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Depositional environments, provenance and sequence stratigraphy of the type Sassenach Formation, Jasper, Alberta.

- Sherry Becker Department of Earth and Planetary Sciences McGill University, Montreal

July 1997

A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfilment of the requirements of the degree of Masters of Science.

8 Sherry Becker 1997 National Library BiMiothèque nationale 1+1 of cana, du Canada Acquisitions and Acquisitions et Bibliographie Services sentices bibliographiques 395 Wellington Street 395. rue Welt'a~gtori OttawaON K1AON4 OarawaON K1AW Canada Canade

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The author retaùis ownership of the L'auteur conserve la propriete du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fkom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. Preface

The followiag statements are made in Mllment of the "Guidelines Conceming Thesis Preparation" of McGili University.

Candidates have the option of including, as part of the thesis, the text of a papex(s) submined or to be submitted for publication, or the clearlyduplicated text of a published paper(s). These texts must be bound as an integral part of the thesis.

If this option is chosen, comecting te- that provide logical bridges between the different papers are mandatory. the thesis must be written in such a way that it is more than a mere collection of manuscripts; in other words, results of a series of papers must be integrated.

The thesis must dlconform to ail other requirements of the "Guidelines for Thesis Preparation". The thesis must include: A Table of Contents, an abstract in Engiish and French, an introduction which clearly States the rationale and objectives of the study, a comprehensive review of the iiterature, a final conclusion and sumrnary, and a thorough bibiiography or reference list.

Additional materiai must be provided where appropnate (e-g. in appendices) and in sufficient detail to aiiow a clear and precise judgment to be made of the importance and origioality of the research reported in the thesis.

In the case of manuscripts CO-authored by the candidate and others, the candidate is required to make an explicit statement in the thesis as to who contributed to such work and to what extent. Supervisors must attest to the accuracy of such staternents at the doctoral oral defense. Since the task of the exarniners is made more difficult in these cases, it is in the candidate's interest to make perfectiy clear the responsibilities of al1 the authors of the CO-authoredpapers. Under no circumstances can a CO-authorof any component of such a thesis serve as an examiner for that thesis.

This project was initiateci in January 1992 under the supe~sionof Dr. E. W. Mountjoy who suggested a study of the Sassenach Formation, adjacent to the Ancient Wall reef complex in the Jasper Basin. Eight weeks in the summer of 1993 and one week in the slllllmer cf 1999 were spent in the field. Data were collected by the author and Dr. Mountjoy hm17 sections in Jasper National Park, Alberta: Mount Hauitain, Thornton Creek, Thomtoa Creek II, Mono Peak, Mount Strange, Gap Lake, F- Section, Overlander, Medicine Lake, Pallisades, Cinquefoil, Greenock Mountain and Roche Miette (Figure 1). Responsibility for the content of this thesis rests with the author, except where indicated in the text. Dr. Mountjoy's name appears as junior author on manuscripts contained within the thesis, having served as supervisor, field assistant, and editor for the dwation of the thesis.

Dr. Sandy McCracken anaiysed samples, provided by the author, for conodonts and provided a summary of his work which is included as Appendix B. In addition, Gil Klapper also provided condont analyses of samples nom the study area which are also included in Appendur B. A discussion of the lelevance of these data is included in Chapter 1, Section 1.45. Thesis Format

This thesis comprises six chapters. Chapter 1 is a general introduction to the thesis and includes a description of the methodology and data used througbout the study. Chapter 2 is titled, "Stratigraphy and Type Section" and comprises a description of the type section of the Sassenach Formation, and a brief description of the bounding stratigraphy. Chapter 3 is titled "Depositional Facies". This chapter describes and interprets and correlates the depositional facies within the Sassenach Formation and in the underlying Mount Hawk Formation and Simla Member. Chaptter 4 is titled, "Sequence Stratigraphy and Depositional Models". Chapter 4 describes and identifies the bounding sucfaces, parasequences and parasequence stacking patterns for the uppermost Simla Member, Mount Hawk and Sassenach formations. Two end- member sequence stratigraphie and depositional models for the Sassenach Formation are proposed for the late Frasnian to early Famennian Jasper Basin. The remainder of Chapter 4 provides a rough estimate for the minimum and maximum possible magnitudes of latest Frasnian sea-level fall, (associated with the Sequence Stratigraphic and Depositional Models 1 & 2 respectively). Chapter 5 is titled "Potential Sources for Sassenach Formation Siliciclastics". Three potentiai sources and transportation routes for the Sassenach siliciclastics are described in detail. Chapter 6 is titled "Discussion and Conclusions". Chapter 6 provides a summary overview and discussion of alternative interpretations for the sequence strattigraphy and provenance of the Sassenach Formation and includes a detailed summary of the conclusions generated in this thesis. Acknowledgemenb

The completion of this rexarch endeavor would not have been possible without the hancial, academic, technical and mord support of many individds and institutions. 1 would like to take this opportunitty to acknowledge their support and contributions-

Firstly, 1 would like to achowIedge and sincerely thank my advisor Professor Eric Mountjoy for a fantastic summer of fieldwork, for his academic contributions and for his encouragement addedication to the completion of this thesis. Mostiy 1 wish to thank Professor Mountjoy for bis fnendship which 1 treaswe.

1 wish to thank Park Canada for granting access to Jasper National Park, and 1 especially would like to thank the black bear 1 met for an exhilarating yet fnendly encounter. "Wade", our helicopter pilot and Alpine Helicopters are sincerely thanked for flying us in and out efficiently and safely, and for the chocolate bars Wade brought on his "1 was in the area md just thought I'd drop in and check on you" visits. 1 want to thank my field assistant Kaj Jensen who tnisted a bunch of strangers enough to fly into a helicopter camp to stay with Prof. Mountjoy and 1 for a month. Kaj brought energy, curiosity and a strong pair of legs to help the "strange" geologists carry their rocks down to camp every night. She also shared with me her laughter and fkiendship and made every rainy, cold day on the rnountajni; seem a little warmer and a Little brighter.

Financial support for this research was provided by NSERC, the AAPG (Student Grant) and the McGi11 University Department of Geology via Ming contributions, SC holarships and teachinghesearch assistantships. The University of Miami, Elf Aquitaine, Professon Gregor Eberli and Michael Whalen provided helicopter and logistic support for this thesis. 1 would also like to thank McGill University for providing my income and Thompson House for a place to spend it.

1 am also indebted to my family and friends. 1 wish to thank my parents for never telling me that 1 can't. My friends provided moral support and encouragement. Lastly, 1 thank my husband for his help in editing, bis love and understanding and for providing the incentive to finish my thesis and begin our life together. Tiiis thesis is dedicated to the memory of Chimo who always loved me anyway. Abstract

In the Jasper Basin, Jasper National Park, Alberta, the late Frasnian Simla Member and Mount Hawk Formation comprise a shallow water carbonate platform (upper part of the Ancient Wall reef complex) and an adjacent slope and basin respectively . The Frasnian-Famennian paracodionnity overlies the Simla Member everywhere within the study area. Basinward, this boundary becomes conformable where it overlies the Mount Hawk Formation. The F-F boundary forms the basal bounding surface for the Sassenach Formation. The early Famennian Sassenach Formation comprises mixed siliciclastic/carbonate strata that overlie, onlap and fiequendy toplap the underlying Mount Hawk Formation and Simla Member dong the northeastem margin of the Jasper Basin.

The stratigraphic relationships within the study area are not unique and may be explained by different sequence stratigraphic and depositional models. Two end member models are considered and illustrate the dficulty in distinguishing between depositional systems where accomodation space is controlled mainly by sedïmentation rate (Model 1) or mainly by sea-level (Model 2). Mode1 1 and Model 2 represent a minimum and maximum amount of relative sea-level faIl across the F-F boundary respectively.

In Model 1, iilustrating a minimum amount of relative sea-level fall, the uppermost Mount Hawk Formation and Simla Member represent initial lowstand deposits that are bounded below by a Type-1 sequence boundary (SB) and above by the Frasnian-Famennian boundary. The overlying lower member of the Sassenach is interpreted to be a lowstand systems tract (LST), progradationai wedgelfan that laps out against the basin margin and is bounded below by a SB and the F-F boundary. The initiai transgressive surface (ITS) is inferred to occur within the upper member of the Sassenach. The transgressive systems tract (TST) includes the upper member of the Sassenach, that locdy toplaps the underlying Simla, and the overlying Palliser carbonates. The contact between the Sassenach and the overlying Palliser may represent a significant marine flooding surface (FS) and also is a transgressive surface of erosion, or ravinement surface. In Model 2, illustrating a maximum amount of relative sea-level fall, the uppermost Mount Hawk Formation and Simla Member represent the LST. The ITS is coincident with the F-F boundary and the Sassenach lower member represents the transgressive systems tract. The upper member of the Sassenach is interpreted as a progradational highstandstillstand systems tract The overlying Palliser is interpreted as a TST and is bounded below by a Type4 SB.

There are three known possible sources for the Sassenach siliciclastics; the Ellesmerian Orogenic Terrane to the north, the Pre-Cambrian Shield to the east and an Antler Orogenic Highland to the West and çouthwest Based on regional geology, stratigraphic relationships and neodymium/somarium isotopes, the most likely source terrane appears to be an Antler Orogenic Highland. Résumé

Dans le bassin Jasper, parc national Jasper, Alberta, le membre Simla du Frasnien Superiéur et la formation du Mont Hawk comprennent une platforme carbonatée d'eau peu profonde et une pente et un basin adjacents respectivément. La paraconformité du Frasnien- Famenian recouvre le Membre Simla dans toute la zone d'étude. Vers le bassin cette limite devient conffonne là où elle couvre la formation du Mont Hawk- La limite FF forme la surface basale détirnitante pour la fonnation du Sassenach, La formation Sassenach du Farnenien précoce comprend des strates siliciclastiques et carbonatées mixtes qui recouvrent onlap et fréquemment toplap la formation Mont Hawk et le membre Simla sous-jacents le long de la marge nord-est du bassin Jasper.

Les relations stratigraphiques dans la zone d'étude ne sunt pas uiques et peuvent être expliquees par différents modèles de séquence stratigraphiques et dépositionnels- Deux modéles de cas êxtreme sont considéres et illustrent la difficulté de faire la distinction entre des systemes de dépot, ou l'accomodation d'espace est controllée principalement par le taux de sédimentation (Mode1 l), ou bien par le niveau de la mer (Model 2). Le Modèle 1 et le Modèle 2 représentent respectivement un montant minimum et maximum de l'abaissement relatif du niveau de la mer le long de la limite FF.

Dans le Modele 1, illustrant un montant minimum de l'abaissement relatif du niveau de la mer, la partie supérieure de la formation Mont Hawk et du membre Simla représentent les dépots initiaux du bas niveau qui sont délimités par en dessous par une séquence limite (SB) de type-l et par dessus par la limite Frasnienne-Famenienne. Le membre inférieur recouvrant du Sassenach est interprété comme étant un systeme de tract de bas niveau (LST), "wedge/fanW progradationnel qui couvre a l'extérieure contre la marge du bassin et est délimité par dessous par une limite SB et FF. La surface transgréssive initiale (ITS) se trouve, par déduction, dans le membre supérieur du Sassenach. Le système de tract transgréssif (TST) inclue le membre supérieur du Sassenach, qui localement recouvre par dessus la sous-jacente Simla, et les carbonates Palliser recouvrants- Le contact entre le Sassenach et le Palliser recouvrant peut représenter une surface marine de crue (FS) et aussi est une surface transgressive d'érosion, ou une surface de ravinnement.

Dans le Model 2, illustrant un montant maximum de l'abaissement relatif du niveau de la mer, la partie supérieure de la formation du Mont Hawk et le membre Simla représentent le LST- Le ITS coincide avec la limite FF et le membre inférieur du Sassenach représente le systeme de tract transgréssif. Le membre supérieur du Sassenach est interprété comme étant un systeme de tract progradationnel de bas-niveau/systeme de tract de stillstand. Le Palliser recouvrant est interprété comme une representation d'une TST est délimité en dessous par un SB de type-II-

il y a trois sources possibles reconnues pour le Sassenach siliciclastiques; le terrain Ellesmerian orogénique au nord, la bouclier Pré-Cambrien a le'est et un Andouiller Orogénique de Hautes-terres à l'ouest et sud-ouest, Basé sur la géologie régionale, les relations stratigraphiques, et les isotopes neodymium/somarium, la source de terrain la plus probable apparait être un Andouiller Orogénique de Hautes-terres. Table of Contents

...... Preface ...... 1 Thesis Format ...... ui-a-... Acknowledgments ...... iv Abstract ...... ,,,...... vï.. Ré...... Vl1... Table of Contents ...... ~l~l List of Figures ...... xi List of Tables ...... xiv List of Appendices ...... xiv

Chapter 1 Introduction. Previous Work, Data and Methods

Introduction ...... 2 Previous Work ...... 7 Purpose ...... 10 GeologiclTectonic Setting ...... 11 Methods and Data ...... 14 Sedimentology ...... 14 Biostratigraphy ...... 14 Nd/Sm Isotopes ...... 15 Dating ...... 16

Cbapter 2 Stratigraphy and Type Section

2 S tratigraphy ...... 21 Type Section of the Sassenach Forniauon ...... 21 Thickness and Distribution ...... 22 Bounding Stratigraphy ...... 27 2.3 1 Simla Member Platform and Basin Margin ...... 27 2.32 Mount Hawk Formation Basui/Slope ...... 27 2.3 3 Palliser Formation Ramp Carbonates ...... 27 Chapter 3 Depositional Facies

3 Introduction ...... 35 3 -1 Latest Frasnian Mount Hawk Formation and Simla Member ...... 43 3-11 Facies 1-Bioclastic/Lithoclastic Wackestone to Grainstone ...... 43 3.12 Facies 2-Calcareous, Litboclast Siltstone...... 47 3.13 Facies 3-Deformed, Interbedded, Silty Limestone and Calcareous Siltstone ...... 52 3-2 Sassenach Formation Facies ...... 55 3.21 Facies 5-Black Shale ...... ,... 55 3.22 Facies 6-Bioclastic Packstone-Grainstone ...... 59 3.23 Facies 7-Siltstone/Lhestone/Mudstone Rhyihmite ...... 60 3 -24 Facies 8-Stromatolite Baffiestone ...... 68 3.25 Facies 9-Oncoid Wackestone to Grainstone ...... 71 3.26 Facies 10-Limestones (Wackestone to Packstone) ...... 77 3.27 (Facies 411 1) Siltstone and Fine-graïned Sandstone...... 83 3 -3 Surnmary; Sassenach Formation; Lower and Upper Members ...... 91 3 -4 Facies Associations ...... 95 3.4 1 Uppermost Simla Member and Mount Hawk Formation ...... 95 3.42 Basin S tope Facies Association, (SMH-A) ...... 95 3.43 Basin Slope Facies Association, (SMH-B) ...... 98 3.44 Basin Slope Facies Association, (SMH-C/LMS-C) ...... 99 3 -45 Lower Member Sassenach Formation ...... 100 3.46 DidBasin Plain Facies Association., (LMS-A) ...... 100 3.47 Basin Plain Facies Association, (LMS-B) ...... 103 3.48 Upper Member Sassenach Formation...... 104 3.49 Lower-Middle Shoreface Facies Association, (UMS-A) ...... 104 3.50 Lower-Middle Shoreface Facies Association, @MS-B)...... 107 351 Carbonate Shoreface Facies Association, (UMS-C) ...... 107

Chapter 4 Sequence Strntigraphy and Depositional Model

4 Introduction ...... 110 4.1 Definition and Recognition of Significant Surfaces ...... 114 4.1 1 Sequence Bomdary (SB) ...... 114 4.12 F-F Boundary (F-F boundary) ...... 117 4.1 3 Initial Transgressive Surface (ITS)...... 117 4.2 Systerns Tracts ...... 118 4.2 1 Highstand/StiIlstand Systems Tract (HST) ...... 118 4.22 Lo-d to Transgressive and Highstand Systems Tracts...... 119 4.22a) Systems Tracts Mode1 1 ...... 120 4.22b) Systems Tracts Mode1 2 ...... 123 4.3 Parasequences ...... 124 4.3 1 Simla Member and Mount Hawk Formation ...... 124 ...... ,,,..,,,, 4.32 Sassenach Formation ...... ,,,..,,,, 125 4.4 Stacking Patterns ...... 126 4.41 Sida Member and Mount Hawk Formation ...... 126 4.42 Sassenach Formation ...... ,.,.... 127 4.5 Depositiod Environments and Models ...... 130 4.5 1 Depositional Mode1 1 ...... 130 4.52 Depositional Mode1 2 ...... 135 4.6 Documenthg and QuantifLing Relative Sea-Level Changes ...... 139 4.6 1 Recognition of Changes in Sea-Level ...... 139 4.62 Stratigraphie Location for Mode1 1 Sea-Level Fa11 ...... 143 4.63 Stratigraphie Location for (Mode1 2) Sea-Level Fa11 ...... 143 4.64 Quantification of Relative Sea-Level Fd...... 146

Chapter 5 Poteatial Source Terranes

5 Introduction ...... 148 Paleogeography ...... 148 Source Terranes ...... 152 5.2 1 Precambrian Shield ...... 152 5.22 Ellesmerian Orogenic Terrane ...... 153 5.23 Western/Southwestem Source Terrane...... ,...... 156 Neodymiurn/Somarium Isotope Analyses ...... 156 Summary ...... 159

Chapter 6 Discussion and Conclusions

6.1 Discussion...... ,...... 163 6.2 Conclusions ...... 166

References ...... 170

Appendices ...... 181 List of Figures

Chapter 1

1.1 Schematic cross-section showing megacycles in Middle to Upper ...... -4 Devonian sequences- 1-2 Location Map. Distribution of Devonian reef edges and basin fiil ...... 6 sedirnents 1-3 Devonian stratigraphy and nomenclature ...... 9 1 Study Area Location Map (palllispastically restored thnist sheet ...... 13 map) highlighting measured section and cross-section locations 1-5 Cross-section illustmting location of conodont samples and ...... 19 positioning of Framian-Famennian boundary

Chapter 2

2.1 Photo of Type Section. Thomton Creek. Jasper National Park, ...... 24 Alberta 2.2 Palinspasticaily restored Jasper Basin margin map highiighting the ...... 26 depositional limits of the Sassenach Formation 2.3 Schernatic Cross Section (Colin thrust sheet) with definitions of ...... 29 stratigraphie temiinology 2.4 A) Photo of Mount Haultain Stratigraphy ...... 31 B) Photo of Mount Haultain, close-up of Simla Member and Upper Member Sassenach Formation 2.5 Photo of Cliff Face, Chetamon thrut sheet, near Mount Ranee ...... 33

Chapter 3

3.1a) Stratigraphie cross.section. Colin thrust sheet ...... 37 3.1 b) Stratigraphie cross-section, Mount Haultain, Colin thrust sheet ...... 38 3.1 c) Facies Legend ...... 40 3.2 Stratigraphie cross.section, Chetamon thrust sheet ...... 42 3.3 Facies 1, Bioclastic Debrite, uppermost Simla Member, Mount...... 45 Haultain 3-4 Facies 1, Bioclastic Debrite, uppermost SidaMember, F-Section ...... 45 3.5 Facies 2, Siltstone Debrite, Sassenach Formation, Mono Peak ...... 49 3.6 Facies 2, Siltstone Debrite, ?Sassenach Formation, Mount Strange ...... -49 3 -7 Facies 2, Photomicrograpù, Siltstone Debrite, uppennost Mount ...... 51 Hawk Formation, Type Section List of Figures Continued

Chapter 3 Continued

3-8 Facies 2. Photomicrograph, Siltstone Debrite. uppennost Mount ...... 51 Hawk Formation, Type Section 3.9 Facies 3. Siltstone SLump. ?Sassenach Formation. Mount Strange...... 54 3.1 0 Facies 3. Siltstone Slump, ?Sassenach Formation, Morro Peak ...... 54 3.1 1 Facies 5. Black Shale. ?Sassenach Formation. Type Section...... 58 3.12 Facies 5 & 6. Black Shale and Bioclastic Turbidite. Sassenach ...... 58 Formation. Gap Lake Section 3.1 3 Facies 7. Siltstow/timestone/Mudstone Interbedr. lower member ...... 62 Sassenach Formation, Mount Strange 3.14 Facies 7. Siltstone/Limestone/Mudstone interbeds. lower member ...... 62 SassenachFormation. Mount Strange 3.15 Facies 7. Siltstone/Limestone/MudstoneInterbeds. upper member ...... 64 SassenachFormation. Mount Strange 3.16 Facies 7. Siltstone/Limestone/MudstoneInterbeds. lower member ...... 64 Sassenach Formation, Medicine Lake 3.1 7 Facies 7. Photomicrograph, Siltstonek imestone/Mudstone ...... 66 Interbeds. upper member Sassenach Formation. Mount Strange 3.1 8 Facies 7. Photomicrograph. Siltstone/Limestone/Mudstone ...... 66 Interbeds. lower member Sassenach Formation. Mount Strange 3.19 Facies 8. Stromatolite Bafflestone. Sassenach Formation...... 70 Mount Haultain 3.20 Facies 8. Stromatolite Bafflestone. Sassenach Formation, Mount ...... 70 Hauitain 3.2 1 Facies 9. Oncolite. Sassenach Formation. Type Section ...... 74 3.22 Facies 9. Oncoid Wackestone. Sassenach Formation, Mount ...... 74 Haultain 3.23 Facies 9. Photornicrograph. Oncoid, Sassenach Formation...... 76 Mount Haultain 3 -24 Facies 9. Photomicrograph, Oncoid. Sassenach Formation...... 76 Type Section 3 -25 Facies 10. Photomicrograph. Pellet/Peloid Wackestone.Packstone...... 80 Sassenach Formation. Mount Haultain 3 .26 Facies 1 0. Photomicrograph. Crinoidal Wackestone. Sassenach ...... 80 Formation. Overlander Section 3.27 Facies 10. Photomicrograph, Brachiopod Packstone.Grainstone...... 82 Sassenach Formation. Type Section 3-28 Facies 1O. Photomicrograph, Algal BalWeloid Wackestone- ...... 82 Packstone. Sassenach Formation. Mount Haultain List of Figures Continued

