. This facies is charactenzed by three components, narnely: laminated sandstone, structureless sandstone, and trough crcss-sbatified sandstone. These beds are generally intercalated with one another. The larninated sandstones are dominated by wavy parallel lamination, with rarer combined flow ripples, aggradational ripples, and planar lamination. Trough cross-stratified sandstone (Figure 3-33 A) and current ripples range from rare to abundant in occurrence. Structureless beds are moderate in occurrence range in thickness from a few meters to 2 m. In the cored interval of 14-06-63- 26W5, the îrough cross-stratified and wavy parallel laminated sandstones are typically capped by current ripples. In the cored interval of 07-06-63-26W5, few structures are discernable as the facies is dorninated with mudstone rip-up clasts and shell fragments (Figure 3-33 B). The sands are moderately sorted, with grain size ranging from lower fine to lower medium. Mudstone rip-up clasts range from rare to abundant. They are mainly characterized by a wispy appearance, with a resemblance to remnants of Asferosornn. They also occur as rounded (and locally sideritized) mudstone balls. Shell fragments range from rare to abundant in occurrence (Figure 3-33 B). Carbonaceous detritus is abundant throughout, as well as coal fragments and siderite-cemented beds. Rare to common mudstone beds are also present. Sphenilitic siderite is found dong stratification in 14-06-63-26W5 (Figure 3-32 C). Bioturbation intensities are very weak to absent and the distribution of trace fossssils are very sporadic. The diversity of ichnogenera is very low and the suite reflects a "stressed"Cnizinnn ichnofacies. Plnnolifes (vr) are mainly located 8 1 within the mudstone beds. Teiclzichnrcs (vr), Asferosornn (vr), Pnlneoplzyctrs (vr) (Figure 3-32 C), and Ophiomorplin (vr) are located in the sandstones. 82 Figure 3-28. Litholog of well07-11-60-ZW5, exhibiting a succession consisting of shïngle El of the Dunvegan Formation. El comprises an intersû-atifïed sandstone, silty mudstone, and shale facies, near the base, and is overlain by a convoluted silty sandstone facies. This is intercalated with a laminated to structureless sandstone facies. Amoco et. al. Bigstone 07-1 1-60-22~5 GRAIN SIZE

Larninated to Structureless Sandstone Facies (Proximal Delta Front)

Shingle El

ConvoIuted Sitty Sandstone Facies (Distal Delta Front)

Interstratified Sandstone, Silty Mudstone,and Shale Facies (Proximal Prodelta) 83 Figure 3-29. Litholog of well14-16-60-21W5, exhibifing a succession consistïng of shingle El of the Dunvegan Formation. El cornpises an interstratified sandstone, silty mudstone, and shale facies that is intercalated upward with a laminated to structureless sandstone facies. Amoco et al. Bigstone 14-16-60-21 WS

GRAIN SIZE I I

Laminated to Structureless Sandstone Facies (Delta Front)

Shingle E 1

lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 84 Figure 3-30. Facies of shingle El of the Dunvegan Formation. (A) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by combined flow ripples and wavy pardel lamination. Sandstones contain robust Teiclzichnzls (Te) and Plnnolites (Pl). Weil 07-11-60-22W5, depth 2075.8 m. (B) Interstratified sandstone, silty mudstone, and shale facies. Physical structures dominated by wavy pardel lamination. Trace fossils include Helminthopsis (H), Anconiclzntis (An), Pln~zolites(Pl), Teichiclznzrs (Te), Cylindrichntrs (Cy), Skolithos (Sk),and hgichnia (fu). WeIl14-16-20-21W5, depth 1977.0 m. (C) Intersbatified sandstone, silty mudstone, and shale facies. Physical structures are doxninated by combined flow ripples. Trace fossils include Anconichntls (An), Plmolifes (Pl), Teiclzichntrs (Te),and an umarned resting trace. Well07-11-60-22W5, depth 2076.7 m. (D) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dorninated by wavy parallel lamination and combined flow ripples. Trace fossils include Plnnolites (PI), Teichichnus (Te),Cylindric!znus (Cy), Pnlneoplyczls (Pa),and fugichnia (hi). Well14-16-60-21W5, depth 1979.5 m.

85 Figure 3-31. Facies of shingle El of the Dunvegan Formation. (A) Convoluted, interstratified sandstone, silty mudstone, and shale facies. A micro-fault is also present. Well13-25-60-22W5, depth 1958.4 m. (B) Convoluted, interstratified sandstone, silty mudstone, and shale facies. Well10-22-60-22W5, depth 2030.4 m. (C)ConvoIuted silty sandstone. WeU 07-11-60-22W5, depth 2072.2 m. (D) Struchueless sandstone Iocated in the larninated to structureless sandstone facies. The sandstone contains abundant carbonaceous detritus. Well07-11-60- 22W5, depth 2066.3 m.

86 Figure 3-32. Facies of shingle El of the Dunvegan Formation. (A) Amalgama ted, low angle planar pardel lamination located in the larninated to structureless sandstone facies. Well10-22-60-22W5, depth 2021.4 m. (B) Laminated to structureIess sandstone facies. Carbonaceous detritus demarcates the low angle planar pardel lamination. Well1416-60-2lW5, depth 1974.3 m. (C) Laminated sandstone and mudstone rip-up clast sandstone facies, with spherulitic siderite, As terosornn (As),and Pdrreoplzy als (Pa) or Oplt iornorphn (O). Well14-06-63-26W5, depth 1964.3 m. (D) Wavy parallel lamuiated sandstone, located in the lamùiated to structureless sandstone facies. Sandstone contains Teicltic~intrs(Te). WeU 07-11-60-22W5, depth 2073.7 m.

87 Figure 3-33. Facies of shgle El of the Dunvegan Formation. (A) Trough cross- stratified sandstone, located in the Iarninated and mudstone np-up clast sandstone facies. Well14-06-63-26W5, depth 1974.6 m. (B) Shell fragments, sidente-cemented nodules, and carbonaceous fragments located in the laminated and mudstone rip-up clast sandstone facies. Well11-05-63-26W5, depth 1952.9 m.

3.4 BELLY RIVER FORMATION

3.41 Cycle D The succession exhibited within Cycle D of the Belly River Formation is characterized by five facies. The basal facies consists of an interstratified sandstone, silty mudstone, and shale facies. This is overlain by an apparently structureless to lamuiated sandstone facies that interfingers with a trough cross- stratified to apparently structureless sandstone facies (Figure 3-34). This grades upward into a current rippled and oscillation rippled sandstone facies (Figure 3- 35). The succession is capped by a silty mudstone facies (Figure 3-36).

Interstratifiecl Sandstone, Silty Mudstone, and Shale Facies The interstratified sandstone, silty mudstone, and shale facies comprises composite bedsets that range in thickness from 4 to 8.5 m. The beds are approximately 1-2 cm thick, with rarer thicker sandstone beds from 25 cm to 1.5 m. The basal contacts are sharp, and the upper contacts are generally bioturbated (Figure 3-37 A) or grade upward into silty mudstone. The sand is moderately well sorted, with grain sizes varying from upper fine to lower medium. Mudstone rip-up clasts are rare and typically found in the thicker sandstone beds. The silty mudstone is a minor component of this facies and generally becomes mked in with the tops of the sandstone beds due to bioturbation (Figure 3-37 8). The shale beds range from 1to 2 cm in thickness. They are very dark, carbonaceous, slightly fissile, and contain rare sand-filled syneresis cracks. Physical structures are dominated by low angle planar parallel lamination (Figure 3-37 C),wavy parallel lamination and oscillation ripples, with rarer convoluted beds (Figure 3-37 D) and combined fiow ripples. The thicker sandstone beds contain amalgamated Ha. The majority of the bioturbation is associated with the thimer sandstone beds. Bioturbation intensities range from absent to weak in the thicker sandstone 89 beds, and weak to moderate within the thinner sandstone beds. Trace fossils are abundant and diversi@ is high. The ichnological suite refiects a Cnrrinnn assemblage, comprising Anconiclinus (a) (Figure 3-37 A, B, and D), Helrnintltopsis (a), Zooplycos (vr), Chundrites (vr), Plmolifes (a), Teichiclznzis (a),Siplioniclzntls (vr), Rosselin (r), Asterosonza (r),~inlnssi~toides (r), Skolitlros (vr), Ophionlorplzn (vr) (Figure 3-37 C), and fugichnia (vr).Tube diameters of Teichidtnits vary from 0.2 cm to 0.7 cm, and range in length from less than 1cm with few spreiten to 1.5 cm with abundant spreiten. Tube diameters of Rosselin range from 0.5 to 1cm, and the bulbs range from 2.0 to 3.0 cm in diameter. Plnnolites Vary from 0.2 to 0.5 cm in diarneter.

S fructureless tu Lamina ted Sandstone Facies The apparently stnictureless to larninated sandstone facies comprises beds that range from 5 to 50 cm in thickness. These are erosionally amalgamated into simple bedsets ranging from 2 to 8.5 m in thickness. The sands are moderately well sorted, with grain sizes varying from upper fine to lower medium. The apparently structureless sandstones (Figure 3-38 A) constitute the majority of this facies, with rare mudstone beds throughout. The Iarninated sandstone consists of low angle wavy parallel larnination (HCS), low angle planar cross lamination, and very rare convolute bedding. The larnination within the beds is quite faint, and mainly highlighted by carbonaceous detritus. A few scour marks are visible (Figure 3-38 B). Bioturbation intensity is very low and trace fossils are sporadically distributed. Ichnogenera diversity is very low and the suite reflects a poorly developed rnixed Skolitltos-Cnlzinnn ichnofacies. Trace fossils include Teiclticlintis (vr) (Figure 3-38 A) and Mncnroniclzntrs (vr) (Figure 3-38 C), with Plcznolites (vr) present in a rare mud bed. The facies also contains some very rare enigrnatic back-filled burrow, lined dwelling structures that remain unidentified. Tube diameter of Teiclziclrnns average 1cm, and of Mncczroniclinzis average 0.2 cm. Trouglz Cross-Stratifiecl Sandstone Facies The trough cross-stratified sandstone comprises beds that range in thickness from 15 cm to 1.7 m. These beds are amalgamated into simple bedsets ranging from 2 to 5 m in thickness. The sands are poorly to moderately sorted and vary in grain size from lower medium to lower coarse sand. Apparently structureless sandstone beds are common and range in thickness from 10 to 50 cm. Mudstone rip-up clasts are rare and "wispy" in appearance. The dominant physicd structures include trough cross-stratification (Figure 3-39 A) and apparently struchireless intervals, with rare wavy parallel lamination and low angle planar parallel lamination. Carbonaceous detritus demarcates the lamination in most intervals. In a single core, root structures occur at the top of this facies. This facies is devoid of other fonns of bioturbation.

Current and Oscillation Rippled Sandstone Facies The current and oscillation rippled sandstone facies consists of beds varying from 1to 5 cm in thickness. These beds are amalgamated into composite bedsets that range in thickness from 1.5 to 2.5 m. The sands are well sorted and grain size varies from lower medium to upper medium. Siltstone layers are common throughout, and generally mantle the current ripples. Mudstone rip-up clasts and coal fragments are also comrnon. Physical shuctures are dominated by current ripples (Figure 3-39 B and C), clirnbing ripples, combined flow ripples, and oscillation ripples (Figure 3-39 C) with rarer wavy parallel lamination, and trough cross-stratification. Carbonaceous detritus is abundant and comrnordy dernarcates the physical structures. This facies is mainly devoid of bioturbation. Trace fossils include Skolithos (r) (Figure 3-39 B) that are approximately 10 cm in length and "mud-lined", and a single escape structure. 91 Silty Mudstone Facies The silty mudstone facies is present in the cored interval of 08-22-49-07W5 (Figure 3-39 D), and is 3.1 m thick. The basal silfy mudstone contains a number of characters indicating that the unit has been pedogenically modified. These features include curved, wavy to glossy slickensides, a mbbly appearance, siderite-cemented beds, coal and plant fragments, root traces. It has a light-grey to brown colour. Within the paleosol, rare thick coal beds, up to 60 cm thick, are present. Grading upward in the facies, the silty mudstone is less rubbly, convoluted, and contains siclerite nodules ranging from less than 1cm to 5 cm in diameter. With the exception of rooting, this facies is devoid of bioturbation. 92 Figure 3-34. Litholog of weU 16-07-49-08W5, exhibiting a succession comprising cycle D of the Belly River Formation. Cycle D consists of interstratified sandstone, silty mudstone and shde facies, overlain by a sÿuctureless to laminated sandstone facies that interfingers with a trough cross-stratified to structureless sandstone facies. The succession is capped by a silty mudstone facies. Pala et al. Oome 16474908w5

'7 Trough Cross-Stratified to 1 Structureless Sandstone Facies (Proximal Delta Front) i

Cycle D ...... a...... ---.- . . a--:. - ...... --.-......

Structureless to Laminated Sandstrlne Facies (Distal Delta Front)

Interstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal P rodelta) 93 Figure 3-35. Litholog of well10-23-48-06W5, exibiting a succession comprising Cycle D of the BeUv River Formation. Cylce D consists of interstratidied sandstone, siltstone, and shale facies, interfingered with the structureless sandstone facies. This is overlain by the trough cross-stratified sandstone facies and the succession is capped by a current and oscillation rippled sandstone facies. Champ. Pemb. Cam. 1 O-23-48-06~5 GRAIN SlZE z 1

Current and Oscillation Rippled Sandstone Facies (Proximal Delta Front)

Cycle D

Trough Cross-Stratified Sandstone Facies (Proximai Delta Front)

Structureless Sandstone Facies lnterfingered with the lnterstratified Sandstone, Siltstone, and Shale Facies (Distal Delta Front) 94 Figure 3-36. Litholog of well08-22-49-07W5, exhibiting a succession comprïsing Cycle D of the Belly River Formation. Cycle D consists of çtnictureless to laminated sandstone facies that grades upward and interfingers with trough cross-stratified to structureless sandstone facies. The succession is capped by a silty mudstone facies.

95 Figure 3-37. Facies of Cycle D of the BeUy River Formation. (A) Interstratified sandstone, silty mudstone and shale facies. Physical structures are difficult to discem but include wavy parallel lamination. Trace fossils include Anconiclznt~s (An), Plnnoli tes (Pl),Teichichnr is (Te), and Rosselin (Ro). Well16-07-49-08W5, dep th 1046.4 m. (B) Interstratified sandstone, silty mudstone and shale facies. Physical structures in the sandstone are not discernible. Trace fossils include Anconiclzntis (An), Plnnolites (Pl), Teicliichnus (Te), Cliondntes (Ch), and Rosselin (Ro). Well16- 07-49-08W5, depth 1045.5 m. (C) A thicker sandstone bed within the interstratified sandstone, silty mudstone and shale facies. The sandstone contains Ha,Ophiornorplzn (0)and fugichnia (fu). Weil 16-07-49-08W5, depth 1041.9 m. (D) Convoluted, interstratified sandstone, silty mudstone and shde facies with shell fragments (shell). Trace fossils include Anconichnus (An) and Terebellinn (Tb). Well16-07-49-08W5, depth 1042.5 m.

96 Figure 3-38. Facies of Cycle D of the Belly River Formation. (A) Stmctureless sandstone bed, located in the structureless to laminated sandstone facies. Trace fossils include Teichidtnz~s(Te) and a possible Diplocrnfe?ion hnbiclzi. WeU 16-07- 49-08W5,1030.6 m. (8) Sîructureless sandstone bed, located in the stntctureless to laminated sandstone facies. The sandstone contains abundant carbonaceous detritus and Mncnroniclrnus (M). Well08-22-49-07W5, depth 1046.5 m. (C) A scour mark (possible gutter cast), located in the structureless to laminated sandstone facies. The sandstone contains abundant carbonaceous detritus and weakly developed wavy pardel lamination. Well08-22-49-07W5, depth 1049.1 m.

97 Figure 3-39. Facies of Cycle D of the BeUy River Formation. (A) Trough cross- stratified sandstone facies. Carbonaceous detritus delineates the stratification. WeIl16-07-49-08W5, depth 1024.3 m. (B) Current and oscillation ripple laminated sandstone facies. Physical structures are dominated by current ripples. Carbonaceous dehitus highlights the sedimentary structures. Trace fossils include Skolithos (Sk). Well10-23-4&06W5, depth 1057.8 m. (C) Current and oscillation npple laminated sandstone facies. Laminâtion is highlighted by carbonaceous dehitus. Well16-07-49-08W5, depth 1023.0 m. (D) Silty mudstone facies. The silty mudstone bed contaiw abundant carbonaceous detritus and coal fragments. Well08-22-49-0W5, depth 1040.2 m.

3.42 Cycle E The succession exhibited by Cycle E of the Belly River Formation is characterized by five facies. The basal facies consists of an interstratified sandstone, silty mudstone and shale facies, which is overlain by a convoluted silty sandstone facies. This grades upward into a laminated to bioturbated sandstone facies (Figure 3-40). The succession is capped by a convoluted silty and muddy sandstone facies that is overlain by, and interfingers with an interstratified sandstone, silty mudstone and shale facies (Figure 3-41).

Interstratified Sandstone, Silty Mudstone, and Shnle Facies The interstratified sandstone, silty mudstone, and shale facies comists of beds ~pically1 to 2 cm thick. These beds are amalgamated into composite bedsets ranging from 0.4 to 1m in thickness. The basal contacts are generally sharp and the tops are sporadically disrupted by burrowing (Figure 3-42 A). The tops of some sandstone beds also grade into silty mudstone locally. The sands are well sorted, and grain sizes Vary from lower fine to upper fine sand. The silty mudstones are rare, generally located at the tops of the sandstone beds, and partially incorporated into the sandstone beds due to bioturbation. The mudstone is very dark, carbonaceous, slightiy fissile, and contains rare sand- filled syneresis cracks. Physical structures are dominated by oscillation npples and wavy parallel lamination. Bioturbation intensities range from absent to weak, and biogenic structures are located in and around the sandstone beds (Figure 3-42 A and B). Ichnogenera diversity is low and the suite reflects a Cnczinnn ichnofacies. Trace fossils include Anconiclznzis (a), Helrni~zt~lopsis(m), Zoopliycos (m), Plnnolites (c), and Teicltic/lnzcs (c). These traces fossils are diminutive in size. For exarnple, Plnnolites ranges from 0.1 to 0.4 cm in diameter. Convoluted Silty Sandstone Facies The convoluted silty sandstone facies ranges from 50 cm to 1.5 m in thickness. It is quite muddy in appearance locally. Carbonaceous detritus is common throughout and marks the convolute structures. This facies is devoid of bioturbation (Figure 3-42 C).

Laminateci tu Biotrrrbated Sandstone Facies The laminated to bioturbated sandstone facies consists of beds ranging from 5 cm to 2.5 m in thickness. These beds are amalgarnated into composite bedsets ranging from 5 to 14 m thick. The sands are moderately sorted, and grain sizes Vary from upper fine to upper medium. Interstitial silt is also present (Figure 3-43 A and B). Mudstone beds are rare to moderate in number, and contain rare sand-filled syneresis cracks. Mudstone rip-up clasts also Vary from rare to moderate in number, and either resemble remnants of burrows (Asterosonin and/or Rosselin) or fragments of mudstone from the underlying interstratified facies. Physical structures are dominated by wavy parallel lamination (HCS), (Figure 3-43 A, B and C), apparently stnictureless beds, and rarer trough cross- stratified beds. HCS beds range from 5 cm to 2.5 m in thickness, and average 30 cm thick. The apparently structureless sandstone beds range from 20 cm to 70 cm in thickness. The trough cross-stratified sandstone beds range from 10 cm to 70 cm thick. The maximum amalgamated thickness of trough cross-stratified beds is approximately 1 m. Subordinate physical structures include oscillation ripples, current ripples (Figure 3-43 C), combined flow ripples, aggradational ripples, convolute bedding (Figure 3-43 D), and very rare micro-faults. Carbonaceous detritus is abundant throughout this facies and demarcates the physical structures. Silt is also present in this facies, and is generally located with the convolute structures or found grading upward from wavy parallel laminated sandstone structures. 1O0 Biotilrbation intensity ranges from absent to weak and is sporadically distributed (Figure 3-44 A, 8,and C). There is a low abundance of ichnogenera but diversity is high. The ichnological suite resembles a Cmzinnn ichnofacies, with rare elements of the Skoliflros ichnofacies. Trace fossiis include Anconiclintrs (a),Helmintkopsis (r), Plnnolites (a), Teichichnus (r-a), Rhizocornllirim (vr), Cylindriclintls (r), Rosselin (c), Pnlneoplzpis (r),Mncnronichnus (r) (Figure 3-44 C), Skolitlios (r), Arenicolifies (vr), and fugichnia (r). In 06-10-23-04W5, the lower portions of Rosselin shafts are Iocated below erosion surfaces. The concentric mud layering of the shaft are well preserved (Figure 3-44 A and B).

Convoluted Silty to Muddy Sandstone Facies Tne convoluted silty to muddy sandstone facies ranges from 1 to 2 m in thickness. The facies is poorly sorted, and grain sizes range from silt to lower medium sand. Carbonaceous detritus and coal fragments are abundant. Rare, 50 cm thick coal beds are also intercalated. Physical structures are dominated by convolute bedding, with rare low angle wavy parallel lamination. This facies is devoid of bioturbation (Figure 3-45 A).

Pinstriped, Interstratified Sandstone, Silty Mudstone, and Shale Facies The pinstriped, intertratified sandstone, silty mudstone, and shale facies is characterized by delicately interstratified layers and beds, forming composite bedsets averaging 1.5 m in thickness. Bed contacts are typically sharp and sporadically disrupted by burrowing (Figure 3-45 B). The sands are well sorted and grain sizes Vary from lower fine to upper fine. The silty mudstone beds are scarce and mainly stnictureless. The shale is very dark and contains moderate numbers of sand-filled syneresis cracks. Carbonaceous detritus and coal fragments are abundant throughout The dominant physical structures include wavy parallel lamination, oscillation ripples, combined flow ripples, and convolute bedding, with rarer current npples and micro-faults. This facies also contains a bentonitic layer, as well as root shuctures. 101 Bioturbation intensity ranges from absent to weak, with the majority of the biogenic structures associated with the sandstone beds. Ichnogenera abundance and diversity are very low. The ichnological suite reflects a Cnrzinnn ichnofacies with rare elements of the Skolitlios ichnofacies. Trace Çossils include Plnnolites (r), Cylindriclinz~s(r), Skolitltos (r), and fugichnia (r-m).Trace fossils are diminutive in size. For example, Skolitlios average 1 cm in length. 102 Figure 3-40. Litholog of well06-11-47-05W5, comprises Cycle E of the Belly River Formation. Cycle E consists of an interstratified sandstone, silty mudstone, and shale facies overlain by a stmctureless to laminated sandstone facies that is locally bioturbated. This is overlain by a convoluted silty and muddy sandstone facies that is capped by and interfingers with a pinstriped, interstratified sandstone, silty mudstone, and shale facies. Ashlandetal Norbuck (#1147QSwS WNS OOOT. '

Pinstripe, Interstratified Sandstone, Silty Mudstone, and Shale Facies (Delta Plain)

Convoluted Silty Sandstone Facies (Delta Plain)

Cycle E

Structureless to Laminated Sandstone Facies (Proximal Delta Front)

Structureless to Laminated Sandstone Facies (Distal Delta Front)

lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal P rodelta) 103 Figure 3-41. Litholog of well06-10-43-04W5, comprising Cycle E of the Belly River Formation. Cycle E consists of an interstratified sandstone, silty mudstone, and shale facies that is overlain by a laminated to bioturbated sandstone facies, grading into a convoluted silty and mudstone facies toward the top of the succession. The succession is capped by coal, which is ovedain by a piwtripe, interstratified sandstone, silty mudstone, and shale facies. Orbit et al. Leedaled

Pinstripe, Interstratified Sandstone, Silty Mudstone, and Shale Facies (Delta Plain)

Convoluted Silty and Mudstone Facies (Delta Plain)

Laminated to Bioturbated Sandstone Facies (Proximal Delta Front)

Cycle E

Laminated to Bioturbated Sandstone Facies (Distal Delta Front)

Interstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 1O4 Figure 3-42. Facies of Cycle E of the Belly River Formation. (A) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by oscillation ripples and wavy paralle1 lamination. Trace fossils include Zwphycos (Z), Anconichn us (An), Chundrites (Ch), and Plnnolites (Pl). Well06-1043-04 W5, depth 1281.9 m. (B) Interstratified sandstone, silty mudstone, and shde facies. Physical structures are dominated by wavy parallel lamination. Trace fossils include Anconichnzcs (An), Chundrites (Ch), Plnnolites (Pl), Terebellina (Tb),and Cylindrichnzls (Cy). Well03-25-46-03W5, depth 1037.4 m. (C) Convoluted silty sandstone facies. Well10-3046-03W5, depth 1108.5 m.

105 Figure 3-43. Facies of Cycle E of the Belly River Formation. (A) Structureless to laminated sandstone facies. Physical structures are dominated by wavy pardel lamination. These structures are demarcated by carbonaceous detritus, and grade upward into silty layers. WelI 02-32-46-03W5, depth 1074.5 m. (B) Structureless to laminated sandstone facies. Physicd structures are dominated by wavy pardel larninatian. Carbonaceous dehitus dernarcates the stratification. A syneresis crack (syn) is located within the sandstone. A single, poorly preserved Pnlneoplzyczls (Pa) is present. Well02-35-46-03W5, depth 1073-4 m. (C) Structureless to laminated sandstone facies. Physical structures are dominated by wavy parailel lamination and aggradational ripples. The stratification is demarcated by carbonaceous detritus. Well06-11-47-05W5, depth 1134.6 m. (D) Convoluted silty sandstone, located in the stmctureless to lamhated sandstone facies. 06-11-47-05W5, depth 1134.3 m.

1O6 Figure 3-44. Facies of Cycle E of the Belly River Formation. (A) Structureless to laminated sandstone facies. The sandstone appears structureless and contains several shafts of RosseIicz (Ro)that are truncated at an erosion surface. Well06-10- 43-04W5, depth 1276.5 m. (8)Structureless to larninated sandstone facies, containing cross-sections of Rosselia (Ro). Note the concenwic layering around the shaft. Well06-10-43-04W5, depth 1276.7 m. (C) Apparently stnictureless sandstone bed Iocated in the stnictureless to larninated sandstone facies. The sandstone contains M~cnronichnz~s(W. Well06-10-43-04W5, depth 1271.5 m.

1O7 Figure 3-45. Facies of Cycle E of the BeIly River Formation. (A) The convoluted silty and muddy sandstone facies. WeU 06-1043-04W5, depth 1267.6 m. (8)The pinstriped, interstratified sandstone, silty mudstone, and shale facies. Physical stnictures are dominated by wavy parde1 lamination and oscillation ripples, with rare current ripples. Trace fossils include Helniintliopsis (HJ, Plnnolites (Pl), Cylindrichnrw (Cy),Skolitlios (Sk)and hgichnia (fu). Well06-11-47-05W5, depth 1119.8 m.

3.43 Cycle F The succession exhibited in Cycle F of the Belly River Formation is characterized by six facies (Figure 3-46). The basal facies is composed of interstratified sandstone, silty mudstone, and shale, and is overlain by a larninated sandstone facies. This is sharply overlain by a shale/pdaeosol facies, that grades upward into an interstratified sandstone, silty mudstone, and shale facies. The succession is capped by a laminated to stnictureless sandstone facies, although this facies is found in only three cores (06-35-47-02W5,16-29-47-02W5, and 10-30-46-03W5). Cod beds are sporadicdy distributed throughout the Iast three facies.

Interstratijïed Sandstone, Silty Mudstone, and Shale Facies The interstratified sandstone, silty mudstone, and shale facies consists of beds and layers that range from 0.5 to 2 cm in thickness, with rarer beds up to 6 cm thick. These beds are amalgamated into composite bedsets that range in thickness from 30 cm to just over 1m. Bed contacts are typically sharp, with the sandstone beds grading upwards into silty mudstone (Figure 3-47 A). The sands are well sorted, and grain sizes Vary from lower fine to upper fine. The silty mudstones are generally structureless. The shales are very dark, and contain rare to moderate numbers of sand-filled syneresis cracks. The dominant physical structures include wavy parallel lamination, oscillation ripples, and convolute bedding, with rarer low angle plana parallel lamination. Carbonaceous dehitus and siderite-cemented beds are comrnonly present. Bioturbation intensities range £rom absent to weak, and are mainly associated with the sandstone beds (Figure 3-47 A and B). Ichnogenera abundance and diversity are low. The ichnologicd suite reflects a Cnizinnn ichnofacies, and comprises Anconiclinzis (a), Helrninthopsis (r-m), Chondrites (r), Plrrnolites (r-m), Teicliic~tnzis(vr) and Cylindricllnz~s(vr). Plnnolites range from 0.1 to 0.6 cm in diameter. 1O9 Laminated Sandstone Facies The laminated sandstcne facies consists of beds ranging in thickness fïom 10 to 70 cm and averaging 40 cm. These beds are amalgamated into composite bedsets that range from 2 to 4 m in thickness. The sands are moderately well sorted, and grain sizes vary from upper fine to upper medium. The majority of the sandstone facies is well laminated. The lamination comprises wavy parallel lamination (Figure 3-47 C), low angle planar parallel lamination, trough cross-stratification (Figure 347 D), rare swaley cross- stratification (Se), and very rare oscillation ripples, combined flow ripples, current ripples, and convolute bedding (Figure 318 A). Shuctureless sandstones are also present and sporadically distributed throughout the facies (Figure 348 8). The structureless sandstone beds range from 60 cm to 1.6 m in thickness. These beds contain no visible structures, and are deemed apparently structureless. At the top of the facies, a silty mudstone to silty sandstone is present that typicdy contains root structures. These beds range from 50 cm to 1.7 in thickness. Carbonaceous detritus is abundant and typically demarcates lamination (Figure 3-47 C). Spherulitic siderite is found in two cores (04-22-47- 03W5, and 16-29-47-02W5) and generaliy is concentrated along the stratification (Figure 3-47 D). Rare mudstone beds are also present. These laminated beds locdy contain rare bioturbated intervals (Figure 3- 48 C, D, and E). The bioturbation intensity is mainly absent to very weak but ichnogenera diversity is moderate to high. The ichnological suite refiects a mixed Skolitlzos-Crzlzinna ichnofacies. Trace fossils located in the rare mudstone beds include Anconiclznris (vr-r) and Plmolites (vr-r). Trace fossils located in the sandstones include Teicliiclinics (r), Asterosomn (r) (Figure 3-48 C),Pdneopltynis (r) (Figure 3-48 D), Arenicolifes (vr-r), Skolith (r) (Figure 3-48 E), Opliiornolplin (r), Mncnronichnzls (r), hgichnia (r), and several enigmatic unidentified structures that have simiiarities both to Asferosontn and Opliiornorphn. 110 S ha le Facies The shale facies ranges from 50 cm to 1m in thickness (Figure 346). The shale is very dark and commonly contains abundant carbonaceous detritus, and coal and wood fragments. In the core of the 0422-47-03W5 and 06-09-47-03W5 wells, the shale has been pedogenicdly modified. This paleosol is rubbly, light grey in appearance, and contains slickensides. This facies is devoid of bioturbation.

Interstratifiecl Sandstone and Shnle Facies The interstratified sandstone and shale facies consists of thin layers and rare beds ranging up to 1cm in thickness, with rarer convolute beds 2 to 3 cm thick (Figure 3-49 A and B). These layers and beds are amalgamated into composite bedsets ranging frorn 1 to 6 m in thickness. Bed contacts are generally sharp but sporadically dismpted by biogenic activity (Figure 349 A and 8). The sandstones are ~ellsorted, and grain sizes vaqrfrom lower fine to upper fine. The shale beds are dark and contain common numbers of sand-filled syneresis cracks. Siderite-cemented beds are common throughout, as well as carbonaceous detritus and coal fragments. In core of the 04-22-47-03W5 well, a bentonite bed 50 cm thick, is present. Siltstone beds and layers are also sporadically distributed throughout the facies. Dominant physical structures include wavy parallel lamination, oscillation ripples, and convoluted beds (Figure 3-49 C), with less abundant combined flow ripples, current ripples, and micro-faults. Bioturbation is associated with the sandstone beds and intensities range from absent to weak. The ichnogenera abundance is low and diversity is moderate. The ichnological suite reflects a Cnizinnn ichnofacies with rare elements of the Skolitlios ichnofacies. Trace fossils include Plnnolites (c), Teiclt iclin tts (r-c), Cy~imiriclznzts(c), Rosselin (c), Arenico lites (r-c), Skolitlios (r), Opltiomorpltn irregrlnire (vr), and fugichnia (r-c). Rare enigrnatic structures tentatively identified as Çcoyeriin (Figure 3-49 B), are also present. 11 1 Larninated to Strtictrireless Sandstone Facies The larninated to structureless sandstone is Iocated in three cores and ranges in thickness from 2 to 4 m. The sands are poorly sorted and vqin grain size from iower fine to lower medium. Carbonaceous dehitus and coal fragments are rare to common. Mudstone rip-up clasts are "wispy",and generally up to 1 cm in diameter. Physical structures in the lower half of the facies are dominated by wavy parallel lamination and oscillation ripples. Beds range from 5 to 50 cm in thickness, amalgamated into simple bedsets up to 1.5 m thick. The upper half is dominated by trough cross-stratification and curent ripples. These beds range from 10 to 20 cm in thickness and are amalgamated into simple bedsets up to 2.5 m thick. Structureless sandstones are intercalated throughout, and range from 10 cm to 1.5 m in thickness. The larninated to structureless facies is devoid of bio turbation. Cod beds are sporadically distributed throughout the last three facies (Figure 346). The coal beds range in thickness from 15 to 50 cm. The coal is bituminous, hard, dark black, and alternates being bright to du11 in appearance (Figure 3-49 D). 112 Figure 3-46. Litholog of wellO4-Z-47-03W5, exhibiting a succession comprising Cycle F of the Belly River Formation. The base of Cycle F consists of an interstratified sandstone, silty mudstone, and shde facies that passes into the larninated sandstone facies. This is sharply overlain by a shale/palaeosol facies that grades upward into a pinstriped, interstratified sandstone, silty mudstone, and shale facies, with sporadically distributed coal beds. Whitehall et al. Pem 04-22-47-03~5

Interstratified Sandstone, Silty Mudstone, and Shale Facies (Delta Plain)

Cycle F

ShaleIPalaeosol Facies (Delta Plain)

Larninated Sandstone Facies (Proximal Delta Front)

Interstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 113 Figure 3-47. Facies of Cycle F of the Belly River Formation. (A) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by oscillation ripples. Trace fossils include Anconiclznz~s(An) and Plnnolites (Pl). Syneresis cracks (syn) are located in the shale beds. Well03-25-46-03W5, depth 1026.3 m. (B) Interstratïfied sandstone, silty mudstone, and shale facies. Physical structures are dominated by wavy parallel lamination and oscillation ripples. Trace fossils include Anconiclznrrs (An), Chundrites (Ch), Plnnolites (PI), and Cylindridnzus (Cy). Syneresis cracks (syn) are located in the shale and silty mudstone beds. Well06-35-47-02W5, depth 1003.1 m. (C) Laminated sandstone facies. The sandstone near the base appears stnictureless. The top half of the sandstone is dominated by wavy parallel lamination, with rare oscillation ripples. Carbonaceous detritus and spherulitic siderite demarcate the stratification. Well04-22-47-03W5, depth 1045.6 m. (D) Trough cross-stratified sandstone located in the laminated sandstone facies. Carbonaceous detritus and sphemlitic siderite demarcate the stratification. Well16-29-47-03W5, depth 1011.9 m.

114 Figure 3-48. Facies of Cycle F of the Belly River Formation. (A) Convoluted sandstone bed located in the laminated sandstone facies. Well06-35-47-02W5, depth 998.6 m. (B) Apparently structureless sandstone bed, located in the laminated sandstone facies. The sandstone contains carbonaceous detritus and sphemlitic siderite. Well04-22-47-03W5, depth 1047.9 m. (C) Laminated sandstone facies. The sandstone appears structureless and contains Asterosonin (As). Weli 02-32-46-03 W5, depth 1067.9 m. (D) Laminated sandstone facies. Trace fossils include Pnlneophps (Pa) and probable Teichiclznzis (Te). Well10-30- 46-03W5, depth 1098.0 m. (E) Laminated sandstone facies. Physical structures are dorninated by wavy parallel lamination. Trace fossils include Pnlneophyais (Pa), Skolithos (Sk)(or truncated Rosselin (Ro),and fugichnia (fu). Well04-22-47- 03W5, depth 1046.9 m.

115 Figure 3-49. Facies of Cycle F of the BeUy River Formation. (A) Pinstriped, laminated interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by oscillation ripples and wavy pardel lamination. Trace fossils include Planolites (Pl), Teiclzichnzis (Te), Cylindrichntis (Cy), and fugichnia (fu). WellO4-22-47-03W5, depth 1039.8 m. (B) Pinçtnped, laminated interstratified sandstone, silty mudstone, and shde facies. Physical structures are domMted by wavy parallel lamination, oscillation ripples and rare combined flow ripples. Trace fossils include Plnnolites (Pl) and ?Secyenin (Sc).Well16-29-47- 02W5, depth 1007.2 m. (C) Convoluted beds located withiri the pinstripe, interstratified sandstone, silty mudstone, and shale facies. Well O4-22-4&7-O3W5, depth 1037.2 m. (D) A cdbed, one of a number that are sporadically distributed throughout the pinçtriped, interstratified sandstone, silty mudstone, and shale facies. Well06-09-47-03W5, depth 968.5 m.

3.44 Cycle G The succession exhibited by Cycle G of the Belly River Formation is characterized by five facies. The basal facies consists of an interstratified sandstone, silty mudstone, and shale facies. This facies may grade upward into a convoluted silty mudstone/sandstone facies. The convoluted silty sandstone/sandy siltstone facies is not found in al1 cores, but where present (06- 23-46-02W5,06-16-46-01W5, and10-09-47-02W5) is generally overlain by a trough cross-stratified and current rippled sandstone facies (Figure 3-50). Where neither the convoluted silty mudstone/sandstone facies nor the trough cross-stratified and current rippled sandstone facies are present, the basal interstratified facies is directly overlain by a larninated to bioturbated sandstone facies (Figure 3-51). The succession is capped by a sandy shale facies (Figure 3-50).

Znterstratified Sandstone, SiIty Mudstone, and Shale facies The interstratified sandstone, silty mudstone, and shale facies consists of beds that are typically 1- 2 cm thick. The bedding contacts are either sharp (Figure 3-52 A and B) and sporadically dismpted by burrowing (Figure 3-52 C) or the tops of sandstone beds grade into silty mudstone (Figure 3-52 B). Sandstone beds average 1 to 2 cm in thickness, with rare thicker beds that range from 15 cm to 1.5 m thick. The sands are moderately sorted with grain sizes that vqfrom upper fine to lower medium. The silty mudstone beds Vary in occurrence from rare to abundant. Where the silty mudstone beds are abundant the facies becomes siltier upwards. The silty mudstone layers are structureless. The shale is dark, carbonaceous, and contains common numbers of sand-filled syneresis cracks (Figure 3-52 A). Sidente-cemented beds are quite abundant. Physical sedimentary structures are dorninated by wavy parallel lamination, oscillation ripples, and combined flow ripples, with rarer convolute bedding. The thicker sandstone beds contain low angle planar parallel lamination, wavy parallel lamination and rare convolute bedding. 117 Bioturbation is associated with the sandstone beds and intensities range from absent to weak. The abundance of ichnogenera is low but diversity is moderate to high. The ichnological suite reflects a Cnlzinnn ichnofacies and includes A tzconicltntis (a) (Figure 3-52 C), Helrnin flzopsis (c),Zooplzycos (vr), Chonrirites (r), Plnnolites (c), Teicliiclzntis (m), Cylindriclrn~w(r), Arenicolites (vr), Skolifltos (vr), and fugichnia (r).

Convoluted Silty Sandstone/Sandy Siltstone Facies The convoluted silty sandstone/sandy siltstone ranges from 1.0 to 4.5 m in thickness. Grain sizes range from coarse silt to lower medium sand. This facies is characterized by a silty, muddy sandstone (Figure 3-52 D) to a sandy siltstone or siltstone. Carbonaceous detritus is abundant throughout. The dominant physical structure is convolute bedding, with rare wavy parallel lamination and some structureless intervals. This facies is devoid of bioturbation, with the exception of a single, diminutive escape stnicture.

Trough Cross-Stratifed and Cutrent Rippled Sandstone Facies The trough cross-stratified and current rippled sandstone facies consists of beds that range from 3 to 65 cm in thickness. These beds are amdgarnated into composite bedsets ranging from 2 to 6.5 m thick. The sands are poorly sorted, with grain sizes varying from upper fine to upper medium. The facies typically fines upward. Mudstone beds are rare, and contain low numbers of sand-filled syneresis cracks. Mudstone rip-up clasts are rare and are characterized by ovd, sideritized, millimeter to 1 to 2 cm diarneter fragments or remnants of muddy burrows. Physical structures are dominated by hough cross-stratification, current ripples (Figure 3-53 A), and climbing ripples (Figure 3-53 B), with rarer combined flow ripples, convolute bedding, oscillation ripples, wavy pardlel lamination, Low angle planar parallel lamination, and structureless intervals. Very rare rnicro-faults are locally present. The trough cross-stratified sandstones mainly 118 dorninate the lower half to three-quarters of the facies. The upper portion of the sandstone is dominated by curent ripples and climbing ripples. Small amounts of silt are associated with the convolute bedding and tend to be located near the top of the facies. Carbonaceous detritus is abundant throughout this facies, typically demarcathg the physical structures (Figure 3-53 A and 8). Root structures are found at the top of the sandstone in a single core. Bioturbation intensities range from mainly absent to weak. Ichnogenera abundance and diversity are very low. The ichnological suite reflects a mired Skolithos-Cmzinnn ichnofacies, and includes Plnnolifes (r) located in the mudstone beds, and Teiclzidmus (r), Cylinlinriridmtis (r), ?Arenicolites (vr), Skolithos (r-c) (Figure 3-53 A and B), fugichnia (r-c), and rare enigmatic, meniscate, backfiiled tubes that are tentatively identified as Scoyenin in the sandstone beds.

Laminated to Bioturbated Sandstone Facies The laminated to bioturbated sandstone facies consists of beds ranging from 2 cm to 2.5 rn in thickness. These are amalgamated into composite bedsets ranging from 10.5 to 17 m in thickness, averaging 15 m thick. The sands are moderately sorted and grain sizes coarsen upward from lower medium to lower coarse. Rare to moderate numbers of mudstone rip-up clasts are present and resemble remnants of Asterosornn and Rosselin. Tripolitic chert, shell fragments, and coal fragments are also present though rare. The laminated to bioturbated sandstone facies generally consists of two components. Generally, the basal two-thirds of the facies is dorninated by low angle planar parallel lamination (Figure 3-54 A), and swaley cross-stratification (SE), with rarer wavy parallel lamination and stmctureless sandstone. These lamuiated beds range in thickness from 10 cm to 80 cm and are erosionally amalgamated into bedsets up to 1.5 m thick. The upper third is generally domùiated by trough cross-shatified and structureless sandstone, with rare low angle planar lamination, and planar lamination. Trough cross-stratified sandstone beds range from 10 to 60 cm in thickness, and are amalgamated into 119 bedsets up to 2 m thick. Stnictureless sandstone beds (Figure 3-54 B and D) range in thickness from 60 cm to 2.5 m, and average 1m thick. Carbonaceous detritus is abundant and typically demarcates the physical shuctures (Figure 3-54 A). Bioturbation intensities range from absent to weak, and busrows are typically located at the tops of the laminated sandstone beds. Ichnogenera abundance is low and diversity is moderate. The ichnological suite reflects a mixed Skolitltos-Cnczinnn ichnofacies. Trace fossils include Rosselin (c), Cylindn'clznus (r), Asterosomn (r),Pczlneopliynls (r-c), Ophiomorplin (r) (Figure B and C), Skolifhos (r) (Figure 3-54 D), Mnc~ronihnt~s(c) (Figure 3-54 E), some enigmatic (unidentified)stnictures, and fugichnia (r). Spectacular examples of Rosselin occur within this facies (Figure 3-55). Along the bedding planes, Rosselin shafts are well defined and characterized by sand-filled tubes surrounded by concentric layers of mud. Spectacular cross-sections of Rosselin bulbs and shah are dso present. The bulbs are generally disconnected from the shafts (Figure 3-55 A and B) and the majority of the shah are truncated and terminate at erosion surfaces (Figure 3-55 C and D). At these erosion surfaces, rip-up clasts may be found that are likely reworked Rosselin mud balls (Figure 3-55 c). In the 16-13-43-43-28W4 well, a partial Rosselin bulb is tnincated, and the shaft is found re-established above it (Figure 3-55 D). The C?l[inrinclrnusshafts are quite heavily lined. The top third of this facies is mainly devoid of any trace fossil other than Mczcizroniclznt~s.

Sandy Çhale Facies The sandy shale to silty mudstone facies ranges from 20 cm to 2 m in thickness. This facies is generally devoid of physical structures, except for low numbers of convoluted beds. The mudstone beds are typically very dark. Shell fragments (probably of oysters) (Figure 3-54 F), coal fragments and abundant carbonaceous detritus are present throughout. A single carbonaceous shale bed is present in the 10-09-47-02W5 well, and overlies this facies. Bioturbation intensities range from absent to weak. Ichnogenera abundance and diversity are very low. The ichnological suite reflects a Cnczinnn 120 ichnofacies, and includes Plnno lites (r), Teidzidtms (r), Cylindriclzn us (vr), and Oplziornorplzn (vr). 121 Figure 3-50. Litholog of well10-09-47-02VJ5, exhibiting a succession comprising Cycle G of the Belly River Formation. Cycle G consists of an interstratified sandstone, siIty mudstone, and shde facies, that grades upward into a convoluted silty mudstone/ sandstone facies. This is overlain by a hough cross- stratified and current rippled sandstone facies. The succession is capped by a sandy shale facies. Super Test1

GRAIN SI2 E

Sandy Shale facies (Coastal P tain)

(Backshore)

Trough Cross-Stratified and Current Rippled Sandstone Facies (Proximal Delta Front) Cycle G

Convoluted Silty Mudstone/ Sandstone Facies (Distal Delta Front)

lnterstratified Sandstone, Silty Mudstone, and Shale (Proximal Prodelta) 122 Figure 3-51. Litholog of well16-13-43-28W4, exhibithg a succession cornprïsing Cycle G and the basal portion of Cycle H of the BeUy River Formation. Cycle G consists of an interstratified sandstone, silty mudstone, and shale facies. This is overlain by a laminated to bioturbated sandstone facies. The succession is capped by a sandy shale facies. Cycle G is sharply overlain by CycIe H, consisting of an uitershatified sandstone, sdty mudstone, and shale facies. PCP Ferrybank

lnterstratified Sandstone. Silty Mudstone, and Shale Facies Cycle H (Proximal Prodelta)

Sandy Shale Facies MFS (Transgressive Deposits)

Larninated to Bioturbated Sandstone Facies (Proximal Delta Front)

Cycle G

Laminated to Bioturbated Sandstone Facies (Distal Delta Front)

lnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta) 123 Figure 3-52. Facies of Cycle G of the Belly River Formation. (A) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by wavy parallel lamination and oscillation ripples. Syneresis cracks (syn) are located in the shale beds. Trace fossiIs include Anconichnzrs (An)and Planolites (Pl). WeIl06-23-46-02W5, depth 1005.9 m. (B) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by wavy pardel lamination, oscillation ripples, and combined flow ripples. Trace fossils include Anconichnzis (An) and Plrinolites (Pl). Well10-09-47-02W5, depth 1019.3 m. (C) Interstratified sandstone, siity mudstone, and shale facies. Visible physical structures include wavy pardel lamination. This section of the core is dominated by Anconichnzrs (An).Well06-16-46-01 W5, depth 1010.3 m. (D) Convoluted silty mudstone/sandstone. Well06-23-46-02W5, depth 1000.5 m.

124 Figure 3-53. Facies of Cycle G of the Belly River Formation. (A) Trough cross- stratified and current rippled sandstone facies. Physical structures are dominated by aggradational npples and current ripples. Carbonaceous detritus demarcates the stratification. Trace fossils include Skolitlzos (Sk) and fugichnia (fu). Well10- 09-47-02W5, depth 1012.1 m. (B) Trough cross-stratified and current nppled sandstone facies. Physical structures are dominated by current ripples with rarer oscillation ripples. Trace fossils include Skolithos (Sk). Well06-29-46-01W5, depth 956.9 m.

125 Figure 3-54. Facies of Cycle G of the Belly River Formation. (A) LKnInated to bioturbated sandstone facies with structureless sandstone intercalated. Physical structures dominated by low angle planar parallel lamination. Abundant carbonaceous detritus highlights the stratification. Fugichnia (fu) are located at the base. Well07-15-47-02W5, depth 957.3 m. (8) Structureless sandstone located in the laminated to bioturbated sandstone facies. The sandstone contains Ophiomorphn (O). WeIl 08-03-44-28W4, depth 1002.5 m. (C) Laminated to bioturbated sandstone facies. Physical structures are dominated by wavy paralle1 lamination. Trace fossils include Ophiomorplm (O). Well08-14-43-28~4,depth 1026.7 m. (D) Stnictureless sandstone Iocated in the laminated to bioturbated sandstone facies. The sandstone contains Ophiomo@n (O). Well16-13-43-28W4, 989.3 m. (E) Laminated to bioturbated sandstone facies. The sandstone contains Mncnroniclzntrs (M). Well16-0143-28W4, depth 952.9 m. (F) Sandy shale facies. Shell fragments, coal fragments, and carbonaceous detritus are present. Well06- 23-46-02W5, depth 994.2 m.

126 Figure 3-55. Facies of Cycle G of the BeUy River Formation. (A) Laminated to bioturbated sandstone facies. The sandstone bed appears structureless and contains Rosselin (Ro). A portion of the sandy shaft is visible and surrounded by a muddy ball. Well16-13-43-28W4, depth 986.5 m. (B) Laminated to bioturbated sandstone facies. The sandstone appears structureless and contains a mud ball of Rosselia (Ro). Well08-22-43-28W, depth 991 .9 m. (C) Larninated to bioturbated sandstone facies. The sandstone appears stcuctureless and contains the lower shaft of Rosselin (Ro), as the upper part has been truncated. Rip up clasts (Rc) above the erosion surface are likely reworked Rosselia mud balls. Well16-13-43- 28W4, depth 989.1 m. (D) Laminated to bioturbated sandstone facies. The sandstone appears structureless and contains two Rosselin (Ro) shafts. The burrow has been hvncated and terminates at an erosion surface. It appears that the burrow was re-established in the overlying sandstone bed. Well 16-1343- 28W4, depth 989.1 m.

3.45 Cycle H The succession exhibited in Cycle H of the Belly River Formation is characterized by five facies. The basal facies consists of an intersbatified sandstone, silty mudstone, and shale facies. This is overlain by and interfingered with a larninated sandstone facies (Figure 3-56) that grades upward into a convoluted silty mudstone/sandstone facies. This is sharply overlain by a coal and silty shale facies, which grades upward into an interstratified sandstone and mudstone facies (Figure 3-57).

lnterstratified Sandstone, Silty mudstone, and Slzale Facies The interstratified sandstone, silty mudstone, and shale facies consists of beds ranging from 1to 50 cm in thickness, averaging 2 cm thick. These beds are amalgarnated into composite bedsets that range from 1to 6 m in thickness, averaging 3 m thick. Al1 the sedirnents in this facies have a greenish tint to them and a talc-like feel (kaolinite or smectite?).The basal contacts are generally sharp, with the tops of the sandstone beds grading upward into silty mudstone (Figure 3-58). The sandstone beds range from 1cm to 10 cm in thickness, with rare 40 to 50 cm thick beds. A single sandstone bed is 1.5 m thick. The sands are well to moderately well sorted and grain sizes Vary from upper fine to lower medium. The interstratified facies in the cored intervals of the 06-23-47-02W5 and 07-15-47-02W5 wells are largely dorninated by the silty mudstone unit, which contain structureless and convolute beds. In the cored interval of the 06-23-47- 02W5 well, the interstratified sandstone, silty mudstone, and shale facies is interbedded with thick larninated sandstone and convoluted siky mudstone beds for 10 m. The larninated sandstones and convoluted silty mudstones both range from 1- 1.5 m in thickness. The shale beds are typically very dark, carbonaceous, somewhat fissile, and contain sand-filled syneresis cracks. The dominant physical structures include oscillation ripples and wavy parallel lamination, with rare combined flow npples, convolute bedding and micro-faults, as well as very rare climbing ripples and current ripples. The 128 thicker sandstone beds typically contain amalgamated low angle planar parallel

Bioturbation intemities range from absent to moderate. In general, the bioturbation intensities are either absent with some weak intemals, or they range from weak to moderate. Biotubation is associated with the sandstone beds. Ichnogenera abundance is low to moderate and diversity is moderate to high. The ichnological suite reflects a Cnizinnn ichnofacies, including Anconiclinzis (a) (Figure 3-58 A, B, and C), Helmintliopsis (c), Zooplzycos (vr), Cltondrites (r), Terebellinn (r), Plnnolites (a), Teicltichnzis (r) (Figure 3-58 B), Siphoniclznus (vr), Cylindriclt nus (r), Rosselin (vr) (Figure 3-58 C), Tltnlnssinoicies (vr), Skolitlzos (vr) and fugichnia (vr). The trace fossils are generally diminutive, with few robust structures. Plnnolites range from 0.2 to 0.5 cm in diarneter. Teihichnus range from very diminutive (0.2 cm in diameter with few spreiten) to 1.5 cm in diameter and 7 cm in length with abundant spreiten. The tube diarneter of Rosselin averages 0.5 cm, with the preserved bulb exceeding 2.5 cm in diameter.

Laminated Sandstone Facies The laminated sandstone facies consists of beds that range in thickness from 5 cm to 90 cm, averaging 40-50 cm thick. These beds are amalgamated into composite bedsets up to 3 m thick. The sands are moderately sorted and grain sizes Vary from upper fine to upper medium. Wood fragments and mudstone rip-up clasts are rare. The mudstone rip-up clasts comrnonly comprise remnants of burrows, or rounded mudstone fragments 1 -2 cm in diameter. This facies is subdivided into two main components: laminated sandstones (Figure 3-59 A) and sh-uctureless sandstones (Figure 3-59 8). Physical structures in the laminated sandstones are dorninated by wavy parallel lamination and low angle planar parallel lamination, with moderate numbers of current ripples, and rare oscillation ripples, combined flow ripples, and convolute bedding (Figure 3-59 C). Trough cross-stratification is also rare and 129 occurs in beds 15-20 cm thick (Figure 3-59 D). The stmctureless sandstone beds range from 10 cm to 80 cm in thickness, and can reach to 2m in thickness. Carbonaceous detritus and coalified debris occur throughout the facies but Vary in abundance. It may be very abundant locally and highlight physical stnictures (Figure 3-59 A and D), or may be very scarce elsewhere. Spherulitic siderite is also present and characterized by spherical grains with a reddish brown appearance. These grains are concentrated as thin stratification (Figure 3- 59 A and D). Root structures may be present at the top of the sandstone. Bioturbation intensities are mainly absent to weak. Ichnogenera abundance and diversity are very low. Trace fossils include Plmzolites (r), Rosselin (vr), Mncnroniclznzrs (m) (Figure 3-59 B), and fugichnia (r).

Conuoluted Silty Sarzdstone Facies The convoluted siIty sandstone facies occurs in only three cores (06-23-47- 02W5,07-15-47-02W5 and 10-09-47-02W5) and ranges from 1.5 m to 4 m in thickness. Grain sorting is moderate to poor, with sizes that range from silt to upper fine sand. The basa1 portion of the facies consists of a muddy, silty sandstone that grades upward into a sandy to silty mudstone. Coal fragments and carbonaceous detritus are abundant throughout. Physical structures are dorninated by convolute bedding with remnants of wavy parallel lamination and oscillation ripples. The beds grade upward into siltstone and are also highlighted by carbonaceous detritus (Figure 3-59 E). The convoluted silty sandstone facies is mainly devoid of bioturbation, as only two identified trace fossils are present: Plnnolifes and Skolitlzos (Figure 3-59 E). There is also a single unidentified enigrnatic, slightly diagonal, lined stnicture that may perhaps be assigned to Scoyenin. Root structures are also present (Figure 3-59 F) Coal and Silty, Sandy Mudstone Facies The coal and silty, sandy mudstone facies ranges from 1m to 3 m in thickness. The facies comprises 30 cm to 50 cm thick coal beds encased within silty and sandy mudstone. The silty, sandy mudstone has been pedogenically modified and contains slickensides, root structures, abundant coal fragments/laminae, carbonaceous detritus, and rounded siderite-cemented nodules that range from millimeters up to 1cm in diameter (Figure 3-60 A and £3). The mudstone ranges from very silty to sandy. With the exception of roots, this facies is devoid of bioturbation.

In terstratified Sandstone and Mtrdstone Facies The interstratified sandstone and mudstone facies consists of composite bedsets ranging from 2 m to 3m in thickness. The sandstone and mudstone layers are typically millimeters thick and impart a pinstripe appearance (Figure 3-60 C). These sediments have been pedogenically modified. Coal fragments are abundant throughout. The sandstone is locaUy quite silty, but generally the sands are well sorted and grain sizes range from lower fine to upper fine. The silty sandstone beds may reach thicknesses of 60 cm to 1 m. The mudstone is locally sandy, but it is generally dark, carbonaceous, and contains sand-filled syneresis cracks. Physical structures are dominated by convoluted beds and wavy parallel lamination, with rarer oscillation ripples, combined flow ripples, current ripples, and micro-faults. Root stnictures are also present in this facies (Figure 3-60 D). Bioturbation intensities range from absent to low, and bioturbated intervals are sporadicdly distributed. Ichnogenera abundance is low to moderate and diversity is moderate (Figure 3-60 C). The ichnological suite reflects a Crtlzinna ichnofacies with considerable contributions from the Skolifhos ichnofacies. Trace fossils include Zoophycos (VI-),Plnnolites (c), Teichichus (r), CyIindrichn~ls(c) ~znlnssinoides(vr), Arenicolites (r), Skolitlzos (c),Diplocraterion (vr), and higichnia (r). Some enigmatic (unidentified) Scoyenin traces are also present, 131 and consist of a meniscate, back-filled tube (Figure 3-60 D). Some tubes are filled with sand, and they are randomly oriented. 132 Figure 3-56. Litholog of weU 08-19-45-01W5, exhibiting a succession comprising part of Cycle H of the Belly River Formation. The basal portion of Cycle H consists of an interstraiified sandstone, silty mirdstone, and shale facies. This is overlain by a laminated sandstone facies. PCP Westrose 08-19-45-01 WS GRAIN SlZE II i

001

OOf

OOE

Cycle H Laminated Sandstone Facies (Delta Front)

OlC

012

11 4

Interstratified Sandstone, Silty 116 Mudstone, and Shale Facies (Proximal Prodelta) 133 Figure 3-57. Litholog of well07-15-47-02W5, exhibiting a succession comprising the upper part of Cycle G, overlain by Cycle H of the Belly River Formation. The basal portion of Cycle H consists of an interstratified sandstone, silty mudstone, and shale facies. This is overlain by a laminated sandstone facies that grades upward into a convoluted silty mudstone/sandstone facies. This is sharply overlain by a coal and silty shale, which grades upward into an interstratified sandstone and mudstone facies. Super Test C.P.0.G- Pem

lnterstratified Sandstone and Mudstone Facies (Delta Plain)

Coal and Silty Shale Facies (Delta Plain)

Convoluted Silty Mudstone/ Sandstone Facies (Delta Plain)

Laminated Sandstone Facies (Proximal Delta Front)

Cycle H

Laminated Sandstone Facies (Distal Delta Front)

tnterstratified Sandstone, Silty Mudstone, and Shale Facies (Proximal Prodelta)

Laminated to Bioturbated Cycle G Sandstone Facies (Delta Front) 2 34 Figure 3-58. Facies of Cycle H of the Belly River Formation. (A) Interstratified sandstone, silty mudstone, and shale facies. Physical structures are dominated by wavy parallel lamination. Trace fossils include Anconiclinzrs (An), Helrninthopsis (H), Chondntes (Ch),and PlnnoIites (Pl). Well06-29-46-01W5, depth 950.5 m. (B) Interseatified sandstone, silty muds tone, and shale facies. Physical stnictures are difficult to discern. Trace fossils include Teicliichnus (Te) andAnconichnzrs (An). WeU 06-16-46-01W5, depth 993.1 m. (C) Intersh-atified sandstone, silty mudstone, and shale facies. Physical structures are domuiated by wavy parde1 lamination. Trace fossils include Anconiclznrrs (An), Chondrites (Ch),Terebzllinn (Tb),and Rosselia (Ro). Well08-03-44-28W4, depth 994.2 m.