Chapter 3 Continued

3.29 Facies 4/11, Siltstone, Sassenach Formation, Mount Strange...... -...... 85 3.30 Facies 4/11, SiltstonelFine-grained Sandstone, Sassenach ...... 85 Formation, Mount Strange 3 -31 Facies 411 1, SiltstondFine-grained Sandstone, Sassenach ...... 87 Formation, Mount Strange 3.32 Facies 4/1 1, SiltstoneRine-grained Sandstone, Sassenach ...... 87 Formation, F-Section

3-3 3 Facies 4/11, Siltstone/Fine-graîned Sandstone, Sassenach ...... --..eded..ededed.... 89 Formatio~Gap Lake Section 3.34 Facies 4/11, Photomicrograph, SiltstonelFine-grained Sandstone, ...... 89 Sassenach Formation, Mount Strange 3-35 Uppermost Simia Member and Mount Hawk Formation ...... 97 Facies Associations 3 -36 Lower Member Sassenach Formation Facies Associations ...... 102 3 -37 Upper Member Sassenach Formation Facies Associations ...... -.....--...-. 1O6

Chapter 4

4 Parasecpence Stacking Patterns (fiom Van Wagoner et al. 1990) ...... fllSfllS..fllS. 11 3 4.1 Schematic Sequence Seatigraphic cross-section ,Jasper National ...... -.se..1 16 Park, Alberta Colin th- sheet: a) Sequence Stratigraphic Model 1, b) Sequence Stratigraphic Model 2; Chetamon thrust sheet: c) Sequence Stratigraphic Model 1, d) Sequence Stratigraphic Model 2 4.2 Baselap Classification (nom Handford 1995) ...... 129 4.3 Schematic cross-sections, 5 Depositional Stages, Deposition Model 1 ...... 134 4.4 Schematic cross-sections, 5 Depositional Stages, Deposition Model 2 ...... 138 4.5 Eustatic Sea-Level Cuve for Devonian-Carboniferous succession ...... 142 of the southern Canadian Rocky Mountains (fiom Savoy and Mountjoy 1995) 4.6 Schematic cross-section, Colin thrust sheet, Estimation of ...... 145 magnitude of relative sea-level fda) Mode1 1 (Minimum), b) Model 2 (Maximum) Cbapter 5

5.1 Distribution of Ellesmerian Orogenic Belt Sediments ...... 151 5.2 Major tectonic featwes of North America in Late Devonian and ...... 155 Early Mississippian time (hmSavoy 1992) 5.3 a) €Nd values for the Mount Hawk, Perdrix and Sassenach formations ...... 1584 (from Stevenson et al. in prep.), 5.3 b) &Ndvalues vs .zircon content for Sassenach Formation ...... 158

List of Tables

3 Summary of Facies and Depositional Environrnents ...... 93

4 Cornparison of Systems Tracts for Sequence Stratigraphie ...... 122 Models 1 and 2

5 Summary of Provenance Study Stratigraphicffetrographic ...... 161 Observations

List of Appendices

Appendix A. Measured Sections. Sample Numbers and Descriptions ...... 181 Facies Legend ...... 182 Colin Thrust Sheet ...... 183 Hauitain 1 (Hl)...... 184 Haultain 2 (H2) ...... 185 Haultain 3 (H3) ...... 186 Haui tain 4 (H4) ...... 187 Hauitain 5 (HS) ...... 188 Type Section ...... 189 Thornton Creek ...... 194 Mono Peak ...... 199 Overlander ...... 204 Chetamon Thrust Sheet ...... 210 Gap-Lake ...... 1 F-Section ...... 216 Mount Strange ...... 222 Medicine Lake ...... 228

Appendix B. Conodont Data ...... 233

xiv Chapter 1

Introduction, Previous Work, Data and Methods 1.0 Introduction

In the Western Canada Sedimentary Basin (WCSB), Devonian strata comprise a series of stacked transgressive and mgressive cycles (Fig. 1.1). Typically, carbonate platfomis fomed duriug initiai transgressions with the development of reef complexes occurrhg during maximum inundation (Stoakes 1980, 1992; Mountjoy 1980; Switzer et al. 1994; Wendte et al 1992). Extrabasinal, fine-grained siliciclastics and fine-grained carbonates eroded fiom intrabasinal carbonate platforms and reefs partly filled the basin during repssive cycles.

These stacked transgressive/regressive cycles have ken grouped into several depositional "stages" or megacycles (Wendte 1992, and Savoy and Mountjoy 1995, etc.). The Duvemay (Perdrix) Formation was deposited in the initial stages of basin flling during the maximum transgression in the Frasnian Woodbend (Cairn, Peechee and Leduc Reefs) megacycle.

The dominantly regressive Frasnian Winterburn megacycle filled most of the basin with fine-grained siliciclastics and carbonates of the Ireton (Mount Hawk) Formation and in shallower regions it was fiiied with carbonate platforms of the Blue Ridge Formation (Simla Member). Three main stages of (ireton) basin fil1 are shown in Figure 1.2. However, by the end of the Frasnian the western portion of the Aiberta Basin, (the Jasper Basin in panicular), was only partially filled by Mount Hawk (Ireton) Formation sediments. The remaining depression was filled during the earliest Famennian by - the Sassenach Formation (Mountjoy 1980, Geldsetzer and Mountjoy 1992; Fig. 1.2).

The Frasnian Simla platform consists of shallow water carbonates that overlie portions of the Ancient Wall reef complex and grade laterally into basin slope sediments of the Mount Hawk Formation (Mountjoy and MacKenzie 1973). in the Miette Range, stratigraphically equivalent, more restricted carbonates of the Ronde Member grade laterally into upper dope facies of the Mount Hawk Formation (McLaren and Mountjoy 1962; Mountjoy 1965,1997; Fig. 1.3). Figure 1.1 Central Alberta composite schematic, west-east cross-section illustrating megacycles in Middle and Upper Devonian sequences, stratigraphy and facies of the Alberta Basin (fiom Wendte 1992)- nuv SlllH NVMS Figure 1.2 Distribution of Upper Devonian Leduc and Swan Hills reef and carbonate platforms, AIberta. The study area is located dong the southwestern margin of the Ancient Wail reef complex (modified fiom Mountjoy 1980, Switzer et al. 1994, and Savoy and Mountjoy 1995). Also shown are progressive stages of basin filling; early, east and west shale basins (diagonal ruling); intermediate, Cynthia Basin (horizontal ding); and late (no pattern). The western portion of the basin was filled with Sassenach sediments (dots). The Rocky Mountain thrusted portion of the map has ken palinspasticaiiy restored (updated fiom Mountjoy 1980).

The Sassenach Formation consists of about 200 m of calcareous sandstones, siltstones, mudstones and argillaceous and silty limestones. This sedimentary succession overlies and onlaps the Late Frasnian Mount Hawk Formation and Simla and Ronde Members of the Southesk Formation, respectively, and underlies the Farnennian Palliser Formation (McLaren and Mountjoy 1962; Mountjoy 1987; Fig. 1.3).

The Sassenach Formation is well exposed in thrut sheets in the Foothills, Front Ranges and parts of the eastem Main Ranges of the centrai and southern Canadian Rocky Mountains (Fig. 1.2). The stratigraphy and facies of the Sassenach Formation and adjacent strata were studied in two thst sheets of the western Front Ranges northeast of Jasper on the northeastem margïn of the Jasper Basin where it overlies and onlaps the southwestern portion of the Ancient Wail reef (Figs. 1.2 and 1S).

1.1 Previous Work

The Sassenach, Simla and Ronde formations were previously assigned to the Alexo Formation (deWit and McLaren 1950, McLaren 1956 and McLaren and Mountjoy 1962). However, the Alexo Formation contained Late Frasniao and Early Famennian strata and uicluded a major extinction event. Revision of the stratigraphy reco-d the importance of the Frasnian- Famennian, (F-F) sequence boundary by separating the (Famennian) Sassenach Formation fiom the underlying (Frasnian) Simla or Ronde members of the reef complexes and shales and basin slope carbonates of the Mount Hawk Formation (McLaren and Mountjoy 1962, Mountjoy 1965).

The Sassenach Formation has ken Little studied since it was fust described by McLaren and Mountjoy (1962) with the exception of studies of the F-F boundary. McLaren (1982) extensively studied the F-F boundary and extinction event. Late Frasnian conodonts have ken studied by various authon (Geldsetzer et al. 1987, Geldsetzer et al. 1993, Klapper and Lane 1985, Klapper and Lane 1988, Orchard 1988, Pollock 1968, etc.). Raasch 1988 and McLaren 1956 snidied brachiopods across the F-F boundary. Figure 13 Devonian stratigraphy and nomenclature for the Ancient Wall and Miette reef complexes and adjacent strata, (from McLaren and Mountjoy 1962, Mountjoy and MacKenzie 1973, Workurn 1983: McLean and Mountjoy 1993 and van Boucham et al- 1996).

Geldsetzer and Upitis (1993) summarized the petrography and depositional facies of the Sassenach Formation southwest of the Fairholme reef complex. They interpreted the Sassenach Formation as a siliciclastic basin fill succession that was deposited in an environment that ranges fiom an "initiai peritidal environment to a shallow subtidai environment", and fdyto a deep subtidal environment. Geldsetzer and Upitis also suggested that an "increase in (quartz) grain size fiom silt to fine sand towards the southwest" was evidence for a possible southwesterly source for the Sassenach siliciclastics (Fig. 1.2).

1.2 Purpose

The stratigraphic relationships between the Sassenach Formation and the underlying Late Frasnian carbonate platfonn margin (Simla) of the Jasper region provide a rare opportunity to map and quanti@ the arnount of sea level change across the F-F boundary.

in this study, the facies and stratigraphic relationships of the Sassenach Formation and the adjacent and underlying strata in the Jasper region are studied and interpreted in terms of depositional envhonments and sequence stratigraphic boundaries. They record a major sea level fa11 and rise across the F-F boundary. Constraints are placed on the maximum and minimum possible ranges for this relative sea-ievel &op, and on the manner of sea level rise in the Early Famennian. The source of the Sassenach siiiciclastics is also examined in terms of regional and Lod stratigraphic relationships i.e. onlap and toplap of the Sassenach Formation itself, as well as feldspar and Nd/Sm composition. During Late Givetian and Frasoian time extensive reefs developed in the central and westem Alberta Basin (Figs. 1.1 and 12)). A slight, continuous West tilt of Upper Devonian strata in the westem portion of the Aiberta Basin records slow subsidence that incrpased to the southwest (Mountjoy 1978; McLean and Mountjoy 1993). As a resuit, the more westerly Frasnian buildups of the Rocky Mountain Main Ranges are more than twice as thick as equivalent units in the Front Ranges.

However, the following relationships suggest that duruig early Fammenian (Sassenach) time, relatively little subsidence occuned within the Alberta Basin (Savoy and Mountjoy 1995, Mountjoy 1987 and 1980): 1) the Sassenach toplaps the Simla platfom by only 1 m - 3 m, and locally is absent above the Ancient Wall reef complex; 2) similar toplap thicknesses were reported by McLaren (1956) and MacKenzie (1969) for the Southesk-Cairn reef complex and by Mallamo and Geldsetzer (1991) for the FairhoIrne reef complex; 3) the Sassenach Formation is 21 m to 36 m thick on top of the Miette carbonate platfom buildups (Mountjoy, 1965) suggesting differential subsidence occurred within the Jasper Basin. Some of these effects may reflect local differential compaction (Le. muddier, less well cemented portions of the platfom). Differing toplap thicknesses may represent Vregularities dong a transgressive surface of erosion or ravinement surface (see Sections 4.42 a) and b), 4.5 1 and 4.52).

During the Columbian and Laramide orogenies most of the Devonian strata of the Main Ranges were thnisted, uplifted and eroded. Thus at present, Sassenach outcrops in Front Range thrust sheets represent only the eastem and northeastem portions of the Jasper Basin. The western extent of the Jasper (and Alberta) Basin(s) is unknown, (Fig. 1.2) but probably extended west of the Rocky Mountain Trench based on Devonian outcrops south of Golden B.C. Figure 1.4 Palinspasticaily restored map of study area, represents southwestern margin of the Ancient Wall reef complex as seen in Figure 1.2. Lines joining A-A' and B-Byillustrate the location of stratigraphie cross- sections within the Colin Fig, 3.1) and Chetamon (Fig. 3.2) thnist sheets respectively .

Measured sections are abbreviated as follows:

Colin Thrust Sheet: M.,Mount Haultain; TS, Type Section; TC, Thornton Creek; MP, Morro Peak. Chetamon Thrust Sheet: GL, Gap Lake; FS, F-Section; MS, Mount Strange; OL, Overiander; and ML, Medicine Lake. Greenock Thrust Sheek CF, Cinquefoil; GR, Greenock; Miette Range: RM, Roche Miette. PALINSPASTICALLY RESTORED JASPER BASIN MARGIN AND SECTION LOCATION MAP 1.4 Metbods and Data

The methods and data coIlection procedures are outlined under the following headings; sedimentology, sequence stratigraphy, biostratigraphy and NdSm isotopes.

1.41 Sedimentoiogy

Detemiining the depositional facies invoIves the meastirement, description, and subdivision of Sassenach Formation sections into distinctive rock types and genetic units. Genetic units or "Facies" are identified by means of lithologic compositions, biogenic content and sedïmentary structures. Mapping Facies in turn provides information for identification of depositional processes and environments at a given place and tirne.

1.42 Biostratigraphy

Biostratigraphy involves creating a chronostratigraphic framework based on the evolution of a specific fiora or fauna (e.g. conodonts, brachiopods, etc.). Biostratigraphic heworks are constructed by analysing a chosen flora or fauna through a given succession of strata, and recording the evolutionary changes through tirne. By assumuig that evolutionary changes (mutations) occur in an essentially instantaneous manner on a global scale; i.e. over an insignificant period with respect to geologic the; strata with a certain flodfauna are considered to be correlative. in this study, a biostratigraphic anaiysis of conodonts fiom selected stratal intervals was used to help position significant sequence stratigraphie bounding surfaces. Published studies of conodonts and brachiopods fiom the study area were also included (Raasch 1988, McLaren 1956, Klapper and Lane 1985,1988). 1.43 Sequence Stratigraphy

The Sassenach and Mount Hawk formations and Simla Member are subdivided into systems tracts foiiowing the definitions of Van Wagoner et al, 1988). By definition, systems tracts are identified by the stacking patterns of sequences, parasequences and parasequence sets, which in tum are defined by the lateral and vertical staclcing patterns of the strata, and by the lateral continuity and geometry of their bounding surfaces and unconfonnities. Sequence stratigraphy helps provide a chronosttatigraphic kmework for the ~natigraphyfiom which relative sea-Ievel fluctuations can be inferred.

1.44 Nd/Sm Isotopes

Isotope geology of the siliciclastic sediments within the Sassenach Formation can provide idormation about potentiai source terranes. Whole rocks are analysed for the haif Iives of their Neodymium (Nd) and Sornarium (Sm) isotopes, these isotopes also yield an age for the source rock fkom which the grains were eroded. By cornparing ages of isotopes fiom a given strata with ages of a source terrane, it is sometimes possible to match sediments with a specific source terrane. Alternatively, as was doue in this study, the ages from isotopes within the interval of interest (Sassenach Formation) was compared with the isotopic ages for multiple stratai intervals (Graminia Silt, and Mount Hawk Formation) to determine whether the sediments were fiom the same source terrane.

Siltstones, calcareous shales and argillaceous limestones of the basin filling Perdrix, Mount Hawk and Sassenach Formations were sampled fiom measured sections near the Miette, Ancient Wall and Fairholme ree f complexes, (McCracken 1996, G. Napper unpub.). (From Stevenson et a& 1995)

"Rock samples were crushed to powder using a tungsten swing-miIl- Nd-Sm isotopic measurpments were performed at Universite de Montreai a Quebec- Methods are simikir to those described in (Meanis 1992)- Whole- rock powders were spiked with Nd/Sm and treated with KF, HN03 and HCL in Parr Bombs until samples were completely dissolved. Standard column chromatography techniques were used to separate Nd and Sm. Concentrations of Sm and Nd were obtained by isotope dilution. TIMS was used to determine l43Nd/lUSm ratios. eNd (T) vaiues were calcdated using the depositional age of 365 Ma and indïcate the deviation of a sample 143NdllWd ratio fiom a chondritic reference at that tirne. Uncertahty of &Ndvalues is estimated at +- 0.5 &Ndunit. Sarnple powders were also analyzed by XRF for major and trace elements at the Geochemical Laboratorïes, McGiI1 University. Major elements were analyzed as fused beads prepared Eom ignited samples. Trace element analyses were done on pressed powder pellets."

Additionally, observations of the local and regional stratigraphie relationships, and thin-section petrography (composition, sorting, roundness and grain counts) were performed to determine composition and maturity of the sediment source.

1.45 Datiag

Combining faunal or biostratigraphic evidence with sedimentology and sequence stratigraphy provides the most accurate method for positionhg the F- F boundary.

Upper Devonian brachiopod faunas have been studied by McLaren (1965), Sartenaer (1969) and Raasch (1988) including some collected fiom 4 sections witbia the study area. Conodonts have been less studied and include samples fiom Mount Haultain by Klapper and Lane (1988) and Medicine Lake by Orchard (1988). In addition conodonts hmthe Medicine Lake and Cinquefoil sections were used to locate the F-F boundary (Gdellow and McLaren 1985, Geldsetzer et al., 1987a and Wang and Geldsetzer 1994). A cross-section (Fig. 1.5) iliustrates the stratigraphie positions of conodont collections fiom 5 sections in the study area (McCracken 1996, Klapper unpub.).

The conodont Late Frasnian linguijiorrnïs Zone (formerly uppermost gigas) has not ken recognized in western Canada, presumably because of the shallow water nature of the lithofacies. Elements of the partly equivdent rhenuna Zone have been found and suggest that close to the youngest part of this zone is present in Simla and Ronde strata of ?he Jasper Front Ranges. The recent studies by Mountjoy with Harrington and Shiraki in the eastem Front Ranges of Jasper National Park suggests that everything above the upper Arcs Member was deposited during the rhenana Zone (=Mn13 of Montagne Noire). Thus only a small part of the Late Frasnian appears to be missing. The conodonts collected so far nom the basal Sassenach suggest that the Early Famennian lower friungularis Zone may be absent. Thus the F-F unconformity appears to represent a relatively short time

Brachiopods also suggest a sudden change in the faunal succession between the Frasnian Simla carbonate platform and overlying Famennian Sassenach siliciclastic sediments at Mount Haultain (McLaren and Mountjoy 1962, Sartenaer 1969 and Raasch 1988). Famennian brachiopods are present in most basinal sections, as an example, the lower part of the lower member of the Sassenach Formation at the Type Section (above the 5 m silty debns flow) and Medicine Lake (above the 11 m siltstone unit) sections- Famennian brachiopods include; Eoparaphorrhynchus walcotti Memam, Sinotectirostmm medicinale deceptum Sarienaer, Cyrtospirifr portae Memam, Athyrs angelicoides Memam and Leioproductus sp., Cyrtiopsis mime tes Crickmay, Productella sp., Leiorhynchus lentgormis Nalivkin, (McLaren and Mountjoy 1962, Sartenaer 1969, and Raarh 1988). Brachiopods within the upper part of the lower member of the Sassenach Formation include; Eoparaphorrhynchus lenti/rrnis Nalivkin, Cjrtïopsis mimetes Crickmay, Cyrtospirfer portae Merriam, Sinotectirosh.um paucirugosum Sartenaer, etc. (Raasch, 1988). Figure 1.5 Stratigraphie cross-section illustrating the position of conodont sarnples in the top of Sùnla member or Mount Hawk Formation and base of Sassenach Formation. Samples were analyzed by (A-D., McCracken 1996 and G., Klapper unpub., Appendyc B). The F-F boundary is based on conodont analyses and on lithostratigraphic relationships where conodoat analyses are sparse or absent. For details see Chapter 3 and Figs. 3.0 to 3.1.

Chapter 2

Stratigraphy and Type Section 2 Stratigrnphy

The stratigraphy of Central Alberta is discussed in McLaren and Mountjoy (1 96î), Workum (1983), McLean and Mountjoy (1993) and the Geological Atlas of Western Canada Sedimentary Basin (1 994), etc.

The stratigraphy of the Sassenach Formation is discussed in the following three sections: Type Section of the Sassenach Formation; Distribution and Thickness; and Relationship to Bounding Stratigraphie Units.

2.1 Type Section of the Sassenach Formation

The Sassenach Formation is bounded at its base by the F-F boundary and unconformity, (Fig. 1.5) md generally is in sharp contact with the overlying Palliser Formation in the western Front Ranges. It forms a distinct and sharp contact with underlying formations (Mount Hawk, Ronde/Simla), but in basinal sections where the contact is ofien covered, this boundary is less distinct.