135 Figure 3-59. Facies of Cycle H of the Belly River Formation. (A) Low angle planar pardel laminated sandstone bed located in the laminated sandstone facies. The stratification is demarcated by carbonaceous detritus (dark) and spherulitic siderite (orange). Well06-23-47-02W5, depth 939.6 m. (B) Apparently stnictureless (massive) sandstone bed, located in the laminated sandstone facies. The sandstone contains M~cmoniclznzrs(M). Well06-30-46-01 W5, depth 965 -4 m. (C) Convoluted sandstone bed, Located in the laminated sandstone facies. Well 06-23-47-02W5, depth 953.8 m. (D) Trough cross-stratified sandstone bed, located in the laminated sandstone facies. Carbonaceous detritus (dark) and sphemlitic siderite (orange) dernarcates the stratification. Weil 14-32-45-01 W5, depth 946.5 m. (E) Laminated sandstone facies containing current ripples that grade upward into siltstone with wavy parallel lamination. Carbonaceous dehitus demarcates the stratification. Trace fossils include Skolitlzos (Sk) and fugicnia (fu). Well lO-09-47-OîW5, depth 1002.8 m. (F) Lamina ted sandstone facies. Carbonaceous detritus is abundant throughout. Root structures (root) and Plnnolites (Pl) are present Well06-23-46-02W5, depth 979.2 m.

136 Figure 3-60. Facies of Cycle H of the Belly River Formation. (A) Convoluted silty mudstone/sandstone facies. Carbonaceous dehitus and coal fragments are abundant throughout. WeU 06-23-46-02W5, depth 939.9 m. (B) Convoluted silty mudstone/sandstone facies that has been pedogenically modified. The palaeosol contains root structures, abundant coal fragments, carbonaceous detritus, and rounded siderite-cemented nodules. Well10-28-48-01W5, depth 783.3 m. (C) Interstratified sandstone and mudstone. Physicd structures include oscillation ripples, wavy parallel lamination, and rarer combined flow ripples. Trace fossils include Plnnolites (Pl), Cylindn'drnus (Cy),Skolititos (Sk),and fugichnia (fu). Well 06-23-46-02W8, depth 975.8 m. (D) Interstratified sandstone and mudstone. The sandstone contains Arenicolites (Ar) and some meniscate, backfilled burrows tentatively identified as Scoyenin (Çc). Root structures (root) are also present. Well 06-23-46-02W5, dep th 975.0 m.

CHAPTER 4 FACIES ASSOCIATIONS AND IbTTERPRETATION OF DEPOSITIONAL ENVIRONMENTS 4.1 Introduction The following chapter compiles the facies from the allomembers or cvcles described in chapter three. The individual facies are grouped into facies associations and the depositional environment is interpreted. For each facies association, the typical sedimentary structures, accessories, and ichnological characteristics are sumrnarized for each facies in a chart. Abbreviations are explained in Appendix E.

4.2 DUNVEGAN FORMATION, ALLOMEMBER D 4.2 1 Facies Association and Typical Features

- Sedimentary Accessories Structures Characteristics *oscillation ripplrs (r) *carbonaceous detritus (a) wery low intensity of *wavy parallel larninae (r) asiderite-crmrnted beds (r) bioturbation ecombined flow ripples (r) p>.rite nodules (vr) *low diversity *Z (vr). Lo (r). Pl (r). Te (r). Si (vr). Sk (vr) 1 Interstntified Sandstone. *oscilIation ripples (a) *sharp brd contacts but *bioturbation mainly *wavy parallrl laminar (m) spondically dismpted by associated witli sandstone *low angle planar paraIlel bioturbation beds laminae (r) msyneresis cracks (r-m) mintensity of bioturbation is ecombined flow ripples (r- *pelecypod mol& (abs.-r) absent to low m) *carbonaceous detrirus (c) *high divenity: acument ripples (r) asiderite-cemented kds Z (r-c). H (r-c). An (r-c). *convolute bedding (r-c) (abs.-a) Lo (abs.-vr). Tb (r-c), Ch *!oad c=ts (abs.) ashell fragments (r) (r). Pl (c-a). Te (r-a). Rh *micro-faults (abs.-m) emudstone rip-up clam (r) (void-r). Si (vr-r), Ro (vr- *lutter casts (abs.-m) *pyrite nodules (abs.4 r). AS (r). Cy (vr-r). Pa (r), Sk (r). M labs.-r). fu (vr-c) amainly destroyed by *carbonaceous detritus (c) *bioturbation intensity is Mudstone-Muddy bioturbation *syneresis cracks (r) high Sandstone Facies *remnant structures: asiderite-ccrnented beds (r) *trace fossil diversity high: oscillation ripples and Z (r-a). An (r-m), H (r-c). tvavy parallel lamination Ch (r), Tb (r-m). Pl (m). Te (m-c), Rh (r), Si (r-rn), As (r-m). Cy (r-a), Pa (vr), Th (vr). Ar (vr), D (m). Sk (r). O (vr). fu Cvr) Laminateci to Bioturbated .wavy parallel larninac (a) .carbonaceous detritus (c) mburrowing spondic and Facies - D2. D3 only .low angle planar paraIIel esiderite-cerneritrd beds (r) mainly located near thc lamination (c) .-.nemis cracks (r) tops of laminated .oscillation ripples (r) wnudstone rip-up clasts (r- sandstone bcds and in otrough cross-stratitïcation rn) sorne resernble muddy sandstone beds. -Facies generally overlies (r) remnants of burrows such obioturbation intensities bioturbated sandy ocornbined flow ripples (r) as Pa Ro. As. range from rnodente to rnudsone-muddy wurtent ripples (r) abundant sandstone f~cies,and is .convolute bedding (r) .trace fossil diversity is overlain by the Iaïïinated high: Lo (r). Te (r-rn). Rh sandstone facies: However. omudstone beds (r-a) (vr). Cy (a). Ro (r). As (vr). it can also be fond Th (r). Pa (r). Ar (vr), D intermittently within the (vr-c). Sk (r). M (r-m), Co laminated sandstone facies (vr). fu (r-a). cnigmztic (r) And typicaily in the mudstone kds: He (r), PI (r-m), Ch (vr), Zo (r). Tb (vr). Si (vr-r)

Larninated Sandstonr *low angle plana paraIlel *carbonaceous detritus (c) obioturbation intensitics Facies - D2. D3 only lamination (a) (demarcates lamination) range from absent to very .Iow angle wavy parallel wnudstone rip-up clasts (r) low .amalgmatcd HCS brds. lamination (a) (Iocated at the bases of .burrowing is very with littlc or no bioturbated *oscillation ripples (r) individual sandstone beds) spondic and diversity is horizons. .current ripples (r-a) *shell fragments (vr) very low .convolute bedding (r) opelecypod and gastropod .Te (r), Sk (vr). enigmatic .suuctureless beds (r) shell rnolds (r) (r-m), fu (r). Lo (vr) otrough cross-stratification oroot structures may br: (abs.-a) located at the top of this facies in shingle D2.

Laminatcd Sandstonc .low angle planas paillei .carbonaceous detritus (c) .bioturbatiori intensity vcq Facies - D 1 lamination (a) (demarcates lamination) low and sporadic .oscillation ripples (r) osiderite cemented-beds (a) .diversi& moderate: erosionally overlies DZ ocurrent ripples (a) *coai Iaminae and wood Te (r), Cy (r), Th (vr). Pa wough cross-stntitïcation fragments (r) (r). Sk (r). O (r). enigmatic (0 mmudstone beds (c) (ml, fu (0 ocombined flow ripplrs (r) myneresis cncks (r-c) .Pl (r-rn) found within the .structurelrss beds (r) rmudstone rip-up clasts (r- mudstone beds. .convolute bedding (vr)

Coal Facies - D1 only Interstratitied Sandstone ~oscilhtionripples (a) mbed contacts are generdly oburrowing sporadic and and Shde - D2 only owal paraIlel larninae (a) sharp but disrupted by mainly associated with the ocombined flow ripples (r) spondic burrowing sandst onc beds .carbonaceous detritus (c) obioturbation intensities osiderite-cementrd beds (r) range frorn Iow to .syneresis cncks (r) moderate ornoderate to high diversity: An (r-rn), Z (r), H (r), Ch (r), Pl (m-a), Te (ml,Cy (r), Ro (m-a), Ar (r), Sk (CL fu (r) 139 4.22 Introduction Allomember D consists of shingles D3, D2, and Dl in ascending order. The facies successions of each shingle have been grouped into a single facies association. A facies association is defined as "groups of facies geneticdly related to one another and which have some environmental signihcance" (Collinson, 1969). The facies association of Allomember D is characterized by eight different facies. The basal facies consists of the shale facies, which is overlain either by the interstratified sandstone, silty mudstone, and shale facies or by the bioturbated sandy mudstone to muddy sandstone facies. These facies are overiain by the laminated to bioturbated sandstone facies that typically grades upward into, or is substituted by the laminated sandstone facies. This may be capped by either the coal facies or the interstratified sandstone and shale facies. Any one of these facies may be erosionally truncated and directly overlain by the laminated sandstone facies of Dl. The laminated sandstone facies is overlain by the interstratified sandstone, silty mudstone, and shale facies, that grades upwards into the bioturbated sandy mudstone to muddy sandstone facies. Each shingle is slightly different with respect to the number and order of the facies found. The sedirnents of shingle D3 were the earliest deposited within Allomernber D and are believed to represent the most distal depositional position relative to the major distributary channels. The interstratified sandstone and shale facies and the coal facies that cap the facies association are not preserved in D3, as they are generally truncated by succeeding shingles. Shingle Dî is characterized by the most complete record of facies. Shingle Dl contains three of the facies but they were deposited in an order opposite to those of D3 and D2. The interstratified sandstone, silty mudstone, and shale facies overlies the laminated sandstone facies. This grades upward into the bioturbated sandy mudstone to muddy sandstone facies. The interstratified sandstone, silty mudstone and shale and the bioturbated sandy mudstone to muddy sandstone facies are compositionally the sarne as those found in D2 and Dl but are interpreted to have been deposited during a transgressive phase. Dl deposits are Înterpreted to reflect the most proximal in position relative to the major distributary channels, and Iocdy contain a channel fil1 succession (cb, Bhattacharya, 1991).

4.23 Interpretation Shale Facies - Distnl Prodeltn The presence of thin, rare sandstone beds and layers with wavy parallei lamination, oscillation ripples, and combined flow ripples, intercalated in relatively fissile, carbonaceous shale, provides evidence of intermittent periods of higher energy activity during overall quiet water deposition. These stnictures indicate occasional periods of weak wave and rarer current activity. The emplacement of these sandstone structures occurred during infrequent but very high-energy river flooding and/or storm events. Interstitial silt is interpreted to have been deposited from suspension, reflecting fluctuations in river sediment volumes carried in buoyant plumes due to flooding events (Reading and Collinson, 1996). The trace fossil suite reflects a low diversity and low abundance distal Cnlzinnn ichnofacies. The Iaminae and beds are generally unburrowed, and ichnogenera are diminutive. The assemblage consists mainly of deposit-feeding structures (e.g., Plmiolites and Teicliiclinzrs) with rare grazing/foraging or deep deposit-feeding structures (Zoopliycos), and very rare suspension-feeding structures (Skolithos), as well as Siplionicltnzls. It also contains rare resting traces of bivalves (Lockein). The suspension-feeding structures and more abundani deposit-feeding structures may reflect behaviour of organisms that were swept basinward during storrns and survived to burrow the tempestite. Altematively, larvae of sand-loving organisms may have settled on the storm sands and sumived to burrow them. However, these vertical dwelling structures do not persist in the facies, demonstrating that they are unsuited to the ambient (fairweather) conditions of the setting (Pemberton et al., 1992; Pemberton and MacEachem, 1997). In tlus regard, they are analogous to the so-called deep sea "doomed pioneers" of Follmi and Grimm (1990). These organisms are swept basinward with flood/storm deposits and begin Living in lower energy environments. The traces are interpreted to be diminutive in size because the population is mainly made up of juveniles, owing to high mortality rates (Pemberton and MacEachern, 1997). The high mortality rate was probably caused by such environmental skesses as reduced oxygen levels, diminished food supply, and fluctuations in salinity and temperature. Since these organisms are mainly restricted to the event strata and are sharply overlain by non- biohirbated dark, fissile shale, it is suggested that conditions are close to anoxic. The dark shales may be the result of a high organic content. As the organic detritus degrades (oxidizes), it lowers the oxygen levels near the bed, resulting in a less hospitable environrnent. This leads to the suggestion that the burrowing infauna were imported by the depositional event (Pemberton and MacEachern, 1997), because when ambient conditions returned, burrowing apparently decreased. Zoopliycos is problematic. It is regarded as a grazing/foraging structure, deposit-Çeeding structure (Kotake, 1989; 1994), a deep deposit-feeding structure (Ekdale and Lewis, 1991; Ekdale, 1992) or a gardening/deposit-feeding structure (Bromley, 1991). Kotake (1994) states that the population of Zooplycos is generally low. Therefore, it is difficult to determine whether environmental stresses played a role in the decreased population or not. Generally, the overall reduced diversity and abundance is likely due to (1) oxidation of interstitial organic detritus lowering oxygen levels, and (2) very high sedimentation rates of mud and sik The burrows present in the sand layers may represent a brief refreshing of the water colurnn and increased oxygen levels. These factors suggest a relatively low energy, periodically anoxic or dyaerobic environment of a distal prodelta setting, which is situated just above storrrt weather wave-base (distal offshore equivalent). 142 Enterstratifiecl Sandstone, Silty Mudstone, and Slrale Facies - Proximal Prodelta/ Distal Delta Front Transition The interstratified sandstone, silty mudstone, and shale facies is found in al1 deltaic shingles. The three components of this facies suggest that there are three different energy regimes operating in the setting. The sharp based sandstone beds with abundant oscillation ripples, wavy pardel lamination (HG),combined flow ripples, and rare low angle planar parallel lunination provide evidence of higher energy activity, reflecting a storm-generated origin dorninated by wave action. Currents were minimal in this setting, indicated by the paucity of curent-generated structures. Rare beds of current ripple laminated sandstone may reflect flooding discharge from distributary charuiels. The flooding and stom events are interpreted to occur simultaneously, as high- precipitation is generally associated with storm events, and induces flooding of the distributary channels. The tops of the sandstone beds are sporadically disrupted by bioturbation. Relatively rare convolute bedding or soft sedirnent deformation provides some evidence of rapid deposition. Rare micro-faults, load casts, and gutter casts are also evident and represent loading, increased pore pressures, and subsequent disruptive dewatering &ter burial. The persistent reworking of sediment by wave processes which created the laminated beds mentioned above, results in the re-ordering, improved sorting, and concomitant tighter packing of the sediment grains (e.g.,Coleman and Prior, 1982). The wave reworking helps to minimize variability in the substrate consistency, and lirnits development of deformational structures. The silty mudstone and highly carbonaceous shale layers reflect deposition from suspension and, like the underlying shale facies, likely arose due to fluctuations in river discharge (Reading and Collinson, 1996). These fine grained beds represent fairweather deposition. The beds contain rare to moderate numbers of syneresis cracks that are pytgmatically folded and sand filled. They are likely a response to the shrinkage of clay minerals and may be caused by salinity fluctuations associated with the introduction of freshwater 143 into the delta front and prodelta environmentç (ch, Burst, 1965; Plumrner and Gostin, 1981). The fresh water is thought to be introduced with the influx of sedirnent from dishibutary channels due to flooding and/or precipitation accompanying stom events. This implies that the sediment laden water flows down the delta front and stays near the bed in the prodelta and delta front. This may be a result from density underfiows generated at the river mouth during times of high discharge (Wright et nl., 1988). The siderite-cemented beds likely formed from incipient diagenesis, catalysed by the in sih breakdown of organic material (Berner, 1980). The carbonaceous shale interbeds reflect the rapid introduction of abundant terrestrial plant debris. This organic material, deposited with the mud, oxidizes and consumes the oxygen near the sediment-water interface. If in high enough concentrations, it eventually exhausts al1 the available oxygen near the bed and induces local development of anoxic or dysaerobic conditions. These conditions largely preclude biogenic reworking of the shales. This mode1 was also proposed for organic-rich mudstone interbeds within the Bow Island wave/storm-dorninated delta front successions (FM) of south-central Alberta (Raychaudhuri and Pemberton, 1992; Raychaudhuri, 1994). MacEachern (1994) and Saunders et al. (1994) also assigned this origin for similar beds intercalated with tempestites of the Cadotte Member in west-central Alberta. Sirnilar mudstones associated with the Colorado River Delta are aIso rich in oxidized plant debris (Leithold, 1989). Pratt (1994) worked on the Upper Cretaceous Hartland Shale and overlying Bridge Creek Limestone Members of the Greenhorn Formation. She inferred that the amount and composition of organic matter preserved in the sediment can be determined largely by the concentrations of oxygen in the bottom water and the extent to which the sedirnent was disrupted by burrowing organisms. Pratt (1994) concluded that the close association between abundance of current-induced sedimentary structures, extent of bioturbation, and amount of organic matter suggests that the sbength and frequency of benthic currents 144 determined the rate at which oxygen was supplied to the bottom water. This largely controlled the concentration of oxygen in the benthic environment. The carbonaceous mudstone beds of interstratified sandstone, silty mudstone, and shale facies are interpreted to reflect " phytodetrital pulses" likely related to short-lived, increased river discharge during periods of high precipitation that typically accompany storm events (Leithold, 1989; Raychaudhuri and Pemberton, 1992; MacEachern, 1994). The increase of discharge maybe accompanied by density underflows, allowing for salinity fluctuations. Some beds are characterized by sandstone passing into silty mudstone, which grades into shale reflecting waning energy conditions. These "pulses" originate from either the settling of material carried out in suspension as a buoyant plume, or from density underflows generated at the river mouth during times of high discharge (Wright et al., 1988). These are more common in river-dominated settings, as it is believed that the majority of the sedirnents are subsequently reworked by wave action before they can be deposited in this way. Buoyant plumes in wave-dorninated settings are suppressed due to the wave- action at the river mouth. "Breaking of the wave" enhances the mixing and momentum exchange between the effluent and ambient waters, causing very rapid deceleration and loss of sedirnent transporting ability within short distances from the distributary outlet (Wright, 1977). The ichnological suite represents the Cnlzinn~ichnofacies, due to the predominance of deposit-feeding structures. The diversity of ichnogenera is high though the intensity of bioturbation is low, which reflects a somewhat "stressed" suite. The bioturbation disrupts contacts between beds, creating a biogenically graded or mottled appearance but not to the extent of destroying the discretely bedded character of the three components of the facies. The majorify of the bioturbation is associated with the tops of the sandstone beds suggesting that some of the organisms were imported by the depositional event and/or are opportunistic (r-selected) (Pemberton and MacEachern, 1997). This is compounded by the occurrence of moderate amounts of Anconichnzcs, which 145 occur in the upper parts of the event beds and are associated with coarser intervals of heterolithic sedirnentation. Several authors consider Anconiclzntrs to also reflect opportunistic behaviour (Goldring et al., 1991; Çaunders et al., 1994). These burrows diminish upward into the shale beds, suggesting that fairweather conditions were unsuitable for colonization. Rare Cnrzinnn ichnofacies elements such as Rosselin and Asterosomn, as well as rare elements of the Skolitlzos ichnofacies (e-g., Cylindnchz ris, Pnlneoplzyais, and Skolitlzos), are intermi ttently distributed in the sandstone beds. Mncnroniciznzis is also found in the sandstone beds. These traces represent early colonizers of the new substrates, a characteristic of r-selected or opportunistic organisms. In general, these traces are diminutive in size suggesting that stresses such as reduced oxygen levels, as well as fluctuations in salinity and temperature might not have facilitated organism growth to adult sizes, although this is more common in salinity stressed situations (Remane and Schlieper, 1971). The most abundant ichnogenera consist of deposit-feeding and grazing/ foraging shuctures. Deposit-feeding structures such as Plcznolifes and Teiclticizrzzts are common to abundant, with the suspension-feeding structure, or carnivore, Zooplzycos and Terebellinn is rare to common. Miller (1995) has argued that "Terebellinn" should now be considered Sc~inzibn~lindncltnzisfieyi.The name " Terebellinn " although currently in question, is used throughout this thesis, pending re-evaluation of the genus. The deposit-feeding structures Cltondrites, Rl~izocornlliz~nz,and Siphoniclintrs are generally rare in occurrence. Ekdale (1992), and Savrda (1992) have argued that C!zondRfes persists in low oxygen settings and the paucity of Clzondntes implies other stresses are operating in the system as well. Grazing shuctures such as Helntinthopsis occur in rare to common numbers. Lockein and fugichnia are rare in numbers. Al1 haces tend to occur in both the event beds and fairweather intervals. They are responsible for destroying the majority of the originally sharp contacts between beds. The persistent reworking of sediment by wave action stabilizes the bed and supplies refreshed marine waters to the sediment water interface, bcilitating 146 unifonn salinity and oxygen Ievels. The lower diversity and abundance refiects fluctuations in energy and therefore subsbate consistency, coupled with the high frequency of stomis and generally high sedimentation rates, reducing substrate colonization times. The dark shale beds are moderately colonized because rather than concenhating the organic detritus, which favors the development of reducing conditions, it is dispersed by wave-action to serve as a food resource for infaunal organisms. When the sedimentological and ichnological data are integrated, the most appropriate depositional environment is the proximal prodelta to distal delta front transition. This setting is interpreted to lie above storm wave base and immediately below fairweather wave base (equivalent to the proximal offshore to lower shoreface transition). This facies is most likely located directly downdip of the distributary mouth, thereby receiving large amounts of rapidly deposited sediment, an abundance of carbonaceous detritus, and mud and silt froin suspension and sediment plumes. This created the intershatified sandstone, silty mudstone and shale layers, which were habitable for only short periods, resulting in reduced diversity and abundance of ichnogenera. Changes in salinity, temperature, and oxygen are less marked by periodic wave-action, and are not regarded as the main cause of low trace fossil diversity and abundance.

Biotzrrbated Sandy MzrdstonefMuddy Sa~zdstoneFacies - ProxinzaI Prodelta tu Distal Delta Front Transition The bioturbated sandy mudstonelmuddy sandstone facies contain few prirnary physical sedimentary structures that have not been deshoyed by bioturbation. Rernnant sh-uctures include oscillation ripples with rarer wavy parallel lamination and combined fiow ripples. The wavy parallel larninated sandstones are interpreted to reflect hurnmocky cross stratification (HCS) associated with storm deposition (cb,Duke, 1985, Duke et al., 1991; Dott and Bourgeois, 1982). The oscillation ripptes and combined flow ripples probably represent weaker storms, or waning storm energies. Rare syneresis cracks 147 suggest fluctuations in salinity, associated with the introduction of freshwater into open marine environrnents (cf., Burst, 1965; Plumrner and Gostin, 1981). Large arnounts of carbonaceous detntulc reflect an abundant influx of (presumably) terrestrial plant material into the water column, wluch is typical of fluvial discharge (Reading and Collinson, 1996). The ichnofossils represent a Cmzinnn ichnofacies, with grazing/foraging structures such as moderate to rare Anconiclinns and Helrninthopsis. The bulk of the suite consists of deposit-feeding ichnogenera such as abundant Zoopliycos, Plnnolites, Teicliiclznils, Asterosonin, with rarer Clrondrites, Rlzizocornlliurn, ~inlnssinoides,and Oplziornorplin, and rare passive carnivore ichnogenera such as Pnlneoplzyn~s.Suspension-feeding structures include rare numbers of Siplioniclinrrs, Terebellinn, Skolitlios, and Arenicolites, with rare to moderate numbers of Diplocrnterion and rare to comrnon numbers of Cyli~zdriclzntls. Fugichnia are also present though rare, and renect disruptions by organisrns entrained in the flows or buried by beds, as they try to reach the sediment-water interface. The ichnological suite is diverse, and the overall intensity of burrowing is high, with a uniform distribution. The ichnogenera are found in a variety of sizes suggesting that both juvenile and adult-trace makers were present. The suspension-feedingstructures likely represent opportunistic colonization of distal storm beds (Frey and Pemberton, 1981; Pemberton et nl., 1992; Pemberton and MacEachern, 1997). The grazing/ foraging and dwelling/deposit-feeding structures mainly reflect colonization or re- colonization of substrates during fairweather conditions. Asteroçomn and Tlznlnssinoirles reflect periods of slightly higher energy activity during fairweather. They could also represent an overall increase in energy from the proximal prodelta to distal delta front, as they typically are located at the top of the facies. In shingle D2, it is believed that th% facies and the interstratified sandstone, silty mudstone, and shale facies were deposited contemporaneously and may be laterally adjacent variants of the same depositional environment. The 148 difference between the two is due to their position of deposition with respect to major dishibutary channels. The interstratified facies is interpreted to have been deposited in a closer proximity to, or down-dip from major distributary channels and therefore more profoundly affected by river influences. The bioturbated sandy mudstone to muddy sandstone facies is interpreted to have been deposited in positions removed from the effects of the major distributary channels. These positions would be less affected by river Ilinuences, creating a less stressful environment with respect to sedirnentation rate, substrate variability, salinity, water turbidity, and organic content, and therefore permitting an increased diversity of ichnogenera. It would also increase the overall intensity and uniformity of burrowing, analogous to that of a typical upper offshore environment. This implies slower, more continuous deposition, allowing organisrns sufficient time to bioturbate the sediment. Additionally, the bioturbated sandy mudstone to muddy sandstone facies is generally overlain by the laminated to bioturbated facies. This shows a shallowing of conditions and concomitant increase in the intensity and frequency of storm events but no other stresses, permitting intervening facies to be bioturbated (MacEachern and Pemberton, 1992; Pemberton and MacEachern, 1997).The interstratified sandstone, silty mudstone, and shale facies is overlain by the laminated sandstone facies. This also shows a shallowing of conditions and concomitant increase in the intensity and frequency of storm events. The paucity of bioturbation suggests, however, that additional stress must be present. The proposed depositional environrnent for the bioturbated sandy mudstone to muddy sandstone is the proximal prodelta to the distal delta front transition. This setting is located above storm weather wave base, and extends to fairweather wave base. In shingle Dl, the interstratified sandstone, silty mudstone, and shale facies and the bioturbated sandy mudstone facies are identical to those found in D2 and D3. The main difference is that the bioturbated facies overlies the interstratified facies. This is interpreted to reflect a trmgressive event and 149 corresponds to the transgressive backfilling of the distributary channel. Bhattacharya (1989b) concluded that these facies represent an estuarine channel

fiIl. Since these facies are identical :O those seen in shingle D2 and D3, it is suggested that the interstrztified facies represent a distal delta front with stronger influence from the distributary channel. The bioturbated facies represents the sarne setting but with wave action predominant and suppression of fluvial influence as the distributary channel became flooded. Estuarine facies are typified by an ichnofossil assemblage with (1) a generally low to very low diversity of ichnogenera, (2) an impoverished marine assemblage, (3) reduced sizes of ichnogenera compared to marine counterparts, (4) a dominance of morphologically simple, vertical and honzontd stnictures, and (5) a mixture of elements which are cornrnon to both the Skolitlros and Crzrzinnrz ichnofacies (Wightman et ni., 1987; Beynon and Pemberton, 1992; MacEachern and Pemberton, 1994). In contrast, the ichnological suite of the interstratified sandstone, silty mudstone, and shale facies is dominated by Teiclziclin~rsand Plnnolites. The diversity of ichnogenera is moderate, and trace fossil size ranges from diminutive to robust. The majority of the ichnogenera consists of simple horizontal burrows with very rare vertical structures. The ichnocoenose resembles an impoverished marine assemblage, reflecting a low diversity, mixed Skolithos-Cnizinnn ichnofacies, and does not appear to reflect an estuary environment. This suggests that there are stresses such as fluctuations in salinity and reduced oxygenation levels; conditions that are cornmon to brackish environments. Characteristics mentioned above suggest that the interstratified facies represents a setting that is somewhat stressed. The higher diversity of ichnogenera (especially in the bioturbated facies), mixtures of robust and diminutive trace fossils, the dominance of horizontal ichnogenera from the Cnrzimzn ichnofacies, and the lack of a truly monotypic ichnofossil assemblage, however, suggests that this facies does not reflect a strict estuarine setting. It is a stressed environment, but one tempered by wave action and better mixing of 150 fresh water with the saline water, therefore reducing large fluctuations in salinity and oxygenation. As the charme1 was flooded back, the interstratified sandstone, silty mudstone, and shale facies was overlain by a bioturbated sandy mudstone to muddy sandstone facies. Reading and Collinson (1996) suggest that intense bioturbation may reflect abandonment and flooding in a delta front setting. The bioturbated facies is believed to reflect the reduction of the effects of fluvial input into the setting, as the marine waters inundate the channel during the transgression.