The type section of the Sassenach Formation occurs on a mountain ridge, on the south side of Thornton Creek, in the Colin thrust sheet, about 4 km southeast of the southem margin of the Simla carbonate plaLform that forms the top of the Ancient Wall reef complex, (Figs. 1.2, 1.4 and 2.1). The Sassenach Formation was first proposed by McLaren and Mountjoy (1962) for 180 m (600 fi) of calcareous shales, silty mudstones and argillaceous limestohes that grade upwards into silty or sandy limestones, and calcareous siltstones and sandstones (McLaren and Mountjoy 1962). They subdivided the formation into two informal members: a lower member, about 153 m thick of grey, fossiliferous, silty mudstones and argillaceous limestones, which weather to a prominent yeiiowish grey or orange, recessive interval; and an upper member, about 3 1 m thick of resistant, well-beddcci, gray, very sandy limestone with calcareous, quartzose sandstones in the middle third. The lower member contains abundant brachiopods that indicate an Early Famennian age for the Sassenach Formation (McLaren 1956, McLaren and Mountjoy 1962, Raasch, 1988).

Complete Sassenach sections display a ?black, shaly, recessive lower member, and a silty, more resistant, upper member. The lower comprises a monotonous sequence of interùedded siity, argillaceous mudstones and calcareous shales.

Sections of the upper member con& of between 18 m and 46 m of resistant, yellow-orange to brownish weathering, thin bedded, silty limestones and sandstones, calcareous siltstones and dolomites and occasional thin interbeds of limestone. Upper member strata are commonly finely lamuiated and crossbedded, occasionally nodular and contain a few beds of in&ormational carbonate conglomerates or breccias (Mountjoy, 1965). Locally, a distinctive oncolite unit occurs near the base of the thui upper rnember dong the northeastem margin of the Jasper Basin in sections at Mount Haultain, Cinquefoil, Greenoch (Geldsetzer and Mountjoy, t 992), and nea. Mount MacKenzie (Shields and Geldsetzer, 1992).

2.2 Thickness and Distribution

In the study area, the Sassenach Formation attains a maximum thicknesses of 225 m in the Chetamon thrust sheet. Southeastward fiom the Ancient Wai1 reef complex within the Colin and Chetamon thnist sheets, the Sassenach Formation remains relatively constant in thickness and appearance. It thuis northward and eastward toward the margin of the Jasper Basin where it onlaps and thinly toplaps the basin margin overlying the Simla platform margin and upper ramp, (Figs. 1.2 and 2.2). At the southeni margin of the Ancient Wall reef complex, between Thomton Creek and Mount Haultain, the Sassenach Formation thins fiom 180 m (at the type section) to less than lm over a distance of about 3.3 km, and is locdiy absent over the Ancient Wall reef complex. The Sassenach thins or is locally absent above the Southesk-Cairn reef complex, Macke~e(1969). Figure 2.1 Sassenach Formation type section, Thornton Creek. Viewed northwest towards Mt Haultain, The Sassenach Formation forms the recessive notch between the overlying resistant cliffs of the Paiiiser Formation. and the underlying resistant knob of the Simla Formation- Gently dipping cfinoforms can be seen in the Simla Formation. on Mount Haultain in the background.

Figure 2.2 Location of the Jasper Basin margin and the depositional limits of the thick Sassenach Formation. JASPER BASIN; LlMlT OF SASSENACH BASIN FlLL 2.3 Bounding Stratigraphy

2.31 Simla Member Platform and Basin Margin

The northeastem margin of the Jasper Basin is rimmed by Late Frasnian, Simla platform carbonates that were deposited over Early to Middle Frasnian Cairn and Peechee, Southesk Cairn, Miette, and Ancient Wail reef complexes (Figs. 1.2, 2.3 and 2.4). The Simla carbonate pladorm extends northward for several ?hundred kilometers from the southeni and western margins of the Ancient Wall reef complex into northeastem British Columbia (Geldsetzer, 1987a).

In the study area, the margin of the Jasper Basin generally soincides with the F-F boundary and reflects the antecedent topography of the latest Frasnian Simla pla~orm,platfonn margin and adjacent ramp or slope deposits (Section 1.45, Figs. 1.2,2.2 and 2.3).

2.32 Mount Hawk Formation BasidSIope

Within the study area, everywhere the Sassenach Formation directly overlies the Mount Hawk Formation, the contact between the two Formations is conforrnable, and represents the F-F boundary, (Figs. 1.3 and 2.3). The Mount Hawk Formation consists of basidslope deposits of calcareous, slightiy silty shales, and interbedded shaly carbonates.

2.33 PaUiser Formation hmpCarbonates

In the western Front Ranges, the Sassenach Formation is in sharp contact with the overiying Palliser Formation. In the study area, the Iowermost Palliser Formation. consists of crinoid and brachiopod wackestones to packstones (Sections 1-5 Mount Haultain, Type Section and Thornton Creek II), bioturbated mudstones to wackestones (Mount Strange, Gap Lake and F-Section), and slightly silty mudstones to wackestones (Morro Peak and Medicine Lake). See Figures 1.3 and 2.4. Figure 2.3 Schematic diagram of the margin of the Jasper Basin in the Colin th- sheet. These diagrarns illustrate the temiinology used in the text in reference to the margin of the Jasper basin during both A) Frasnian e.g. Simla platfonn and margin and B) Famennian times e-g. the margin of the Jasper Basin overlying the Simla plaform. JASPER BASIN

SE A) End of Frasnian

B) Early Famemian Figure 2.4 A) Mount Haultain stratigraphy. Pa = Palliser, Ss = Sassenach Fm., Si = Simla Fm., Mh = Mount Hawk Fm., USx = Peechee Fm., Px = Perdrix Fm-,and CN = Cairn Fm.

Figure 2.4 B) CIoseup of Mount Haultain viewed lmking northwest illustrating gently dipping, basin sioping, progradational clinofomis in Simla Fm., and horizontal oniap of the unconfonnity surface by Sassenach strata.

Figure 2.5 Photo of a cliffface southeast of the Ranee in the Chetarnon thmt sheet. In the accompanying sketch, severai relationships are illustrated. From base to top; progradation of the Arcs memùer AC, aggradationaUhorizontaiiy deposited strata in the lower Simla member SI, and an upper Simla member unit truncsites the underlying Simla strata and overlies the projpding clinoforms of the Arcs member.

Cbapter 3

Depositionai Facies 3 Introduction

Facies in the Simla Member carbonates and adjacent Mount Hawk basinal strata are described and interpreted to provide the depositional and sequence stratijpphic îhmework for the interpretation of the sea-level changes that occurred across the F-F boundary dong the nortbeast margin of the Jasper Basin. However, a detailed description of the entire Sirnia Member or the Mount Hawk Formation is not provided. Only the uppennost, Latest Frasnian portions of the Mount Hawk Formation and Simla Member carbonate pladorm, and the Early Famennian Sassenach Formation are discussed in this thesis- Figures 3,3-1 and 3-2 are the summary facies legend and cross-sections (location map Fig. 1.5) for the Colin and Chetamon thrust sheets respectively.

Within the study area the uppermost portion of the Simla Member comprises one facies; bioclastic, carbonate debrites deposited on a ramp and slope. The uppermost Mount Hawk Formation comprises three facies: 1) slumps; 2) siltstone debrites; and 3) calcareous siltstones. The Sassenach Formation was divided into seven facies: 1) black shale; 2) bioclastic turbidites; 3) siltstone/lirnestonel mudstone interbeds or "rhythmites"; 4) oncoid wackestone to grainstone; 5) stromatolite bafnestone; 6) limestone (wackestone to packstone); and 7) siltstone to fine grained sandstone. in the eastem Front Ranges, only the upper member of the Sassenach Formation is present and comprises only the coarse siltstone to sandstone and silty limestone facies (Geldsetzer and Mountjoy 1992, McLaren and Mountjoy 1962, Geldsetzer and Upitis 1993). Table 3 summarizes the characteristic constituents, structures, bedding type and depositonal environment for each interpreted Facies. Figure 3.1 a) Colin thrust sheet stratigrapbic cross-section. Measured sections: Mount Hauitain, Hi, H2, H3, H4, H5, Type Section, Thornton Creek II, Morro Peak and Overlander.

Figure 3.1 b) Close-up of Mount Haultain, Colin thnist sheet. Measwd sections: Mount Haultain, H 1, H2, H3, H4 and H5.

For facies legend see Figure 3.1~.For details of measured sections see Appendix A. COLIN THRUST SHEET

Ovcdarbcr Morro Peak ns 114 ILI n2 ni

üiDPERMEMBER SIMLA MEhfBER

SASSENACH FORMATION

LOWER MEMBER MOUNT HAULTAIN, COLIN THRUST SHEET

Sassensch Formation Upper Member

Sequencc Boundary

Simla Member Carbonates Figure 3.1 c) Facies Legend for late Frasnian, uppermost Mount Hawk Formation and Simla Member, and early Famennikm Sassenach Formation. Legend for Figures 1.5,3.1,3.2 and Appendix A.

Figure 3.2 Chetamon thrust sheet stratigraphie cross-section- Measured sections: Gap Lake Section, F-Section, Mount Strange and Medicine Lake. For facies legend see Figure 3. lc. For details of measured sections see Appendk A. CHETAMON TIIRUST SHEET

MOUNT llAWK FORMATION 3.1 Latest Frasnian Mount Hawk Formation and Simla Member

Four facies within the snidy area represent deposition during the latest Frasnian, Lower to Upper rhenana Zone (Figs. 1.5,3,3.1 and 3-2)- They comprise bioclastic carbonate and siltstone debrites, slumps and calcareous siltstones. These facies were everywhere interpreted to underlie the F-F boundary (Figs. 3,3.1 and 3.2), and are classified as either uppermost Mount Hawk dope and basin (siltstone debrites, calcareous siltstones and ?slumps) or Simla Member platform, rnargin and proximal dope (bioclastic carbonate debrite).

3.1 1 Facies 1-Bioclastic/lithocIastic Wackestone to Grainstone

Description: Facies 1 comprises 2 m to 3 m thick beds of poorly sorted, ungraded, matrix supported bioclasts and lithoclasts (?intraclasts) in a caicareous matrix. Clasts include: pellets, megalodonts, ?ostracdes, calcispheres, foraminifers, stromatoporoids, lithoclasts (occasionally reddened or blackened), peloids and brachiopods (Figs. 3.3 and 3.4). Bioclasts may be whole or broken, and are not in growth position. In thin-section, Facies 1 consists of a fossiliferous, wackestone to grainstone ma&. The upper and lower contacts of Facies 1 beds are both abrupt.

In the Colin thrust sheet, dong the upper margùi of the Jasper Basin, Mount Haultain, Facies 1 occurs as a thin, 10 cm - 30 cm unit directly underlying the F-F Boundary (Figs. 3.1,3.3 and 3.4). This unit partiaily fills local depressions at the top of the uppermost Simla Member shallow water carbonates, Mount Haultain sections 2,3 and 4, and is thinnest overiyhg the Simla Member carbonate platform and margin 0.1 to 0.3 rn, and thickens basinward to 0.5 to 1 m units that may be stacked, or interbedded with calcareous shales and argillaceous to slightly silty mudstones at the Type Section and at Thornton Creek II (Figs.2.1 and 3.1).

In addition, at the Type Section these bioclastic uni& are intercalated with black mudstones, silty shales, and siltstones or siltstone debris flows (Figs. 2.1 and 3.1). Figure 33Facies 1: bioclastic debrite containing megalodonts, brachiopods, and intraclasts, uppermost Simla Member, Om above base of Section 3, Mount Haultaui.

Figure 3.4 Facies 1: bioclastic debris flow with clasts of stromatoporoids, solitary corals, and darker lirnestone in a wackestone to packstone ma&, uppennost Simla Member at base of F-Section.

In the Chetamon th.sheet, Facies 1 occurs as basinward thickening, 0.8 to 5 m thick beds overlying calcmus shales and argillaceous to slightly silty mudstones at Gap Lake and F-sections (Fig. 3.4) and is overlain by a calcareous siltstone at F-section. This overlying siltstone pinches out to the northwest towards the basin margin and is not present at the Gap Lake section, (Fig. 3.2). At the Gap Lake section bioclastic units are overlain by an argiilaceous mudstone (Fig. 3.2 and Appendix A).

Facies 1 was sampled for conodont analyses in the Colin thnist sheet at Mount Haultain (HICON), Thornton Creek @55CON, N56CON, NS9CON) and in the Chetamon thrust sheet at Gap Lake Section (G19), (see section 1.45, Fig. 1.5 and Appendix A). Conodont dysessuggest that Facies 1 has a probable range within the Lower to Upper rhenana Zone (Late Frasnian).

Interpretation: Poorly sorted, non-graded, matrix supported bioAithoclastic debris in a muddy carbonate matrix is interpreted to represent a carbonate debrite (Cook 1983, Nardin et al. 1979, Reading 1986). Debrites represent transport in which clasts are supported by the cohesive strength of the mud matrix and clast buoyancy, (Cook I 983, Nardin et al. 1979).

Reddened clasts within the bioclastic debnte overlying the uppermost Simla Member at Mount Haultain and the Type Section (Figs. 3.3 and 3.4) and blackened clasts within debntes at Gap Lake and F-Section (Fig. 3.1) record erosiod reworking and downslope deposition of material derived fiom the underlying Simla carbonate platform and rarnp. The restriction of bioclastic debntes to within 1.5 km of the northeastern margin of the Jasper basin margin also suggests that carbonate debns flows comprise resedimented material was derived from the underlying Simla platform.

The significant facies changes obsemed directiy above the uppermost Facies 1 surface at Gap-Lake, F-Section, and Mount Haultain strongly suggests that this contact represents a sequence boundary (Appenh A, Figs. 3. la, and 32). 3.12 Facies 2--Calcareous, Lithodast Siltstone

Description: Facies 2 comprises massive, coarse, silty to sandy deposits that form sesistant units O. 1 m to 5 m thick near the base of the Sassenach Formation in the Colin thst sheet (Fig. 3.1) at Type Section, Thornton Creek II and Morro Peak, and in the Chetamon thrust sheet at Mount Strange (Fig. 3.2). These deposits comprise rnatrix supported, non-graded, poorly sorted Iithoclasts in a caicareous siltstone to fine grained sandstone matrix (Appendix A). Clasts are tabular to subrounded and range in size from 1 to 15 cm long and predominantly comprise peiletal/peIoidal wackestones to packstones (Figs. 35 and 3.6). Clasts may display parallel silt laminations, or may be bioturbated, and contain various fossil fragments, e.g. brachiopods and foraminifera (Figs. 3 -7 and 3.8).

At the Type Section, lithoclastic siltstones are restricted to the lowest 8 m to 25 rn of the section and wcur in units up to 5 m thick (Fig. 3.1). In thin section, some intraclasts are iron stained, e.g. Sample N60 (Fig. 3.7 and Appendix A).

At Mount Strange Facies 2 occun in the lower 36 m of the section (Figs. 3.2, 3.5 and 3.6). A -65 m unit, 35 m above the base contains larninated, ?imbricated, "soft sediment deformation" clasts of silty wackestone/packstone within a calcareous siltstone rnauix. Downslope, this unit grades into folded or slumped interbeds of siltstone to fine grained sandstone and silty wackestone to packstone. Also at Mount Strange, a 4 m unit. 25 m above base of section, is matrix supported and contains imbricated silty wackestone/packstone clasts (15% clasts) in a siltstone matrix. Laterally, toward the basin rnargin, this unit grades into ?folded, interbeds of 2 cm to 5 cm siltstone to fine grained sandstones and wackestones to packstones.

At Morro Peak Facies 2 also occurs as a 3 m unit 66 m above the base of section. Carbonate clasts are similar to those described for Thomton Creek and Mount Strange (see above descriptions) and weather recessive to the calcareous siltstone to fine grained sandstone matrix. This unit is matrix supported and contains > 25% clasts.

Interpretation: Sharp based units of matrix supported. poorly sorted, angular to subrounded clasts with no visible grading are interpreted as debrites (Scholle. Bebout and Moore 1983, Nardin et al. 1979). Figure 3.5 Facies 2: siltstone debrite, 3 m thick, with recessive, silty, poorly sorted, occasionally laminated wackestonelpackstone intraclasts 2- 10 cm long in a calcareous, siltstone matrix; Sassenach Formation, 66 m above base of Mono Peak section.

Figure 3.6 Facies 2: siltstone debnte, 4 rn thick, with silty, recessive, poorly sorted, tabular to subrounded, wackestone/packstone clasts 2-1 5 cm long in a calcareous siltstone ma&. Clam are occasionally laminated, e.g. tabular clast to the right of the hammer head, ?Sassenach Formation, 27 m above base of Mount Strange section.

Figure 3.7 Facies 2: photomicmgraph of packstone/wackestone intraclasts in siltstone (mody white) debrite, uppermost Mount Hawk Formation, 18 m above base of Type Section. Scale bar represents 1 cm.

Fipre 3.8 Facies 2: photomicrograph of packstone/wackestooe iron-stained intraclast in siltstow (mostiy white) debrite, uppermost Mount Hawk Formation, 5 m above base of Type Section. Scaie bar represents 1 cm.

Facies 2 is similar to Facies 1 and also represents transport in which clasts are supported by the cohesive strength of the mud matruc and clast buoyancy (Scholle, Bebout and Moore 1983, Reading 1986; see section 3.1 1). Debrites at Mount Strange (Fig. 3.6) may represent npup clast/scour features that resulted hm turbidity flows down/?along the flank of the Jasper Basin. This mechdsm could produce massive bedding, poor soriing and soft sediment deformation of clasts (Mount Strange). Alternatively, the position of the debrites which occur; downslope to interbedded sütstone to fine grainecl sandstones and wackestone to packstones (35 m above base of section, Mount Strange, Fig. 3.2 and Appenduc A); and upslope of slurnped bedding; suggests that these debntes may represent the basal zone of a translational or rotational slide (Cook and Mdins 1983)- Debns flows may also result fiom oversteepening caused by rapid deposition on the slopes of the basin margin during lowstaad deposition.

3.13 Facies 3-Deformed, Interbedded, Silty Limestone and Calcareous Siltstone

Description: Facies 3 comprises interbeds of 2-5 cm caicareous siltstones to fine- grained sandstone and silty wackestone to packstone that contains deformed, (Fig. 3.9) overtumed or folded bedding (Fig. 3.10) at Morro Peak and Mount Strange respectively.

At Mom Peak, approximately 16 km fiom the basin margin, interbeds of 2-3 cm siltstone/fine grained sandstone and wackestone/packstone comprise 13 metres of spectacular irregular folds and slumps. This unit occurs directly above the basal black shale unit (covered at this locality) 18 m above the base of the Lower Member of the Sassenach Formation (Fig. 3.10). Smaller (2 to 3 m thick) folded or deformed units also occur at 38 m and 66 m above the base of the Sassenach Formation at this locaiity. The lower 13 m slump bed can be mapped for .5 to 1 km, but is absent to the West and south in the Pallisades and at the Overlander Section respectively-

Similarty, uiterbeds of 2 cm to 5 cm siltstone/fine grained çandstone and wackestonei packstone form 2 m to 4 m units of deformed andior folded bedding occur between 1 km and 1.5 kms fiom the adjacent plaaonn margin at Mount Strange (Fig. 3.9 and Appendix A). Figure 3.9 Facies 3: siltstone with laminated and distorted, silty, wackestone/packstone clasts that weather slightly recessive. Secümentary stmctures are absent in the siltstone matrix, ?Sassenach Formation, 35m above base of Mount Strange section.

Figure 3.10 Facies 3: base of 13 m thick slurnp fold, comprises 2 to 4 cm interbeds of siltstone and wackestone/packstone, with well preserved bedding, ?Sassenach Formation, 18 m above base of Mono Peak section-

At Medicine Lake, 1lm of bioturbated, cdcareous siitstones occur at the base of the measured section (Fig. 3.2 and Appendix A). These siltstones are continuous for ?several kms to the southeast dong the Chetamon thrust sheet.

Interpretation: Sharp based uni& of folded and deformed bedding with intemal bedding at an angular discordance to enclosing strata are interpreted to be slump deposits (Scholle, Bebout and Moore 1983; Reading 1986). See Table 4.

Shear failure dong discrete shear planes was the probable rnanner of movement for this facies. Rotational slides move dong discrete concave-up shear planes accompanied by rotation of the slide. Siump deposits appear to be restricted to near the base of slope of the Jasper basin margin. In the study area, shear failure probably resulted corn oversteepening due to rapid deposition on the slopes of the basin. These deposits record a significant change in depositional environment within the basin and may represent the rapid influx of siliciclastics into the basin during a relative sea-level lowering.

3.2 Sassenach Formation Facies

Seven facies were recognized in the Sassenach Formation of the study area: (Figs. 1.5,3,3.1 and 3.2). They comprise: 1) black shale; 2) bioclastic turbidites; 3) siltstone/limestone/mudstone interbeds or "rhythmites"; 4) oncoid wackestone to grainstone; 5) stromatolite bafflestone; 6) limestone (wackestone to packstone); and 7) siltstone to fine grained sandstone. For convenience, interbeds of argillaceous mudstone, siltyfargillaceous wackestone to packstone and cdcareous shale were grouped into a single facies; the siltstone/limestone/shale interbeds, because they are interpreted to represent phases within one depositional event (see Facies 7, section 3.23).

3.21 Facies 5-Black Shale

Description: Black, calcareous, fissile shale occurs in units 0.3 to 18.5 m thick. Shaie units tend to be unfossiliferous, but may contain rare brachiopods and ?Tentaculites. The thickest shale uni& occur at Morro Peak (18.5 m), Overiander (8.5 m) and Mount Strauge (15 m). Shaies occur rnainly within the basal 8 to 18.5 m of the Lower Member Sassenach Formation and are generally covered except in very well exposed sections (TC, GL, and FS, Figs. 3,3.1 and 3.2).

At Medicine Lake, the bottom-most 1.85m black shale is underlain by 5-10 cm silty shale containing silty pyritic cross-beddïng (Fig. 3.2, Appendix A). The pyritic foreset beds are underlain by 1lm of resistant, dolomitic siltstones. This shale is interpreted on the basis of conodonts to represent deposition in the trimguIuris Zone (Goodfellow et ai. 1988, Geldsetzer et al. 1987%Chapter 1. At Gap Lake and F sections, thin (2m to .7 m) shales are interkdded with silt and crinoidal turbidites -2 m to -5 m thick. At Gap Lake, this shale is interpreted based on conodont stratigraphy to occur within the Lower irianguZuris Zone through the Middle crepida Zone (McCracken 1995). At Thornton Creek thin (0.3 m - 2 m) shales are interbedded with a series of calcareous siltstonel carbonate debris beds (2 m - 3-5 m) and occur directly beneath the basal oncolite bed (Figs. 3.1,3.11 and 3.12). The uppermost black shale 29 m above the base of the Type Section contains Upper rhenana Zone conodonts (Section 1-45, Fig. 1-5).

Iaterpretation: Black, fissile shales are interpreted to represent deposition in a quiet, low energy, anoxic depositional setting. The black colour (i.e. high organic carbon content) and general lack of fauna is interpreted to represent deposition in an anoxic to suboxic setting.

The potential maximum depth of deposition for the Sassenach Formation black shales (ignoring subsidence) would be the thickness of the Sassenach Formation, or 200 m. Anoxia does not however preclude deposition in a shallow water regime. Early Devonian black shales (Perdrix and Maligne) interfingered with shailow reefal carbonates were interpreted to represent deposition in a shallow water 25-50 m, anoxic environment (Wendte er al. 1992, Stoakes 1980, 1992, Mountjoy 1980). They suggest tint this type of depositon would be consistent with density stratification caused by the warmïng and evaporation of a shallow epeinc sea- In addition, anoxic zones could have been produced by the restriction of the Jasper Basin, or by an anomalous expansion of the oxygen minimum zone bringing anoxic waters up ont0 the shelf, killing benthonic organisms and depositing laminated shdes, (Geldsetzer 1987a). Figure 3.11 Facies 5: recessive, black shale above and below a Facies 6, 10 cm carbonate turbidite, Sassenach Formation, 5 m above base of Gap Lake Section- Marker is 15 cm long,

Figure 3.12 Facies 5: recessive, black shde underlying the lower oncolite bed, Sassenach Formation, 3 1 m above base of Type Section.

While it is not possible to fÛUy constrain the depth of deposition of black shales wîthin the study axa, these shah obviously did not result fiom a signifïcant increase in water depth. On the con-, these shales represent a restriction of the Jasper Basin- The existence of these shaies above and below the FF-Boundary is somewhat problematic and makes correlations dif5cult without biostratigraphic dating .

3.22 Facies 6-Bioclastic PackstoneGrainstone

Description: Facies 6 comprises coarse, biocIdc debris that forms thin, 1O cm - 50 cm thick units that are mappable for up to 1 km into the basin. Bioclasts predominantly comprise; crinoids (2 mni - ?5 mm), and brachiopod hgments (-5 cm - 3 cm). These units are sharp based, normal graded and have a relatively coarse base that passes upwards into planar laminations. The upper part of these unit ?grades into or ?is interbedded with a caicareous and sometimes slightiy silty, black shale-Facies 5 or mudstone (Fig. 3.1 1). The packstonedgrainstones of Facies 6 are present only withh the basal 15 m of Sassenach Formation at Gap Lake and F- Section approximately 1 km fiom the basin margin (Fig- 3.2 and Appendix A)- Beds are thicker closer to the basin margin in the Gap Lake section. Facies 6 occurs within black shales above the FF-Boundary and represent deposition during the early Famennian Lower ii-iangularis Zone through the Middle crepida Zone (McCracken 1995, Section 1.45, Fig. 1.5)-

Interpretation: The upward vertical association fiom a sharp base through normal grading to pardel larninations and into an overlying muddy unit is interpreted to represent deposition by either turbidity currents or by storm generated tempestites (Walker 1992 and Bouma et aL 1962). The overlying calcareous black shale is interpreted to represent suspension deposition that occurred between the intermittent storm or turbidity events- The close proxirnity of Facies 6 units, to wiùiin about 1 km of the adjacent platform margin and an increase in abundance and thickness of these units towards the basin margin (fiom F-Section to Gap Lake section, Fig. 3.2) suggests that the carbonate debris was derived nom earliest Famennian "upslope" or basin margin carbonates. 3.23 Facies 7-Silbtonc/Limestone/Ma&tone Rhythmite

Description: Most of the Sassenach Formation consists of a monotonous, succession of interbedded siltstone/limestone/mudstone"rhythmic" deposits, (Figs. 2.1,3.1 and 3 -2)These "rhythmic beds" form distinctive 50 to 80 m thick planar and horizontal units mappable over several kilometres (Figs. 3.1 and 3.2). Facies 7 comprises a senes of altemating interbeds of OScm - 30 cm of slightly silty, calcareous shale to slightly shaly, calcareous siltstones and silty or argillaceous rnudstones to wackestones with a rare to fiequent Famennian brachiopods (McLaren 1956, Raasch 1988, Chapter 1, Figs. 3.13,3.14 and 3.1 5). The thickness of interbeds may be of approximately equal thickness, and may contain thicker siltstone or limestone beds with minor argillaceous or silty laminationdpartings, and less fiequently contain resistantt, thin (.5 cm - 2 cm) interbeds of calcareous siltstone/sandstone within argillaceous mudstone to wackestone units (Fig. 3.13). Siltstone/sandstone interbeds are sharp based, display load casts or bioturbation traces on their base, are usually normal graded and pass upwards into laminations and occasionally cross laminations (Fig. 3.14). Normal graded beds with parallel laminations passing upwards into cross-laminations were observed in siltstone and silty mudstone/wackestone interbeds both in outcrop, 0.5 cm - 30 cm and thin- section, 0.05 cm - 1.5 cm (Figs. 3.2,3.17 and 3.18). Silty shale interbeds display fme parallel laminations and rarely cross laminations. Mudstones and wackestones display fine parallel laminations, rarely contain siIty cross-laminations and occasionaily are nodular.

Nodules predominantly occur where mudstones/wackestones are interbedded within siIty/sandy units or where mudstone/wackestone beds are much thinner than the silty, argillaceous interbeds (Fig. 3.16).

These rhythmic interbeds grade upwards nom more argillaceous mudstone and calcareous shde (facies 7a) into coarse calcareous siltstone-silty wackestone/ packstone (facies 7b). This facies also becomes gradually thicker upwards fiom 7a to 7b with an increasing abundance of coarser (coarse siltstone to fine-grained sandstone size) siliciclastic grains. In more basinward sections, e.g. Mount Strange, rhythmic units are shalier, contain much less carbonate and have significafltly fewer limestone interbeds. Figure 3.13 Facies 7a: alternating pale, argiiiaceous mudstondshale 8 to 10 cm thick and dark, thin, resistant wackestooe/packstone aud light siltstone interbeds 2 to 5 cm thick. Sassenach Formation, 48 m above base of Mount Strange section.

Figure 3.14 Facies 7a: alternating paie, argillaceous mudstonelshale, and dark, wackestone/packstone and siltstone interbeds- Dark wackestone/packstone and light siltstone interbeds are -5 to 2 cm thick. Recessive, paie coloured argikiaceous mudstone/shale beds are 8 to 10 cm thick. Sassenach Formation, 34 m above base of Mount Strange section.

Figure 3.15 Facies 7b: wackestone/packstone and silty shale interbeds truncate the underlying laminated, calcareous siltstone in the lower 113 of the photograph. The tmcated surface (cear the middle of the hammer) displays 40 cm of reliet Sassenach Formation, 79 m above base of Mount Strange section.

Figure 3.16 Facies 7a: nodular, 3 to 5 cm mudstone/wackestone beds interbedded with .5 to 1 cm argiiiaceous mudstone interbeds, Sassenach Formation, 34 m above base of Medicine Lake section- Figure 3.17 Facies 7b: photomicrograph; nonnally graded packstone and silty packstone. Sassenach Formation, 197 m above base of Mount Stninge section. Scale bar represents 1 cm. Top to le&

Figure 3.18 Facies 7b: photomicrograph of normdy graded laminations in calcareous siltstone of Figure 3.15. Sassenach Formation, 34 m above base of Mount Strange section. Scale bar represents km-Top to left.

Rhythmic hterbeds comprise thin (2 cm - 5 cm) beds of gradeci, interbedded slightly calcareous thin siltstones and shdes and very argiiiaceous mudstones that pass upwards into thicker (8 cm - 10 cm) interbeds of coarse, slightly calcareous siltstone and silty/argiilaceous wackestone/packstone (Figs. 3.1 3 and 3.1 4).

Interpretation: Several factors suggest that interbedded siltstone to fine grained sandstone units were deposited rapidly: the paucity of organisms; persistence of fine lamination throughout much of the sediment; normal grading of sediments passing upwards to parallei laminations with occasional cross-laminations; load casts and bioturbation traces on the bases of siltstone interbeds; and the presence of escape structures (Reading 1986, Figs. 3.14,3.17 and 3-18).

The thick, monotonous succession of "rhythmic interbeds" is interpreted to represent rapid and episodic deposition of either storm generated sediment gravity flows or distailbasinal (abc) turbidity currents. The interbedded calcareous shale and argillaceous to silty mudstone to wackestone is interpreted to represent suspension deposition that occurs between stom or turbidity current events. Thin bedded turbidites lacking significant scouring features are generally interpreted to be intermediate to distal basin turbidites deposited by currents that are not strong or dense enough to suspend a coarseheavy sediment load, or to erode the underlying beds (Walker 1992, Bouma 1962, Reading 1986. Bebout et al. 1983, Reinich and Singh 1980). Storm generated sediment gravity flows couid have been generated by storms reworking coarser shoreline deposits. Conversely, turbidity currents could have resulted fiom earthquakes associated with Antier orogenic activity.

Mount Strange represents the thickest Sassenach section measwed within the study area (225m,Fig. 3.2). This thick section occurs above a thui Mount Hawk and Perdrix basinal section (Coppold 1976, Hopkins 1972, Mountjoy 1980,1987). The increase in argillaceous content within the interbeds at Mount Strange is interpreted to represent the fme fiaction of storm events ador represents background sedimentation deposited between stem or turbididty currents in deeper water environrnents in the study area (Fig. 3.2). Carbonate rich sequences at Thomton Creek, and Medicine Lake appear to reflect proximity to carbonates produced dong the margin of the Jasper Basin (Sections 324 and 3.25 and Chapter 5). 3.24 Facies &-Stromatolite Blifflestone

Stromatolites were observed only in the upper part of the Sassenach Fornation (20 m below the top) dong the margin of the Jasper Basin at Mount Haultain (Fig. 3.1 and Appendix A). The stromatolite unit is up to 3.1 m thick and has a gradua1 contact with the underlying oncoliteloncoid wackestone to grainstone facies (Section 3.25, Figs. 3.19 and 3 -20). Basinward the stromatolitic facies grades into dolornitic, cemented, peloidal, algal ball, and algal fiagment packstones. Toward the platfom, they onlap over the underiying oncoid facies and Simla carbonate debris units (Sections 3.1 1,3.24 and 3.25, Fig. 3.1). This stromatolite unit is overiain by siltstones and slightly noduiar packstones (Section 3.24, Fig. 3.1) that also fil1 in around the upper -15 to .30 m of the stromatolites.

Stromatolites are columnar in form, have siightly rounded to irregular upper surfaces, and are generally 10 - 15 cm wide. Stromatolites are composed of several algae genera including: Sphaerocodium; ?GintonelIa; and Renalcis, (Figs. 3.19 and 3.20). Inter-stromatolite sediments are completely dolomitzed and consist of silty, peloidal-algal bail wackestones in the upper part of the unit, and scattered oncoids witha wackestone in the lower portion. Bedding horizons (obse~edbetween the stromatolite coiumns) are generafly indistinct but suggest that the synoptic relief of the stromatolites was approxirnately -30 to 50 m-

Interpretation: Stromatolites currently grow in shallow, hypersaline, highly agitated conditions and generally grow in waters < 3.5 m deep. Logan et al. (1 964) and Hoffinan (1 967) documented the relationship between modem stromatolite morphology and environmental setting and their use in stratigraphie correlation respectively. The colurnnar to club-shaped foms with up to lm relief, grow in the intertidal zone around headiands. Probably, the columnar stromatolites in the upper Sassenach member were deposited in a high energy intertidal zone in less than 3 to 5 m water depth, Figure 3.19 Facies 8: stromatolite baffiestone. Stromatolites are da& irregular columns 8 to 10 cm wide. Dark, sub-spherical blobs in the inter-stromatolite sediments are peloids or oncoids, Sassenach Formation, 2 m above base of Mount Haultain Section Hî.

Figure 3.20 Facies 8: photograph of stromatolite bafllestone displaying the rounded/iieguiar upper surfaces of strornatolites. Siltstone and wackestone/packstone interbeds infil1 around the tops and overlie the stromatolites, Sassenach Formation, 5 m above base of Mount Haultain Section H2. Lens cap is 6 cm in diameter.

Stratigraphie relationships may also serve to constrain the depth of deposition. Within the Sassenach Formation, stromatolites occur 15 m beneath the base of the Palliser Formation (Appendk A, Fig. 3-1). Because the Sassenach Formation is locally absent over the Simla pladonn at the Ancient Wail reef cornplex, sea-level could not have exceeded the highest level of the Simla platfonn during Sassenach deposition. Therefore, assuming that there was littie erosion of the cemented Simla platform, it is unlikely that the water depth for deposition of the stromatolites exceeded 15 - 20 m.

The stromatolite unit grades basinward into a completely cemented algai ball, peloidal packstone (see Section 3.26). This packstone is interpreted to represent deposition of aigal detritus shed nom the stromatolites into a highly agitated, shallow water environment. The lack of silt in the lower portion of the inter-stromatolite sediments and their lateral equivalents suggests that the stromatolites grew during or just after a (?minor) relative sea-level rise that temporarily suspended the influx of siliciclastics. Siliciclastics between the upper portions of the stromatolite heads and directly overlying them suggest that stromatolite deposition was terminated by the influx of these siliciclastics.

3.25 Facies 9-Oncoid Wackestone to Grainstone

Description: Oncoids are rounded to oval and are fond predominantly as grainstones (oncolites), but also fonn floatstones in a fossil hgment wackestonelpackstone ma& (Figs. 3.2 1 aud 3.22). Oncoids generally consist of a brachiopod or intraclast? nuclei and are coated with irregular laminations of encmsting aigae that were identified as Gin>anella tubules (Figs. 3.23 and 3.24). Oncoid wackestones generally comprise rare pellets or peloids and brachiopod fossil debris in a micrite or microspar rnatrix. Oncolites contain less brachiopod debris and have little or no mud.

Oncolites fonn the basal unit in the upper member of the Sassenach Formation overlying the Simla platform and upper ramp at Cinquefoil, Mount Greenock, and Mount Haultain. At the type section a stratigraphically lower oncolite unit occurs near the base of the Sassenach above a black shale, Merdown the basin slope, (Figs 3.1,3.1A and Appendix A). At Mount Haultain, oncolites and oncoid wackestonelpackstone units directly overlie a thin, c.30 m, early Famennian (Fig. 1.5, HXON, McCracken 1996) carbonate debris unit compnsing megalodont. stromatoporoid and aigae etc. fragments (Section 3.1 1) that rests unconformably on Simla platform carbonate clinoforms. Oncoid units grade upwards into either an ovedying stromatolite unit, Facies 8 (Appendix A, Section 3.2 1 Figs. 3.19 and 3-20), or a peloidd wackestone to grainstone (Appendix A, Section 3.26, Fig. 3.28).

At the Type Section oncolites occur at the F-F boundary and at 7.7 rn above tbe base of the F-F boundary (Appendix A, Fig. 15 and 3.1). The lower oncolite unit is in sharp contact with the underlying (Frasnian) fissile, black shaie. This oncolite consists of weU rounded oncoids with Iittle matrix. Oncolites at Mount Haultain and at Thornton Creek have similar sphericity, composition (Le. Girvanella tubules), and packing/matrix composition based on thin-section and outcrop observations. In fact, oncoids from different Iocation are not distinguishable.

Interpretation: Oncolites represent in-situ growth of Girvanelia around a nucleus, e.g. brachiopod fragments or intraclasts, in an agitated environment above wave-base by normai wave action or storms (Peryt 198 1, 1983a, 1983b). Subsequently, the sphencity of oncoids is interpreted to indicate the degree of agitation during oncoid growth, (Peryt 198 1. 1983a, 1983b). Sphericd oncoids are interpreted to develop in highly agitated waters, i-e. above wave base. Ginanella oncoids are believed to flourish in marine subtidal environments and have been interpreted to be indicator of low sedimentation rates, (Peryt 198 1, 1983a, 1983b). Girvanella oncolites in Devonian strata of the Canning Basin; Western Australia are interpreted to have ken deposited in water depths ranging from O - 15 m and cornmonly between 3 - 5 ml (Playford et al. 1976). Thus it is reasonable to interpret the spherical, tightly packed oncolites of the Sassenach Formation as having been deposited in a highly agitated, shallow subtidal, (O - 15 m water depth), environment with Iittle or no siliciclastic sediments. Figure 3.21 Facies 9: oncoids 1 - 2.5 cm in diameter, Sassenach Formation, 3 1 m above base of Type Section.

Figure 3.22 Facies 9: oncoid wackestone with 1 - 2.5 cm oncoids in a matrix of brac hiopod debris, Sassenach Formation, 0.5 m above base; Mount Haultain Section H4.

Figure 3.23 Facies 9: photomicrograph of 1.5 cm9 sub-spherical oncoid with Ginanelta tubules and irregular growth layers, Sassenach Formation, 0.3 m above base of Mount Haultain Section H3. Scaie bar is 4 mm.

Figure 3.24 Facies 9: photomicrograph of oncoid displaying Ginanella tubules, Sassenach Formation, 3 lm above base of section, Type Section. Scale bar 4 mm.

Also at Mount Haultain, stromatolites grew over the oncolites, (Appendix A, Figs. 3.1 and 3.1 A). Stratigraphie relationships discussed in the stromatolite facies interpretation (Section 3.24) suggest that stromatolites were deposited in waters no deeper than 5 - 20 m. Because the stromatolite unit appears to be conformable with the underlying oncolite (Appendix A, Figs. 3.1 and 3- 1A ), it is reasonable to interpret that the oncoids grew in waters no deeper than 10 - 25 m. Because the base of the lower oncolite at the Type Section, (near the base of the Sassenach, Appendix A) is sharp and there is no indication of reworking of the underlying shale this oncolite unit is interpreted to represent the downslope transport of oncoids or the transport of a lithined or semi-lithifïed oncolite unit (Figs. 3.1 and 3. IA). Oncoid wackestones at Mount Hadtain (Figs. 3.1 and 3 .1 A, Appendix A - H4 and H5) Iikely reflect periodic, storm generated transport of oncolites fiom their growth environment.

3.26 Facies 10-limestones (Wackestone to Packstone)

Description: Wackestone to packstone unis occur in al1 sections throughout the Sassenach Formation. Allochems include: brachiopods, crinoids, pellets, peloids, algal balls, algal hgments, oncoids, foraminifers, intraclasts, etc.. The type of allochems within these limestones varies at different stratipphic levels and between sections (Appendix A, Figs. 3. la-c and 3.2).

Three limestone subtypes have ken identified: a) brachiopod, b) crinoid and c) pelletaVpeloidaL

Brachiopod wackestone to packstone units occur in the upper portions of the Sassenach Formation in many basinal sections including: Gap Lake, F-section, Medicine Lake and Overlander (Appendix A, Fig. 3.2). Brachiopod limestones correlate fiom Gap Lake to F-section and change basinward fkom grainstones at Gap Lake to packstones in F-section (Appendix A, Fig. 3-2). These limestones comprise several brachiopod genera including; Famennian rhynconnelids and spiriferids in a calcareous micrite or microspar, (McLaren 1962, Section 1.45).

Crinoidal wackestones occur in the upper member of the Sassenach Formation at the Overlander and Beaver Lake sections. Crinoids are the predominant allochem, but brachiopods, gastmpods, intraclasts and peloids are also present, The matrix is mostly micritic, but also comprises microspar. Sorne silt size quartz grains form 2% to 10% of the rock Silty burrow traces are present at Medicine Lake, (Appendoc A). Crinoid wackestones fiom the Overlander section contain red stained intraclasts, and between 5% and 10% coarse silt to fine sand (40 - 100 p), (Appendix A, Fig. 3.26).