Larninated to Biotzrrbated Sandstone Facies - 02, D3 - Distal Delta Front The larninated to bioturbated sandstone facies contains a dominance of wavy parallel laminae and rarer low angle parallel lamination, interpreted to represent humrnocky cross-stratification (Ha)and swaley cross-stratification (Sa). The presence of the sharp-based sandstone beds suggests erosiond emplacement during storms, and that storm-action played a significant role in this depositional setting. Rare oscillation ripples, combined flow ripples, and current ripples capping the HCS beds sigmfy waning storm period energies, as well as wave and current action during fairweather conditions. Rare, intermittent zones of trough cross-shatification throughout provide evidence of some stronger current activity. The presence of convolute bedding suggests some periods of rapid deposition. If the sedirnents were deposited quickly, loading would increase pore pressure and trigger dewatering derburial, resulting in the development of convoiute bedding. This process iç rare in this setting, presumably because persistent wave-action at the bed caused re-ordering, improved sorting, and tighter packing of the grains (cf., Coleman and Prior, 1982), thereby decreasing the pore pressure. stratification is demarcated by carbonaceous detritus, suggesting there was ample organic matter in suspension. The large arnount of plant material in the water column is typical of fluvial input (Reading and Collinson, 1996). Many 151 of the lamuiated sandstone beds are capped by biogenically mottled tops, and interbedded with rare mudstone beds and muddy sandstone intervals. These beds reflect fairweather deposition, allowing sufficient time for muds to settfe from suspension. Rare syneresis cracks are also present withh the mudstone beds, possibly indicating salinity fluctuations associated with the introduction of freshwater into the open marine environment (cf., Burst, 1965; Plurnrner and Gostin, 1981). Burrowing is çporadicdy distributed but bioturbation intensities range from moderate to abundant. This facies contains a well-developed and diverse, mixed Skolitlzos-Cnizznnn ichnofacies that reflects fluctuations in energy levels (Pemberton and Frey, 1984; MacEachem and Pemberton, 1992; Pemberton and MacEachem, 1997). Immediate post-storm conditions provide a favourable setting for substrate colonization by infaunal oppomtnists. Oppoministic organisms employ a r-selected strategy in population dynamics, enabling them to quickly locate and exploit a new habitat such as a storm bed (Pemberton and MacEachem, 1997; MacEachem and Pemberton, 1992). In general, opportunistic species can respond rapidly to an open or unexploited niche. They are characterized by: (1) a lack of equilibrium population size; (2) a density independent mortality; (3) the ability to increase abundance rapidly; (4) a relatively pcor cornpetitive ability; (5) high dispersal ability; and (6)having a high proportion of resources devoted to reproduction (Grassle and Grassle, 1974; Pemberton et nl., 1992).Short generation span is the most important mechanism for increasing population size, thereby shortening lifespans, and allowing sexual maturation to be reached earlier (Rees et al., 1977). Rapidly exploiting new habitats is tenable as they are able to tolerate a broad range of environmental conditions, and cm utilize generalized feeding habits (Pianka, 1970).They are able to Vary their feeding habits depending on the type of food available (Cadee, 1984). This means if suspension-feeding is the most viable strategy, the organism will utilize it. Oppoministic organisms also tend to live in dense clusters (Rhoads et al., 1978). They also tend to settle in an area 152 based on the presence of others rather than the avdability of a preferred substrate mtlatch and Zajac, 1985). They also tend to brood their larvae, resulting in rapid crowding in a given space. This type of colonization cm inhibit competitors from settling. Opportunistic trace makers are represented by ichnogenera such as Diplocrn ferion and Cylindriclznzrs, which are the most common within this facies, with less abundant Skol itlios, Arenicolites, and Pnlneopliyczcs. These ichnogenera comprise elements of the Skolitltos ichnofacies and are generally located in the sandstone beds. Within this facies, higher energy, deposit-feeding organisms of the proximal Cnrzinnn ichnofacies are also common. These ichnofossiIs include rare Rosselin, Asterosornn, and 77zcilnssinoides. Rosselin and Asferosorna can exploit their own deposits rather than relying on encountering them in the substrate, and are excellent indicators of storm-dominated, shallow marine settings, such as lower shoreface and comparable delta front environments (Pemberton et al., 1992; Saunders et al., 19%). As storm conditions wane, and as deposition and energy levels decrease towards those of faimeather, the opportunists are subjected to normal ambient depositional conditions. If the opportunists are unsuited to these conditions, they gradually die off and are replaced by the resident (equilibrium or k-selected) trace fossil suite. These conditions are reflected by a dominance of the Cnizinnn ichnofacies elements including moderate numbers of deposit-feeding structures such as Plnnolites, and Teidlicltntls, and rare Clzondrites, Zoopltycos, and Nzizocomlli~rrn.Suspension-feeders like Siphonidinus, Terebellinn (which may also be a passive carnivore), and Lockein are present though uncomrnon. Rare grazing structures such Hehintltopsis are also present. Fugichnia are highly variable in abundance. The trace fossils are found in a variety of sizes, ranging from diminutive to robust. This suggests that juveniles were capable of living to their adult stage. An example of this is the ichnogenus Zooplzycos, which is robust in one interval and is diminutive in a dark shale elsewhere with a syneresis crack 153 near by. This suggests that there are stresses affecting the organisms but these stresses are only sporadicdy imposed. The mixed Skolitlzoç-Cmzinntr ichnofacies reflects in loco fluctuations in energy rather than changes in relative sea Ievel or variations in distance from the shoreline (Pemberton and Frey, 1984; MacEachern and Pemberton, 1992).The general lack or decreased nurnbers of suspension-feeding ichnogenera and the dominance of deposit-feeding structures in cornparison to stom-dominated shorefaces is interpreted to be attributable to increased water turbidity, water salinity, fluctuating/episodic depositional rates, and reduced oxygen levels (Moslow and Pemberton, 1988; MacEachem and Pemberton, 1992; Saunders et al., 1994; Gingras et nl., 1998). These factors are characteristic of fluvial influx into a marine setting. High water turbidity and increased volume of suspended sedirnent within the water column interferes with the efficiency of the organism's suspension feeding apparatus. Water turbidity does not seem to affect predaceous organisms or most deposit-feeders, and this is reflected by their dominance in the trace fossil assemblage. Fluctuations in salinity affect the entire hace fossil assemblage, which is reflected by a general decrease in numbers and diversity of ichnogenera compared to storrn-dominated shorefaces. It also reduces specialized feeding behaviours and favours trophic generalists (Wightman et al., 1987; Beynon and Pemberton, 1992; Ranger and Pemberton, 1992; MacEachem and Pember ton, l994). The overall paucity of burrowing is believed to be a preservational taphonomic bias associated with high frequency and/or high intensity erosional amalgamation of storm beds, which intermittently removes the record of fairweather community in this facies. Frequent recurrence of storms would result in insufficient tirne for fairweather communities to colonize the substrate. The rare occurrence of burrowed fairweather deposits, however, attests to some extended periods of interstom conditions. Some of the paucity in preseïved fainveather deposits may be attributed to stom intensity and erosional amalgamation of the tempestites. Fairweather deposits may have been 154 erosiondy removed by subsequent storm events. The mudstone rip-up clasts within some of the tempestites may represent the remnants of these fairweather deposits, which they lithologically resemble. Since fairweather muds and the rnixed SkolifJzos-Cmzinnn ichnofacies are present, it is concluded that the deposits indicate a distal delta front setting where overdl energy levels are lower and the fairweather cornmunity had a higher preservational potential. This is located immediately above fainveather wave base (lower shoreface equivalent; MacEachem et al., 1999). This facies is predominant in shingle D2, mainly overlying the bioturbated sandy mudstone to muddy sandstone facies. The laminated to bioturbated facies may also grade upward into the laminated sandstone facies. In shingle D3, the mudstone beds are more abundant and contain a very low abundance and low diversity of ichnogenera of the Cnizinnn suite and the Skolitlios assemblage is scarce with only rare Skolitltos.

Lamil-rated Sandstone Facies - 02, D3 - Distal to Proximal Delta Front to Foreslzore The lower part of the laminated sandstone facies consists of a dominance of wavy parallel lamination and low angle planar lamination, representing HCS and Sa, respectively. As in the underlying facies, these are regarded to reflect the domination of storm activity. These deposits are generally erosionally amalgamated and contain little to no preservation of mud, suggesting a generally shallower, persistently wave agitated environment than the laminated to bioturbated sandstone facies (cf., Aigner and Reineck, 1982; MacEachem et al., 1992; Walker and Plint, 1992; Pemberton and MacEachern, 1997). Rare mudstone rip-up clash located at the base of individual sandstone beds may be digned paxallel to lamination, or are distributed randomly. Rare oscillation ripples represent wave action during the waning stage of the storm, or the return of fairweather conditions. A rare occurrence of current ripples and intermittent trough cross-stratified sandstones suggests the presence 155 of current action, likely originating from closely positioned distributary channels. The abundance of carbonaceous detritus demarcating the stratification also suggests some enhanced fluvial influence (Reading and Collinson, 1996). The presence of very rare convolute bedding suggests rninor sedirnent loading and dewatering. The majority of the sandstone is well sorted, suggesting that persistent wave processes were effective at winnowing the finer grains and shifting them basinward. Structureless sandstones are also distributed sporadically throughout the facies, though rare. The origin of the apparently stmctureless sandstone is problematic, though it is typically associated with sediments that are interpreted as broadly deltaic (cfi, Reading and Collinson, 1996). The structureless sandstone is likely the product of very rapidly deposited sedirnent, without the formation of equilibrium bedforms and therefore, of stratification (Bhattacharya and Walker, 1991). The sandstone could also lose stratification by bioturbation frorn animals or plants. Power (1989) interpreted the cause of the structureless sandstones in the Belly River Formation to bioturbation by a M~cnroniclznzrs generating organism. The structureless sandstones are more abundant in the river-dominated settings of the Dunvegan and the Beily River Formation, than in Allomernber D. More recently, researchers have appealed to the action of meiofauna. These meiofauna live between grains of sediment, disrupt grain arrangement and obscure or obliterate physical structures (cc, Saunders et nl., 1994). Though, this is unlikely do to the large scale structureless sandstone. The lower part of this facies is devoid of burrowing. Due to the high intensity and/or frequency of the storm events, suggested by amalgarnated HCS and SCS beds, it is interpreted that trace-makers had insufficient time to colonize the substrate or, if they did exist, their structures were removed by subsequent storms. This Iower portion of the laminated sandstone facies is interpreted to reflect the distal delta front (lower shoreface equivalent). The lower portion passes upward, but sporadically, into a more unilorm occurrence of trough cross-stratified and current rippled sandstone, though HCS 156 and SCS beds are still quite common. Carbonaceous detritus demarcates the lamination, suggesting a high concentration of organic matter in the water. The sübstrate in this environment tends to be noncohesive, highly mobile, and was probably well oxygenated, and is interpreted to refIect the high-energy surf zone. The dominant physical processes in this setting are wave-forced currents. Storm events are predominantly erosional, and convolute bedding and dewatering structures may occur in response to wave-induced liquefaction (cj, Greenwood and Davidson-Arnott, 1979; Greenwood and Mittler, 1985; Pernberton and MacEachern, 1997). The facies represents a higher energ). setting, and is interpreted to reflected a proximal delta front environment. Root structures can be found at the top of this facies (e.g., 07-10-63-01W6). The sandstones may take on a tan to brown colour, and appear leached. The low angle planar stratified sandstone reflects very high-energy conditions and is interpreted as the foreshore. The proximal delta front and foreshore are dominated by physical structures. Burrowing intensities are sporadic and range from absent to very low. Diversities are very low. The trace fossil suite is represented by a mked Skoliflios- Cnrzinnn ichnofacies. Trace fossils include Teiclriclzniis, some enigrnatic (unidentified) burrows, and fugichnia, with Skolithos cornmonly restricted to the current rippled sandstone. Teiclzidintls are generally located near the tops of the HCS beds, and are very sporadic in occurrence. Again, it is believed that due to the high intensiw and/or hequency of storm bed emplacement, trace-makers did not have ample time to develop burrows or, if they were present, the stnictures were destroyed by subsequent storm action (e.g., Howard and Frey, 1984; MacEachern and Pemberton, 1992; MacEachern, 1997). The absence of bioturbation in the laminated sandstone is also likely the result of episodic deposition during storm events. 157 Laminated Sandstone Facies - Dl - Channel Fil1 The laminated sandstone facies of shingle Dl typically has an erosive base and is found abniptly overlying prodelta to distal delta front deposits of D2. The domination of intermingled low angle planar paralle1 lamination, trough cross- stratification, and current rippled sandstone, with rare oscillation ripples, aggradational ripples, and combined flow ripples suggests channel filling bv a series of waning flows, perhaps associated with flood stages of the nver (Bhattachqa and Walker, 1991). The sandstones also contain abundant mudstone rip-up clasts. These clasts are characterized by: (1) long, thin mudstone fragments with sand interlaminations, which are sirnilar to the underlying prodelta and distal delta front deposits of D2; (2) possible remnants of Asterosornn and/or Rosselin structures; (3) rnillimetre- to centimetre-sized angular to sub-angular clasts; and (4) rounded sideritized nodules. Rare fragments of coal and wood are also found throughout. Mudstone beds are commonly intercalated and typically contain sand- filled syneresis cracks, Plnnolites and rare Teidziclzn~rs.These mudstone beds reflect periods of waning flow after nver flood stages. These less turbulent periods would permit deposition of mud from suspension. The syneresis cracks are likely a response to the shrinkage of clay minerais, which can be caused by salinity fluctuations associated with the introduction of freshwater into saline conditions (cfi, Burst, 1965; Plumrner and Gostin, 1981). The erosively based sandstones overlying prodeltaic deposits, the occurrence of abundant rip-up clasts throughout, and repeated current- generated fining-upward successions created by a series of waning flows are consistent with channel deposition associated with flood stages of a river. The channel deposit has minimal laterd extent, and demonstrates marine influences through the presence of Plnnolites, Teidriclznrrs, remnants of Asterosornn, and Rosselin, and syneresis cracks. These factors are characteristic of distributary channels (Reading and Collinson, 1996). 158 The laminated sandstone represents the infill of the Waskahigan Channel (Bhattacharya, 1989). It reaches up to 13 m in thickness (Figure 3-12). In the northwest, shingle Dl lies erosionally upon D2, and is interpreted to represent a regressive surface of erosion (Bhattacharya, 1989). D2 erosiondy overlies D3, and al1 three become conformable toward the basin. Dl was created due to an allocyclic seaward shift in the position of shoreline, which was accompanied by channelling in the Waskahigan area. The laminated sandstone of the charme1 fil1 was overlain by interstratified sandstone, silty mudstone, and shale facies which grades upward into the bioturbated sandy mudstone to muddy sandstone facies. Shingle Dl was terminated due to a transgression, resulting in an overall fining- upward succession.

Interstratified Sandstone and Shale Facies - 02- Transgressive; Distd Delta Front The interstratified sandstone and shale facies is found only in shingle D2, and overlies proximal delta front sandstones. The tcvo components of this facies suggest 2 different energy levels. The sandstone beds contain a dominance of wave-induced structures such as oscillation npples and wavy parallel lamination, with rarer combined flow ripples and convolute bedding. These structures provide evidence of higher energy activity, probably reflecting a storm origin. The shale beds are very dark and carbonaceous, with syneresis cracks. The dark shale also reflects the rapid introduction of abundant terrestrial plant debris. Such organic material, deposited in mud, typically oxidizes, consuming the oxygen near the sediment-water interface. If in high enough concentrations, this eventually uses up al1 the available oxygen and causes anoxic or dysaerobic conditions to occur locally. Such conditions largely preclude biogenic reworking of the shales. Within the facies, burrowing is sporadic, and mainly associated with the sandstone beds, though the diversity of ichnogenera is moderate to high. This is accompanied by a generally low to moderate intensity of burrowing, and 159 constitutes a "stressed"mixed Skolitllos-Cnrzinnn ichnofacies reflecting fluctuations in energy (Pemberton and Frey, 1984; MacEachern and Pemberton, 1992). The traces are generally diminutive in size, suggesting that mainly juveniles were present, and this may indicate that stresses such as fluctuations in salinity or oxygen were present that inhibited growth or resulted in high mortdity rates. Not al1 the traces mentioned below are found in a single core. The dominant ichnogenera include Plnrrolites, Skolitlzos, Rosselin, and Teichiclzniis. Skolithos, dong with rare Cylindrïclzniis, Arenicolifes, Pnlneoplzyars, and Anconichnzrs are found within the sandstone beds. These traces represent early colonizers of new substrates, a characteristic of r-selected or opportunistic behaviour of the trace-makers. Many of these traces are elements of the Skolifllos ichnofacies. Plnnolites and Teicliiclznirs are trophic generalists, and constitute both post-storm opportunists and fairweather elements of the Cnizinnn ichnofacies. The dominance of kophic generalists may indicate a fluctuation in salinity (e-g., Beynon and Pemberton, 1992; Ranger and Pemberton, 1992; MacEachern and Pemberton, 1994). Rosselin is an example of an ichnogenus that appears to favour higher energy conditions in the CniMnn ichnofacies, and is abundant in storm- don~atedsandy environments, such as the lower shoreface or delta front (Pemberton et al., 1992). The fairweather suite includes rare numbers of Zoophycos, Helrnintlzopsis, and ChonWtes. These traces are indicative of marine settings, though Cltondrites is considered to be well-adapted to low oxygen setkgs, particularly in offshore and shelf environments (Bromley and Ekdale, 1984; Savrda, 1992). It is mainly the occurrence of the fairweather deposits and their positions overlying the proximal delta front sandstones that suggesh that this facies represents a period of flooding/abandonment of the delta lobe, or a transgressive event. This "transgressive"deposit may be autocyclically induced, such as by distributary channel avulsion. The cessation of active sediment supply, coupled with continued basin subsidence, would have caused relative 160 deepening and the transition of proximal delta front deposits passing into a distal delta front to proximal prodelta setting. The presence of syneresis cracks, dark shales, convolute bedding, and mixed "stressed" Skoliflzos-Cruzinn~z ichnofacies suggest that there were still some fluvial influences on the overail setting, favouring the interpretation of lobe abandonment and autocyclic flooding rather than allocyclic transgression.

Coal Facies - Nonmarine The cod facies is found in only one core (ie. 07-10-63-01W6) overlying a rooted horizon located at the top of the lamuiated sandstone facies (foreshore) of slungle D2. The coal is very dull in appearance and presurnably contains abundant interstitial clastic material. It is interpreted to represent a largely nonmarine to marginal marine environment, such as a swarnp on the lower delta plain. 4.3 DUNVEGAN FORMATION, ALLOMEMBER E 4.31 Facies Associations and Typical Features Sedimentary Accessories Ichnological Structures Characteristics orare sandstone and ocxbonaceous detritus (r- .rna.înly dcvoid of siltstone beds c ) bioturbation. ~5% -EL €3 ooscil1a:ion npplss (r) osidcrite-cementcd beds (r) .H (vr), Pl (vr), fu (vr) -El (top ofsuccrssion) ocornbined flow ripplcs (r) *traces are diminutive ocumnt ripplcs (vr) OE1: An (vr), Pl (vr), Zo ewavy parallel lamination (vr). Cy (vr): not al1 at once (vr) and found at the base of the facies ocontacts cm be sharp or ove- dark shale obioturbation mainly Silty Mudstone. and Shale grade upward into sil- osyneresis cracks (c-a) located around sst. beds; rnudstone ocarbonaceous de tritus (c) spondically distributcd wavy parallei lamination omudnone rip-up clasts (r) ointensi- is variable; (a) .the silty rnudstone has a absent low in Eî and E 1 : ocornbined tlow ripples (a) massive. stmctureless goes to modente in €3. ocurrent ripples (r-c) appemce adiversity is high BUT not oconvolute bedding (m-c) al1 the ichnogenen are .micro-faults (r) never found in a single olow angle planar parallel core lamination (r) -typically find PI and Te: with few others in one core *oscillation ripplcs (r-c) H oaggradational ripples (r) OZ(vr-r), (vr-m). An (m), Tb (vr), Ch (vr), Lo (vr). Pl (rn-a), Te (m-a), Si (vr), AS (vr-r), Ro (vr). Th (vr). Cy (r-rn), Pa (vr), Ar (vr), Sk (vr-rj, O (vr). fu (cl .traces are genenlly diminutive .In €2; only about 5-1044 ofthe intend in biogenically dismpted .In E3; diversity of ichnogencra in a single core is quite high cornpared to El and E2. .massive and apparrntly ocarbonaceous detritus (c) otypically devoid of -in €2: instead of structureless osidcrite-crmented beds (c) bioturbation interstratified facies osandstone (c) throughout -in E 1: top of succession and demarcates convolute bedding &.id loading structures Convoluted Silty .convolute bedding (a): .carbonaceous detritus (c- otypically devoid of Sandstone Facies oversteepened beds. a) bioturbation -EL El Ioading structures. massive osiderite-cemented beds (r- .He (vr). An (vr): tbund in apparently structureless m) a single core in a mud bed beds ocoal fragments (r) -Te (vr); diminutive Owavy parallel lamination mrnudstonr np-up clasts (rj (vr) mrnicro-faults acombined flow ripples (vrj .oscilIation npples (vr)

Laminated to Structureless .structureIrss beds (c) mcarbonaceous detritus (c) omainly devoid of Facies otrough cross-strat. (r-m) (demarcates lamination) bioturbation; to find dl olaminated sst (c) :wavy omudstone beds (r-m) ichnogenera, many cores -EL E 1 paralle1 lamination (r-c). asiderite-cemented beds (r) would have to be looked rit -this facies may also be low angle planar parallel mmudstone np-up clasts (r) *Pl (vr). Te (vr) associated interbedded wirh the lamination (c). oscillation osynrresis cracks (vr) with the mudstone beds convoluted silty sandstone ripples (r-m), planar (E2) facies sporadically Iarnination(r-m), current aroot traces (vr) found at .Te (vr). Cy (vr). fu (vr). ORfAND, and in smdI ripples (r-m), combined the top of the facies in only enigmatic; very sporadic thickness, the interstratified flow ripples (vr) one core nature; and located in the facies. These 3 components are Iaminated sandstone typically interbeddrd tvith one another -the trough cross-strat. are generally found toward the top of the facies Larninated to Bioturbated wavy parallei lamination ocarbonaceous detritus (m) obioturbation intensity Sandstone Facies (cl osiderite-cemented beds (r) ranges from moderate to -E3. E2 .oscillation ripples (c) oshell fragments (r) common ocombined flow rippIes (r- omudstone beds jr-m) oichnogenera are locally c) msyneresis cracks (r) common ocurrent ripples (r-m) odiversity is high but to olow angle planar pmllel osphemlitic siderite only find al1 ichnogenera, many lamination (r-m) found in one core in E3 cores need to bc: studied wonvolute bedding (r-m) .He (m-c). Z (r-c), An (r- .structureless beds (c)-E3 m), Ch (vr), Tb (r), Pl (m- c), Te (rn-c), Si (vr-m), Rh (vr), CY (m), As (r-m ), Ro (vr), Th (vr), Pa (vr-r), Ar (vr), D (vr-r), Sk (vr)?O (vr-r). M (r). fu (vr-r) Interbedded Sandstone and ~wavyparallel lamination mvery sharp bed contacts: mintensity weak to absent Mudstone Facies (d with a totd lack of silt mdiversity is high: but -E3 .oscillation rippks (c) .carbonaceous detritus (m) rnany cores need to bc olow angle planar parallel wery dark mudstone bcds studied to find ail lamination (r-m) osyneresis cracks (c-a) ichnogenen. ocombined flow ripples (r- *pyrïie nodules (r) *In mudstone: Z (vr). H m) mshell fragments (r) (vr), Ch (vr), Tb (vr), Pl (r- Ocurrent ripples (vr) a), Te (r-a), Si (vr). Rh (vr) .In sandstone: Io (vr), Te (r-a), As (vr-m). Cy (r), Th (vr-r). Pa (vr), Sk (vr-m), O (vr), M (vr). fu (r-m)

Channel Fill owavy panilel lamination warbonaceous detritus (a) obioturbation intensiq very -E 1 (a) osiderite-cernented beds (a) lodabsent mtrough cross-stnt. (r-a) .mudstone beds Cr-c) ove- low diversity oabruptly overlyin_e ocurrent ripples (r-a) woa1 fmgments (r-a) min mudstones: Pl (r-m) prodelta shales and mcombined flow ripples (r) wip-up clasts (r-a) osporadic in sst-; Te (vr), interstratified facies *aggmdational ripples (r) *shelI fragments (r-a) As (vr). Pa (vr). O (vr) mplanar lamination (r) ~structureless(m) espherulitic siderite (vr): only in one core (along .In 07-06 no structures can stratification) be identified; only stnicturcless sandstone because full of rip-up clasts. shell fragments and coaI fraynents. 164 4.32 Introduction Allomember E consists of shingle E4, E3, E2, and El in ascending order (E4 is uncornmon in the study area and will not be discussed further). The facies succession of each shglehas been grouped into a facies association. The facies association of Allomember E is characterized by seven different facies. The basal facies consists of shale, which is overlain by the interstratified sandstone, silty mudstone, and shale facies or a silty mudstone facies (only in E2). This typically grades upward into the convoluted silty sandstone facies, that is intercalated with or overlain by the laminated to structureless facies. Shingle El may be topped by the shale facies (e.g., 13-25-60-22W5). In shingle E2, the laminated to bioturbated sandstone facies typicdy overlies (e.g., 08-12-63-27W5,05-27-61- 01W6, and 06-11-62-03W6) or in a single core (e.g., 06-35-62-27W5) replaces it. The laminated to bioturbated sandstone facies is typically overlain by the shale facies of Allomember D. Shingle El also contains the Iaminated sandstone and mudstone rip-up clast facies. This facies abruptly overlies the interstratified sandstone, silty mudstone, and shale facies of shingles E3 and E2.

4.33 Interpretation Sha le Fncies -DisfnlProdelfa The shale facies is interpreted to refIect distal prodelta deposition, situated above stonn weather wave base but well below fainveather wave base. The presence of thin rare sandstone beds and layers with rare oscillation ripples, combined flow ripples, and very rare wavy parallel lamination, intercalated in relatively fissile, carbonaceous shale provides evidence of intermittent periods of higher energy during overall quiet deposition. The physical sedimentary structures indicate periods of weak wave and current activity. The emplacement of these sandstones is interpreted to have occurred during high-energy river flooding and/or storm events. The relative abundance of current generated structures provides evidence that considerable sedirnent volume may have 165 originated from the distributary channel and carried basinward in buoyant plumes (Reading and Collinson, 1996) or sediment gravity flows. The trace fossil suite reflects a very low diversity and low abundance "distal" Cnlzinna ichnofacies. The facies is generdly devoid of bioturbation. Only one or two traces are found in any one cored interval. Ichnogenera are diminutive in size, and include very rare Zooplzycos, Helrninthopsis, Anconicltnz~s, Plnnolites, Cylindric~znris,and fugichnia. This indicates a shessful and relatively inhospitable environment. The dark, fissile carbonaceous shale is cornmon throughout. The oxidization of the organic material likely produced lower oxygen levels, creating conditions that may have been intermittently dysaerobic. Zooplzycos and HeIminthopsis are associated with the shale beds and are deemed the fainveather assemblage. Frey and Seilacher (1980) associated Zoophycos with lowered oxygen levels related to abundant organic material in quiet water settings. The dysaerobic conditions were sporadically disrupted by periods of oxygenation, suggested by the appearance Plnnolites, Anconiclznus, and Cylindriclzn~lswithin the sandstone beds. Plnnolites is interpreted as the structure of a trophic generalist (e.g., Beynon and Pemberton, 1992). PZnnolites is capable of tolerating and even preferentially inhabiting iow oxygen niches (Ekdale, 1988; Beynon and Pemberton, 1992). Emplacement of the sandstone occurred under higher energy conditions that would likely have brought oxygenated water to the setting. This oxygen was probably soon depleted by oxidation of organics and respiration of macrobenthos. Anconiclinus and Cylind~cli~zusreflect opportunistic behaviours (Goldring et n1.,1991; Saunders et al., 1994). These burrows diminish in abundance upward into the shale beds, suggesting that fairweather conditions were unsuitable for infaunal colonization and epifaunal foraging. The main food supply may also have been brought in by the flood/storm events, but soon after the event, this food supply may have diminished or become greatl y reduced, directly affecting the fairweather community. 166 Interstratz$Yeed Sadsfane, Si29 Mzm?sfane, and Shale Facies - ProxidProdelfa to Dis ta2 Delta Front Transition The interstratified sandstone, silty mudstone, and shale facies is found in al1 deltaic shingles and is interpreted to reflect the transition from the proximal prodelta to the distal delta front. This is situated above storm wave base and below fairweather wave base. The three components of this facies suggest that three different energy regirnes operated in the setting. The sharp based sandstone beds display abundant wavy paralle1 lamination, combined flow ripples, rare to comrnon current rippIes and oscillation ripples, with rare aggradational ripples and low angle planar paraIlel lamination. This refiects a variety of wave and current processes operating in the setting. The abundance of preserved current-generated structures suggests that generous amounts of sediment may have originated from the distributary channels during river flood events/storrn events. Many beds are characterized by current-rippled sandstone grading through silty mudstone and into shale, and resembles a turbidite. Where an organic-rich shale caps the sandstone, it is interpreted to reflect a "phytodetrital pulse". These "pulses" originate from either the settling of material carried out in suspension as a buoyant plume, or from density underflows generated at the river mouth during periods of high river discharge (Coleman, 1981; Wright et al., 1988). These buoyant plumes or density underflows are responsible for the fornation of the current-generated shuctures. The abundance of the graded beds and current generated structures suggests that the plumes and fluvial influence dorninated the sedimentation. The silty mudstone and highly carbonaceous shale layers reflect deposition from suspension and like the underlying shale facies, probably accumulated due to fluctuations in river discharge (Reading and Collinson, 1996). These fine grained beds represent fainveather deposition or post-event suspension fallout of sediment. The silty mudstone has a massive, structureless appearance. It was likely the product of very rapidly deposited sediment. 167 (Bhattacharya and Walker, 1991). The carbonaceous shale interbeds reflect the rapid introduction of abundant terrestrial plant debris. This organic materiai, deposited within the mud, oxidized and consumed the oxygen near the sediment-water interface (Pearson and Rosenburg, 1978), induchg local development of anoxic or dysaerobic conditions. These conditions largely precluded biogenic reworking of the shales. This mode1 has been proposed for organic-rich mudstone interbeds in other successions. Syneresis cracks occur in some silty mudstone and shale beds. They are pytgmatically folded due to burial compaction, and are sand filled. They are interpreted to be due to the shrinkage of clay rninerals caused by salinity fluctuations associated with the introduction of freshwater into open marine environments (c$, Burst, 1965; Plumer and Gostin, 1981). Syneresis cracks are comrnon to abundant in the facies suggesting marine waters were frequently diluted with fresh water. This suggests that density underflows of fresh water, due to an inertia-dominated flow were characteristic of this setting. When flows are hyperpycnal (inertia-dominated) they are characterized by exceedingly high sediment concentrations and form hyper-concenhated flows that evolve downslope into a turbidity curent (e.g., Bhattacharya, 1999, Mulder and Syvitsky, 1995; Wright et al., 1988). The interstratified facies also commonly show convoluted bedding. This suggests that the sediments were rapidly deposited. Where sediments are rapidly deposited, the subsurface becomes soft and unstable, as they cannot disperse fluids quickly enough, and therefore deform during early compaction (Scholle and Spearing, 1982; Coleman and Prior, 1982; Bhattacharya, 1989; Bhattacharya and Walker, 1991; Power, 1993; Reading, 1996). Rare micro-faults load casts are also evident, and were probably generated by loading, increased pore pressures, and subsequent dewatering after burial. Factors such as salinitv fluctuations, oxygen deficiencies, unstable substrates, turbid waters, and an abundance of suspended sediment alI affect the diversity, abundance, and size of ichnogenera (Pemberton et nl., 1992a,b; 168 Pemberton and Wightman, 1992; Gingras et al., 1998). These "stresses" may account for the absent to low intençities of burrowing (e.g., Howard, 1975), and general low diversities of ichnogenera at any one location. The overall diversity of ichnogenera is high within the facies as a whole, but in any one cored interval, generaily only a few fomare found. Numerous cores had to be examined in order to acquire the entire trace fossil suite. The assemblage reflects a "stressed" Cnmiznn ichnofacies composed mainly of deposit-feeding sb-uctures, such as moderate to abundant Plnnolifes and Teic~ziclznzis,very rare to rare Zooplycos, and very rare Clzonclrifes, Asferosomn, Rosselia, Arenicolifes, and ~zalnssinoicles.Rare to moderate numbers of the grazing structure Helminfliopsis, moderate numbers of Anconiclmis, very rare numbers of the resting structures Lockeirr, and common numbers of fugichnia are also present. There are also rare elements of the Skolitlios ichnofacies, including suspension-feeding structures such as Cylindridtnzrs, Skolitlios, Sipkoniclinris, and Ophiornorph, and a rare occurrence of the passive carnivore structure Pnlneopliyalc. The majority of these ichnogenera are diminutive in size. Reduced salinity affects the size of benthic organisms in a number of ways, including decreased metabolism, retarded growth and development, and promotion of an early omet of sexual maturity, among others (Remane and Schlieper, 1971; Beynon and Pemberton, 1992). The rigours of inhabiting waters of varying salinity impose an increased demand for oxygen on benthic organisms. By decreasing their effective surface area, these organisms can decrease their total oxygen consumption and therefore function more efficiently. This reduction in size also serves as an adaptation to facilitate osmo-regulation of intemal body chemistry in response to salinity fluctuations (Remane and Schlieper, 1971; Beynon and Pemberton, 1992). Plnnolifes and Teicliiclt~zzisare the most cornrnon ichnogenera, found in the majority of core. It is typical to find these two traces with only one or two of the others throughout a single cored interval. Planolites and Teichiclznt~shave been interpreted as structures of trophic generalists, which means the trace rnakers employs nonspecialized feeding strategies, enabling them to thrive in harsher 169 conditions unsuitable for specialized feeders. This feature is related to their relative morphologie simplicity (Beynon and Pemberton, 1992). It is believed that even shdow burrowing organiçrns are signihcantly removed from the harsh physical and chernicd environment of the sediment-water interface and overlying column. As the organisms burrow, the sediment acts as a buffer to these variations in the environment (Sanders et al., 1965; Ekdale et al., 1984; Wightman et nL, 1987; Beynon and Pemberton, 1992), affording an additional benefit to the infaunal organisms. The burrows are sporadically distributed and are associated with the sandstone beds, suggesting that the event/flood deposits imported some of the organisms, and/or reflect opportunistic behaviours. The occurrence of Anconic~znrrs,which may be present in the upper parts of the sandstone beds and are associated with coarser intervals of heterolithic sedimentation, may reflect such opportunistic behaviour (e.g., Goldring et al., 1991). These burrows dirninish upward into the shale beds suggesting that fairweather conditions were unsuitable for such grazing behaviour. Ichnogenera of the Cnrzicinci ichnofacies that are typical of higher energy conditions such as Asferosomcr and Rosselicr, as well as traces of the Skolifhos ichnofacies are sporadically distributed throughout the sandstone beds. These traces represent early colonizers of new event-generated substrates, a characteristic of r-selected or opportunistic organisms. These traces are very rare, in spite of the abundant event beds, probably due to overall high sedimentation rates and increased water turbidity related to abundant river discharge into the basin. This would make the substrate unstable and difficult to colonize by trace- makers that require permanent dwelling structures, as the sediment on the substrate is continudy shifted. This may also account for the low diversity of trace fossils. The increased sediment in suspension and turbid waters create havoc on suspension-feeding organisms. Srispension-feeding organisms require ciean water, so that clay does not clog the filter feeding apparatus. Abundant sediment in suspension decreases their percentage of food per unit volume of 2 70 materid ingested, creating an unsuitable setting for colonization by suspension feeders (Moslow and Pemberton, 1988; Gingras and et al., 1998; Coates and MacEachem, 1999, MacEachem, 1999,2000).

Si@ Mzds fmeFacies - ProxihaZ Prodelfa to Dis fdDelta Fronf Tkmïtzon The silty mudstone facies is also interpreted as part of the proximal prodelta to distal delta front. This setting lies above storm weather wave base and below faairweather wave base (upper offshore to transition equivdent). It is found only in shingles E2 and E3. The facies has a massive, structureless appearance, which may be the product of very rapid deposition. Interspersed shatified sandstones are present throughout, which demarcate convolute bedding and loading structures. This may suggest that rapid sediment deposition occurred repeatedly in the setting. Micro-faults and load casts represent loading, increased pore pressures, and subsequent dewatering af3er burial. The stnictureless fine-grained nature of the facies with dispersed carbonaceous detritus reflects deposition predominantly from suspension (Reading and Collinson, 1996). It is interpreted that the silty mudstone facies occurred in close proximity to the distributary channels, in response to sediment plumes repeatedly debouched from the river mouth that flowed into the proximal prodelta. This facies replaces the intershatified sandstone, silty mudstone, and shale facies, which is interpreted to reflect a more distal or lateral position to the distributary channel. The silty mudstone facies is devoid of bioturbation. The lack of bioturbation is interpreted to be due to constant and rapid input of sediment, which led to unstabIe, soupy substrates, and overlying turbid water. As the substrate was continually aggrading with abundant sedirnent in suspension colonization was precluded. 171 ConuoZzrfed Si2t-y Sandstom Facies - Dis fat DelfaFro~f The convoluted silty sandstone facies is interpreted to reflect distal delta front deposition. This setting is located immediately above fairweather wave base. The facies contains convolute bedding, oversteepened beds, and loading structures, reflecting rapidly deposited sediment. Accompanying high interstitial water content led to a substrate that had a soupy consistency. Loading of the sediment, increasing pore pressures, and subsequent dewatering &ter burial, resulted in the development of convolute bedding. The abundant disseminated organic material within the fine-grained units was also subjected to rapid degradation by biochernical processes, producing accumulations of sedirnentary gas (primarily methane and carbon dioxide). Conditions of sedirnent failure ensued when stresses exerted on the sediment were sufficient to exceed its strength (Coleman and Prior, 1982). Massive, apparently structureless beds are intercalated and reflect very rapid deposition. Organisms were unable to bioturbate the facies, probably due to a combination of factors, including the unstable, soupy substrate, abundant suspended sedirnent, rapid sediment influx, and the introduction of fresh waters. These conditions led to areas devoid of bioturbation. Very rare laminated sandstone beds occur within the facies as well. The presence of very rare wavy parallel lamination, combined flow ripples, or oscillation ripples indicates rare storm beds. Helrnin tliopsis, Anconidznus, and Teichiclznirs disrup t primary physical structures, but they are very rare and diminutive, suggesting that the environmental stresses were extensive.

The Ihatedto smictureless sandstone facies is interpreted to reflect delta front to lower delta plain deposition (upper shoreface and foreshore equivalent). This facies contains trough cross-stratified and current rippled sandstone interbedded with wavy parallel laminated, and Iow angle planar 173 parallel laminated sandstone. Oscillation ripples and planar pardlel lamination are also present. This facies suggests a setting characterized by both episodic flood deposition and wave/storm reworking. Deposition occurred in pulses, indicated by abundant shdy interbeds. Structureless sandstone beds are dso common throughout the facies reflecting periods of very rapid deposition. The convoluted silty sandstone facies typically found interbedded with the laminated to stnictureless sandstone facies also suggests periods of very rapid deposition (cfi, Coleman and Prior, 1982). There is a general upward coarsening of sediment grain size, and the trough cross-stratification becomes slightly more dominant toward the top of the facies, reflecting higher energy and shallowing, associated with the progradation of the delta front. Rare root traces at the top of the facies suggest continued shoaling through the foreshore to the lower delta plain. Abundant carbonaceous detritus demarcates the stratification and rare to moderate mudstone beds reflect deposition from suspension, related to fluctuations in river discharge (Reading and Collinson, 1996). The terrestrial organic material and mudstone provides evidence of quieter periods between flooding and storm events. Syneresis cracks are present in the mudstone beds but very rare. They are interpreted to reflect salinity fluctuations associated with the introduction of density underfl ows of sediment-laden freshwater into open marine environments (Burst, 1965; Plummer and Gostin, 1981). The density underflows occur due to high sediment concentrations, which may have helped create an inertia-dominated hyperpycnal flow. This facies is largly devoici of burrowing, probably due to persistent river flood and/or storm events, abundant sediment in suspension, rapid influxes of sediment and fresh water near the bed, unstable substrate consistencies, and overall high water turbidity. Storm events are typically accompanied by high rates of precipitation, resulting in an increase in discharge from the distributaries and large amounts of terrestrial organic detritus and mud. When the storm subsides, the mud and organic material made the sandy storm bed, creating a "barrier" against opportunistic colonization of the sand. The organic material 173 oxidizes and reduces levels of oxygen at the sediment-water interface (Pearson and Rosenberg, 1978), creating a less hospitable setting to colonize (c$, Leithold, 1989; Raychaudhuri and Pemberton, 1992; Saunders et al., 1994; Coates and MacEachem, 1999; MacEachem, 1999). The ichnological suite resembles a stressed Cnrrinnn ichnofacies. A few burrows are present but very rare and sporadically distributed in the laminated sandstone. The ichnogenera include very rare Teiclridtnzis, CylinciricJznus, fugichnia and enigmatic (unidentified) burrows. The trace-making organisms colonized the laminated sandstones, which are interpreted to have been slightly reworked by wave action. This reworking created a more stable subsbate, by re- ordering grains and improving sorting (Coleman and Prior, 1982). The paucity of bioturbation is due not to a single factor, but to numerous factors working simultaneously, creating an inhospitable environment. In the rare mudstone beds, very rare PLnnoLifes and Teichiclznus are locally present. During periods of lower energy, the trace-making organisms of Plrinolites and Teiclriclrnlrs utilize the mudstone beds. These traces are very rare and diminutive in size. Plnnolites and Teidricllnzrs are regarded to reflect the structures of trophic generalists.

Lamiizn fed tu Bio tzdwfed Facies - Delfa Frun f The laminated to bioturbated facies is interpreted to reflect delta front deposition. The dominance of wave-generated structures in the laminated to bioturbated facies, such as common wavy parallel lamination, and oscillation ripples, rare to moderate low angle planar parallel lamination, and combined flow ripples suggests that relative river influence in the area had decreased. The wavy parallel lamination and low angle plana pardlel lamination represent hummocky cross-stratification (Ha).The oscillation rippies, combined flow ripples, and current npples capping the HCS beds mav sigrufy post-storm waning energy conditions, as well as wave and current action during fainveather conditions. Rare to moderate amounts of convolute bedding suggest some 174 periods of rapid deposition occurred as well (Coleman and Prior, 1982). Rare to moderate numbers of mudstone beds present throughout this facies reflect fainveather deposition. Rare syneresis cracks also occur within the mudstone beds suggesting sporadic salinity fluctuations (Burst, 1965; Plummer and Gostin, 1981). The persistent reworking of sedirnent by wave processes caused re- ordering, improved sorting, and concomitant tighter packing of the grains (Coleman and Prior, 1982), thereby decreasing interstitial pore pressures. The waves also worked clay seaward and lifted it higher into the water column, decreasing water turbidity immediately above the bed. Wave action also reoxygenated the water above the subsbate and helped disperse terrestrial organics. This generated a more hospitable environment for infauna, and enabled organisms to colonize the subshate more easily. Bioturbation intensities range from moderate to common, and diversities of ichnogenera are high. The ichnological suite reflects a Cnrzinnn ichnofacies due to the predominance of deposit-feeding structures. These structures include inoderate to conunon numbers of Plnnolites and Teiclriclznzis, rare to moderate Asterosonrlr, rare to common Zoophycos, and very rare Clioncirites, RlzizocornZli~m,Rosselin, Mncnroriichnus, and ~znlrrssinoides.Moderate to common amounts of the grazing structures Helmintlzopsis and Anconiclznzts are present, as well as rare elements of the Skolit?ros ichnofacies. The Skditltos ichnofacies includes moderate numbers of Cylindriclznzrs, rare to moderate Siplionidt~ztis,and very rare Pnlneopliynts, Arenicolites, Diplomfe~ion,Skolitlzos, and Ophiomorphn. This assemblage is very diverse compared to other facies of Allomember E, and includes many different trophic groups. This seems atypical of the delta front environment, as seen elsewhere, though in order to identify the complete assemblage, many cored intervals needed to be examined, as not al1 ichnogenera are located within a single cored interval. The facies reflects some stressful factors induced by river influxes, such as fluctuations in salinity, some unstable subshates, and periods of rapid deposition. The dorninant ichnogenera are also those that reflect trophic 175 generalist or opportunistic behaviours (e.g., Plmolites, Teichiclznz~s,Anconicl~nzls, and QIinh-idinus). This suggests that the setting was characterized by physico- chemical stresses, though not as pronounced as in the laminated to structureless sandstone facies. This facies represents shallowing conditions of the delta front located in positions marginal to the distributaries. In this position, the infrequent storms could generate He,and there would be longer tirnes avaiiable for fainveather colonization.

La~ninatedSandstuneandMudcfone Rip-u,v CZasfsFacies - Channel Fil'l The presence of trough cross-stratified sandstones with curent ripples and aggradational npples, interbedded with wavy pardlel larninated, combined flow ripples and planar lamination suggests episodic river flood deposition altematirtg with wave reworking (e.g., Reading and Collinson, 1996) (litholog 14- 06-63-26W5). Structureless sandstone beds are also moderately common throughout the facies, suggesting very rapid deposition. The presence of mudstone and abundant organic matter may correspond to deposition from suspension and fluctuations in river discharge (Reading and Collinson, 1996). The rare to common numbers of mudstone beds indicate periods of quiescence, possibly refiecting periods of waning flow after flood events. These less turbulent times would permit deposition of mud fiom suspension. PLznolites are locally found in these mudstone beds, and are regarded as the structure of a trophic generdist. The presence of aggradational npples also provides evidence of periodically increased sedirnent rates. Structures cannot be identified in the cored interval of 07-06-63-26W5; however, because the sediment is packed with variable amounts of mudstone rip-up clasts, shell fragments, and coal fragments, this suggests that erosion of the underlying substrate or channel margins occurred. 176 Spherulitic siderite is present in one cored interval (Figure 3-32 C) and is interpreted to originate from erosion of paleosols on the delta plain. As the distributary channel avulsed, it may have eroded the delta plain and transported the siderite spherules. TIUSsiderite behaves as a sand grain in the water columri and as it is deposited, is aligned dong the skaafication. The physicd and chernicd stresses of a channel environment, such as fluctuations in salinity, abundant suspended sediment, and increased/rapid deposition of sediment creates an environment di€ficult for infauna to colonize. This is reflected in very low to absent bioturbation intensity and diversity. Trace fossils that are present are sporadically distributed and include very rare Teiclziclt nir s, Pnlneophjcz r s, Oplt ionzorplin, and As terosorna (mainly interpre ted from rip-up clasts). Although this setting reflects high energy conditions, no structures of suspension-feeding organisrns are present. This is interpreted to be due to the abundance of sedirnent in the water column, which would "clog" the filter feeding apparatus of the suspension-feeding organisrns as well as reduce the ratio of food to inorganic material. Teiclticltnzrs, Pnlneopltyczis, and Oplziornorpltn irregzilaire occur as the dominantly horizontal burrows of organisms tolerate the harsh setting. In some locations, the normal succession is interrupted by the incision of this facies into underlying prodeltaic deposits of E2 and E3 (litholog 1446-63- 26W5). Due to the stratigraphie position of this facies, the fact that it is always abruptly overlying prodelta deposits of shingles E2 and E3, and its interna1 characteristics, this facies is interpreted as a distributary channel fil1 deposit. 4.4 Belly River 4.41 Facies Associations and Typical Fea fures

Facies Sedimentary Accessories Ichnologicai Structures C haracteristics *ab=absent InterstratifÏed Sandstone. *low angle pIanar parailel *basal contacts-sharp *associated with sst. beds Silv ivludstone and Shale lamination (r-a) eupper contacts are ointensity; absent to weak; owavy paralle1 lam. (a) bionirbated or grade into (very locally; moderate) -in al1 cycles *oscillation ripples (a) silty mudstone (minor *diversin. is high: but *convoIute bedding (r-a) component but cmbe many cored intervals need ocombined flow ripples (r- locally abundant) to be esamineci to find c) omudstone rip-up clasts (r) whole assemblage: oaggradational ripples (vr) oshale: typicaliy tind only a couple ocurrent ripples (vr) dark/fissiIe/carbonaceous of traces in one intend *syneresis cracks (r-c) .An (a). tI (r-a). Z (vr-m), *carbonaceous detritus (c) Ch (vr-r), Tb (ab-r). Pl (r- esiderite-cemented beds (r- a). Te (r-a). Si (ab-vr). R *silty mudstones are c) (ab-r), As (ab-r),Th (ab-r), structureless (and locally Cy (ab-r). Ar (ab-vr), Sk convoluted) (ab-vr). O (ab-vr), fu (ab-r)

~onvolutedSilty *carbonaceous detritus *carbonaceous devitus (a- devoid of burrowing Sandstonel Sandy Siitstone rnarking the convolute c) *in cycle G, diminutive Facies bedding ocoal fragments (r-a) escape structure (vr) -in cycles E. and G *structureless sst. (r) wavy parallel lamination (r) *oscillation ripples (r) *larninated sands tone; oeither carbonaceous is mbioturbation intensity is Facies wavy parallel lamination absent or very abundant very rare (HCS). low angle planar and demarcating eburrowing is sporadically -in ail cycles. lamination (SCS). mer stratification distributed -intrrcalated and overlain oscillation ripples, *mudstone brds (r-m) odiversity is modemte BUT by the trouzh cross- aggndational ripples. *syneresis cracks (r) only ever find a few traces stratified sandstone facies current ripples, combined *mudstone rip-up clasts (r- in any one corcd interval flow ripples, planar m); rnainly resemble *in mud beds: PI (vr-a), An lamination remnants of burrows (ab-a), H (ab-r), Rh (ab-vr) *generalIy erosionally acoal fragments (vr-r) *Te (vr-a), Ro (ab-c). As amalgamated HCS bsds *shelI fragments (vr) (ab-r). Cg (ab-r), Pa (ab-c), *sVUcturelrss sst. ointerstitial silt Sk (ab-r), Ar (ab-r), O (ab- *spherulitic siderite (r-m) r). Ma (r-cl, fu (r)

oseveral enigmatic unidenti fied structures, though similar to rfsterosoma and Ophiomorpha Trough Cross-Stntified otrough cross-suatifkation ocarbonaceous detritus rdevoid of bioturbation to and Cumnt Rippled dominant dernarcates stratification low divenit). and Sandstone Facies mstructureless sst. (c). wavy (c-a) abundance pmllel lamination (r), low esiltstone (r-c) mantles the - found prominently in angle planar paral le1 current ripples .Pl (r) located in the rare cycles D, and G but prexnt larnination (r), combined rmudstone beds (r): mudstone beds throughout al1 cycles tiow npplrs (r). climbing contain syneresis cracks (r) Sk (r-c), Te (r)- Cy (r), Ar ripples (r), current ripples ecoal fragments (abcj (vr). possible Scoyenia or (r). oscillation ripples (r). emudstone clasts, wispy Scolicia convolute bedding (r) appeamce, ovd. or resemble xrnnants of ogrades upward into bumws (r) sandstone dominated by *micro-faults (vr) current ripples, clirnbing aroot structures (r) ripples, combined flow (generally consistent ripples (r), osciIIation throughout al1 cycles) ripples (r), trough cross- stratification (r). wavy paralle1 lamination (r) .convolute bedding (r) Silty Mudstone Facies opedogenically rnodified l skkensides *al1 qcIes devoid of mrubbly appearaxice bioturbation escept G. -al1 to some estent but al1 esiderite-cemented beds with slight variations rcoal and plant fragments oburrowing absent to weak mroot structures at top .Pl (vr), Te (vr), Cy (vr). ocarbonaccous detritus 0 (vr) asiderite nodules eshell fngrnents 179 4.42 Introduction The Belly River Formation in the shidy area consists of cycles D, E, F, G, and H in descending order. The facies succession of these cycles has been grouped into a single facies association. The facies association of the Belly River Formation is characterized by six discrete facies. The basal facies consists of intershatified sandstone, silty mudstone, and shale. In cycles E and G, this grades upward into the convoiuted silty sandstone/sandy siltstone facies, and is overlain by the Iaminated sandstone facies. In Cycles E, F, and H, the basal facies is directlv overlain by the larninated sandstone facies. The Iaminated sandstone facies typically grades upward into, or is intercalated with, the hough and current rippled sandstone facies. This is overlain bv the silty mudstone facies and/or the pinstriped facies, which caps the facies succession.

4.43 Interpretation Inferstrafz~edSandstone, SiZq Mdsfon~,and ShaIe Facies - Proxikd ProdeZf@istalDeZhz Frmf The interstratified sandstone, silty mudstone, and shale facies is interpreted to reflect proximal prodelta to distal delta front deposition. This setting is situated above storm weather wave base but below fairweather wave base. The three components of this facies suggest that there are three different energy regimes operated in the setting. The sharp-based sandstone beds display abundant wavy parallel lamination (HCS), oscillation ripples, low angle planar parallel lamination, and combined flow ripples. This provides evidence of higher energy activity, interpreted to reflect storm events. Current and aggradational ripples are minimal in this setting. The rare to cornmon convoluted beds and combined flow ripples suggests, however, that large amounts of sediment were supplied from the distributary channels during river flooding and concomitant storm events. The river flood and storm events are interpreted to occur simultaneously, as storm events are accompanied by high precipitation, which induces flood discharge through the distributary chamel. 180 The sandstones generally grade upwasd into the silty mudstones, capped by shde. This resembles a turbidite-induced bed. These beds are thought to originate from sediment-laden, inertia-dominated flows. This type of ff ow may result in fine-grained material being swept into the basin by density underflows (Wright et n1.,1988; Mulder and Syvitsky, 1995; Bhattacharya, 1999).The silty mudstone beds have a massive (apparently structureless) to convoluted appearance. They were likely the products of very rapidly deposited sediment. The dark, fissile, highly carbonaceous shale beds reflect the rapid introduction of abundant terrestrial plant debris with the clay. These beds are typically devoid of burrowing are thought to represent dysaerobic conditions due to oxidation. The shale beds also contain rare to common numbers of sand-filled syneresis cracks that are pytgmatically folded due to burial compaction. They are interpreted to be due to the shrinkage of clay rninerals, caused by salinity fluctuations associated with the introduction of freshwater into the delta front and prodelta environments (CF, Burst, 1965; Plumrner and Gostin, 1981). The overall diversity of ichnogenera is high, but burrowing intensities are very low. Numerous cored intervals had to be analyzed in order to find the complete trace fossil assemblage. This reflects a "stressed" Cnizinnn ichnofacies, composed mainly of deposit-feeding structures such as rare to abundant Plnnolites, Teiclticlznzrs, rare to moderate Zoopkycos, rare Clzondrites, and very rare Arenicolifes, Asterosomn, Rosselin, and Tlznllzssinoides. Abundant Anconidzntrs, and rare to abundant numbers of Helrrzintlzopsis constitute the grazing structures in the facies. Rare to abundant fugichnia are aIso present. Suspension-feeding structures are very rare, characterized by Siphonic~rnzis,Cylindrichnus, Skolifhos, and Oplziorrzorplin. The dwelling/passive carnivore structure Terebellinn is very rare. Anconiclznzrs, Plnnolifrs, and Teichiclinzls are the most common ichnogenera, and are found in the majority of core. Anconiclznzrs is considered to reflect opportunistic behaviour. Plnnolites and Teiclziclrnus are considered to represent trophic generalists, characteristic of trace-makers that thrive in harsher 181 conditions. The upper parts of some sandstone beds contain these ichnogenera, suggesting that some of these organisms were irnported by the episodic events and/or reflect an opportunistic behaviour. The burrows diminish upward into the shale beds. The ichnogenera of the Cnrzinnn ichnofacies that are typical of relatively higher energy conditions, such as Asterosornn, Rosselin, as well as the suspension-feeding stnictures of the Skolithos ichnofacies are sporadically distributed throughout the sandstone beds. These traces represent early colonizers of the newly available event-generated substrates, also regarded as a characteristic of opportunistic organisrns. The increased sedirnent in suspension creates havoc for suspension- feeding stnictures. iIigh sedimentation rates also result in unstable substrates, which are difficult to colonize by ùilauna that require permanent dwellings, as the sediment is continually shifting. It is interpreted that factors such as oxygen deficiencies, unstable substrates, suspended-sediment laden waters, and fluctuating salinities contributed to the low intensities of burrowing and the sporadic distribution of ichnogenera. Locally, wave action was also common, which re-worked and stablized the sediment, and supplied refreshed marine waters to the sediment-water interface. The facilitated more uniform salinity and oxygen levels, contributing to an overall higher diversity of ichnogenera present.

ConvolzcfedSilty S~zndston~SaandySiltsfone - Distd Delta Frunnf The convoluted silty sandstone/sandy siltstone facies is interpreted to reflect a distal delta front setting. This setting is located above fairweather wave base. In addition to the convolute bedding and structureless beds, this facies also contains rare wavy parallel lamination (HCS), and oscillation ripples. The convolute bedding and structureless bedding reflect rapidly deposited intervals. The laminated bedding reflects intervals of regular wave/storm action and sediment deposition. Abundant organic material capping the convolute bedding possibly reflects sediment deposition from suspension. The facies accumulated in close proximity to distributary charnels, and some sediment was deposited from 182 plumes derived from the river mouth. Those successions not containhg this facies are interpreted to have occupied a position laterd to the distributary chamel, and were subsequentty re-worked by wave action. Organisms were unable to bioturbate this subsbate, probably due to a combination of factors, including the unstable, soupy substrates, abundant suspended sediment, rapid sediment influx, and intermittent presence of fresh waters. These conditions likely led to a facies devoid of bioturbation.