PelletaVpeloidal wackestones-packstones occur as interbeds within sandstones, siltstones, silty shales and mudstones in al1 sections in both the upper and Iower members of the Sassenach Formation (Fig. 3.25 and 3.27). Wackestone/packstone beds are sometimes noddar where interbedded with siltstones and sihy shales, Wackestones/packstones are locally graded, bioturbated, andlor may contain fme silthhale laminations The matrix generally consists of a calcite microspar. Pellets are the dominant allochem athough peloids, calcispheres, forarns and ?ostracodes are also present. Pellets and peloids generally contain siIt grains that range in size fiom coarse silt to fme sand, (40 - 100 pm),

PelletaVpeloidal wackestone facies occur in the upper member of the Sassenach Formation at Mount Haultain Cinquefoil and within the Iower member of the Sassenach Formation at Thornton Creek. Allochems range fiom poorly to medium sorted and include: Girvanella peloids, pellets, calcispheres, foraminifera, fragments of brachiopods, ?Puruchaetes, Solenopora and Sphaemcodium fragments (Fig. 3.28). Allocherns may have micrite envelopes, but are othenvise texturally well preserved. The matrix consists of a fme to medium crystalline calcite microspar ?pseudospar that is occasionally dolomitized. At Mount Haultain these wackestones grade laterally into the stromatolite facies (Facies 8) towards the basin margin (Appendix A, Section 3.24). At the Type Section a lower Sassenach wackestone 48 m above the base of section (Appendix A) forms a thin, (.60 m), distinctive, resistant bed that weather red on its upper surface- Allochems are iron stained ?hematized and include pisolites andlor ooliths. Fipre 3.25 Facies 10: photomicrograph of pelletlpeloid wackestone/packstone, Sassenach Formation, 4.5 m above base; Mount Haultain section 4. Scale bar is 1 cm.

Figure 3.26 Facies 10: photomicrograph of c~oidalwackestone, with gastropod and brachiopod hgments, Sassenach Formation, 157 m above base of Overiander section, Scale bar is 1 cm.

Figure 3.27 Facies 1 0: photomicrograph of brac hiopod/peIoid packstone/grainstone, Sassenach Formation, 47 m above base of Type Section. Scale bar is 2.5 mm.

Figure 3.28 Facies 10: photomicrograph of dgal bail, algal hgrnent peloid wackestone/packstone. Sample comprises pisolites, brachiopod and algal fragments, and Ginanella dgal bds, Sassenach Formation, 9 m above base; Mount Haultain Section H4. Scale bar is 2.5 cm.

Interpretation: C~oidand brachiopod wackestone/grainstones are interpreted to reflect deposition in an open marine, sub-tidal environment. Brachiopod grainstone units may represent a high energy setting. Poorly bedded, pellet-peloidal packstones to grainstones rnay be interpreted as either suspension deposition "rains from above" adorthe fecal pellets fiom algae and neritic organisms in open marine conditions. The Iack of bedding suggests these deposits were oxic and were extensively biohirbated. Wackestone/grainstone units generally contain less than 10 - 15% silt suggesting that carbonate production was not occurring simultaneously with significant siliciclastic influxes. The carbonate content of the upper Sassenach Formation in the Colin thnist sheet graddy increases toward the basin margin suggesting that carbonate was king produced mostiy in the shallow waters dong the margin of the Jasper Basin.

3.27 (Facies 4/11) Siltstone and Fine-grained Sandstone

Description: Coarse silt to fine-grained sandstones -50 - 3.0 rn thick form massive, resistant units at two stratigraphic levels; the uppemost Mount Hawk Formation and the upper 25 m of the Sassenach Formation (Appendix A, Figs. 3.1 and 3.2). Beds are fiequently laminated and cross-laminated, and may display nppled upper contacts (Fig. 3.29). Siltstone or sandstone units are in places interbedded with recessive, locally nodular wackestoned packstones (Figs. 3.3O,3 -31 and 3-3 2). Carbonate nodules Vary in leagth and thickness fiom 1 - 20 cm, and fiom 1 - 3 cm respectively. Nodular units locally grade into thicker .10 - -3m carbonate rich units or are overlain by calcareous sandstone units. Hummocky or swaley 5 - 10 cm troughs were observed in siltstone and silty wackestonelpackstone interbeds at Mount Strange and Thomton Creek (Fig. 3.32). Beds may be mottied, or display bioturbation tracery on their upper or lower surfaces. Some beds may contain scattered brachiopods (Fig. 3.33). Sandstones at Mount Hauitain also contain black chert nodules (Appendix A). Erosional or exposure related features are absent.

Siltstones with wackestond packstone interbeds occur as slumps or debntes in the lower 25 m of the Sassenach Formation at the Type Section. Mono Peak, and Mount Strange (Section 3.13, Figs. 3.1 and 3.2). At Medicine Lake, 11 rn of bioturbated, calcareous siltstones occur in the uppemost Mount Hawk Formation, (Appendix A, Fig. 3.2). Figure 329 Facies 411 1: lamùiated silty packstone bed 7 cm thick overlain by a 1.5 cm siltstonelfuie-grain4 sandstone bed. The non-laminated portion of the silty packstone layer is normally graded. Escape structure of sea anemone (George Pemberton pers. comm.) dimipting silty laminations, Sassenach Formation, 72 m above base of Mount Strange section. Load structures occur at the base of the uppermost 1.5 cm siltstone/sandstone layer. Marker is 15 cm Long.

Figure 3.30 Facies 4/11 :siltstonelfine grained sandstone and recessive packstone interbeds. LocaiIy laminated siltstone/fïne-grained sandstone beds with load structures Sassenach Formation, 53 m above base of Mount Strange section.

Figure 331 Facies 4/11 :poorly bedded, siltstone/fhe grained sandstone with recessive packstone nodules. Locally, siltstone/fine-grained sandstone interbeds display laminations and cross-laminations, Sassenach Formation, 172 rn above base of Mount Strange section.

Figure 332 Facies 4/11 : trough cross bedding in 2 - 4 cm siltstontdfine grained sandstone units, Packstone nodules weather recessive to siltstone/sandstone layers, Sassenach Formation, 199 m above base of F-Section.

Figure 3.33 Facies 4/11 :bioturbation on upper Mace of siltstone/he-grained sandstone beds, Sassenach Formation, 6 1 rn above base of Gap Lake section.

Figure 3.34 Facies 4/11 :photomicrograph of normally graded, hely laminated calcareous siltstone/fine-gmined sandstone unit, 203 m above base of Mount Strange section. Siliciclastic grains range fkom 60 - 100 Pm. Scale bar represents I cm.

Generally all Sassenach dtstones and sandstones have a caicareous micrite matrix and contain quartz, feldspar and heavy mineral grains. Pardel laminations, cross-taminations and normal grading are visible in some thin-sections (Fig 3.34) . Quartz and feldspar grains are sub-mgular to sub-rounded and range in size fiom 60 - 120 p. In addition, calcareous siltstone and wackestonelpackstone ïnterbeds also grade upwards fiom quartz rich bases to more argillaceous, andor carbonate nch (usually pellet packstones) paralle1 laminations and cross-laminations.

lnterpretation: Several features suggest that the siltstones and sandstones were deposited in relatively rapid pulses including: 1) the presence of primary bedforms; 2) normal grading progressing to paralle1 laminations and occasionally to cross- bedding; 3) load casts and bioturbation traces observed on the bases of beds; 4) escape burrows disrupting primary laminations; and 5) the presence of a calcareous matrix which may indicate a lack of winnowing/reworking of the sediments.

Planar and cross-lamination, and normal gradhg of beds may result fkom deposition by currents and has ken interpreted as unidirectional flow within the lower part of the upper flow regime (Men 1993). Therefore, the upper Sassenach silts and sands are interpreted to represent deposition in some of the shallowest and highest energy environmena in the Sassenach Formation. Bioturbation of some siltstones and sands together with carbonate nch interbeds suggests that the deposition of the siliciclastic sediments was episodic. The lack of exposure related features combined with the stratigraphie position of the siltstone/fine grained sandstone nits at Mount Haultain (15m below the top of the Simla platfonn) suggests that these units were mostly subtidal. Therefore Facies 7 is interpreted to have been deposited above storm wavebase by storm generated sediment gravity flows or turbidity currents. interbedded wackestones and packstones represent suspension sedimentation occurring between storm events. The nodular character of sorne limestones is interpreted to result nom differential cementation and compaction. 3.3 Summay; Sassenach Formation; Lower and Upper Members

Historically, the Sassenach Formation has ken subdivided into Lower and Upper Members based on signifiant, mappable changes in Lithofacies and textures (McLaren and Mountjoy 1962, Chapter 2). The boundary between the Lower and Upper Members of the Sassenach Formation is gradationai and is placed where there are significant increases in the relative residance, thickness and coarseness of siliciclastic interbeds. in terms of facies, the lower member of the Sassenach Formation comprises deeper water facies; 5,6,7a and 10, and the upper member comprises intermediate to sMowwater facies; 7b. 8,9, 10 and 4/11. Table 3.0 is a surnrnary Tabk for dl facies descri'bed hmthe late Frasnian, uppermost Mount Hawk Formation and Simla Member (Facies 1,2,3 and 4/11) and fiom the early Famennian Sassenach Formation (Facies 5,6,7,8,9, 10 and 411 1).

The overail depositional environment that existed in the Jasper Basin during the latest Framian to early Famennian cmbe deduced from the interpreted facies; their depositional environments and stratigraphic relationships. First it is necessary to identify facies associations, map the bounding surfaces and then place the strata (Simla Member, Mount Hawk and Sassenach formations) into a seqence stratigraphic fkmework.

In Chapter 4, facies associations within and between the uppermost Mount Hawk and Simla and the overiying Sassenach Formation are used to recognize and classi@ the parasequences and parasequence stacking patterns which form the basis for the interpretation of sequence stratigraphic and depositional models. The depositional environments were then interpreted within this hework. Table 3 Summary of diagnostic bedding, structures, key constituents and the interpreted depositionai environment of facies observed in the study area. Facies Constituents Bedding Mimentory Structures

Deeper Water Facies

1) Bioclastic Wacktn- to pack*. Basin Margin and Debrite rnatrütMassive. indistinct Basin Slopc carbonate lithoclans, fossil debrk cgstromatoporoids algac bryozoa mgose and tabular corafs.crinoids and brachiopods~cgalodon~-

2) Silîstone Calcarcous siftsmne Massive Bain Slopc Debrite carbonaw ?inaacIasts- indinina laminatcd or bioturbatcd me brachiopods.

3) Stumps Siltstondtine graincd Massive to Folds. rotartd and/ Basin Margin and sandstone. wackcstone thin bedded. or ovemrmed bedding Basin Slopc CO packstone 2cm-5cm and/or dcfonncd interbcds bedding

5) Black Calcamus shalc to Thin bedded Shale argi llaceous mudstonc. 1 cm-2cm black IO grayhrown to indûtinctly rare tentaculites or non-bcdded uni&

6) Bioclastic Limcsfonc. grainstone Massive. Chaotic. Basin Margin and Turbidite to packstone, indistinct occasionally Basin Slope brachiopods, crinoids. graded.

Wackenone to pack- Laminatcd Limestond stoncs.Coarsc silt to cross laminatcd. Mudstone fine grained sandstoncs, nomal gradcd lnterbeds argillaceous mudsiona me mugh and calcareous shalc cross laminations intcrbcds and Bouma abc sequcnces Table 3.0 Continued

Facies Constituents Interpreted Deposiîiond Environmeab

Intermediate Facies

7b) CoanJ Wackcsmne to t cmto 10cm Laminaicd Lowcr to Middle SiltstonJ packnones.Coane silt intcrbeds cross laminate& Shorcfact FG SU to fine graincd sandstoncs. normal @cd. Limestone argiIlaocous mudstoncs rare trough cross and calcarcous shale laminations and inmbds Boumaabc squcnccs

Sballow Water Facies

8) Columnar Calcarmus sittnone Massive. Colmns UPW Stromatolite matnx Oncoid-pcloid one unit 5- 10 cm widc Shore facc Packstone wackcstonc to packstonc, Columnar smmatoporoids.

9) Oncoid None, fntcr-oncoidal UPP~~ Wacke- indistinct argillaccous Iaminae Shoreface Crainstone

10) Lime Mudstonc to pack- 5 cm IO 25 cm Occasional silty ?Lower to Stone none and argillaccous bcds usudly 1aminations Middle Shorefacc mudstone. brachiopods, interbcddcd with ainoids. various gmn siltstonc or silty algac. forams. rare mudstonc bcds siliciclastic grains

411) SiIV Fine-graincd sandstonc 1 cmto I m Lamination Middle to ?Upper Sand- chen nodula, to indistinct cross-lamination Shoreface Stone rare brachiopods? somctimcs nodular 3.4 Facies Associations

The facies descriid earlier in tbis chapter have been grouped into facies associations. Each association represents a vertical succession of facies that is bounded above and below by either sequence boundaries, transgressive surfaces of erosion, or flooding surfaces. Three basin slope facies associations (uppermost Simla Member, Mount Hawk Formation and lower member Sassenach Formation), two distal basin plain (lower member Sassenach Formation), two lower to middle shoreface (upper member Sassenach Formation) and one carbonate shoreface (upper member Sassenach Formation) facies association were interpreted within the study area Basal and upper contacts, fithological and grain size trends fonned the basis for the description, definition and interpretation of the facies associations presented below.

3.41 Uppermost Simla Member and Mount Hawk Formation

Two basin siope facies associations (SMH-A & SMH-B) have been identified in the uppermost Simla Member and Mount Hawk Formation. One additional basin slope facies association also occurs within the lower member Sassenach Fonnaton (SMH-CLMS-C, section 3 -45). They follow two basic basal contact and grain-size trends; 1) sharply based, coarsening upward and 2) erosionally based coarsening upward. In addition, Iithological trends nom the accompanying field descriptions (Appendix A) were used to define and interpret these associations.

3.42 Basin Slope Facies Association, (SMII-A)

Description: The facies association ranges between 1 -0 to greater than 7.0 m thick, and is found at the Type Section in the Colin thrust sheet, and at Mount Strange in the Chetarnon thnist sheet (Figs. 3. la and 3.2, Appendix A). This association (Fig. 3.35a) has a sharp base, and progresses upwards from calcareous, ?silty shale (facies 5) to bioclastic/lithoctastic siltstone (facies 2). The upper contact is sharp and locally (type section), where it is overlain by carbonate debris flows (facies 1, section 3.42 SMH-B) the upper contact may be erosional (Appendix A, type-section A). The vertical facies relationship is a coarseaing upwards succession. Locally (type Figure 3.35 Uppermost Simla Member and Mount Hawk Formation facies associations: a) SMH-A comprises fiom the base upwards facies 5 calcareous shaie overlain by facies 2 bioclastidithoclastic siltstone/fme grained sandstone; b) SMH- B comprises a basal unit of facies 1 bioclasticAithoc1ast.i~wackestone to packstone overlain by facies 2 bioclastic/lithoclastic siitstone/fine grained sanàstone; and c) SMH-C/LMS-C comprises fiom the base upwards facies 5 caicareous shale overlain by facies 3 folded/deformed interbedded Iimestone and siltstone interbeds.

For facies legend see Figure 3.1 c. Facies Associations Uppermost Simla Member & Mount Hawk Formation (SMH)

SMH-A section A) SMH-A and SMH-B occur as a series of stackd interbedded facies associations (Section 3 -43, Figs. 1 .5,3. la and Appendix A).

Interpretation: This facies association was deposited in a low energy basin dope environment. The basal calcareous, siity shale is suggestive of low wave energy and predominantly suspension deposition (Section 3 -21 ). The upper portion of the facies association, (facies 2, Section 3.12) is massive, poorly sorted and contains allochthonous reddened carbonate and siltstone clam fiom the adjacent carbonate platform and a more distal clastic source (Chapter 5) respectively. This facies is interpreted debrites that represent transport in which clasts are supported by the cohesive strength of the mud rnatrix and clast buoyancy (Schde, Bebout and Moore 1983, Reading 1986). Debris flows may result fiom oversteepening caused by rapid deposition on the slopes of the basin margin during a relative sea-level fa11 or may represent ripup clast/scour features that resulted fiom turbidity flows down/?along the flank of the Jasper Basin (Sections 3.1 1 & 3.1 2). Basinward, this facies association is laterally replaced by calcareous, silty shales (Figs. 3.1 a and 3.2).

3.43 Basin Slope Facies Association, (SMH-B)

Description: The facies association is charactenzed by a sharp/?erosiond basal contact and ranges fiom 2 to 6 m thick (Fig. 3.35b, Appendix A). At Gap-Lake and, F-Section (Appendix A, type section A, Figs. 1.5 and 3.2) this facies association is underlain by a sequence boundary. The sharp basai contact is overlain by up to 3 m of bioclasticAithoclastic wackestone to packstone (facies 1). This is followed by up to 3 m of biocIasticAithocIastic siltstone, facies 3 (type section, Fig 3. la, Appendix A) or calcareous siltstone, facies 411 1 (F-section, Fig. 3-2, Appendix A). Both types of debntes contain hematized, reddish lithoclasts. At the Gap-Lake section only the lower member, (facies 1) of this facies association is developed (fig. 3.2, Appendix A). Both facies 1 and 3 are massive whereas facies 411 2 is massive to weakly bedded in layers 0.02 to 0.1 rn thick (Section 3.27). The upper contact of this association is sharp and/or erosional where they occur as a stacked set or interbedded with the SMH-A facies association (Section 3.41, Figs. 1.5,3. la and 3.2, Appencbx A, type- section A) Interpretation: This facies association is interpreted as a basin slope association based on its vertical association with the SMH-A facies association, its basinward, lateral correlation to calcareous shales and its proximity to the adjacent basui margin. In addition, the sharp/?emsional basal contacts and the deposition of facies 1 and 2 massive, poorly sorted debntes is suggestive of transport in which clasts are supported by the cohesive strength of the mud matrix and clast buoyancy (Scholie, Bebout and Moore 1983, Reading 1986). As in section 3 -41, carbonate (facies 1) and bioclasticllithoclastic (facies 2) debris flows are interpreted to represent a mixture of material eroded fiom the carbonate platform, (Le. not cemented pnor to exposure), and the initial influx of siliciclastic material into the basin fiom a more distal clastic source respectively(see Chapter 6)- Further, debris flows were generated by various mechanisms that are related to instabilities dong the basin margin (Section 3.41).

3.44 Basin Slope Facies Association, (SMH-C & LMS-C)

Description: This facies association ranges between 4 to greater than 13 m thick, and is found at the Type Section and Morro Peak in the Colin thnist sheet, and at Mount Strange in the Chetamon thrust sheet (Figs. 3. la, 3.2,3.35c and 3.36~ Appendix A). This association (Fig. 3.2, Appendix A) has a sharp base, and progresses upwards fiom calcareous, ?silty shale (facies 5), 1 to 18 m thick, to foldedldeformed, interbedded Iimestone and siltstone (facies 3) that ranges fiom 2 to 13 m (Morro Peak) thick. At Morro Peak, the thick basal shale (facies 5) may have either the conformable, basinal equivalent of a sequence boundary anaor the Frasnian-Famennian boundary at its base (Fig. 3. la). The upper contact is irregular and forms a distinct boundary with the overlying succession and is interpreted as a marine flooding surface (Fig. 3.2, Appendix A, Morro Peak-A)-

Interpretation: This facies association is also interpreted as a basin dope succession deposited in a subtidal, lower energy environment as evidenced by the calcareous shale (facies 5) at its base. The folded/deformed, interbedded limestone and siltstone facies is interpreted to indicate episodic slope failure that was the result of oversteepening caused by rapid deposition on the slopes of the basin margin during a relative sea-level fdl. The lack of reworking and bioturbation of the foldecVdefo~ne4(facies 3) interbedded units suggests that these sediments were removed quickly from the sedimedwater interface. 3.45 Lower Member Sassenach Formation

Two distal basin plain facies associations (LMS-A and LMS-B) have been identified in the lower member Sassenach Formation. One additional basin slope facies association (SMH-C/LMS-C) occurs both within the uppermost Simla Member .Mount Hawk and lower member Sassenach formations. These associations foiiow one basic basal contact and grain-size trend; sharply based, coarsening upward. In addition, lithological trends fiom the accompanying field descriptions (Appendix A) were used to define and interpret these associations.

3.46 Distal Basin Plain Facies Association, (LMS-A)

Description: This facies association (Fig. 3.36a) progresses upwards fiom calcareous, ?siity shale (facies 5), 0.1 to 2 m thick, to siltstone/wackestone/mudstone interbeds (facies 7A) that range fkom ?2 to ?5 m thick. The interbeds most commonly display parallel lamination, but may display repetitive layes of normal grading overlain by parallel laminations that progress upwards to cross-laminations. The basal contact is sharp, but it is difficult to distinguish upper contacts (flouding surfaces) due to the repetitivel monotonous nature of the deposits (Sections 2.1 and 3.23, Figs. 3.1 a & 36). This association is found within the lower mernber Sassenach Formation at al1 basinal Iocalites (Le. excepting Mount HauItain sections, Figs. 3.1 a & 3-2, Appendix A).

Interpretation: This facies association is interpreted as a distal basin plain fil1 that represents rapid and episodic deposition of either stom generated sediment gravity flows or distaübasind (abc) turbidity currents. Several factors suggest that interbedded siltstone to fine grained sandstone units were deposited rapidly: the paucity of organisms; persistence of fine lamination throughout much of the sediment; normal grading of sediments passing upwards to paraIlel laminations with occasional cross-laminations; load casts and bioturbation traces on the bases of siltstone interbeds; and the presence of escape structures (Reading 1986, section 3.23, Figs. 3.14,3.17 and 3.18). Figure 3.36 Lower member Sassenach Formation facies associations: a) LMS-A comprises fiom the base upwards facies 5 calcareous shale overlain by fices 7a siltstone/wackestone/mudstone interbeds; b) LMS-B comprises a basal unit of facies 5 calcareous shale overlain by facies 6 normal graded bioclastic packstone- grainstone; and c) LMS-CfSMHC comprises fiom the base upwards, facies 5 calcareous shale overlain by facies 3 folded/deformed interbedded limestone and siltstone. For facies legend see Figure 3. lc. Facies Associations Lower Member Sassenach Formation (LMS)

LMS-B It is difficult to distinguish upper, flooding dâceswithin this facies association because the repetive and rapid deposition of sediment combined with a deeper water environment both mask the effects of relative sea-level change.