Lamina fed Snnds fone F~cies- Disfal fo Proxima 2 Delta Front The laminated sandstone facies is interpreted to reflect distal to proximal delta front deposition. This facies is dominated by wavy parallel lamination and low angle planar larnination, interpreted to represent hummocky cross- stratification (Ha)and swaley cross-stratification (SCS), respectively. The presence of these sharp-based sandstone beds reflects erosional emplacement during storms, and demonstrates that storm action played a sigruficant role in this depositional setting. Rare oscillation ripples, aggradational ripples, current ripples, combined flow ripples, planar parallel larnination, and stnictureless sandstones sigrufy deposition during the waning penod of the storms, as well as wave and current action during fairweather (post-storm) conditions, accompanied by abundance of sediment. Abundant carbonaceous detritus demarcates the stratification. Rare to moderate numbers of mudstone beds reflects deposition from suspension. Both characteristics are related to fluctuations in river discharge (cf., Reading and Collinson, 1996). The terrestrial organic material and mudstones provide evidence of quieter periods between river flood discharge and/or storm events. Syneresis cracks are present, though rare, in the mudstone beds and are interpreted to reflect salinity fluctuations associated with the introduction of density underflows of sediment-laden freshwater into the open marine environments. Rare to nioderate arnounts of reworked spherulitic siderite are distributed throughout this facies. It is interpreted to have originated from 183 pedogenic development on the delta plain. As the distributary channel avulsed, it eroded the delta plain and transported the siderite sphedes as bedload where it was deposited dong shatification. Burrowing is sporadically distributed, and bioturbation intensities are very low. Nonetheless, this facies contains a diverse assemblage, though many cores had to be analyzed in order to obtain the entire trace fossil assemblage. The ichnofossil suite resembles a mixed Skolitlros-Cnizinnn ichnofacies. This reflects in loco fluctuations in energy associated with storm activity rather than changes in relative sea level or variations in distance from the shoreline (Pemberton ancl Frey, 1984; MacEachem and Pemberton, 1992; Pemberton and MacEachem, 1997). The fairweather mudstones contain abundant deposit-feeding sh-uctures such as Plmzolites, and very rare Rliizocornllit~ntand Arenicolifes. In addition, abundant grazing shvctures such as Anconiclznirs and rare Helnzinthopsis are also intercalated. These ichnofossils represent the fairweather " Cnizinnn" ichnofacies. The number of mudstone beds decreases upward in the facies. Deposit-feeding structures predorninant within the sandstone, and include absent to rare Asterosonrn, rare to abundant Teiclriclzizz~s,and rare to common Rosselin. Mobile deposit-feeding structures prone to higher energy regimes are reflected by Mncnronidtnns. The dwelling/passive carnivore structure Pdneopl~yczlsis locally present. Immediate post-storrn conditions provide favourable settings for colonization of the substrate by infaunal opportunists. Mncczroniclinzis are associated with higher energy regimes and are deemed opportunistic. Mncnronichnzrs are widely spaced within the storm beds, but lack the density associated with "toe-of-the-beach"assemblage (cJ, Saunders et al., 1994). Other opportunistic organisms include the trace-makers of Skolitlzos and Oplriornorplia. Higher energ, deposit-feeding structures of the proximal Cnlzinnn ichnofacies are also common. These ichnofossils include Rosselin and Asterosomn interpreted as the faheather in€aundcornrnunities. Rosselin and Asterosomn can 184 exploit their own deposits rather than relying on encountering deposited foods in the substrate, and are exceedingly cornmon in storrn-dominated, open marine settings, such as lower shoreface and comparable delta front environments (e.g., Howard and Frey, 1984; Pemberton and Frey, 1983; Saunders and Pemberton, 1986; Frey, 1990; MacEachem and Pemberton. 1992; Pemberton et nl., 1992; Saunders et al., 1994). The dwelling tubes of Rosselin are commonly truncated by storm beds. Rosselin mud "bulbs"are also found detached from the dwelling structures, and nearby, thickly mantied tubes with concentric layering may be present. This suggests that some of the trace-makers were able to readjust their structures in response to the shifting sediment-water interface. Rare to moderate numbers of mudstone rip-up clasts occur in the storm beds, and resemble remriants of Rosselin or Asferosomn burrows. The paucity of suspension-feeding ichnogenera (e-g., only rare numbers of Cyliniiricltniis, Skolitlros, and Opltiornorplzn) and the dominance of deposit-feeding structures contrasts with that of storm-dominated shorefaces, and is interpreted to be a response to increased water turbidity, reduced water salinity, and fluctuating/episodic depositional rates (e.g., Moslow and Pemberton, 1988; MacEachem and Pemberton, 1992; Gingras et nZ.,1998; Coates and MacEachern, 1999,2000). These factors are characteristic effects of fluvial idluences on the coastal regime. High water turbidity associated with increased volumes of suspended sediment within the water column interferes with the efficiency of the organism's suspension feeding apparatus. Water turbidity does not seem to affect predaceous organisms or most deposit-feeders, and this is reflected by the dominance of their structures in the trace fossil assemblage. The overall paucity of burrowing is believed to be a preservatioanl bias reflecting the high frequency and/or high intensity erosiond amalgamation of storm beds. The sporadic occurrence of the fairweather cornmunity in this facies, therefore, is due to the high frequencies and intensities of storm events, coupled with high sedirnentation rates, high water turbidities, and periodically reduced salinities. 185 This facies is intercalated with and overlain by the trough cross-stratified facies. This general upward coarsening of sediment, and the upward dominance of the trough cross-stratified facies refl ects higher energies probably associated with shallowing, attributed to progradation of the proximal delta front.

The laminated sandstone is intercalated with and overlain by the trough cross-stratified sandstone facies. Locally, the facies also contains rare wavy parallel lamination, low angle planar parallel lamination, oscillation ripples, combined flow ripples, climbing ripples, current ripples, and convolute bedding. This suggests the interplay of current action and wave processes, possibly reflecting close proximity to distributary channels (Reading and Collinson, 1996). Structureless sandstone beds are also cornmon throughout this facies, suggesting very rapidly deposited sediment. The presence of convoluted laminae also suggests some periods of rapid deposition. The abundance of carbonaceous detritus and rare to cornmon amounts of coal fragments reflects deposition of terrestrial plant debris from suspension, associated with fluctuations in river discharge and increased fluvial influence (e.g., Reading and Collinson, 1996). The deposits are generally erosionally arnalgarnated and contain little preserved mud, suggesting a generally shallower, and more persistently agitated environment (c5, Aigner and Reineck, 1982; MacEachern et al., 1991; Walker and Plint, 1992; Pemberton and MacEachern, 1997). The rare mudstone beds that do occur typically contain syneresis cracks, suggesting salinity fluctuations associated with the i~troductionof freshwater during post-storm/flood conditions (CF,Burst, 1965; Plumer and Gostin, 1982). The facies grades upward into beds dominated by current and climbing ripples mantled by siltstone. Root shuctures typically cap this facies, and are consistent with the progradation of the proximal delta front. The physical and chernical stresses associated with this facies (eg., fluctuations in salinity, abundant suspended sediment, rapid deposition and the 186 continuous of beds) created an environment difficult for infauna to colonize, and resulffng in an overall low preservation potential for Wace fossils. This is reflected in the very low diversity of ichnogenera and reduced bioturbation intemities. Plrinolites is very rare and is restricted to the uncoxrunon mudstone beds. Due to the continuously migrating bedforms, permanent domiciles are rare and only the deep penehating structures are preserved (Howard and Frey, 1984; MacEachem and Pemberton, 1992). The h-ace fossil suite is represented by a "stressed" Skditltos ichnofacies. The main ichnogenera include rare to common Skolitlzos, rare Cylindnclrnus and very rare Arenicolites There is also possibly Scoyenin present. Suspension-feeding structures may dso be rare due to the problems that abundant suspended sediment imposes upon the filter feeding apparatus of the hace makers. The deposit-feeding structure Teiclziclzntis is also present though rare, reflecting the wide environrnentd tolerances of opportunistic trace-makers. FACIES CRITERIA FOR DIFFERENTIATION OF DELTAIC END MEMBERS: RIVER- VS. WAVE-DOMINATED DELTAIC SUCCESSIONS

5.1 INTRODUCTION This chapter compares the facies associations of Dunvegan Formation Allomembers E and D, interpreted to reflect successions of river-dominated and wave-dorninated deltas. This chapter also compares successions of the Belly River Formation, representing deltaic cycles characterized by mixed river and wave influence. The subaqueous delta, the area that lies below low tide mark, constitutes the principal area of concern. The uppermost portion of the subaqueous delta is referred to as the delta front and the remaining seaward part is referred to as the prodelta. These areas are further subdivided into proximal and distal portions. Each section of the subaqueous delta is discussed individually. The allomembers and cycles are compared with one another, in order to identify facies criteria for their differentiation in the rock record. These criteria can then be used to augment paleoenvironmental interpretationç based on regional mapping of delta lobes. Al1 modem end rnember deltas are fiuvially dominated to some degree, but where basinal processes are very weak, the system may be ovenvhelmed by the river processes. This typically generates an elongate birdsfoot delta rnorphology. The Atchafalaya lobe of the Mississippi Delta, Louisiana iç an extreme, hurnan-enhanced example of a river-dominated delta. Fine-grained clays and silts characterize the prodelta. These deposits generally show a wide lateral continuity (Coleman, 1981). Thin Sand laminations become thicker upward. The sand is generally deposited in the delta front within bar fingers, channel mouth bars, and within the channels. The very straight nature of bar fingers is largely due to the lack of reworking of the sands in the marine environment, and the finer-grained, mixed-load character of the deposits. The rate of fluvial sediment input is very high, and the tidal processes and wave 188 action are subdued within the Gulf of Mexico- Soft-sedirnent deformation features characterize the delta front, resulting from high sedimentation rates. These occur on a very large scale and involve large areas of the delta front sediments. The deposits are characterized by a generaily upward-coarsening succession. In settings where waves dominate and tides are weak, the persistent high- energy waves cause much of the distributary mouth sediment to be reworked dong the coast The waves redistribute the sedirnent in the delta front by longshore drift producing beaches, barrier bars, and spits, and cause deceleration of river outflow. A good modem example is the Sao Francisco Delta, Brazil, where the sediment concentration within the river channel equds or exceeds that of the Mississippi River during flood. The Paraibo de Sol Delta, also of Brazil, is aiso strongly wave-dominated. The coastline displays a smooth, arcuate delta profile, due to extensive reworking by extremely high wave energy. The mud is w-innowed and moved seaward where it is deposited in the distal delta front and prodelta. Most mud on the delta plains cornes from river floods. The prodelta shales consist of sandy and silty clays. Sand is generally deposited dong beach ridges and in the delta front. The prodelta shales grade upward into mud, silt, and sand layers. This is overlain by altemating sands and silts with small-scale fine lamination (oscillation ripples and small scale HCS beds), into well-sorted, clean sands dominated by HCS and Se.This reflects a delta front strongly influenced by storms. Wave-dorninated deltas tend to from single coarsening upward successions. Such successions can be difficult to distinguish form strandplains. FACIES CRITERIA: Dunvegan and Belly River Formations 5.2 PRODELTA The prodelta is subdivided into the distal prodelta and the proximal prodelta. Each setting is discussed separately.

Distal Prodelta The distal prodelta lies immediately above storm weather wave-base (lower offshore equivalent; c5, Frey and Howard, MacEachem and Pemberton, 1992; MacEachem et al., 1999). The sedimentological features of the distal prodelta in both river- and wave-dominated successions are quite similar, consisting of the shale facies. It is characterized by fissile, carbonaceous shale, with intermittent sandstone beds and organic detritus. The prodelta shale is common to both Allomember D and E of the Dunvegan Formation. The cored intervals studied from the Belly River Formation did not contain this facies. Most deposition is from suspension. The placement of sandstones, consisting of oscillation ripples and wavy parallel lamination, occurred during distal storm events. The moderate abundance of current ripples and combined flow ripples in Allomember E suggests deposition originating from the distributary channel and sediments carried basinward in buoyant plumes; these are interpreted to have occurred during high-energy river flood event and concomitant stoms. Both river- and wave-dorninated successions contain the distal Cnïzicrna ichnofacies in this subenvironment. However, on average, the trace fossil abundance tends to be slightly higher in the wave-dorninated Allomember D, although there remains a very low intensity and diversity of ichnogenera. In AUomember D, fairweather ichnogenera are dominated by deposit-feeding structures such as Plnizolites and Teichiclznzis with rarer occurrences of Zoapltycos. The rarer suspension-feeding shvctures such as Siphoniclznus, Skolitlzos, and the resting structure Lockeia are associated with the thin sandstone beds, and represent the so-called "doomed pioneers" (cc, Follmi and Grimm, 1990). In the river-dorninated Allomember E, the shale facies of the distal prodelta is mainly 190 devoid of burrowing. The fairweather ichnogenera, where present, comprise Plinzolifes and Helrninfhopsis, and are diminutive in size. Grazing reflects surface foraging and is common to positions basinward of fairweather wave base. The overall reduced diversity and abundance of ichnogenera in both the river- and wave-dominated successions are likely due to (1) the high terrestrial organic content of the sediment, which consumes dissolved oxygen at the sediment- water interface as it oxides, and (2) high sedimentation rates of muddy material, generating soupy substrates. The abundance of the organic matter is attributed to river discharge due to flooding, which may also accompany storm events. The suspension-feeding structures in the sandstone beds of the wave-dorninated successions suggest bnef short-lived re-oxygenation of the water colurnn and increased oxygen levels. Such storm sands provide the noncohesive substrate necessary for vertical domicile construction. The apparent paucity of trace- making organisms in sandstones of the river-dominated successions is attributed to waters that were not re-oxygenated sufficiently to facilitate colonizing, fluctuating salinity associated with hyperpycnal sediment plumes, generally higher water turbidity and higher sedimentation rates.

Proximal Prodelta The proximal prodelta is regarded to lie above storm wave base but below fainveather wave base, and landward of the distal prodelta. This is roughly equivalent to the upper offshore to transitional offshore of the shoreface setting but affected to varying degrees by relative storm activity (Frey and Howard, ; MacEachem and Pemberton, 1992; MacEachem et RI., 1999). The wave- and river- dominated deltas of the Dunvegan Formation and mixed wave/river dominated deltas of the Belly River Formation contain proximal prodelta deposits in the form of interstratified sandstone, silty mudstone, and shale facies, characterized by generally high sedimentation rates. The most distinctive deposit comprises the massive (apparently structureless), silt-rich mudstones with dispersed carbonaceous detritus. This facies is most common to river-donünated successions, and is exceedingly rare in the wave-domùiated deltaic lobes. The interstratified sandstone, silty mudstone, and shale suggest three different energy regimes operated in this setting. AU sandstone beds are sharp- based. The dominant sedirnentary structures within these sandstones Vary. In the wave-dorninated delta succession, the abundance of oscillation npples and wavy parallel lamination reflects a storm-generated origin, dominated by wave action. Current-generated structures are rare, and where present, probably reflect river influences. Convolute bedding may correspond to storm-induced liquefaction and/or founde~gin soupy prodeltaic mud, as a consequence of generally high sedirnentation rates. River fioods and stom events probably occurred simultaneously in many instances, as hi@-precipitation is generally associated with storm events, and would have induced flooding of the distributary channel. However, wave action did not suppress al1 the current activity or re-work all the sediment, reflected by the presence of rare current ripples, and rare to moderate numbers of combined flow ripples. The silty mudstone and shale layers reflect deposition from suspension, and likely arose due to fluctuations in river discharge and/ or post-storm suspension fall-out. In the river-dominated successions and the mixed river/ wave successions, the sandstones grade through silty mudstones, and into shale. This may reflect density underflows generated at the river mouth during periods of high discharge. In the river-dominated successions the sandstone beds are characterized by wavy parallel lamination, combined flow ripples, current ripples, and convolute bedding, with rare to common oscillation ripples and aggradational ripples. This suggests that wave/ storm activity was subordinate and sedimentation rates were high. Fissile, black mudstone iayers drape the rare tempestites, recording rapid post-storm, suspension Ml-out of clay with abundant land-derived plant debris. These mudstone beds probably reflect "phytodetrital pulses" (c-,Leithold, 1989; Raychaudhuri and Pemberton, 1992). The mked river/wave delta successions of the Belly River Formation contains 192 the "graded" beds similar to the river-dominated successions, but more of the sandstone beds contain sedimentary structures that are similar to those of the wave-dominated successions. This reflects the more common occurrence of storxn events and wave reworking in this delta type. Syneresis cracks are more common in the river-dorninated successions, reflecting more frequent and/or greater magnitudes of salinity fluctuation. The proximal prodelta deposits of the deltaic successions generally contain a "stressed" Cnizinnn assemblage. They contain moderate to high diversities of ichnogenera, and the intensity of the bioturbation is absent to low. Many cores had to be examined in order to determine the entire trace fossil suite. The burrowing is typically associated with the sandstone beds. In the Dunvegan Formation wave-dominated AUomember D, bioturbation diversities are high, and the sandstone contacts are sporadically disrupted by biohirbation. This does not occur in the river-dominated and the mixed river/wave successions, where the sandstone contacts remain sharp and erosional. The trace fossil abundances are also markedly lower in the river-dominated and mixed river/wave successions, with only about 5-10%of the interval biogenically disrupted. The majority of the trace fossils are diminutive in size as well. The suite would be better termed a "highly stressed" Cntzinnn ichnofacies. In al1 successions, the dominant trace fossils are the deposit-feeding structures Plnnolites and Teiclzichnzis. nie grazing structure Helmintlzopsis is variable in abundance, ranging from rare to abundant in numbers. The opportunistic grazing structure Anconiclinzis is abundant, particularly in the Belly River mixed river/ wave successions. The widespread presence of HeIrninthopsis and Anconichnus indicate that nearly normal marine conditions were largely maintained in the proximal prodelta. The fairweather trace fossil cornrnunity is dominated by Plnnolites, Teichichnns, and Helminfhopsis. AU other structures are typicdy absent to rare in numbers and are found sporadically. These consist of rare deposit-feeding 193 structures such as Zoophjcos, Chondrites, Asterosomn, Rosselin, Rhizocornllizrrn (only in wave-dominated successions) 7IuiInssinoides and Mrrcmonicltnzis. Suspension-feeding structures, believed to represent opportunistic organisms, comprise Sipltonicltnz~s,Cylindriclzn us, Skolitlzos, Arenicolities, with Opliiornorplzn only in river-dominated and mixed river/wave successions. Very rare numbers of the passive carnivore structure Pnlneophycus and Terebellinn are also present. The differences in the comparable facies are subtle but predictable. The main reason for the differences may be due to the slightly different positioning downdip of the distributary mouth. In the river-dorninated and mixed river/wave delta successions, the interstratified sandstone, silty mudstone, and shale facies are believed to have been deposited laterally adjacent to the distributary mouth. In the wave-dorninated succession, this same facies preferentially occurs directly downdip of the distributary mouth, and storm worked laminated sandstones accumulate in the lateral positions. Physical and chernical variables such as changing salinity, increased water turbidity, and fluctuating oxygenation at the sediment water interface were more pervasive in the river-dominated and mixed river/wave influenced successions. However, they were not great enough to preclude bioturbation. In the wave-dominated successions, more pervasive wave action acted to dissipate these stresses, perrnitting more thorough bioturbation. In the river-dorninated and mixed river/wave succession the stresses were somewhat suppressed due to the adjacent position of deposition, as they did not receive the full impact of the river influence. However, the stresses were more pervasive creating a less abundant and diminutive trace fossil suite. There are extreme differences in the river- and wave-dominated end- members when comparing the facies downdip of the distributary channels. This position in the river-dominated and mixed river/ wave successions is characterized by the sûxctureless silty mudstone facies and the convoluted silty sandstone/sandy siltçtone facies, respectively. In contrast, the down-dip position 194 in the wave-dominated succession is characterized by the interstratified sandstone, silty mudstone, and shale facies (described above). The bioturbated sandy mudstone/ muddy sandstone facies characterizes the Iaterally adjacent position of deposition in the wave-dominated succession. Comparatively, the interstratified sandstone, silty mudstone and shde facies characterizes the laterally adjacent position of deposition in the river-dorninated and mixed river/ wave successions, and shale facies mentioned. In the mixed river/wave succession, the silty mudstone facies is massive (apparently structureless) grading into zones of convolute bedding and loading structures. In the river-dominated succession, the convoluted silty sandstone/sandy siltstone facies contains convolute bedding with some structureless sandstone throughout. These structures are attributed to rapidly deposited sediments that were not able to dewater leading to a substrate that had a soupy consistency. Organisms were unable to bioturbate this facies due to a combination of factors, including variable though generally unstable soupy substrate consistencies, abundant sediment in suspension, and rapid influx of sediment and fresh waters. In contrast, the wave-dominated succession possesses only minor amounts of the silty, convoluted mudstone or silty sandstone. These facies are not as abundant because the sediment-water interface was intermittently reworked by wave processes, which resulted in re-ordering, improved sorting, and concomitant tighter packing of the sediment grains. The bioturbated sandy mudstone/muddy sandstone facies characterizes deposition in positions laterally adjacent to the distributary channels in the wave-dominated successions. This facies contains few primary physical sedirnentary structures that have not been destroyed by biohirbation. Those primary structures that do survive resemble Hm, and therefore probably represent tempestites. There are also features that suggest freshwater and current infimes, such as syneresis cracks, and rare current ripples. There is also an abundance of carbonaceous detritus throughout this facies. In contrast to river- 195 dominated successions where it is concentrated in mud beds, favoring the development of reducing conditions, in wave-dominated successions it is dispersed and may have served as a food resource for infaunal organisms. The ichnofossils represent a comparatively unstressed Cnrzinna ichnofacies to mixed Skolitlzos-Cnrzinnn ichnofacies, with greater abundance and diversity compared to the other facies of the proximal prodelta. The bulk of the suite consists of ichnogenera reflec ting deposit-feeding infauna such as abundant Zoophycos, Plnnolites, Teiclzichnzts, Asferosorna, with rarer Clzondrifes, Rlzizocornllitini, Thnlnssinoides, and Ophiornorph, and rare ichnogenera reflecting the dwelling of passive carnivores such as Pnlneoplzycus. Moderate to rare grazing structures such as Helminthopsis. Anconichnzis are also present. These traces comprise the fairweather community. Suspension-feeding stnictures are also much more abundant compared to river-dominated and rnixed river/ wave successions and represent opportunistic colonization of the storm beds. Ichnogenera associated with the tempestites include rare to cornmon numbers of Diplocraterion and Cylindriclznus, and rare Siphonichnns, Skolithos, Arenicolifes, and Terebellinn. Burrowing is more uniform in distribution, creating a biogenically graded or mottled appearance. This facies represents a succession where fluvial factors were minimal and wave and storm action dominated between quiet water periods, generating an assemblage tending toward a more equilibrium community.

5.3 DELTA FRONT The subaqueous delta front is regarded to begin imrnediately just above the fairweather wave base and extend to low tide mark (Le., shoreface equivalent; MacEachem and Pemberton, 1992; MacEachem et al., 1999). There are two principal differences between the delta front successions of river- and wave- dominated complexes. The first is that the silty, convoluted sandstone facies is relatively common in the river-dominated deposits but rare in the wave- dominated successions. The second is the paucity of burrowing in the river- 196 dominated successions, manifest by either the presence of a highly stressed Cnrzinnn ichnofacies or by the large intervals that are entirely unburrowed. In contrast, the wave-dominated intervals either possess a welI-developed, mixed Skolithos-Crrczinnn ichnofacies or consist of erosionally arnalgamated HCS/SCS beds with little or no preserved bioturbated horizons. The silty, convoluted sandstone facies is overwhelmingly confined to river-dorninated distal delta front successions. The facies reflects an abundance of silt, sand, and mud deposited from suspension from distributary-generated sediment plumes (Reading and Collinson, 1996). The facies was deposited rapidly and was unable to dewater easily, leading to a substrate that had a soupy consistency. Loading, increasing pore pressure, and subsequent dewatering after burial resulted in developrnent of convolute bedding. Organisms were probably unable to bioturbate this facies due to a combination of factors, including unstable soupy substrates, abundant suspended sediment, rapid sediment influx, and the intermittent presence of fresh waters. In the river-dorninated Dunvegan lobes and Belly River mixed wave/river successions, the convoluted silty sandstone/sandy siltstone facies is found in the distal delta front and may grade into or is intercalated with the laminated (to stnictureless) sandstone facies of the proximal delta front. Where the convoluted facies is more prevalent, it is interpreted to occur downdip from the main distributary channels. Where this facies is scarce or absent, the succession is interpreted to occupy positions marginal to the main distributary channels. The laminated to structureless sandstone facies of the river-dorninated and mixed river/ wave succession is characterized by lamination reflecting both episodic flood deposition and wave/storm reworking. The structureless sandstones and the convoluted silty sandstone are interbedded throughout, and refiect periods of very rapidly deposited sediments. In contrast, the wave-dominated successions possess only minor amounts of the silty, convoluted mudstone or the silty sandstone facies in either the distal or proximal delta front settings. The laminated to bioturbated facies of the river- 197 dominated and mU

The rnixed Skolitlros-Cmzinlza ichnofacies characterizes the laminated to bioturbated sandstone facies. This facies typically overlieç the bioturbated sandy mudstone/muddy sandstone of the proximal prodelta, interpreted to occur in positions marginal to the main distributary channels. The laminated sandstone facies, which generally overlies the intershatified sandstone, silty mudstone, and shale facies of the proximal prodelta, is interpreted to occur downdip of the main distributary charnel. The laminated sandstone facies is also characterized by a mixed Skolitlios-Cnrzinnn ichnofacies, consisting of Teiclzichnus, Skolitlios, Lockein, and fugichnia. Many structures are enigmatic (unidentified). Diversity of ichnogenera and bioturbation is very sparse and ichnogenera are sporadically distributed. Physical structures are characterized by amalgamated HCS/SCS believed to reflect high intensity and/or high frequency of storm bed emplacement. As a result, trace-makers either did not have ample tirne to burrow the substrate or, if they were present, their structures were subsequently destroyed by successive storm events (cJ, Pemberton and Frey, 1984; MacEachern and Pemberton, 1992; Pemberton and MacEachern, 1997; Saunders et nl., 1994). CH-APTER6 CHARACTERISTICS OF RTVER-DOMINATED, WAVE-DOMINATED, AND MD(ED WAVE / RIVER LNFLUENCED DELTMC SUCCESSIONS: DIFFERENTIATION FROM SHOREFACE DEPOSITS

6.1 INTRODUCTION The analysis of the Dunvegan Formation and the Belly River Formation has led to ichnological and sedimentological criteria that aid in identifying and differentiating the subenvironments of river-dominated delta, wave-dominated delta, and mixed wave/river uinuenced delta from shoreface successions (Coates and MacEachem, 2000). Shoreface successions have been extensively studied with respect to sedimentology and ichnology throughout the western interior seaway (cg., Frey and Howard, 1982; Howard and Frey, 1984; MacEachem and Pemberton, 1992; Pemberton et cil., 1992; Raychaudhuri and Pemberton, 1992; Saunders and Pemberton, 1986; Saunders ef al., 1994)).The main differences in the facies are found within the prodelta and distal delta front deposits of deltaic successions, and the analogous offshore and lower shoreface of the shoreface setting. The more proximal delta front and the equivalent upper shoreface/foreshore complex are more difficult to differentiate from one another because of the higher physical energy conditions, which create very similar facies Iargely devoid of biohirbation within both settings. The purpose of this chapter is to descnbe the characteristic features of river- and wave-dominated deltaic successions of the Dunvegan Formation, and the mixed wave/river deltaic succession of the Belly River Formation; and to compare them with those of the typical shoreface succession of the Cretaceous interior seaway. Key lithologs from each succession illustrate the characteristics, facies, and depositional environments. Core photographs of typical features are referred to from Chapter 3. This synopsis gives a check-list of what to look for to assist in the recognition of deltaic successions and how to differentiate between 20 1 river- and wave-dominated deltaic end-members. Finally, the chapter outlines criteria that permits the differentiation between deltaic and shoreface successions. The prodelta and offshore environments both lie below fairweather wave base, but may be affected to varying degrees by storm activity. The deposits lie seaward of sandier deposits of the delta front and the lower shoreface, respectively. The delta front comprises the uppermost part of the subaqueous delta. The analogous shoreface constitutes the shallow subaqueous portion of the shoreline cornplex. Deposition in these sub-environments is typically above fainveather wave base, and facies predominantly comprise sands. The river-dominated delta succession (e.g., Allomember E, of the Dunvegan Formation) is characterized by the interstratified sandstone, silty mudstone, and hale facies in the prodelta. This is overlain by the convoluted silty mudstone/silty sandstone facies that grades into the laminated to structureless sandstone facies of the delta front. This succession is characterized in litholog 10-34-61-26W5 (Figure 6-1) and litholog 08-12-63-27 W5 (Figure 6-2). The wave-dorninated delta succession (eg., Allomember D of the Dunvegan Formation) is dso characterized by interstratified sandstone, silty mudstone, and shale facies in the prodelta setting. This is generally overlain by laminated to bioturbated sandstones which grade into laminated sandstones (Figure 3-7 C). The vertical succession represents delta front progradation, typically coarsening upward, and may be capped by a rooted and/or a coal facies (Figure 6-3; litholog 07-10-63-01 W6). The laminated to bioturbated sandstone facies of the delta front may be erosiondly incised by laminated sandstone facies (cycle Dl) which represent the switching of the chamel and delta abandonment. Examples of this scenario are shown in Litholog 10-26-63- 24W5 (Figure 6-4) and litholog 02-18-64-23W5 (Figure 6-5). In litholog 02-1û-64- 23W5, the laminated sandstones are overIaui by the interstratified sandstone and shale facies, which grades into the bioturbated sandy mudstone facies. 202 Mixed wave/river delta successions (eg., Cycles of the Belly River Formation) are characterized by the interstratified sandstone, silty mudstone, and shale facies of the basal prodelta, shown in Litholog 10-09-47-02W5 (Figure 6- 6) and litholog 16-07-49-08W5 (Figure 6-7). This grades upward into the convoluted silty sandstone/sandy siltstone facies of the distal delta front (Figure 6-6). The Iaminated to bioturbated sandstone facies either replaces the convoluted silty sandstone/sandy siltstone facies (Figure 6-7 and Figure 6-8 litholog 16-13-43-28W4) or interfingers it upward. This grades upward into the proximal delta front deposits, characterized by the hough cross-stratified and current rippled sandstone facies (Figure 6-6,6-7,6-8).

6.2 PRODELTA

6.21 Prodelta of the River-dorninated delta complexes The interstratified sandstone, silty mudstone, and shale facies charactenze the prodelta depositional environment. This facies is characterized by sharp- based sandstones displaying wavy parallel lamination, combined flow ripples, current ripples, and oscillation ripples. Syneresis cracks are common throughout (Figure 3-19 B, D). The current-generated structures, massive (apparently structureless) sandstone and silty mudstone, and abundant soft-sediment deformation features such as Ioading siructures, slump structures, and small- scale gravity faults, are al1 distinctive elements of this facies (Figure 3-31 A, B; Figure 3-24 E). These features are exceedingly rare in wave-dominated deltaic lobes, and have not been observed within any of the shoreface successions studied in the Cretaceous intenor seaway of Alberta (Coates and MacEachem, 1999,2000). The structureless character and the presence of soft-sediment deformation features both generally reflect high sedimentation rates. Storm beds are localIy present, but are subordinate elements (Figure 3-24 C). In storm- influenced successions, fissile, black mudstone layers commonly drape the 203 tempestites, recording rapid post-storm, suspension fa-out of clay, with abundant terrestridy-derived plant debris. Ichnologically, prodeltaic deposits of river-dorninated delta successions are largely devoid of bioturbation, reff ecting high sedimentation rates and pronounced environmental stresses (e.g., reduced but fluctuatïng salinity, variable substrate consistency, high water turbidity, and reduced oxygenation) that are common to this setting (Moslow and Pemberton, 1988; Gingras et al, 1998; Coates and MacEachern, 1999,2000) (Figure 3-24 A, D). Burrowing, where present, is sporadically distributed and ichnogenera are diminutive in size. The suite reflects a very low abundance but moderately diverse "highly stressed" assemblage of the Cntzinnn ichnofacies. Principal structures include the trophic generalist burrows Teiclzichnus and Plnnolites (Figure 3-30). These are the most cornrnon ichnogenera; al1 others are very rare and may be found in only a few cored intervals, with the exception of moderate numbers of Anconichnz~s.Very rare deposit-feeders include Zoophycos, Chondrites, Asterosorna, Rosselin, Arenicolites, and ndzczlnssinoides, as well as the grazing/ foraging structure, Helrninthopsis (Figure 3-19 A, 8,and C). Lockein are locally preserved and fugichnia are common throughout. There are also very rare suspension-feeders including Skolithos, CylindricJznns, Siphonichnus, and Opliiomorphn, and the passive dwelling carnivore structure Pnlneophyczrs. The burrows are sporadically distributed and principally associated with the sandstone beds, suggesting that the storm event/river flood deposits imported some of the organisms, and/or reflect an opportunis tic (early, post-stonn colonization) behaviour.

6.22 Prodelta of the Wave-domitrated delta complexes Like the river-dominated delta successions, the interstratified sandstone, silty mudstone, and shale facies characterizes the prodelta depositional environment of the wave-dominated systems. This facies is characterized by lenticular to wavy bedded mudstones, thin sandstones, and siltstones. UnIike the river-dominated complexes, though, the prodelta in these systems contain sharp- 204 based sandstones, with oscillation ripples, wavy pardel lamination, combined fiow ripples, and low angle parallel lamination (Figure 3-2 A; Figure 3-6 A). Current npples and convolute bedding do occur but are rare, in contrast to the river-dominated delta counterparts. The sandstone and siltstone beds refiect hummocky cross-stratification and storm-Ïnduced oxilIation ripple-laminated tempestites. The tops of the sandstone beds are either burrowed or mantled by dark, organic-rich, fissile mudstone layers. The mudstone Iayers may contain rare syneresis cracks (Figure 3-2 B). The prodelta deposits in these wave-dorninated systerns yield a diverse, but Iow abundance "stressed"assemblage of the Cnizinnn ichnofacies. Bioturbation may disrupt contacts between beds, creating a biogenicdly graded or mottled appearance, but does not destroy the discrete bedded character of the facies (Figure 3-14 A; Figure 3-6 B). The majority of the bioturbation is associated with the tops of the sandstone beds, suggesting that some of the organisms were irnported by the depositional event and/or reflect opportunistic behaviours. The numbers of burrows diminish upward into the shale beds suggesting that fainveather conditions were unsuitable for extensive infaunal colonization. The overail assemblage is characterized by ichnogenera that are typically diminutive in size. Reduced numbers of burrows in prodelta deposits probably indicate much higher sedimentation rates compared to the offshore units of the shoreface complexes, though lower than in the river-dorninated counterparts. The main grazing/ foraging stmctures comprise Ancotzidtn us and Helrnin fhopsis, indicating that nearly normal marine conditions were largely maintained. There is a predorninance of deposit-feeding skuctures, including abundant Plnnolites and Teichichnus (Figure 3-2 A) as well as moderate numbers of Terebellinn, Clmndnles, and Zoophycos. This group is far more common in the wave-dorninated setting than in the river-dorninated setting suggesting that there was more deposited food, and fewer environmental stresses present (e.g., lower sedimentation rates and less marked salinity fluctuation). Rare Rhizocornllium and Asterosorna, and very rare numbers of Rosselin and Lockein are also locally present. Escape 205 structures are also present in moderate numbers. Suspension-feeding structures are confined to opportunistic suites at the tops of tempestites, but are very rare and represented by Skolithos, Cylindriclinils, and Siphonichnzls (Figure 3-2 E). The passive carnivore dwelling structure Pnlneoplzyczs is also present, but rare. Mncrrronichnzis occurs locally in some sandstones, but are also very rare. Many ternpestites are totally unburrowed, and are mantled instead by dark fissile mudstones attributed to rapid post-storm suspended sedirnent fallout.

6.23 Prodelta of the Mixed WavmiuerInfluenced Delta Complexes The interstratified sandstone, silty mudstone, and shale facies also characterizes the prodelta depositional environment of the mU

6.24 Prodelta: Cornparison of Environmental Controls In the prodelta, the interstratified sandstone, silty mudstone, and shale facies is found in al1 three successions. The river-dorninated successions contain abundant current-generated structures, massive (apparently shuctureless) sandstones, and silty mudstones, and abundant soft-sediment features. These features, which are exceedingly rare in wave-dorninated successions, reflect current transport and high sedimentation rates. Syneresis cracks are common throughout. Storm beds are locally present, but comprise subordinate elements. In the wave-dominated successions, wave-generated stmctures dominate the sandstones, and reflect hummocky cross-stratification and storm-induced oscillation ripple lamination. Syneresis cracks are also present, but rare. Synsedimentary deformation stnictures are uncomrnon. The xnixed wave/river delta succession contains sedirnentological features of both river- and wave- dominated delta successions. These prodeltaic deposits typically contain soft- sedirnent deformed and massive (apparently structureless) sandstones and silty mudstones, current generated sandstones, tempestites, and syneresis cracks. The prodelta deposits of river-dominated delta successions are largely devoid of burrowing. Where present, burrowing is sporadically distributed and ichnogenera are diminutive in size. The suite reflects a very low abundance but moderately diverse "highly stressed" Cnizinnn ichnofacies. Principal stnictures 207 include those of trophic generalists, such as Plmolifes, Teiclziclrnzis and moderate numbers of Anconiclzntrs, though sporadically dispersed in the wave-dominated delta succession. Bioturbation in this succession may disrupt contacts between beds, creating a biogenically mottled appearance. Ichnogenera are also diminutive in size. Plnnolifes and Teichictznzls are the most abundant traces. Anconiclmz~s,Helmintltopsis, and Zooplzycos are also comrnon, indicating that nearly normal marine conditions were largely maintained. The mked wave/river delta succession yields a diverse, but low abundance "stressed" Cnlzinnn ichnofacies. Principal structures include the trophic generalists Plnnolifes and Teichiclznus, and moderate numbers of Anconichnus, reflecting opportunistic behaviour. In all the deltaic successions, there is a predominance of deposit- feeding structures, and suspension-feeding stnictures are conspicuously very rare: where they are present, they reflect opportunistic ternpestite colonization. The paleoenvironmental factors that are responsible for the differences in the trace fossils suites of river-dorninated, and wave-dominated, and mixed wave/river infiuenced deltaic successions include changes in salinity, abundances of organic matter, increased water turbidity, increased sedimentation rates, fluctuating oxygenation, and variable substrate consistency. The differences in trace fossil suites are unlikely to be due to a single factor, but rather, to several factors working in concert to create sufficient physeo-chernical stresses to affect the entire assemblage. Nonetheless, certain ichnological and sedirnentological respowes are probably largely attributable to specific environmental stresses. The prodelta of the river-dominated delta succession is characterized by overall high sedirnentation rates and high water turbidity. Reduced salinity may be due to density underflows of fresh water, due to inertia-dominated flow. These flows are characterized by exceedingly high sediment concentrations and form hyper-concentrated flows that evolve downslope as turbidity currents (e.g., Wright et nl., 1988; Mulder and Syvitsky, 1995; Bhattacharya, 1999). This would result in salinity fluctuations that typically Lead to the decreased trace fossil sizes 208 and low trace fossil diversities observed in the river-domuiated successions. (e.g., Pemberton et al., 1992a,b; Pemberton and Wightman, 1992; Gingras et al., 1999). Reduced salinity or oxygen reduction was not likely a persistent problem but may have been sporadically important, pa-tcularly where black fissile mudstone beds are cornmon. The suite of Plnnolites-Teidzichnus are common to salinity- stressed settings, particularly those associated with reduced salinity conditions such as estuarine incised valleys and bays (e-,o.,Whightman et al., 1987; Beynon et rzl., 1988; Pemberton et al., 1992; MacEachern and Pemberton, 1994; MacEachern et al., 1998,1999; Gingras et al., 1999). In addition, the paucity of specialized normal marine traces such as Zoophycos, Helmintlzopsis, Arenicolites, Asferosomn may also support salinity fluctuations. Reduced sdinity- also is further supported by the abundance of syneresis cracks. With the high sedimentation rates originating hom fluvial flood discharge, the high amounts of organic matter in suspension in the river-dorninated successions may also contribute to the unburrowed state of the mudstone interbeds. The carbonaceous shale interbeds contain abundant plant debris, likely of terrestrial origin. When this organic rnatter deposited within the mud, oxidized it, and consumed oxygen it may have induced local development of anoxic or dysaerobic conditions near the bed. Such conditions would largely preclude biogenic reworking of these shales. The prodelta environment of river-dominated delta settings are more susceptible to lowered oxygen and salinity fluctuations, compared to the wave- dominated counterparts. In wave-dominated successions, the persistent reworking of the sediment by wave action stabilizes the sediment and supplies refreshed marine waters to the sediment-water interface, facilitating more uniform salinity and oxygen Levels. In these settings, the reduced trace fossil diversity may reflect in loco fluctuations in energy and high sedimentation rates. This restricts most of the burrowing to the interfaces between the tempestites recording pauses in sedirnent accumulation. Overall high sedimentation rates reduce burrow abundance and therefore bioturbation intensity, as this gives 209 infauna reduced periods of tune to colonize the substrate. High rates of clastic input also generally reduce the concentration of deposited food percent volume of sediment, lirniting the abundance of deposit feeders. In the wave-dominated delta successions, however, the abundant terrestrial organic matter may have been dispersed by wave-action, and therefore served as a food resource for infaund organisms, rather than concenhating it in layers and causing local development of anoxic or dysaerobic conditions. Consequently, evidence of salinity fluctuations and reduced oxygen, though locally present, is uncornmon in contrast to the river-dominated delta successions. Al1 these factors account for the low abundance but diverse "stressed" Cmzzana ichnofacies in the wave- dominated prodelta. Comparatively, the river-dominated prodelta succession yields a very low abundance, and only moderately diverse "highly stressed" Cnizimin ichnofacies, as the physeo-chernical stresses are more pronounced in these settings.

6.3 DELTA FRONT

6.31 Delta Front of the River-Dominated Delta Complexes The distal delta front of Dunvegan river-dominated successions is characterized by the convoluted silty sandstone facies. The distal delta front may be strongly affected by storms, tides, and/or fluvial currents. The storm deposit intervals consist of thin (5-15 cm thick) HCÇ beds. These are interstratified with massive silty mudstones and soft-sediment deformed heterolithic units. Gravity faults are locally common. Current rippled sandstone and loaded, slumped or convoluted units dorninate some intervals (Figure 3-25 A, B). The convoluted silty sandstone facies is typicdy devoid of burrowing. Very rare lamhated sandstone beds occur locally, and may contain Helrnintlzopsis, Anconichnus, and Teichichizus. 210 The convoluted silty sandstone facies is intercdated with the laminated to stnictureless sandstone facies of the distal to proximal delta front. Amalgarnated, storm-generated HCÇ beds (Figure 3-25 C; Figure 3-31 C)interfinger with units of convoluted or massive (apparently shuctureless) (Figure 3-31 D) sandstone. The tempestites and convolute bedding are commonly draped by black mudstone layers, recording rapid post-storm, suspension fall-out of clay and abundant terrestrial plant debris. There is a general upward coarsening of sediment grain size, and trough cross-stratification becomes more dominant with the transition into the proximal delta front. The delta front is largely devoid of burrowing, mainly due to the persistent river flood and/or storm events, abundant suspended sediment, rapid uifIuxes of sediment and fresh water near the bed, unstable substrate consisiencies, and overall high water turbidity. The ichnological suite reflects a very low abundance and very low diversity, "highly shessed" assemblage of the Cruzinnn ichnofacies. A few burrows are present and sporadically distributed in the laminated sandstone. The ichnogenera ùiclude Teiclriclzntis, Cylindnc?zntis, fugichnia, and some enigmatic (unidentified) burrows (Figure 3-32 D). In rare mudstone layers, Planolites and Teiclriclznris are present.

6.32 Delta Front of the Wave-Dominated Delta Complexes The laminated to bioturbated sandstone facies characterizes the distal portion of the delta front in the wave-dominated deltaic succession. The facies is best shown in litholog 07-10-63-01W6 (Figure 6-3). The facies is characterized by a dominance of wavy parallel laminae and low angle parallel lamination, representing hurnmocky cross-stratification (Hm)and rarer swaley cross- stratification (-). The presence of sharp-based sandstones, reflecting stacked erosionally amalgarnated tempestites, indicates that storm-action played a major role in this depositional setting. Oscillation ripples, combined flow npples, and very rare current ripples capping the HCS beds signïfy the waning periods of storms, as well as wave and current activity during fairweather conditions. Convolute bedding is locally common. Stratification is demarcated by carbonaceous detntus, reflecting abundant organic matter in suspension. This facies passes upward into erosionally amalgarnated SCS laminated sandstones (Figure 3-9A) of the proximal delta front Sandstones contain organic- rich mudstone rip-up clasts or rare thin mudstone layers. Current-generated structures are uncornmon, but become more abundant upward as shoaling conditions cause waves to break. The proximal delta front is similar to the upper part of a shoreface, and is characterized by breaking waves, surf zone conditions, and ultimately wave swash. The interval consists of fairweather trough cross- stratified (Figure 3-9 8)and current rippled sandstones truncated by storm- generated erosion surfaces, ultimately capped by low angle, planar parallel laminated sandstones reflectùig swash zone stratification of the foreshore. The ichnological suite of the wave-dominated delta front deposits comprises a moderately diverse and locally abundant assemblage of the mked Skolitlzos-Cntzinnn ichnofacies (Figure 3-7 A, B). There is a decrease in abundance and diversity of trace fossils upward into the proximal delta front, attributed to higher energy conditions. Immediate post-storm conditions provided a more favourable setting for colonization of the substrate by infaunal opportunists. Opportunistic organisms are represented by ichnogenera such as the suspension- feeding structures Diplo~aferio~~(Figure 3-8 A, B) and Cylindrichnus (Figure 3-8B), which are most common in this facies. Less abundant ichnogenera include Skolithos, Arenicolites, Pnlneophyncs, Mncnronicl~nt~s,and Conichnzcs (Figure 3-8 D). These ichnogenera comprise elements of the Skoliflzos ichnofacies and are generally confined to the sandstone beds. Within this interval, higher energy, deposit-feeding stnichires of the proximal Cruzinnn suite are present, and include Rosselin, Asferosornn, and Thnlnssinoides (Figure 3-8 C). As storm conditions wane and energy levels decrease towards those of fairweather, the opportunists are subjected to normal ambient depositional conditions. If they are unsuited to these conditions they gradually die off and are replaced by the resident community. Fairweather conditions are reflected by a 212 predominance of deposit-feeding structures, including moderate numbers of Plnnol ites and Teichicl~nus~and rare Cltondrites, Terebellinn, Siphoniclinzcs, Zoopliycos, and Rlr izocornllitrm. Rare grazing structures such as Helrnin thopsis are present. Lockein is locally preserved.

6.33 Wave-Dorninated Delta Front: Relative Transgression The bioturbated sandstone facies is also a characteristic feature of the deltaic successions (Figure 6-5, litholog 02-18-64-23W5). This corresponds to the more normal marine conditions during the destructive phase of the delta and relative transgression. This facies shows what the normal marine (non-deltaic) signal of the basin is like because it accumulates while the delta is not prograding. The bioturbated sandstone facies is an important facies as it can be contrasted with the prodelta deposits when the delta is active. This facies typically has an erosive base and is locally found abruptly overlying prodelta to distal delta front deposits. The sandstones are characterized by low angle parallel lamination, trough cross-stratification (Figure 3-13 D), and current ripples (Figure 3-13 E), with rare oscillation ripples and combined flow ripples. Mudstone rip-up clasts are abandant throughout (Figure 3-13 B, C). Mudstone beds are common and typically contain sand-filled syneresis cracks, Plnnolites, and rare Teiclzidznzcs. This facies contains few prirnarv physical structures that have not been destroyed by bioturbation. Remnant stmctures include oscillation ripples with rarer wavy paralle1 lamination (HSC) and combined flow ripples. Large arnounts of carbonaceous detritus are present. Rare syneresis cracks are locdly preserved. The ichnologcal suite is diverse and the overall intensity of burrowing is high, with a uniform distribution. The suite represents the Cnczinnn ichnofacies, and includes grazing/foraging structures such as moderate to rare Anconichnus and Helmintlzopsis. The bulk of the suite consists of deposit-feeding ichnogenera such as abundant Zoophycos, Plnnolites, Teichichnzcs, and Asterosornn, with rarer Clzondrites, Rlzizocornlliurn, and Tluilnssinoides. Ophiomorphn as well as the passive 213 carnivore dwelling stnictures Palneophyars and Terebellinn are also present. Suspension-feeding structures are uncommon and include rare nurnbers of Skolithos, Cylindriclznus, Siphonidznus, and moderate numbers of Diplocraterion (Figure 3-14 C, D).

6.34 Mixed WavmiverDelta Front The distal delta front of the Belly River Formation is sirnilar to the river- dorninated succession and is characterized by the convoluted sandy siltstone/ silty sandstone facies, which consists of convolu te bedding and structureless beds reflecting rapid deposition (Figure 3-52 D). The bedding is demarcated by carbonaceous detritus, reflecting abundant organic matter in suspension. This facies is devoid of bioturbation. Organisrns appear to have been unable to burrow this subshate, probably due to a combination of factors, including unstable, soupy substrates (e-g.,abundant deformation structures), abundant suspended sediment (e.g., lack of suspension feeding stnictures in the sandstone beds), rapid sediment influx (e.g., massive beds), and the intermittent presence of fresh water (e.g., syneresis cracks). The distal delta front also contains the larninated to bioturbated sandstone facies common to the wave-dominated successions. What is unique to the mixed wave/river influenced delta successions is that the tempestites are regularly interstratified with massive and deformed beds, showing a altemation of storm wave and river flood depositional processes. The large intervals of massive (apparently structureless) sandstone (Figure 348 B, C) and convoluted sandstone beds (Figure 3-59 C; Figure 3-38 C) reflect rapidly deposited intervals with minimal reworking. This is intercalated with erosionaily amalgamated HCÇ and SCS (Figure 3-59 A) sandstone beds, reflecting emplacement during storms, and demonstrates that storm action played a sigmficant role in this depositional setting as well. Rare oscillation ripples, aggradational ripples, current ripples, and combined flow ripples sigmfy deposition during the waning periods of storms, as well as wave and current action during fairweather (post-storm) 214 conditions. This was also accompanied by an abundance of sediment (Figure 3-59 E). Rare to moderate numbers of mudstone beds, reflecüng deposition from suspension, decrease in abundance upward in the facies (Figure 3-43 8).These mudstone beds locally contain syneresis cracks. These distal delta front deposits pass upward into proximal delta front and foreshore deposits, dominated by trough-cross stratified and current nppled sandstones. This transition is associated with shoaling during delta lobe progradation (Figure 3-39 A, B, and C). These structures are also intercalated with massive (apparently struchireless) sandstones, indicatïng periods of rapid sedimentation. The ichnoiogical suite of the proximal delta front deposits comprises a moderately diverse and locally abundant mixed Skolitlzos-Cnrziann ichnofacies. The suite reflects in loco fluctuations in energy associated with storm activity. The fairweather mudstones contain deposit-feeding structures, including Plcznolites, and very rare Rlzizocornllium, and grazing/foraging structures such as Anconzchntis and Helrnin fhopsis. These ichnofossils represent the fairweather " Cnrzinnn" ichnofacies. Deposit-feeders predominated within the sandstones, and generated ichnogenera such as Asterosomn, Arenicol ites, Teichicltntrs (Figure 3- 38 A), and Rosselin. These structures are interpreted as post-stom opportunistç. Rosselin mud "bulbs"are found detached from their dwelling structures, and nearby, thickly mantled tubes with concentric layering may be present (Figure 3- 55 A-D; Figure 3-44 A, B). This suggests that some trace-makers were able to readjust their structures in response to the shifting sediment-water interface, while others were uprooted or buried, and unable to survive. Mudstone rip-up clasts, resembling remnants of Rosselin and Asterosomn burrows, are found throughout this facies. Mobile deposit-feeding structures prone to higher energy regirnes, reflected by Mncnronichnus sirnplicntus (Figure 3-38 B; Figue 3-54 E), are locdy present. The passive carnivore dwelling structure Pnlneoplzyms is locally present. Suspension-feeding structures are rare, but include Cylzndrichnus, Skolithos, and Oplliomorphn (Figure 3-54 B, D). 6.35 Delta Fronf: Cornparison of Environmental Controls In the distal delta front, the most distinctive facies is the convoluted silty sandstone facies of the river-dominated and mixed wave/river deltaic successions. It consists mainly of massive silty mudstones and soft-sediment deformed, loaded, slumped or convoluted units. Gravity faults are locally common. This facies is typically devoid of burrowing. In the river-dominated succession, this grades upward into the laminated to stmctureless sandstone facies. Amalgamated HCS beds are intercalated with convoluted and massive sandstone beds, which pass upward into trough cross-stratified sandstones of the proximal delta front. The convoluted facies does not occur in the wave- dominated delta successions. Instead, the distal delta front is characterized by the laminated to bioturbated sandstone facies reflecting stacked tempestites. HCS and SCS beds dominate, though convolute bedding is locally common. This passes upward into erosionally amalgamated ÇCS beds and the trough cross- stratified sandstones of the proximal delta front. The convoluted sandstone of the mixed wavelriver influenced delta succession also grades into the laininated to bioturbated sandstone facies. This facies is more like the wave-dorninated delta succession, but the amalgamated HCS and SCS beds are intercalated with thick intervals of convoluted and massive sandstone beds. In the delta front, the mUted wave/river influenced delta successions and wave-dominated delta successions both yield a moderately diverse and locally abundant, aedSkoliflzos-Cmzicrnn ichnofacies. In contrast, the river-dorninated delta succession yields a very Iow abundance and very low diversity, "highly stressed" Cniziann ichnofacies. Few burrows are present and are sporadically distributed, including Teichichm

6.4 DIFFERENTIATING DELTA SUCCESSIONS FROM SHOREFACE SUCCESSIONS

6.4 Introduction The subenvironments of typical shorefaces from the western interior Seaway of North America are compared and contrasted to the deltaic subenvironments described within this thesis. These environments are found adjacent to one another, and therefore it is important to recognize differences and similarities in each corresponding subenvironment in order to distinguish between the depositional settings. The two settings are similar in that they are shoaling/ progradational successions which generate coarsening- and sanding- upward successions. Both occur in marine to marginal marine conditions and therefore are subjected to tide and wave processes, and contaîn marine fossils. Both are also attached to or are near the shoreline. They are different in that the deltaic successions are affected by direct fluvial infiux of sedirnent and 219 freshwater into the basin. Depending upon whether the delta is river- or wave- dominated, the succession generated rnay display varying degrees of similarity or difference to that of a shoreface.

6.42 Prodelta us. Offshore Offshore deposits associated with shoreface successions typically contain diverse and abundant distal and archetypal Cnizinnn ichnofacies, though they rnay display a close affinity with the prodelta deposits of sorne wave-dorninated deltas (Gingras et al., 1998; Coates and MacEachem, 1999,2000). Although there are subtle differences, discrimination may be difficult, and locally reflect dong- strïke gradation between these systems (e.g., Cadotte Member, Saunders et nl., 1994; Bow Island Fm, Raychaudhuri and Pemberton, 1992). This is particularly true for storm-dominated successions, where burrowing intensities decline markedly due to episodic but generally high sedimentation rates. In storm- dominated offshore settings, tempestites may also be mantled by unburrowed, dark, fissile mudstone layers from suspension fallout, sirnilar to those of wave- dominated prodeltaic settings. Where storm influence is less marked, the preservation of fairweather deposits permits discrimination of offshore environments (c5, MacEachern and Pemberton, 1992; Pemberton and MacEachem, 1997). In the Cretaceous Western Interior Seaway of North America, lower offshore deposits consist of subtly bioturbated sihy mudstones representing slow sediment accumulation in quiet water conditions. Substrates are typically soft and soupy. Thin pardel laminated sandstones are locally present and represent distd tempestites. The upper offshore setting is more proximal and generdy one of continuous and uniforrn deposition, except where the storm regime is high. Facies consist of biogenically mottled sandy mudstones reflecting variable but generally quiet water conditions. Fairweather substrates are soft, with the developrnent of sandy substrates typicalIy following tempestite deposition 220 during storms. These sandy beds are typically characterized by oscillation rippled or wavy parallel laminated CHCç) sandstones. This differs from the interstratified sandstone, silty mudstone, and shale facies found in the prodelta of deltaic successions. The river-dominated deltaic succession is easily distinguishable from the offshore deposits by the cuïrent- generated stnictures, massive (apparently structureless) sandstones, and siltstones, soft-sediment deformation features, and syneresis cracks. Syneresis cracks, massive silty mudstone beds, and intensely soft-sediment deformed intervals have not be recognized in any of the offshore deposits described from the Cretaceous Western Interior Çeaway. Differences are not as apparent in the wave-dominated delta successions, as both these deltas and shorefaces are dominated by wave-generated structures. The wave-dominated deltaic deposits still display rare occurrence of syneresis cracks, and the facies are not as biogenically mottled, as offshore deposits of shoreface successions. Lower offshore deposits are characterized by uniformly dishibuted trace fossils and intense bioturbation. Trace fossil diversity is generally high, and characterized by grazing and deposit-feeding structures with rare passive carnivore structures. Ichnogenera include Helrninfhopsis, Anconic~zni~s,Chondrites, Zoophycos, Plcznolifes, Terebellinn, and rarer Thnlnssinoides. This reflects a distal suite of the Cnlzinnn ichnofacies or the Zoophycos ichnofacies (MacEachem and Pemberton, 1992; MacEachern, 1994; MacEachern et al., 1999). Deposits of the upper offshore are also characterized by intense and uniform bioturbation, but bioturbation is typically more sporadic, particularly with increasiiig storm influence (MacEachem, 1994; Pemberton and MacEachern, 1997). Trace fossil diversity is generally high, but this also declines with increasing storm influence. Fairweather suites are dominated by deposit-feeding stnictures with abundant numbers of grazing structures and rarer dwelling structures. Suspension feeding/dwelling structures and escape structures may be associated with the thicker tempestites. Ichnogenera include Helrnin thopsis, Chondntes, Zoophycos, Anconichnzcs, Terebellinn, Planolites, Asterosomn, 22 1 T7urlnssinoides, Teichichnzrs, Rosselin, and Rliizocornllizun, with rarer Cylindrichnzrs, Schubcylindrichnzis, Palneophycus, Skolithos, Siphonichn~rs, and Diplomnterion. The overd suite reflects the archetypal Cruzinna ichnofacies. The degree of bioturbation and diversity of trace fossils are profoundly different from those of prodeltaic deposits of deltaîc successions. In fact, the most similar facies of the Dunvegan Formation to the typical offshore deposit is that associated with transgression and a cessation in delta lobe progradation (e.g., Figure 3-13; 3-14; 6-5).The river-dominated successions are largely devoid of burrowing and ichnogenera are diminutive in size. In contrast prodekas of the wave-dominated successions are broadly similar to deposits of the offshore, but bioturbation only dismpts the contacts between beds, creating a biogenically mottled appearance. Offshore deposits are more commonly thoroughly homogenized unless interspersed with remnants of tempestites. Principal biogenic structures of the prodeltaic deposits ïnclude those of trophic generalists, such as Plmolites, Teichic?zntrs, and Anconichntrs, representing a "stressed" Cruzirrnn ichnofacies. Anconiclznus and Helnzinthopsis are abundant in the wave-dominated delta successions, indicating that normal marine conditions were largely maintained similar to the offshore. The presence of synersis cracks in unburrowed horizons suggests that intermittent periods of reduced salinity occurred as well. The offshore and prodelta are also similar in that deposit-feeding structures dominate. The main differences are with respect to trace fossil abundances, diversities, and sizes. The fluvial influence on the deltaic successions accounts for very low abundances, low to moderate diversities, and diminutive sizes of the trace fossil. Increased water hirbidity accompanying river discharge also accounts for the rarity of suspension-feeding structures even on available sandy substrates.