3.47 Basin Plain Facies Association, (LMS-B)

Description: This facies association (Kg, 3.36b) progresses upwards fiom a sharp basal contact to a calcareous, ?silty sMe (facies S), 0.1 to 2 m thick, that is in turn overlain by coarse, bioclastic debris (facies 6) that forms thin, 0.1 0.5 m thick units that are mappable for up to 1 km into the basin. The overlying bioclastic debris units are sharp based, normal graded and have a relatively coarse base that passes upwards into planar laminations. This facies association is present only within the basal 15 m of Sassenach Formation at Gap Lake and F-Section, approximately 1 km from the basin margin (Fig. 3.2 and Appendix A).

Interpretation: The bioclastic debns facies is interpreted to represent deposition by either turbidity currents or by storm generated tempestites (Walker 1992 and Bouma et al. 1962). This is suggested by: the upward vertical association fiom a sharp base through normal grading to parallel laminations and into an overlying muddy unit. The underlying calcareous black shale is interpreted to represent suspension deposition that occurred prior to and between the intermittent storm or turbidity events. The close proximity of Facies 6 units, to within about 1 km of the adjacent p1abmargin and an increase in abundance and thickness of these units towards the basin margin (fiom F-Section to Gap Lake section, Fig. 3.2) suggests that the carbonate debris was derived fiom earliest Famennian "upsiope" or basin margin carbonates (Section 3.1 1, Fig. 3-2, Appendix A).

3.48 Upper Member Sassenach Formation

Two lower to middle shoreface facies associations (UMS-A and UMS-B) have been identified in the lower member Sassenach Formation. One carbonate shoreface facies association (UMS-C) was aiso identified within the upper member Sassenach. These associations follow one basic basal contact aud grain-size and; sharply based, coarsening upward, In addition, Lithological trends fimm the accompanying field descriptions (Appendk A) were wdto define and interpret these associations.

3.49 Lower-Middle Shoreface Facies Association, (UMS-A)

Description: This facies association (Fig -3.37a) comprises coarse siltstond packstone/mudstone interbeds (facies 7B) that range fkom 2 to ?5 m thick These interbeds commonly display normal grading overlain by paraiiel laminations that progress upwards to cross-laminations (Section 323, Figs. 3. la, 3.2). These interbeds progress upwards to siitstone/fhe grained sandstone (facies 411 1) beds 0.3 to greater than 10 rn thick. The basal contact is sharp, but it is dificuit to distinguish upper contacts (flooding surfaces) due to the repetitivel monotonous nature of the deposits (Sections 2.1,3.23, Figs. 3.1 a & 3.2). This association is found within the upper member Sassenach Formation at al1 locaiites (Figs. 3.1% b & 3.2, Appendix A).

Interpretatioa:This facies association is interpreted as a lower to middle shoreface fil1 that represents rapid and episodic deposition of either stonn generated sediment gravity flows or distal/basinal (abc) turbidity currents. This facies association is interpreted to be more proximal to the clastic source than the LMS-A facies association because of its thicker beds and coarser grain size (facies 7B, Section 3.33). In addition, wave reworking of sediments within the interbedded unit (Section 3.23, Fig. 3.30) also suggests that this association was deposited within storm wave- base. Again, several factors suggest that interbedded siltstone to fuie grained sandstone units were deposited rapidly: the paucity of organisms; penistence of fine lamination throughout much of the sediment; normal grading of sediments passing upwards to paraiiel laminations with occasional cross-laminations; Ioad casts and bioturbation traces on the bases of siltstone interbeds; and the presence of escape structures (Reading 1986, Sections 3.23 and 3.46, Figs. 3.14,3.17 and 3.1 8). The uppermost siltstone/£ine grained sandstone beds represent brief, relative sea-level stiIlstands that temporarily restrict accomodation space and force the siliciclastics to rapidly prograde basinward. Figure 3.37 Upper member Sassenach Formation facies associations: a) UMS-A comprises fiom the base upwards facies 7b coarse siltstone/packstone/mudstone interbeds overlain by facies 411 1 siltstone/fine-grained sandstone; b) üMS-B comprises a basal unit of facies 10 silty limestone-wackestone to packstone overlain by facies 7b coarse siltstone/packstone/mudstoneinterbeds; and c) UMS-C comprises from the base upwards, either facies 9 oncoid wackestone to grainstone overlain by facies 9 silty Iirnestone-wackestone to packstone or comprises facies 9 overlain by facies 8 stromatolite baffiestone- For facies legend see Figure 3.1 c. Facies Associations Upper Member Sassenach Formation (UMS)

UMS-B 3 SO Lower-Middle Shoreface Facies Association, (ZIMS-B)

Description: This facies association (Fig. 3 -3%) comprises limestone, wackestone- packstone (facies 10) beds 1 to 4 m thick (Figs. 3. la and 3.2, Appendix A) that are overlain by coarse siltstone/ packstone/mudstone interbeds (facies 7B) that range fiom 2 to ?5 m thick. These interbeds cornmoaiy display normal grading overlain by parailel laminations that progress upwards to cross-laminations (Section 3.23, Figs. 3 -31 and 3 -32). The basai contact is sharp, but it is dificult to distinguish upper contacts (floodhg surfaces) due to the repetitivd monotonous nature of the deposits (Sections 2.1 and 323, Figs. 3-la & 3.2). This association is found within the upper member Sassenach Formation at al1 localites (Figs. 3. la, b & 3.2, Appendix A).

Interpretation: This facies association is interpreted as a lower to middle shoreface fil1 that represents rapid and episodic deposition of either storm generated sediment gravity flows or distailbasinal (abc) turbidity currents. This facies association is interpreted to be proximal to the clastic source because of its thicker beds and coarser grain size (facies 7B, Section 3.23) and because there is evidence of wave reworking of sediments withui the interbedded unit (Fig. 3.30). Again, several factors suggest that interbedded siltstone to fuie grained sandstone units were deposited rapidly (see previous Section 3.49). The basal limestone beds represent bnef, relative rises in sea-level that temporarily haited the siliciclastic influx into the basin.

3.51 Carbonate Shoreface Facies Association, (UMS-C)

Description: Shoreface carbonate facies associations comprises fiom the base upwards; an oncoid wackestone to grauistone base (facies 9) 0.3 to 1 m thick, overlain either by a stromatolite unit (facies 8) 2 to 3 rn thick andior silty, peloidal wackestone to packstone (facies 10) (Appendix A, Mount Haultain H2, H3, H4 and HS, Fig. 3. l b and 3.37~). The oncoid facies comprises spherical to subsphencal oncoids (Section 3.25). This basal unit onlaps the underlying Simla platform margin and is in tum onlapped by the overlying stromatolite facies. Basinward, the stromatolite facies grades laterally into the peloidal wackestone to packstone facies (Figs. 3.1%b, Sections 3.24 and 3.26). The basal contact is erosional and represents the Frasnian-Famennian boundary, and in places it is also coïncident with a sequence boundary. The upper contact of this association is a flooding surface that brings lower to middle shoreface sediments over top of the sWow water, intertidal carbonate succession- This facies association is obmedonly dong the upper margin of the Jasper Basin (Sections 3 24, 3-25 and 3 26, Figs. 2-4b, 3.1 a and 3.1 b, Appendix A)

Interpretation: This facies association is interpreted to comprise a shallowing upwards carbonate shoreface succession. This association was deposited in a shallow, high energy, inter-tidal, shoreface environment- This is suggested by; spherical to subspherical oncoids that fomed almost mud-k oncolites (Section 3.25, Figs. 3.1 a, 3.1 b, 32 1,3 -22,323 and 3.24) Le. they must have been well winnowed and reworked by waves and by the stromatolite facies whose modem equivalents are deposited in O to 5 rn water depth- The erosionai basal contact associated with the sequence boundary provides evidence for exposure of the underlying Simla platfonn carbonates during a relative sea-level lowerkg- Oncoids represent the initial stages of carbonate deposition during the earliest Famennian. Chapter 4

Sequence Stratigraphy and Depositional Models 4 Introduction

Recent studies of the sequence stratigraphy within the Jasper Basin have ken focused primarily on the biostratigraphic record adon assessing the "tirne gap" across the F-F boundary (Geldsetzer 1987% Wang and Geldsetzer 1996, Raasch 1988, Klapper and Lane 1988, etc-). Van Buchem et ai. (1996) have completed a broader sequence stratigraphic study of the upper Devonian succession, but to date, the sequence stratigraphy of the Sassenach Formation, and its submface equivalent the Graminia Formation have not been discussed in the literature-

In general, sequence stratigraphy divides a basin succession into depositional sequences bounded by discordant surfaces or sequence boundaries based on the assumption that eustasy is the primary control on depositional sequence geometry; where tectonic subsidence or upl* do not override the signal (Vail et al. 1977, Posarnentier et al. 1988, Van Wagoner et al. 1988, Van Wagoner 1990). There are three components which may contribute to or cause sequence geometrïes; eustasy, sedimentation rate, and tectonic subsidence/uplift, (Van Wagoner et al. 1988, Van Wagoner 1990). Therefore, the identification of sequence stratigraphic boundaries must involve some knowledge of, or some assumptions must be made regardhg the regional geology, tectonic setting and subsidence rates and possible sediment source/s and supply routes for a given basin.

For the study area, regionai stratigraphic knowledge is incomplete partly due to erosion of Devonian stratta during mountain uplift, and partly due to a lack of regional infiormation regarding the Sassenach Formation and its lateral equivaients. For the purposes of this chapter, it was assumed that the source terrane was the Antier orogenic highland that developed somewhere to the West or southwest of the Jasper Basin. See Chapter 6 for discussion of source regions.

Eustasy for this tirne period has been discussed and interpreted extensively in the literature, partly due to the many workers interpreting the F-F extinction event. In general, most authors agree that there is a significant eustatic sea-level fa11 across the F-F boundary (Savoy and Mountjoy 1995, Johnson et al. 1985, Sandberg et al. 1988, Johnson and Sandberg 1988, etc.). Within the study ma,the erosional paraconformity and the stratigraphic relationships comprise evidence for a eustatic sea-level fdacross the F-F boundary (Section 1-45, Figs. 1.5,3. la-b and 3.2).

The most difficult assumption to make for the study area relates to the dominant control for the creation of accomodation space Le. accomodation rate vs sediment supply rate for the Sassenach Formation. This is due to the lack of direct evidence of the source terrane and siliciclastic supply routes that filied the Jasper Basin. However, there are three basic alternatives; sediment supply rate » accomodation rate, sed. supply rate «accomodation rate, and sed. supply rate = accomodation rate (Van Wagoner 1990, Fig. 4). Badon the stratigraphic relationships two possible models were developed; Model 1 assumes that sediment supply rate exerts the dominant control on the creation of accomodation space and the resultant sequence stratigraphic relationships, whereas Model 2 assumes that the rate of relative sea-level change exerts the pritnary control. While these modeIs represent two end member interpretations, the facies associations (Chapter 3, Figs. 3.35,3.36 and 3.37) and stacking patterns are similar for both models. The differences between the two models involve the interpretation and placement of the significant surfaces e-g. Initial Transgressive Surface (ITS) and Maximum Flooding Surface (MFS) and the interpretation of the systems tracts-

This chapter defines and identifies the significant stratigraphic surfaces and boundaries for both Models 1 and 2 . Next, the systems tracts are interpreted for the Simla Member, Mount Hawk Formation, for both Models 1 and 2 for the Sassenach Formation. Then the parasequences and stacking patterns are discussed for the Simla Member, Mount Hawk and Sassenach formations.

The nature of the stratigraphic relationships and the location of sequence stratigraphic boundaries is criticial for interpreting the behavior of relative sea-level during the Iatest Frasnian and early Famennian and also forms the basis for the Depositional Models 1 and 2 (see Section 4.6). Figure 4 Parasequence-stacking patterns in parasequence sets. Stacking patterns reflect differences in the relative rate of deposition vs the rate of accomodation. Modified fiom Van Wagoner 1990- PARASEQUENCE-STACKING PATTERNS IN PARASEQUENCE SET;

PROGRADATIONAL PARASEQUENCE SET

RETROGFIADATIONALPARASEQUENCE SET I

AGGRADATIONAL PARASEQUENCE SET I C I

RATE OF DEPOSITION RATE OF ACCOMMODATION 4.1 Definition and Recognition of Sipifiennt Suflaces

The following criteria were used to define significant surfaces in the study area: 1) vertifal and lateral Lithostratigraphic relationships, eg. baselap, facies changes, increases in silt content, exposure horizons (discordant surfaces); 2) biostratigraphic dating, e-g. the presencdabsence of fauna andlor condont zones (Section 1.45); and 3) laterd tracing of strata and contacts in the field and on oblique photographs (Figs. 2.4% 2.4b and 2.5). Mount Haultain and the Type Section in the Colin thrust sheet are the oniy Locations in the study area where onlapping relationships codd be mapped and sarnpled (Figs. 2.1,2.4a and b, 3.1 a<). In the Chetamon thrust sheet, stratigraphie relationships were mapped fiom oblique photographs and field sketches of an inaccessible mountain cliff south of The Raoee (Figs. 2.5 and 3.2).

4.11 Sequence Boundary (SB)

For Models 1 and 2, a Type-1 sequence boundary is represented by a sharp erosional contact between the Simla Member carbonate platform, and thc overlying Sassenach Formation. In the Colin thrust sheet, (Figures 3.1 a and 4.1 a and b), towards the basin the sequence boundary overlies the Simla Member margin (Appendix A sections H 1-5) and underiies the interbedded latest Frasnian uppermoa ?Mount Hawk Formation calcareous siltstones and upper Simla Member debrites (Appendix A, Type Section a, Thomton Creek a). Further basinward the sequence boundary is apparently conformable between the uppermost Mount Hawk Formation and the Sassenach Formation (Appendix A Overlander a, ?Mount Strange a). For these cases, biostratigraphic dating is required for the accurate placement of-the sequence or FF-boundary. In the Chetamon thnist sheet, (Figs. 3.2 and 4.1 c and d) the sequence boundary aiso occurs between the Simla carbonate platform and the overlying Sassenach Formation and truncates the underlying Simla Member dong the platform margin (Figs. 2.5 and 3.1 b). Figure 4.1 a) and c) MODEL 1Stratigraphic relationships in Colin (a) and Chetamon (c) thnist sheet showing prograding shdowwater Simla Member carbonates (Highstand, HST) and latest Frasnian Mount Hawk and Simla Member debrites (Initial Lowstand). Early Famennian Sassenach Formation unconformably overlies the uppermost Frasnian Strata; F-F Boundary, FFB and Type 1 Sequence Boundary (SB, thick line). Lower member and portions of the upper member Sassenach Formation onlap the basin margin and comprise the Lowstand Systems Tract (Lowstand, LST). The Initial Transgressive Surface (ITS, dashed he) occurs within the uppet member of the Sassenach Formation. The boundary between the Sassenach and the overlying Pdiser Formation represents a signifïcant maring Flooding Surface (FS, thin line). The upper member Sassenach Formation (overlying the ITS) and the Paiiiser Formation represent the Transgressive Systems Tract (TST).

Figure 4.1 b) and d) MODEL 2 Stratigraphic relationships in Colin (b) and Chetamon (d) thnist sheet showing progradhg shallow water Simla Member carbonates (Highstand, HST) and latest Frasnian Mount Hawk and SidaMember debntes (Lowstand, LST). Early Famennian Sassenach Formation unconformably overlies the uppermost Frasnian Strata and onlaps/toplaps the basin margin; F-F Boundary, FFB and Type 1 Sequence Boundary (SB, thick line). The lower member Sassenach represents the Transgressive Systems Tract (TST) and is bounded at its base by the Initial Transgressive Surface (ITS, dashed line). The upper member Sassenach Formation comprises a prograding highstand systems tract (HST). The Initial Transgressive Surface (ITS) occurs within the uppermost Sassenach Formation. This boundary also represents a Type II Sequence Boundary (non erosional contact). The boundary between the Sassenach and the overlying Palliser Formation represents a significant maring flooding surface (FS, thin line). The Palliser Formation represents the Transgressive Systems Tract (TST). Basinward, this boundary is mapped beneath the uppermost Frasnian carbonate debrites and siltstones (Figures 3.1 a-b, 3.2 and 4.1 a) and b)). On the basin plain the sequence boundary becomes confonnable and placement of the boundary is no longer possible. b) COLIN TIIRUSTSIIEET; MODBL 2 se nmwm~ ML ~lullrhi

d) CHETAMON TIIRUST StlRET; MODEL 2 SE NW 4.12 F-F Boundary (FF-Boandary)

Within the study area, the F-F boundary is recognized by: 1) conodont and brachiopod biostratigraphy which indicates that a tirne gap occurs across the boundary in platformal and platform proximal sedirnents; 2) discordant stratal relationships across the boundary, e.g. downlapping and prograding Simla Member clinoforms are horizontally onlapped by the Sassenach Formation, Colin thrust sheet (Figs. 2.4a-b, 3. la-b and 4.2 a-b); 3) significant changes u1 lithology across the boundary in platform or platfonn proximal sections, illustrated by correlations of the basal 40 m of several measured sections e.g. carbonate debntes odapped by siltstones (Gap Lake and F-Section, Chetamon thrust sheet, Fig. 3.2,4.1 c-d); and 4) hematized clasr and fossil debris in carbonate debrites overlying and underlying the boundary at Mount Haultain and the Type section, (Figs. 3.1 a-b, 3 -2, and 4. la- b). In basinal sections where the Sassenach and Mount Hawk Formations are conforniable, the boundary cari ody be located by biostratigraphy or by the top of a prominent siltstone horizon (Fig. 4.1 and Appendix A; Overlander a, Medicine Lake a, Mount Strange a).

In the Chetamon thnist sheet the FF-boundary overlies aggradationd horizontal and progradational strata of the uppermost Simla Member (Figs. 2.5,4 and 4.1 c-d). ln the Coiin thrust sheet, the FF-Boundary overlies the uppermost Sida Member clinoform (Figures 2.4a-b, 3- 1a-b and 4.1 a-b).

4.13 Initial Transgressive Surfiace (ITS)

The initiai transgressive surface (ITS) is the fïrst flooding surface created after depositon of the lowstand systems tract, and separates the lowstand systems tract fkom the transgressive systems tract (Vail er al. 1977, VanWagoner et. al 1988, VanWagoner IWO). The placement of this surface represents the fiuidamental difference between the two sequence stratigraphic models for the Sassenach Formation. The location of this surface has implications for the amount of relative sea-level fa11 and thus the degree of infiuence that relative sea-level exerted on the creation of the observed sequence stratigraphic relationships. In Mode1 1, in both the Colin and Chetamon th- sheets (Fig. 4. l), the transgressive surface is interpreted to either be coincident with the contact between the lower and upper members of the Sassenach Formation or may occur at sume level within the upper member. The onlap and toplapping of the Sassenach Formation over the Simla Member at the margin of the Ancient Wd (O to 0.5 m) and Miette reef (2 1 m) complexes and the lack of exposure features within the Sassenach indicates that sea-level had begun to transgress at some tirne during the upper Sassenach. The differences in the amount of toplap between the Miette and Ancient Wall reef complexes dso implies that differential subsidence was active locally-

4.2 Systems Tracts

Highstand systems tracts interpreted fiom the uppemost Simla Member are similar in both models in the Colin and Chetamon thnrst sheets (Fig. 4.1). However, the interpretation of the lowstand and transgressive to stillstand (Mode1 2) systems tracts within the Sassenach Formation ciiffers between Models 1 and 2. The Highstand/StiUstand systems tract is discussed first and then the systems tracts for both models are describeci separately. The systems tracts for both sequence stratigraphie models are summarized in Table 4.

4.21 HighstandIStillstand Systems Tract (HST)

The highstand systems tract (HST) is defined as occurring when sea-level has reached its maximum level prior to a relative sea-Ievel fdl, (Vail et al. 1977, VanWagoner et ai. 1988, VanWagoner 1990). Within the study area, the shallowing upward. peritidal carbonate cycles/parasequences within the upper Simla Member are interpreted to represent a late Frasnian, highstand systems tract (HST) as shown in Fig. 4.1.

In the Colin thnist sheet, the Late Frasnian HST is bounded above by a Type- 1 sequence boun- and below by a Maximum Fboding Surface (MFS)(Fig. 4.1). The MFS is not defmed, but in the Colin thmt sheet, Van Buchem et al. (1 996) suggest that the MFS occurs between the Mount Hawk Formation and the overlying Simla Member clinoforms, and basinward becoxnes lost in a marine subtidal sequence (Figs. 2.4 a and b, 3.1 and 4.1 ). In the Chetarnon thrut sheet, the uppermost Simla Member is interpreted to comprise a series of aggradational to progradationaVdownlapping parasequences that are overlain and truncated by a Type-1 sequence boundary, visible on the oblique cliff-face photo (Figs. 2.5,3.2,4 and 4.lc and d).