6.43 Delta Front us. Lower to Upper Shoreface and Foreshore The shoreface is dorninated by wave and storrn processes. In the Cretaceous Western Interior Seaway of North Arnerica the deposits of the lower 222 shoreface typically consist of mottled muddy sandstones (fairweather) with interstratified undulatory pardel laminated (Ha)sandstones (tempestites). Some muddy and silty Ïnterbeds may be present. Substrates are generally noncohesive and shifting, reflecting deposition in a zone of persistent wave shoaling (ie., above fairweather wave-base). The midde shoreface may also consist of interstratified burrowed sandstones and parallel Iaminated sandstones. The particular facies generated depends upon the degree of storm domination, and range from amalgamated SCS sandstones to well burrowed sandstone. In settings where longshore currents are strong, or in barred systerns, current ripples and hough cross-stratification may be intercalated (Wright et nl., 1979; Thom et al., 1986). Upper shoreface deposits are dominated by wave-forced currents generated by breaking waves, producing current rippled and small- scale trough cross-stratified sandstones and conglomerates (cc, Davidson-Amott and Greenwood, 1976; Roy et nl., 1980; Reinson, 1984; Thom et al., 1986). Continued shallowing into swash zone conditions of the foreshore is manifest by low angle planar parallel laminated sandstones in wedge-shaped sets (CF, Clifton, 1969). nie sedimentology of the shoreface is broadly similar to that of the wave- dominated delta front. The distal delta front is also characterized by the laminated to bioturbated sandstone facies. Like the shoreface, this setting is strongly affected by stem, consisting of stacked tempestites. HCS and SCS beds dominate, passing upward into erosionally amalgamated SCS beds of the proximal delta front. One difference is the presence of locally comrnon intervals convolute bedding in the delta front successions. Convolute bedding is atypical of the shoreface successions. The lower shoreface and river-dorninated distal delta front are quite different The river-dominated delta front successions consist mainly of massive silty mudstones and soft-sediment deformed, loaded, slumped or convoluted units. This grades upward into amalgamated HCS beds intercalated with 223 convoluted and massive sandstones beds. The proximal delta front is dominated by trough cross-stratified sandstones. The rnixed wave/river influenced delta successions resemble those of shoreface successions, though with one major difference. The amdgarnated HCS and SCS beds are intercalated with thick intervals of convoluted and massive silty mudstones and silty sandstone beds. The silty, convolute bedded mudstone and massive to convoluted silty sandstone facies are more common and perhaps even unique to the deltaic successions (cj, Bhattacharya and Walker, 1992; Reading and Collinson, 1996). These deposits reflect the high rates of fine sediment deposition that are typically associated with deltaic settings. A second difference between the delta front and shoreface deposits is associated with organic-rich mudstone interbeds. The unusual and persistent development of the dark, organic-rich and unburrowed mudstone interbeds within the facies successions appears comrnon to the deltaic intervals, but are uncornmon to most shoreface successions. These interbeds reflect the rapid introduction of abundant plant debris with suspended sediment, which, during oxidation, generates local reducing conditions at the sediment-water interface. These interbeds are interpreted to reflect "phytodetrital pulses", likely related to short-lived, increased river discharge during periods of high precipitation that typically accompany storm events (CF,Leithold, 1989; Raychaudhuri and Pemberton 1992; MacEachern, 1994; Saunders et al., 1994; Coates and MacEachem, 1999). Consequently, tempestites in the deltaic settings commonly becorne mantled with organic-rich mud during post-storm conditions, limiting their availability to sandy-substrate infaunal colonizers. The lower shoreface is dominated by an archetypal to proximal suite of the Crzrzinnrr ichnofacies under faimeather conditions, with considerable contributions from the Skolithos ichnofacies (MacEachern and Pemberton, 1992; MacEachern et al., 1999). These fairweather assemblages consist of a large diversity and high abundance of trace fossils. The intensity of burrowing is higldy variable, depending upon the degree of storm dominance (MacEachern, 224 1994; Pemberton and MacEachem, 1997). The fairweather muddy sandstones are typically unifody and intensely burrowed. Deposit feeding and dwelling structures dominate and include robust Rosselirr, Asfeuosomn, Teiclzidzn~rs, Cylindrichnus, Zooplzycos, Schubqlincïric~zn~is,Terebellinn, Plnnolites, Thnlnssinoides, Anconichnus, Çiplzonichntis, horizontal Opliiornorphn nodosci, 0. iweprlnire, rare O. nnnzilntn, Chondn'tes, and Rhizocornllium. Grazing structures include Helrnintliopsis, Cosrnorhrrphe, Scolicin, and A zr Iicl~nites.Structures of the Skolithos ic hnofacies include Skolitlzos, Conidinirs, rare Diplocrnterion, rare Bergazierin, and the passive carnivore dwelling stnicture Pnlneophyczcs (MacEachern and Pemberton, 1992; Pemberton and MacEachern, 1997). As the energy of the setting increases to the middle shoreface, bioturbation intensity becomes highly variable and is sporadically distributed, generally due to increasing storm Muence associated with shdow water conditions. The middle shoreface is typically dorninated by the vertical to inclined dwelling structures of suspension-feeding orgarùsms with subordinate deposit-feeding structures. Fairweather suites are characterized by Skolifhos, Oplziornorplin, Dipl~crnterion~Arenicolites, Conichniis, Bergnzrerin, Rosselin, Asterosornn, SchnubajIindnchnzrs, Cylindriclznirs, Terebellinn, Plnnolites, Teichichnirs and Pnlneophyczrs, with rarer Rhizocor~lliirmand Chondrifes (MacEachem and Pemberton, 1992; MacEachem, 1994; Saunders et RI, 1994). Tempestites are generally unburrowed or weakly burrowed by opportunistic suites, with bioturbation intensity greater toward the tops cf beds (Pemberton and MacEachem, 1997). Typical ichnogenera include Skolithos, Arenicolites, Ophiornorphci, Diplocrnterion, Rosselin, Pnlizeophyctrs, and Anconich~~us.As the storm effects become more pronounced, the diversity of the associated deposit-feeding structures declines. This may be attributable to the abundance of well-winnowed sand and the general paucity of deposited food for the tracemakers (MacEachern and Pemberton, 1992). Rosselin, Asterosomn, and Cylindrichnus are the exceptions, and may be found persisting upwards well into middle shoreface deposits. 225 In upper shoreface deposits, trace fossils are locally common but rarely abundant, and diversities are low. Only deeply penetrating dwelling structures of the Skolitlzos ichnofacies, such as Diplocraterion, Skolithos, and Coniclznzr s, or mobile but infaunal deposit-feeding structures such as Mncnroniclinus are common. Foreshore settings are largely devoid of bioturbation except in sheltered localities where the Skolitlzos ichnofacies may be developed, or in open areas where Mncnroniclznzrs segregntis may fom, corresponding to the "toe-of-the- beach assemblage (Saunders et al., 1994). In contrast, however, dweUing/suspension-feeding structures are comparatively uncornmon in the sandstones of delta fronts, and are interpreted to reflect two major factors: 1) Direct stresses on infauna. River discharge into the basin increases water turbidity, making suspension feeding difficult or impossible. The filter feeding apparatus of such organisrns may become clogged by this suspended sediment. In addition, the high amounts of suspended sediment lowers the ratio of food to ingested sediment adding additional stress on the organisms (Moslow and Pemberton, 1988; Gingras et al., 1998; Coates and MacEachern, 1999). 2) Post-storm/flood discharge effects. Storm events are typically accompanied by high rates of precipitation. Near distributaries, resulting river flood discharge results in large arnounts of organic detritus and clay being swept into the basin. During post-storm conditions, this material settles onto the storm beds, shielding them from opportunistic colonization by sand-favouring infauna. High organic content in the mud may also result in its rapid oxidation and concomitant oxygen depletion at the sea floor, diminishing the ability of infauna to colonize the bed (c5, Leithold, 1989; Raychaudhuri and Pemberton, 1992; Saunders et al., 1994; Coates and MacEachern, 1999). With increasing storm influence, the diagnostic fallureather trace fossil cornmunities of the shoreface are progressively lost, and are replaced instead by an abundance of post-storm opportunists. These post-storm suites cmbe diEficult to discem from trace fossil assemblages associated with wave- dominated delta front successiow. Hence, differentiatïng between wave- dominated deltaic successions and storm-dominated shoreface deposits can be problematic. The paucity of suspension-feeding structures within sandstones of the delta front is in marked contrast to their abundance in storm sands within true shoreface successions. Although this paucity is less rnarked in wave-dominated deltaic successions than in their river-dominated counterparts, it remains discrete from the suites of storm-dominated shorefaces. Post-storm opportunistic colonization of tempestites within the shoreface regime is characterized by some deposit-feeding structures and a predomuiance of dwelling structures of suspension-feeding organisrns (Pemberton et nl., 1992; Pemberton and MacEachem, 1997). In contrast, the delta front tempestites show a notable absence of most suspension-feeding structures. Oil et al Simonette Delta Front Progradation 10.3441-26w5 Typical Facies Succession - GRAIN SlZE cobble 7mbble

sand

Laminarad 10 Pmxirnal Stmcrureless Delta Front Sandstone Facies

Convolured Silty Distal Sandstone Facies Delta Front

lntersrratilied Sandstone. Silty Mudsrone. and Shale Fa cies

Figure 6-1. Litholog of well 10-34-61 -26W5, exhibiting 5;hingle E2 of the Dunvegan Formation. Oil Merland Sirnonette Delta Front Progradation lnterupted 08-12-63-27w5 by Abandonment/Flooding

t%i!s

Shale Facies Distal Prodelta

Larninated 10 AbandonmenV Bioturba ted Flooding of Sandstone Faces Delta Front

Laminated to Sl~ctureless Distal Sandstone Facies Della Front

Inf ersira iified Sandstone. Silty Proximal Musione. and Pmdelta Shale Facies

Intersrrafified Sandsione. Silty Proximal Mustone. and Prodelta Shale Facies

Figure 6-2. Litholog of well 08-1 2-63-27W5, exh iting shingle E3 and E2 of the Dunvegan Formation. Esso Simonette 7-10 Delta Front Progradation 07-1 0ô3-01w6 Typical Coarsening Upward GRAiN SlZE

Laminated ProUrna1 andstone Facies Delta Front

Larninated to Bioturbated Dista: andsrone Facies Delta Front

Iioturbated Muddy Proximal Prodelta- Sandstone Facies DisBi Delta Front

Laminated Discal iandstone Facies Delta Front

tersifarilied Sandstone. Proximal Silty Mudstone. and Prodelta Shale Facies

Figure 6-3. Litholog of well 07-1 0-63-01 W6, exhibiting shingle D2 and D3 of the Dunvegan Formation. 230 Amoc0 Waskahigan Delta Front Cu?Down lnto and 1O-2663-24w5 Overlain by the Channel Facies

Laminared Channel FiIl iandstone Fanes

Laminaied Dislal ;andsrone Fanes Delta Front

ïrerstra rified Sandstone. Proximal Silry Mudstone. and Prodelta Shale Facies a""

Figure 6-4. Litholog of well 10-26-63-24W5, exhibiting shingle D2 and Dl of the Dunvegan Formation. Amoco Mobile Waskahigan Channel Fil1 1 02-1 8-64-23w. I

GRAIN SlZE Mbbb pebble c-d

Bioturbared Sandy Prvximal Pmdelta Mudsrone Facies In Channel

ntentratified Sands:one. Proximal Pmdelta Silty Mudstone. and h Chanel Shale Facies

Lamina ied Channel Fi(l Sandstone Facies

.itsrstratiiied Sandstone. Proximal silty Mudstone. and Pmde »a Shale Faciès

Figure 6-5. L tholog of well 02-18-64-23\1\15, ex1 itir iingle D2 and Dl of the Dunvegan Formation. Super Test' Delta Progadation 10-09-47-02~5

GRAIN SlZE

granule 2 sand 1:

iough and Curreni Foreshore Rippled Sandstone cacies

Larnindted to Proximal eioiurbated Deltü Front Facies

:onvoluted Sandy Distal Siltstone Facies Delta Front

ntentratified Sandstone. proxjma~ Silty Mudsione. and Pmde/fa Shale Facies

Figure 6-6. Litholog of well 10-09-47-02W5, exhibiting cycle G of the Belly River Formation. Pajaetal. ~ome Typical Delta Front Progradaion 1~74908w5 Abrupfly Overlying Prodelta Deposits

la?

1m Proximal Delta Front

!El

la3 Laminated to Bioturbated randstone Facies

ta

la%

aif Distal Delta Front

038

w

Intersrratified Proximal Sandstone. Silty M2 Prodelta Mudstone. and Shale Facies

014

ws

Figure 6-7. Litholog of well 16-07-49-08W5, exhibiting cycle D of the Belly River Formation. PCP Ferrybank Typical Delta Front Abruptly 16-1 3-43-28w4 Overlying Prodelta Deposits

Interstrabfied Sandstone. Sdfy Proximal Mudstone. and Prodelci Shale Facies

Fcreshore

Proximal Delta Fronr

Lamindled ro Biorurbaied iandsiane Facies

...... i ...... m... -* ...... -' ...... -i ...... -- _..._...... , ...... Dislal ...... :...... 3* Delta Front - --.- . - - . - - ...... m..-...... - .-.-.;de, ...... --a .--l.r-S. -...... -*..---...... -.--?.->...... * . . - -.--..- . - - - . ....- nleniraiified Sandsfone. Proximal Silfy Mudstone. and p&na S(uleFac*# Figure 6-8. Litholog of welli6-13-43-28W4, exhibiting cycle G of the BeUy River Formation. CONCLUSIONS

1) Detailed facies analysis of 70 cores demonstrates that AUomember D of the Dunvegan Formation represents a wave-dominated delta succession. AUomember E of the Dunvegan Formation represents a river-dominated delta succession, and the cycles of the Belly River Formation represent a mixed wave/ river influenced delta succession.

2) The principal ichnological and sedimentological differences between these successions lie within the prodelta and distal delta front deposits.

3) In the prodelta, the interstratified sandstone, sil~mudstone, and shale facies is found in ail three delta types. The sandstones in the river-dominated succession, however, are dominated by curent-generated structures and abundant soft-sediment deformation structures. In contrast, the sandstones of the wave-dorninated delta successions comprise hummocky cross- stratification and storm-induced oscillation ripple Laminated tempestites, though soft-sediment deformational structures are intercalated throughout. Syneresis cracks are also located throughout the successions of al1 three delta types. The prodelta deposits of river-dominated delta successions are largely devoid of burrowing. The suite reflects a very low abundance but moderately diverse "highly stressed" Cnrzinnn ichnofacies. h the prodelta deposits of the wave- dominated delta successions, bioturbation comprises a diverse, but low abundance "stressed" Cnizinnn ichnofacies. Bioturbation in these prodelta deposits may disrupt contacts between beds, creating a biogenically mottled appearance. The mixed wave/river influenced delta successions also yield a diverse, but Iow abundance "stressed" Cruzinnn ichnofacies. Principal structures include those of trophic generalists, such as Plrrnolites and 236 Teiclzic~inzisand moderate numbers of Anconichnrrs. Ichnogenera are typicdly diminutive in size in ail successions studied. The prodelta deposits of river-dominated delta successions feature overd higher sedimentation rates, high water turbidities, variable substrate consistencies, reduced salinities, and reduced oxygen contents near the sediment-water interface. These are all conbibuting factors to the "highly stressed" Cnizicznrr ichnofacies. In the wave-dominated successions, the intermittent reworking of prodelta sediment by storm wave action helps to stabilize the sedirnent and supply refreshed marine waters to the sedirnent- water interface, facilitahg more uniform salinity and oxygen levels. The reduced trace fossil diversity in the wave-dominated successions instead reflects in loco fluctuations in energy, and therefore variations in substrate consistency, coupled with the high storrn frequency and generdy high sedimentation rates. The key deltaic "indiriators"of the prodelta deposits are convolute bedded sandstone/siltstone, massive (apparently structureless) silty mudstones, syneresis cracks, low diversity and Iow abundance of trace fossils, and the diminutive size of the traces. The discrete bedded character of the succession is evident due to the paucity of bioturbation. These factors help to differentiate between deltaic and the offshore deposits of shoreface settings.

4) In the distal delta front, the river-dominated and mixed wave/river influenced delta successions are typically devoid of burrowing. The interval is characterized by the convoluted sandstone facies. Organisms are largely unable to bioturbate this facies, as they would have a difficult time creating domiciles in these unstable, soupy substrates. Due to rapid sediment influx, infauna would also have had lirnited time to burrow the facies. In contrast, the wave-dominated successions possess only minor amounts of the convoluted silty sandstone/ mudstone, because the substrate was persistently 237 reworked by wave processes. The convoluted facies has not been encountered in any of the Cretaceous Western Intenor Çeaway shoreface deposits.

5) In the proximal delta front, the mked wave/river influenced delta successions and wave-dominated delta successions both yield a moderately diverse and locally abundant, mixed Skolithos-Cruzinnn ichnofacies. Stacked

HCS and ÇCÇ beds dominate, though convolute bedding is locally comrnon in the wave-dominated successions. In the mixed wave/river influenced delta successions, the convoiute and massive bedding is ubiquitous, and intercalated with the laminated sandstone. In contrast, the river-dominated delta succession yields a very low abundance and very low diversity, "highly stressed" Cruziann ichnofacies, with amalgamated HCS beds intercalated with abundant convoluted and massive sandstone beds. The proximal delta front is dominated by trough cross-stratified sandstones. The convoluted facies is typically devoid of burrowing. The increase in the abundance of convolute bedding and soft-sediment deformation structures from wave-dominated to river-dominated successions would indicate that these features are related to river/flood depositional events. The HCS and SCS laminated sandstones are largely unburrowed; where present, and trace fossils are domuiated by higher energy, deposit-feeders of the proximal Cnlzinna ichnofacies (e.g., Rosselin, Asterosorna) with rarer dwelling/suspension-feeding opportunistic organisrns of the Skolifhos ichnofacies. This is an important differentiating feahue between the deltaic successions and shoreface environments. Shoreface settings typically possess abundant suspension-feeding structures, particularly with increasing shallowing. The copious quantities of suspended clay and silt associated with river discharge in the delta front would interfere with effective filter-feeding behaviours through dilution effects, and likely choke such apparatuses with sedirnent. High amounts of suspended sediment also lower the ratio of food 238 to ingested sediment, irnposing an additional stress on the organism. The deposit-feeders that do occur tend to be those tolerant of higher energy settings (e-g., Rosselin, Asterosorna, and Cylindricltnus). These deposit feeders are unlikely to be adversely affected by high water turbidities and sedimentation rates, provided they are able to maintain their positions relative to the sediment-water interface during deposition. These burrows also tend to be robust, which probably helped to stabilize them in the othenvise unstable substrate. The suspension-feeding stnictures are more cornmon in the wave-dorninated delta successions, compared to the river- dominated and mixed wave/river iduenced delta successions because the substrate was persistently reworked by wave action. This reworking would have dampened the effects of fine sediment on the substrate, and moved suspended sediment seaward, decreasing overail water turbidity as well.

Deltaic successions have mainly been recognized at a regional scale, employing rnethods such as regional stratigraphy or seismic refiection analyçis. Many regard deltas and strandplains to be composed of the same subenvironments and, therefore, comprise identical facies. In contrast, this ichnological and sedimentological study has shown that there are key differences that permit the differentiation of deltaic successions from shoreface successions. Within the prodelta to delta front setting, recognition may require relatively few cored intervals. In the Dunvegan Formation and Belly River Formatiori, differences between wave-dominated and nver- dominated delta successions can also be distinguished. Continued study of other deltaic successions will determine whether these differences are universal, and provide the necessary data to develop a fully integrated ichnological-sedimentologicalfacies mode1 for deltas. Appendix A I CORE LOG LEGEND LITHOLOGY [-1 [-1 siltstone siky shale Coai . .. - - - - shaie sandy shale

PHYSICAL STRUCTURES fi - Current ripples '-5 Trough Cross-strat. --,, - Planar Laminations A - Oscillatory Ripples - Climbing Ripples - HummOcQ CiOsS->trat. S - Low Angle Planar Laminai - Wavy Parallel Laminae - Fau\, /VM - Convolute Bedding Syneresis Cracks A - Combined Flow Ripples .# - Çlickençides - LiTHOLOGlC ACCESSORIES .+-...... - Sand Lamina ___- - _ Silt Lamina ------Shale Lamina 0090 - Pebble/Granule Stringer -- Coal larnina/Fragmentç - Organic Shale Lamina $id - Siderite vvv - Bentonite Py - Pyrite - R~DUD Ciasts - - Cafùonaceous Detritus wd - Wood Fragments $66 - ~hellFragments PiM - Paleosol Horizon ICHNOFOSSILS

Fossils - Brachiopods 8 - Pelecypods Appendix B

DUNVEGAN FORMATION:

Well Location Cored Interval Core Length Township 59 11-19-59-03W6 33.2111

Township 60 02-25-60-22W5 15.2 m 07-11 -60-22W5 18 m 07-30-60-21W5 18 m 1O-22-60-22W5 15.9 m

18 m 18 m

36 m 18 m

Township- 61 03-28-61-24W5 11.2 m 05-27-61-01 W6 36 m 07-17-61-03 W6 40 m 10-34-61-26 W5 15 m 12-24-61-03W6 17 m 13-28-61-02W6 20.7 m 16-01-61-22W5 37 m

Township 62 06-11-62-03W6 69.2 m 06-35-62-27W5 15 m

43.5 m 27.8 m 18.2 m 18.2 m

Township 63 01-08-63-26W5 18 m 0408-63-02W6 44.3 m

18 m BELLY RIVER FORMATION:

WeIl Location Cored Interval Core Length Township 43 06-01-43-28 W4 06-10-43-04W5 06-23-43-28 W5 08-14-43-28 W4 08-22-43-28 W4 16-01-43-28W4 16-13-43-28W4

Township 44 08-03-44-28 W4 993.0-1011.0 m

Township 45 08-1945-01W5 1003.0-1016.8 m 14-32-45-01W5 925.0-950.5 m

Township 46 02-32-46-03W5 1079.0-1060.7 m 03-25-46-03 W5 1037.5-1024.5 m 06-1646-01W5 1011.2-971.2 m 06-23-46-02W5 1006.5-974.0 m 06-29-46-01W5 Township 47 02-0237-02W5 04-22-47-03 W5 06-09-47-03W5 06-11-47-05W5 06-23-47-02W5 06-35-47-02W5 07-1547-02W5 lO-09-47-02W5 16-29-47-02W5

Township 48 10-23-48-06W5

Township 49 08-2249-0W5 16-07-49-08W5 Appendix C

Cored intewals that contain the listed shingle or cycle.

Dunvegan Formation Allomember D

Shingle D2 Shingle Dl Dunvegan Formation Allomember E

Shingle E3 Shingle El Belly River Formation

Cycle D Cycle E Cycle F Cycle G Cycle H

06-01-43-28 W4 06-01-43-28 W4 06-23-43-28W4 16-01-43-28 W4 08-14-43-28 W4 16-13-43-28 W4 08-2243-28 W4 08-1U3-28 W4 16-01-43-28W4 06-23-43-28 W4 16-13-43-28 W4 08-22-43-28 W4 08-03-44-28W4 08-03-44-28 W4 06-16-46-01 W5 08-19-45-01W5 06-29-46-01 W5 14-3245-01W5 06-30-46-01 W5 06-1 6-46-01W5 06-23-46-02W5 06-2946-01 W5 08-26-46-02 W5 06-30-46-01 W5 02-02-47-02W5 10-28-48-01 W5 07-15-47-02W5 143348-O1W5 10-09-47-OZW5 06-2347-02W5 08-26-46-02W5 02-0247-02W5 IO-0947-02W5 07-1 5-47-02 W5 06-23-46-02W5 Appendix D

Trace fossils found in the Dunvegan and Belly River Formations

Trace fossil Ethology Trace rnaker Habitat Welmitzthopsis Systernatic Grazing trails of Normal marine shdow (H) grazing structure worm-like organisms; sh&, proximal/ dfs ta1 annelid Cntzia na ichnofacies and Zouphycos ichnofacies. Also maybe associated with low energy, fine- grained bay environments if salinity is sufficient Anconichnus Systematic Grazing trails of Cruziana ichnofacies in (An) grazing structure worm-like organisms normal marine conditions. Skolithos ichnofacies in normal marine conditions; some maybe opportunistic colonizers of storm deposited sands. Zoophycos A veriform organism Open marine, quiet (Z) with a fdy water settings, extensible-re tractable consistent with body (as phylum offshore, shelf and Sipunadida) (Ekdde, deep-sea environments

3ther suggestions: an melid Chondrites Deposit feeding Mainly marine (Ch) ;ipunculid situated on zonditions. Cruziana the substrate surface, ichnofacies. its proboscis extends Eonsidered well- hto substrate creating 3daptive to low oxygen tunnels. :onditions Suspension- 5îmXIar to sabelliarid Distal Cruziana feeding structure ?olychaete wom ichno facies Dwelling burrow Uarine offshore Suggested by mvironments. Miller (1995) to 41so in low energy, be renarned narginal marine Scfzuubcylind~clrnus mvironments such as Yays and lagoons 247 Planolites Deposit-feeding Mobile infaunal Trophic generalist (Pl) structure poIychaetes or other VU-tually ali Feeding burrow worm-like organisms environments from freshwater to deep marine -- Deposit-feeding Worm-me organism, Trophic generalist. structure migrates upward in Lower shoreface to DweUing its burrow to keep offshore environments, structure of a pace with Cruziana ichnofacies, deposit-feeder sedimentation. Also in brackish-water Annelids, or O ther lagoons, bays, tidal worm-like phyla flats, tidal point bars, and estuarine bay head delta environments. Rhizocorallium Deposit-feeding Crus tacean origin? Fully marine offshore (Rh) structure conditions. Dweiling Distal Cruziana structure of a ichnofacies. deposit-feeder Also an element of the Glosszfungites ichnofacies. Asterososna Deposit-feeding Verifonn organism Fully marine (As) structure conditions. (sdective) Upper-lower shoreface, Feeding burrow commonly Cruziarra (thought to ichnofaaes. exploit its own resources or deposits than relying on encountering them in the substrate. (MacEachern and Pemberton, 1992) 3uspension- Polychae te, genus ïrophic generalist. Feeding structure Vereis, or the Fdy marine Dwelling burrow msteacean genus :onditions. Eallinassa. &O persist in brackish ivater settings such as 2stuarine channel and >ointbar deposits, ;andy lagoonal je ttings, brackish-water 3ays and some sandy idal flats. Zommonly Skolithos chnofacies and proximal end of Cruziana ichnofacies, Rosselin (Ro) Deposit-feeding Terebellid polychae te Fdymaxine stnicture conditions. DweLling/ feeding Brings Crunaana burrow ichnofacies type of (thought to behaviour into exploit its own comparatively higher resources or energy settings, such as deposits than the middle and iower relying on shoreface. encountering May persist into them in the marginal marine substrate setfings but typically lie (MacEachern and in the more marine Pemberton, 1992) portions. Thalass ino ides Deposit-feeding Decapod crus tacean Cruziana ichnofacies, (Th) structure. (thalassinoid shrimp) lower shoreface to Dwelling offshore environments. structure of a Also found in low deposit feeder diversity, brackish water assemblages.

Conichnus Commonly assoaated (Co) with high energy arenaceous substrates, and in a typical beach to offshore transect is found in the upper shoreface to middle shoreface position. Skolifhos ichnofacies.

Palaeophycus D welling A predaceous Skolithos ichnofaaes, in (Pa) structure of a poIy chaete (passive both high and Iow passive carnivore. carnivores) (Glycena energy shoreface has been taken as an environments. Also excellent modem found in storm sands ana10 g) . and brackish water assemblages.

Suspension- Probable: Found in a wide variety feeding structure. polychae tes, of marine and brackish- Dwelling burrow echiuroids, and water environments. crustaceans Distal end of Skolifhos (amphip ods) ichnofacies. Skolithos (Sk) Suspension- Probable trace maker Virtually every type of feeding structure varies from marine environment. or passive polychaetes to Skolithos ichnofacies. carnivore. phoronid, to insect Dwekg burrow larvae. Suspension- Decapod crustacears, Marine shoreface feeding structure? induding numerous environment. Also Dwelling burrow species of calianassid associated with shrimp. brackish water, sandy substrates including estuanes and tidal shoals. Skolithos ichnofaàes. Opheliid polychae te High-energy (veriforxn organism) environments with shilting substrates. (up to several (They eat micro- Foreshore to proximal meters below the organismç colonzing upper shoreface sediment/ water the surfaces of sand settings. interface, &r-) Also high energy tidal favouring shoal deposits preservation. The associated with the intense swash mouth of the estuary infiltrates into the zone. beachface within With the presence of the foreshore and hemoglobin they are carries dissolved able to exploit oxygen and deposited food below nu trien ts well the sediment-water below the interface, pro tected sediment/ wa ter from the high-energy interface, conditions. Reduced permitting numbers Iocdy epigranular present in sandy bacteria to middle and lower flourish) shoreface deposits. (Saunders et al, 1994). Lockeia (L) Resting structure Bivalve (suspension Preselved best in and deposit feeding environments subjected bivalves) to frequent episodic depositional events. Brackish and fresh water environments.

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