4.22 Lowstand to Transgressive and Highstand Systems Tracts

For siliciclastic systems, a lowstand systems tract is defined as an onlapping wedge of strata that occurs above the previous sequence boundary but below the previous shelf break (Vail et aL 1977, Van Wagoner et al. 1988, Van Wagoner 1990, etc.). Stated simply, the lowstand systems tract represents a basinward shift in facies, (Vail et al. 1977, Van Wagoner 1991)-

In carbonate systems, lowstand deposits are rare and tend to be poorly developed. This is partly due to lithification of the upper dope and planorm pnor to exposure. There is little sediment to be eroded and the adjacent dope and basin become starved of carbonate sediments. If the carbonate shelf borders a temgenous landmass, prograding fluvial or deltaic sediments can spi11 over the shelf edge forming a clastic lowstand fan or wedge (James and Kendall 1992).

Altematively, Schlager (198 1, 1989,1993) has argued that oniapping wedges of fine-grained, deep water siliciclastic strata flanking carbonate platforms actually record sea level rises and the sudden demise of platforms via submergence, suffocation by siliciclastic sediments, or by environmental collapse (e-g. anoxic conditions or poisoning by nutrient excess). This is probably not the case for the Simla Mernber because there is clear evidence of exposure of the platfiorm carbonates which suggests that the demise of the carbonate planorm was due to exposure. In addition, although there was an influx of siliciclastics in the early Famennian, the presence of an early Farnennian carbonate shoreface (UMS-C, Figs. 3. la-b, 3.37 and 4.1) suggests that carbonates were not suffocated by siliciclastics until later in the Farnennian. 4.22a) Svstems Tracts Mode11

In the study ma, latest Frasnian uppermost Simla Member and Mount Hawk Formation, interbedded carbonate and cdcareous siltstone debrites and siltstones in facies associations SMH-A, SMH-B and SMH-C (Figs. 1.5,3. la-b and 3.35, e-g. Type Section, Appendix A) represent a significant change in depositional environment within the basin that coincides with an interpreted eustatic sea-level fall (Johnson et al. 1985, etc.). Therefore, these facies associations are interpreted to represent deposition of allochthonous debris during the initial lowstand (Fig, 4.1)- These deposits directiy overly the Type-1 sequence boundary (Figs. 3.1 a, 32,4.1) and are the primary evidence for the interpretation and placement of the sequence boundary. The upper surface of the Initial Lowstand Deposits (LLD) is a marine flooding surface and is coincident with the FF-Boundary (Fig. 4. la and 4. lc) Overlying the FF-Boundary, the monotonous series of upward thickening and coarsening facies associations (LMS-A, UMSA and UMS-B) of the lower and upper membea of the Sassenach Formation are interpreted as the Lowstand Systems Tract (Figs. 3.la-b, 3.2,4,4.la, 4.1~).

Although the transgression may have begun earlier, the Initial Transgressive Surface (ITS) is interpreted to occur within the upper member of the Sassenach Formation for two reasons; 1) the uppermost Sassenach was deposited in a subtidal environment that lacks exposure features which indicates that the Sassenach did not shallow up to sea-level, (Le. sea-level rose during the late stages of Sassenach deposition), and 2) the Sassenach Formation locally toplaps the underlying reef complexes e-g. Miette and Fairholrne (Mountjoy pers. comm.) and therefore must be at lest partially transgressive. The upper member Sassenach carbonate shoreface, UMS-C, observed dong the margin of the Jasper Basin (Appendix A, Figs. 3.1 and 4.1 a) may represent either early lowstand deposition that was contemporaneous with the lower member of the Sassenach Formation, or may represent early transgressive deposits depending on the placement of the ITS. The latter case implies that an older carbonate shoreface facies association, which has not yet been observed, must exist somewhere Merdown the basin margïn (see Mode1 2 below). The carbonate shoreface facies association UMS-C on Mount Haultain is bouaded below by the Type 1 sequence boundary and above by a marine flooding surface (section 3.5 1, Figs. 3.1% 3.lb, 3.37 and 4.la). Table 4 Summary of sedimentary facies and Formations and the corresponding systems tract(s) and facies association interpretations for Models 1 and 2. Mode1 1 Mode1 2 Facies Associations

Simla Member Late HST Late HST ~ggradationaUProgradational Wackestone to Grainstone

Mount Hawk Formation Initial LST LST and Simla Member

1) Bio/LithocIastic Carbonate Debrite SMH-A, SMH-B 2) Bio/Lithoclastic Siltstone Debrite and SMH-C 3) Slumps 4/ 1 1) Calcareous Siltstone

Sassenach Formation LST TST

Lower Member 5) Black Shales LMS-A, LMS-B, 6) Bioclastic, Normal Graded facies and LMS-C 7) Siltstone/Limestone/ Mudstone Rhythmites

Upper Member LST HST 7) Siltstone/L.imestone/ Mudstone Rhythm ites UMS-A, UMS-B 8) Oncoid Wackestone to GrainStone and ?UMS-C 9) Stromatolite Bafflestone 10) Limestone; Wackestone to Packstone 41 1 1) Calcareous SiItstone to Fg Sandstone

Sassenach Formation and TST HST to Palliser Formation TST 1 1) Calcareous Siltstone to Fine UMS-A, UMS-B UMS-A, UMS-B, Grained Sandstone and UMS-C PaIliser Formation Limestones Within the study area, the carbonate shoreface facies association UMS-C, (Figs. 3.37,4.1a) is interpreted as earliest Famennian carbooates that correlate with the lower rnember of the Sassenach Formation. This is suggested by: 1) a Iack of intefigering between the carbonate shoreface and the UMS-A and UMS-B facies associations; rather, the carbonate shoreface is overlain by UMS-A and UMS-B (Figs. 3.1 a, 3.1 b and 4.1 a); and 2) a transported oncolite horizon overilies the initial lowstand deposits at the Type Section (Figs. 3. la, 4. la, Appendix A, type section A).

A significant marine flooding surface (FS) within the TST separates the Sassenach Formation hmthe overiying carbonates of the Palliser Formation (Fig. 4. I a and 4.1 c). This FS generalfy marks an abrupt change fiom the coarse siltstones and fme-grained sandstones of the Sassenach Formation to the overlying muddy carbonates of the Palliser Formation. However, locaily this contact is gradational, occurring within a one tu five meter interval of silt laminated, bioturbated wackestones to packstones that exist behrveen obvious Sassenach Formation siltstones and Palliser Formation carbonates (e-g. MOLTOPeak, Appendix A, Figs. 3.1 and 4.1). It is also possible to interpret this contact as a transgressive surface of erosion or ravinement surface. Therefore, in Model 1 the upper member Sassenach lower to middle shoreface facies associations, UMS-A, UMS-B (Figs. 3.37,4.1 b and 4.1 c) represent the preserved portion of the transgressive systems tract (Fig. 4.1).

4.22b) Svstems Tracts Model 2

For Model 2, (Fig. 4. l), the uppermost Frasnian Simla Mernber and Mount Hawk Formation facies associations, LJMS-A, UNIS-B and UMS-C (Section 3 .42,3.43 and 3.44, Fig 3.35) are interpreted as the lowstand deposits. The ITS is placed much lower, e.g. at the type section; between the uppermost ?Frasnian limestone and the overlying black shale (Figs. 3.1 a and 4.1 b). In this interpretation the facies associations in the lower and upper members of the Sassenach Formation would represent transgressive (LMS-A, LMS-B and LMS-C) and highstandlstillstand (UMS-A, UMS-B and UMS-C)systems tracts respectively (Figs. 3.36,3.37,4.1 b and d). Hence, the lower member represents deposition during a graduai sea-level transgression and oniy the upper member represents progradation during a relative sea-level stilistand (Fig. 4.1). In addition, in this mode1 the oncolites near the base of the lower member in the Type Section (Figs. 3.1 and 4.1 b and d) are interpreted to have been uansported only a short distance kom an inferred lower member, carbonate shoreface Fig. 4. lb). However, a MaxFS was not identified between the TST and HST. The oniy candidate for a MaxFS within the study area is a resistant, reddened, bioclastic grainstone bed at the type-section. (48 m above base of section. Appendix A, type section B) which may represent a condensed surface.

The contact between the Sassenach and Palliser formations is interpreted as a Type II sequence boundary (?SB in Fig. 4.1 b and c). in this interpretation, the contact between the Sassenach Formation and the overlying Palliser Formation is interpreted as a major flooding surface (FS) that simply shuts down the influx of siliciclastics into the basin (Figs. 4.1 b and d). Altematively, this flooding surface may be interpreted as a surface of erosion (SB). In this case, the upper member Sassenach Formation represents the preserved highstand systems tract. and the upper bounding surface represents a Type 1sequence boundary (Figs. 4.1 b and d).

4.3 Parasequences

In the next two sections, parasequences and parasequence stacking patterns are discossed for the Sida Member, Mount Hawk and Sassenach formations. Al t hough the significant surfaces and sequence boundaries differ between the two sequence stratigraphie rnodels, the pamsequences and stacking patterns are common to both and are only presented once.

4.31 Simla Member and Mount Hawk Formation

As discussed earlier, previous workers have identified a series of shaiiowing upward. peritidal cycles within the upper Simla Member platform carbonates (Mountjoy and MacKenzie 1973, Van Buchem et al. 1996). Each "cycle" comprises a parasequence; bounded both at its top and base by a flooding surface (Van Wagoner et al. 1988, Van Wagoner 1990).

In basinal sections it is difficult to detennine what comprises the base and top of each parasequence, but the lateral equivaients comprise Mount Hawk Formation mudstones and shaies and Simla Member carbonate debris tongues (Appendix A, between one (e.g. Gap-Lake and FSection) and seven (Appendix A, type section A) parasequences can be identified. These parasequences comprise facies associations SMH-A, SMH-B and SMH-C. The number of parasequences that cmbe identified decreases away from the carbonate margin. This is most easily observed as a thinning of the initial lowstand deposits (Model 1, Figs. 4. la and 4. lc) or lowstand systems tract (Model 2, Figs. 4.lb and 4. Id).

4.32 Sassenach Formation

The lower rnember of the Sassenach Formation comprises facies associations LMS-A, LMS-B and LMS-C (Sections 3.44.3 -46 and 3.47, Fig. 3-36) that were deposited on the basin dope and distal basin plain below storm wavebase. It is difficult to identiv parasequences in the basin plain or lower shoreface because shallowing upward features cannot be recognized in these units (Van Wagoner 1990). Thus, the definition of parasequences in these subtidd settings is arbitrary at best. In fact, it is only possible to locate one to three flooding surfaces within the lower rnember (Appendix A). This seems highiy uniikely for a 50+ m thick succession. Therefore, it was not possible to accurately identify parasequences within the lower member Sassenach facies associations.

Similarly, the upper member of the Sassenach Formation is interpreted to comprise lower to middle shoreface facies associations UMS-A and UMS-B (section 3.28). Within the upper member, three to five flooding surfaces may be identified (Appendix A, e.g. F-Section E). This also seerns unlikely for 50 to 70 m of section and once again it appears that the nature of deposition (sediment gravity flows or turbidity currents) within this environment has overprinted the effects of relative sea- level change and it is not possible to accuktely identiw parasequence boundaries. Along the margin of the Jasper Basin, a carbonate shoreface facies association was identi fied (UMS-C, Fig. 3.37). These carbonate shoreface parasequences comprise a shallowing upwards carbonate succession, from the base upwards; an oncoid wackestone to gninstone base overlain either by stromatolites and/or silty, peloidai wückestone to packstone (Mount Haultain), (Figs. 3.1a, 3. lb and 3.37). 4.4 Stacking Patterns

4.41 Simla Member and Mount Hawk Formation

In carbonate systems, parasequences aggrade up to sea-level, füling the available accomodation space. Commonly there is an oversupply of carbonate sediment resulting in basinward progradation. In the Colin thnist sheet, the Late Frasnian Simla Member is interpreted to comprise a series of clinofonning parasequences that prograded basinward (Figs. 2.4a-b, 3.1 and 4.1). These clinofomis represent a variation of descending downiap (Fig. 4.2.4.3) which occurs when a pladorm margin progrades into a pre-existing depression and the depositional sequence thickens basinward and clinoforms become longer and thinner, (Handford 1995, Tucker and Wright 1992, Bosellini 1984).

From the oblique ciiff photo of the Simla platforni in the Chetamon thnist sheet (Fig. 2.5 ), the series of stacked, horizontal Simla Member parasequences represent aggradation for the lower two thirds and basinward progradation for the upper third. The prograding/downlapping ?carbonate unit that tnincates the underlying aggradational cycles cm be interpreted to represent the shedding of excess carbonate produced on the platform when parasequences have shoaled up to sea-level, or may represent the initiai stages of latest Frasnian sea-level fall (Figs. 3.5, 3.2 and 4. Ic-d). These different interpretations can only be resofved by direct sampling and dating of this unit, e-g. if the downlapping unit is erosional, there should be clear evidence of exposure such as reddened or iron-stained lithociasts contained within the unit. Unfortunateiy the criticai outcrops occur on inaccessible cliffs (Fig. 2.5).

Basinward, the uppemost Simla Member and Mount Hawk Formation thin frorn at least seven, e-g. type section, to one parasequence, e.g. Thornton Creek, (Figs. 2.1, 3. la-b, 3.2 and 4.1). 4.42 Sassenach Formation

In terms of sequence stacking patterns, a succession that coarsens and thickens upwards is interpreted to represent a progradational sequence or parasequence set, Le. the depositional environment shailows upwards, and younger parasequences become progressively coarser and thicker (Figs. 4 and 4.2, Vail et al. 1977, Van Wagoner et al. 1988, VanWagoner 1990). In lieu of parasequences, the facies associations 4ththe Sassenach Formation provide evidence for an upward coarsening and thickening succession. The lower member comprises finer grained, thinner bedded facies associations LMS-A and LMS-C cornpared to the upper member UMS-A and UMS-B facies associations. Perhaps the clearest evidence for a coarsening upwards succession is facies 7 which is subdivided into 7a and 7b based on a thickening and coarsening of bedding within the upper member Sassenach (Section 3.23, Figs. 3.36 and 3.37). in addition, the upper member Sassenach is thickest in basinal sections to the southwest and is thinner and appears to occur at stratigraphically higher intemals as the Sassenach Formation onlaps the Ancient Wall reef complex (Figs. 3. la and 3.2). A cornparison of Figures 3.1 and 3.2 with the baselap relationships illustrated in Hdord's 1995 diagram (Fig. 4.2) suggests that the Sassenach Formation represents a type of apparent distal horizontal onlap (1C) or apparent distal climbing downlap (2B). Funher, Hdord(1995) aiso suggested that Iithologic evidence of climbing downlap wouid be an upward- coarsening succession dong the downiap surface.

The Sassenach Formation is interpreted to represent a basin restncted wedge of siliciclastics that prograded fiom a westerly direction across the Jasper Basin to odap the Ancient Wall reef complex. It would be most dificult to develop the geometry of the Sassenach Formation by transport of sediment fiom the east (see Chapter 6). Figure 4.2 Classification of major types of bçwlap; onlap, downlap and toplap configurations. Sida Member choforms represent descendhg downlap, (ZC). Sassenach Formation represents apparent distal horizontal onlap (1C) or apparent distd clirnbing downlap (2B). Figure 1 C fiom Haadfiord (1 995). BASELAP PAmERNS

Onlap Downlap

Classes of baselap and their stmtal geometrfds Baselap Classes CIass 7 - Onlap CIass 2 - Dow~I~P Subclass la-Platfonn Proximal Onlap Subclass 2a-Horuontal Downlap

Topset onlaps topset or upper foreset " toeset domlaps horizontal bottomset Subclass 1bBasinal Proximal Onlap Subclass 2bClimbing Oownlap Bottomset onlaps lower foreset or toeset Toeset downlaps opposing toeset Subclass Ic-Distal Horizontal Onlap and foreset. May encroach topset Bottomset onlaps opposing lower foreset or Subclass 2c-Descmdlng Oownlap toeset Toeset downlaps foreset-toeset Subclass Id-Distal Inclined Onlap surface inclined downward in the lnclined bottomset onlaps opposing twset direction of downlap The gradual upward coarsening, thickening and increased occurrence of wave genented cross-lamination in parasequences Le. a progradational parasequence set, is interpreted to result from a relative oversupply of siliciclastics into the basin, i.e. Rate of (Deposition or) Sediment Supply (SSR) »Rate of Accomodation (AR), (Van Wagoner 1990, Fig. 4). Aggndational or retrogradational parasequence sets, occur for SSR=AR and SSRccAR respectively (Fig. 4). Carbonate content increases in sections nearest the Ancient Wail reef cornplex and decreases upwards in all measured sections (Fig. 3.1). This is interpreted to represent a gradual basinward dilution of the carbonate generated dong the basin margin (Figs. 3. la, 3.2 and 4.1).

4.5 Depositional Environments and Models

The depositional models for the Sassenach Formation, Jasper Basin comprise a range of sedimentary environrnents that characterize a bain fill succession, Depositional environments Vary from carbonate shoreline/margin to a deeper siliciclastic basin plain that graduaily shaiiows up to a lower or middle shoreface environment. These depositional rnodels correspond to die two sequence stratigraphie rnodels (Section 4.22 a and b). The depositional environrnents for each mode1 are depicted in five stages (Figs. 4.3 and 4.4).

4.51 Depositional Mode1 1

Late Frasnian, Simla Member carbonates represent a shaliow water, high energy platform and margin (Fig. 4.3 Stage 1) deposited during a relative sea-level highstand (Section 4.4 1, Fig. 4.1). in the adjacent basinal sections the Mount Hawk Formation is interpreted to represent deeper subtidal suspension deposition of dominantly fine-grained siliciclastics and carbonates (Fig. 4.3 Stage 1). These mixed siliciclastic and carbonate deposits are interpreted to occur as a result of reciprocal sedirnentation; sili6clastics being deposited during relative lowstands. and carbonate rnuds during relative highstands (Stoakes 1980, Wendte 1992, etc.). However, others have suggested that during the Winterburn siliciclastics were also deposited dunng relative highstands because the siliciclastic supply was proximal and most of the basin was already filled. Thus, with little accomodation space available, siliciclastics prograded basinward. Based on the presence of reddened bioclasts and Iithociasts within the debntes and thek stratigraphie relationships, uppermost Frasnian dtstone and carbonate debntes in the Colin and Chetamon thrust sheet are interpreted to represent carbonate debris eroded hmthe exposed Simla platfonn magin (Sections 3.1 1 and 3.1 2, Figs. 4.1 and 4.3 Stage 2 Appendk A; Type Section a, F-Section a and Gap Lake a, Section 1-45, Figs. l.S,3.1,3.2 ). ). The uppermost Mount Hawk Formation coarse silt deposits occur as locaiized siltstone/fme-grained sandstones (e.g. Medicine Lake) that are intercalated with carbonate debrites (Type Section) suggestuig that siliciclastics were deposited in ?rapid, punctuated pulses (Vail et aL 1977, Van Wagoner 1990). These silty deposits represent an initial influx of si1iciclastics deposited during and immediately following the exposure of the adjacent plaaorm. Black shaies interbedded with the debrite deposits (e.g. Type Section, Appendix A, Figs. 3.1 and 4.4 Stage 2) represent "background" suspension deposition. In this model, shales represent an anoxic eveat and record a restriction and stratification of the water column in the basin caused by a relative sea-level fall.

During the Late Frasnian sea-level fdl, carbonate production was halted by exposure of the Simla Platform. In Mode1 1, relative sea-level fdl is not considered to be significant enough to have caused the demise of the carbonate pladorm, but caused a basinward shifi of carbonate depostion (Fig. 4.3 Stage 2). Earliest Famennian oncolites (Section 3 -25, Figs. 3.1,3. la, 4.1, and 4.3 Stages 2 to 5) are interpreted to represent the initial stages of carbonate deposition following the late Frasnian sea-level fd. These spherical to subsphencal, Girvanelta oncolites were deposited in a high energy, subtidavperitidal basin margin environment. The dramatic changes in diversity and abundance of carbonate organisms across the FF- Boundary are related to factors that aEected a world-wide extinction of carbonate organisms across the F-F boyndaq (McLaren 1982, Goodfellow et al 1988, Wang and Geldsetzer 1996, etc.). It was possible for some minor lowstand carbonate production to occur dong the basin matgin rnainly because Sassenach siliciclastics did not toplap the Simla Member carbonate plaâorm until the end of Sassenach time (Section 4.32 and Chapter 6, Figs. 4.1 and 4.3 Stages 2 to 5).

The transporte4 earliest Famennian oncolites deposited immediately overlying the initial lowstand carbonate and siltstone debntes and black shales at the Type Section suggest that carbonate production was re-established locally dong the Jasper Basin margh immediately after the restriction of the basin, and the deposition of exposure related initial lowstand deposits, Facies 1 to 4, (Table 4, Figs. 3.1,4.1 and 4.3 Stage 2).

Following the initial Iowstand deposition, the Jasper Basin was filled with a siliciclastic wedge (Fig. 4.3 Stages 3 and 4). The upwards and westwards coarsenùig and thickening of beds and the apparent distal climbing downlap reiationship is interpreted to represent the eastwardhortheastward progradation of a Iowstand wedgdfan or ?delta into the Jasper Basin (Sections 4.22,4.5 1 and 4.52, Figs. 4.1, 4.2,4.3 and 4.4). The lower member of the Sassenach Formation (Table 4, Fig 4.4 Stage 3) was deposited as tempestites or distal, basin plain turbidites and background suspension deposits respectively (Section 3-23, Figs. 3.1,3 2,4.1 and 4.3). The upper member of the Sassenach Fornation (Stage 4) is interpreted as a shallower, moderate to high energy, subtidal, lower shoreface environment deposited above storm wavebase (Figs. 3.1,3.2,4.2 and 4.3 Stages 4 and 5). The gradual fiiiing of the Jasper basin reduced the amount of available accomodation space and caused the basinward progradation of Sassenach siliciclastics (Figs. 4.2,4.3 and 4.3 Stages 3,4 and 5). Within both the lower and upper members of the Sassenach Formation, there is a gradual decrease of carbonate content away fiom the eastem basin margin. This relationship is mort easily explained by the production, influx and dispersai of carbonate sediment derived fiom smailer (oncoidstrornatoporoid/algae)and more local carbonate envïronrnents dong the basin margin adjacent to the Ancient Wall buildup (Figs. 3.1,3.2 and 4.3 Stages 3 to 5).

Near the end of Sassenach tirne, with progressive filhg of the Jasper Basin these carbonates were ovenvhelmed by siliciclastics and the basin rnargin was locaity toplapped (Section 4.22, Fig. 4.3 Stage 5). The Paliiser Formation may represent the time at which sea-level had transgressed sunIciently to shut down the influx of siliciclastics into the basin or may represent a transgressive erosion or ravinement surface (Section 4.22). Figure 43 Five depositional stages for the Sassenach Formation Deposition Model 1. The associateci sequence stratigraphie boudaries are shown in Figure 4.1 A). Stage 1: bold arrow represents progradation of Simla Member carbonates; Stage 2; thick, grey unit overlying the Simla Member and Mount Hawk Formation represents the Iatest Frasnian initial lowstand deposits (Facies I to 4, Table 4), dotted unit represents Facies 9, lowstand carbonate deposition and bold arrow represents basinward transport or rafting of oncolites; Stage 3; thin horizontal (Hz)lines represent onlap of lower member Sassenach Facies 7% Table 3, bold arrow represents transport of siliciclastics to the east; Stage 4; thick Hz lines represent onlap of upper member Sassenach Facies 7b, Table 3; Stage 5; deposition of Sassenach is terminated. See text (Section 4.5 1) for description of Depositional Model 1.

4.52 Depositional Model 2

The five depositional stages of Model 2 for the Sassenach Formation and the underlying Sïmia Member and Mount Hawk Formation are illustrated in Figure 4.4 Stages 1 to 5. As in Model 1, Simla Member carbonates represent a shallow water, high energy platfonn and margin (Fig. 4.4 Stage 1) deposited dririog a relative sea- level highstand (Section 4.4 1, Figs. 4.1 and 4.4 Stage 1). In the adjacent basinal sections (Fig. 4.4 Stage 1) the Mount Hawk Formation is again interpreted to represent deeper subtidal suspension deposition of dominantly fine-grained siliciclastics and carbonates. The latest Frasnian lowstand (Fig. 4.4 Stage 2), is represented by the uppermost Mount Hawk siltstones and uiterbedded siltstone debntes and Simla carbonate debrites (Appendk A; Medicine Lake a and Type Section a sections respectively). In this interpretation, the lowstand carbonate debntes also represent carbonate debris eroded fkom the exposed Simla platform deposited in the adjacent basin by debris flow currents. The uppennost Mount Hawk Formation siltstones and siltstone debrites represent the initial influx of proximal siliciclastics into the basin. Because of the localized nature of the siliciclastic deposits and the interbedding of siity/sandy debrites with carbonate debrites (Type Section), the deposition of siliciclastics is interpreted to record a series of rapidkatastrophic depositional puises. Black shales interbedded with and overlying the latest Frasnian Simla and Mount Hawk strata (e.g. Type Section, Appendix A, Fig. 3.1) are interpreted, as in Model 1, to represent suspension deposition in a restricted, stratified basin setting (see above).

Figure 4.4 Stage 3 illustrates the initiai stages of the early Famennian transgression. The early Famennian peloidal limestone and oncolite horizon are interpreted to represent initial transgressive deposits and also are interpreted to track the relative sea-level rise up the basin margin (Section 4.22, Figs. 4.1 and 4.4 Stages 3,4 and 5). Therefore, in Model 2 it is assumed there were other lower member Sassenach Formation oncolites deposited dong the Jasper Basin margin which remain buried under the talus slopes on Mount Haultain or in the Thomton Creek Valley (Figs. 3.1,4.1 b and 4.4 Stages 3 to 5). These lower member oncolites provided the source for the transported oncolite deposits at the Type Section (Appendix A, Fig. 4.4 Stage 3). The remainder of the lower member is fiiied by tempestite/turbidite siltstones and the background, peloidal, suspension carbonates during gradua1 transgressive events (Fig. 4.4 Stage 3). The upper member of the Sassenach Formation is interpreted to have been deposited during a relative sea-level stillstand. The upper rnember of the Sassenach Formation appears to have shaiiowed upwards and prograded eastward, onlapping the northeast margin of the Jasper Basin. Therefore, by definition, a maximum flooding event must bave occurred somewhere near the base of the upper member of the Sassenach Formation between the transgressive and highstand/stillstand systems tracts (Fig. 4.1, VanWagoner 1990). Unfortunately no surfaces were identifïed that codd be interpreted as a maximum floodingkondensed surface. However it would be difficult to identifjr such a surface in the study area because the relatively continuous deposition dong the basin margin would mask the surface (Figs. 3.1.4-1 and 4.4 Stages 3 and 4).

There is renewed transgression within the uppermost Sassenach Formation (Fig. 4.4 Stage 5). The Sassenach locally toplaps the northeast margin of the Jasper Basin e.g. Miette reef complex (Section 4.22). The Palliser Formation carbonates were deposited as sea level rose and the siliciclastic influx was shut down. Alternatively, as in Mode1 1, the contact between the Sassenach and PaIliser formations may represent a transgressive surface of erosion or ravinement surface, (Figs. 4.1 and 4.4 Stage 5). Figure 4.4 Five depositional stages for the Sassenach Formation Deposition; Model 2. The associated sequence stratigraphie boundaries are shown in Figure 4.1 B). Stage 1: bold arrow represents progradation of Simla Member carbonates; Stage 2; represents latest Frasnian relative sea level fall and restriction of the basin; Stage 3; thin horizontal (Hz) lines represent odap of lower member Sassenach Facies 7% Table 3, bold horizontal arrow represents transport of siliciclastics nom the West, dotted unit represents Facies 9, lowstand carbonate deposition and bold arrow represents basinward transport or rafting of oncolites; Stsige 4; thick Hz Iines represent progradation and onlap of upper member Sassenach Facies 7b, Table 3, dotted unit (Facies 9) tracks sea-level transgression up the basin margin; Stage 5; deposition of Sassenach is terminated. See text Section 4.52 for description of Depositional Model 2.

4.6 Documenting and QuantiQing Relative Sea-Level Changes

Relative changes in sea-level are the result of a combination of three main Extors; 1) changes in eustatic sea-level, 2) tectonics (e-g. uplift or subsidence) and 3) sedimentation rate. Unfominaely, it is ciiflicult to quant* eustatic sea-level changes because it is generally not possible (other than for the present) to measure these quantities directiy. Therefore most measured sea-level changes refer to relative sea-level and represent a combination of al1 three factors (for a specitïed time and location). in some cases, reasonable estimates of ail three factoa may be obtained fiom direct measurements fiom stratigraphic or seismic cross-sections and by making reasonable assumptions for two factoa and thus solving for the third. It was not reasonable to derive estimates for sedimentation or subsidence rates for the Upper Devonian strata in the study area. Various authors have derived a Devonian eustatic sea-level curve (Fig. 4.9, but the quantification of eustatic sea-level changes (other than for modem environments) is highly problematic (Johnson et al. 1985, Johnson and Sandberg 1988, Savoy and Mountjoy 1995). 'Ibis section describes procedures for the recognition of relative sea-level fa11 during the Latest Frasnian, and explains how stratigraphic relationships may be used to roughly constrain the magnitude of late Frasnian relative sea-level fall, and to characterise the early Famennian transgression.

4.61 Recognition of Changes in Sea-Level

In general, changes in relative sea-level are recognized by: 1) unconfonnity/exposure horizons or depositional hiatus Le. Type 1 sequence boundary; and 2) abrupt landward or seaward shifts of facies or depositional environrnents (Vail et ai. 1977, Van Wagoner 1990). Relative changes in sea level are effectively recognized and defmed by stratigraphic relationships.

A relative lowenng of sea-level in the study area is interpreted to occur during the latest Frasnian based on the following observations and interpretations: 1) subaerial exposure of the Simla platforni and margin (Figs. 2.4 a and b, 3.1 and 4.1); 2) a Type 1 sequence boundary is located beîween the Simla Member and the Sassenach Formation, and overiies the Mount Hawk Formation; 3) a significant change in depositional environments in the basin fiom calcareous shales and argillaceous limestones of the Mount Hawk Formation to the deposition of siltstones and carbonate and siltstone debntes (Thomton Creek, Mount Strange, Gap Lake etc., Figs. 3.1,3 2,4.1,4.3 and 4.4); and 4) shallow water carbonate facies (oncolites) are deposited above the Type-1 sequence boundary, basinward of the uppemost Frasnian, Simla Member carbonates and therefore represent a basinward shift of shallow water facies (Figures 3.1,4.1,4.2 and 4.4).

In the Chetamon thrust sheet, sea-level lowering is also suggested by a downlapping surface in the uppermost Simla Member that tnincates the underlying horizontaYaggradational and progradational strata of the Simla platforni (Figs. 3 -2, 4.1,4.3 and 4-4)- Therefore, within the study area, the level fÏom which sea-level began to fdl was at least fiom the top of the exposed Simla pladorin, (Figs. 3.1,3.2, 4.1,4.2 and 4.4). The Palliser-Sassenach contact was used to approximate this horizon (Fig. 4.6).

The lowest level reached during the lowstand is somewhat less certain, and is represented by the point at which the erosionai surface and the correlative conformity meet. This is difficult to determine within the study area because the contact between the erosionai swface and the correlative conformity is covered by talus in the Thomton Creek valley in the Colin thrust sheet (Figs. 2.1,2.4 a and b and 3.1) and could not be positively identified on inaccessible cliff faces in the Chetamon thmt sheet (Figs. 2.5,3.2 and 4.1).

Alternatively, the lowest point reached during a sea-level falI may be constrained by stratigraphic relationships and by assigning an approximate bathymetry for the strata/facies fiom the interpreted lowstand deposits. In the study area, the lowest level reached is different for Models 1 and 2, and is approximated by the placement of the Initial Transgressive Surface (Fig. 4.1 ). The placement of the ITS in the Sequence Stratigraphie Models 1 and 2 is dependent upon the interpretation of the amount of relative sea-level fall, and on the depositional interpretation of the Sassenach Formation shallow water oncolite and stromatolite horizons (Sections 4.22,4.5 1 and 4.52).

The maximum and minimum possible amounts for latest Frasnian relative sea-level fa11 in the Jasper Basin are discussed in the foilowing sections. The minimum and maximum amounts of relative sea-level fall correspond to the sequence stratigraphic and depositionai Models 1 and 2 respectively. Figure 4.5 Eustatic sea-level curve for Devonian-Carboaiferous succession of the southem Canadian Roçky Mountains, fiom Savoy and Mountjoy (1995). The Devonian portion is modified fiom Johnson et al. (1985) and Johnson and Sandberg (1 988). The Carboniferous portion is reproduced fiom Ross and Ross (1 98ïa). Devonian and Lower Carboniferous stratigraphc units are plotted by age. Arrows and brackets highiight intervals when siliciclastic sediments were transported into the Alberta Basin fkom a ?westerly source, possibly Antler-age highlands to the west.

4.62 Stratigraphie Location for Model 1 Sea-Level Fail

The minimum amount of relative sea-level fall for the Sassenach cmbe estimated by using stratal relationships; Ginan& oncoids probably deposited in O to 15 m water depth (Playford, 1980); or the stromatolite horizon, O to 5 m water depth, (e-g. Type Section and Mount Haultain, Appendix A, Figs. 3.1,3. la, and 4.6). in addition it is assumeci that the underlying Simla carbonate plat6orm was fully cemented pnor to burial and did not undergo signiricant amount of compaction.

The stromatolite horizon gives a minimum sea-level fdl of 20 to 25 rn (the elevation of the Simla Platform/Palliser-Sassenach contact above the stromatoIite horizon) minus O to 5 m (water depth for the stromatolite horizon or 15to 20 m relative sea-level fd or:

(20 to 25 m) - (O m to 5 m) = 15 - 20 m below the top of the Simla platCorm (Fig. 4.6 a).

4.63 Stra tigmphic Location for (Model 2) Sea-Level Fa11

For depositional Model 2 it is assumed that additional oncolite shorelines (currently covered in Thornton Creek valley) developed much merdown the basin margin within the lower member Sassenach Formation (Figs. 4.1 and 4.4). If this assumption is correct, then the oncolite and algal-bal1 pellet/peloid units observed at the Type Section are interpreted to be derived fkom local transport (Figs. 4.1 and 4.4). In this case, the shoreline is interpreted to occur at or just above the stratigraphic level of the algal-bal1 pellet peloid horizon near the base of the Sassenach (Sections 4.22 and 5.52, Figs. 4.1 and 4.4). Based on this interpretation, sea-level for a maximum sea-level fd(ignoring compaction) is approxirnated by using the height of the Simla planorm above the algal ball/peloid horizon (168 m) minus the bathymetry previously estimated for oncolite deposition, O - 15 m (Section 4.62, Figs. 4.1 and 4.4) or:

(168 m) - (O rn - 15 m) = 153 m - 168 rn below the Simla platform. (Fig. 4.6 b) Figure 1.6 a) Illustration of amount of Iate Frasnian relative sea-level fa11 for Model 1. Estirnate applies to Sequence Stratigraphic and Depositional Models 1 and represents approximately c 25 m of relative sea-level fall. See section 4.62.

b) Illustration of amount of late Frasnian relative sea-level fa11 for Model 2. Estimate applies to Sequence Stratigraphic and Depositional Models 2 and represents approximately 100 to 150 m relative sea-level fdl. See section 4.63. Relative Sea-Level Fa11

Model

B) Model 2 4.64 Quantification of Relative Seri-Level Fd

To quatltifjr the amount of relative sea-level fdl it is necessary to define both the level fiom which sea-level began to fall, and the lowest level attained during the subsequent lowstand (Pigram et- al lm,),and to correct for compaction. The estimate for a maximum amount of relative sea-level fail would require a moderate correction due to compaction of about 100 m of argiliaceous mudstones and calcareous shales of the underlying basinal Mount Hawk and Perdrix formations (Figs- 4.1,4.3 and 4.4)-

However, the purpose here was to provide a rough estimate for the relative magnitude of late Frasnian, relative sea-level fail, Indeed, the available data suggest something < 25 m of relative sea-level fa11 for Model 1, and asuming 20 to 50 % compaction for the underlying argillaceous strata, Model 2 represents up to t 50 m of relative sea-level fall. Chapter 5

Potential Sources for Sassenach Formation Siliciclastics 5 Introduction

To date there bas been littfe discussion in the literature about the potential sources for Sassenach/Graminia Formation siliciclastics. Switzer et al. Ch. 12, WCSB Atlas (1994), suggest that the Graminia Formation may represent the deposition of siliciclastics that were reworked during the early Famennian transgression. Other workers suggest that the Graminia and Sassenach Formations may represent the deposition of aeolian sands that were transported westward across the Blue Ridge carbonates Uito the Sassenach Depression (Shields and Geldsetzer 1992, deWit pers. corme). Stili others suggest that the Sassenach Formation represents the deposition of siliciclastics derived Corn a highland terrane to the West (Mountjoy 1980, Savoy and Mountjoy 1995, Upitis and Geldsetzer 1994). In addition, Mountjoy (1980) and Savoy and Mountjoy (1995) suggest that the Sassenach Formation may represent the fmt evidence of siliciclastics in the WCSB sourced fiom the Antier orogenic event to the southwest. in the following section three potential sources for the Sassenach siliciclastics are discussed: I) the Canadian Shield; 2) the Ellesmenau fold belt in the Arctic Archipelago (Stoakes 1980; 1992, Chp. 8, p. 189, Chp. 5, p. 141); and 3) Antier orogenic highlands, (Savoy and Mountjoy, 1995).

Unfortmately, interpreting the provenance of the Sassenach Formation is extremely dificult because the Jasper Basin is distal, 500 km + away, fkom every apparent source terrane. In addition, uplifi and erosion of the western Rocky Mountains limits the Devooian outcrop availabte for study. Indirect evidence (NdSm isotopes, petrography and stratigraphie relatiomhips) provide constraints for the most likely source area for the Sassenach Formation siliciclastics.

5.1 Paleogeography

The configuration of the Western Canada Sedimentary Basin (WCSB) during late Frasnian tirne is depicted in cross-section and map views (Figs. 1.1 and 1.2 and 5.1). The dominantiy regressive, Frasnian Wmterbuni megacycle filled most of the WCSB with fine grained siliciclastics and carbonates of the ireton (Mount Hawk) Formation (Figure 1.2). Lower Ireton Formation. sediments were probably introduced into the basin between the southem edge of the Grosmont Shelf and the northern end of the Killam Barrier, completely fwgthe East Shale Basin (Oliver and Cowper 1963, Stoakes 1980, Switzer et al. 1994). The Upper Ireton Formation thins dramaticaüy southward from Peace River Arcb and siliciclastics may have been transponed into the West Shale Basin between the Grosmont Shelf and the Peace River Arch andor around the western side of the Peace River Arch between the arch and the Simonette reef complex (Stoakes 1980, Switzer et ai. 1994).

The regional distribution of the Ireton Formation i.e. eastward and northward thickening and evidence of interna1 southward and westward dipping clinoforms within the Ireton Formation (2-marker, Wendte et al. 1995) suggesl ihat these sediments were transported kom the Ellesmerian fold belt of the Canadian Artic Archipelago and were distributed into the WCSB by longshore currents dong its eastern margin (Figs. 1.1, 1.2 and 5.1 Embry and Klovan 1976. Stoakes 1980). However, by the end of the Frasnian the western rnargin of the WCSB, (the Jasper Basin in particular), was only partially filied by Mount Hawk (Ireton) Formation sediments. The remaining depression, the Jasper Basin was filled during the earliest Famennian by the Sassenach Formation.

Regionally, the Sassenach Formation thickens and coanens to the West and south (Upitis and Geldsetzer 1994). Additionally, beds within the Sassenach Formation also thicken and coarsen upwards and westwards and forrn an apparent distal, horizontal climbing downlap relationship with the underkying Ancient Wall and Miette Reef complexes (see Chapters 3 and 4, Figs. 3.1, 3.2, 4.1, 4.2 and 4.3). This baselap relationship represents a change in sedimentation patterns from the westerly dipping clinoforrns in the underlying calcareous shales of the Mount Hawk/Ireton Formation (see above) and may be interpreted to represent a change in the direction of sediment source. The westward coarsening and thickening of the Sassenach Formation is a direct consequence of filling a depression chat remained after deposition of the westw'ard thinning clinoforms of the Mount Hawk Formation (Figs. 1.1 and 1.2). This evidence suggests that the main influx of sificiclastic was from a westerly/southwester~ydirection (Figs. i 2, 3.1,3.2,4.3,4.4 and 4.5). Figure 5.1 Major tectonic features of western Canada in Late Devonian tirne (der McNicoll et al. 1995, and Richards 1989). The Richardson Trough provides a plausible transportation route for siliciclastics sourced f?om the Ellesmerian Orogenic Belt to the north. See section 5.22.

5.2 Source Terranes

5.21 Precambrian Shield

Although the Precambrian shield to the east is believed by many authors to be a potential source of Sassenach siliciclastics (Halbertsma pers. comm., Switzer et al. 1994), it is diflïcult to envision a pathway or depositional mechanism fiom the east that could account for the westward coarsening and thickening and apparent distal horizontal clhbing downlap that occurs dong the northeast margin of the Jasper Basin (Figs. 1.1, 1.2,4.3,4.4 and 4.5).

For instance, it seems improbable that the amount of siliciclastic sediment found in the upper Mount Hawk and Sassenach Formations in the snidy area could have been transported fiom the Precambrian Shield to the western side of the WCSB by an aeolian mechanism (Fig. 1.2). In such an interpretation, aeolian sands must be transported across the underlying Blue Ridge platform during either a sea-level highstand or lowstand aad deposited (?by longshore/contour currents) as a northeasterly prograding wedge. There is also a lack of known features that are consistent with aeolian transport, i.e- fiosted or etched grains, large scale cross- bedding, bimodality, etc. Further, paieogeographic reconstructions suggest that the Precambrian shield may have ken covered by Devonian or older Paleozoic carbonate rocks (Switzer, et al., 1994).

An alternative mechanism for transporting siliciclastics westward into the Jasper basin would be nom an eastem shoreface andlor fluvial channel system. In the Late Frasnian, the Blue Ridge Member prograded westerly over underlying carbonates, and almost completely filled the eastem portion of the WCSB (Switzer et al. 1994). During the latest Frasnian lowstand, a small fa11 in sea level would therefore shift the shoreface westward into the low-relief basin and might allow siliciclastics to be transported to a shoreline dong the basin margin via incised fluvial channel systems. During storms, or major flood events, silt and sand size particles codd then be lransported from the shoreface into the deeper Jasper Basin via storm generated tempestites or hubidity currents.

The eady Famennian transgression could have reworked ador eroded siltstones, sandstones and fluvial channels on the underlying Blueridge carbonates, leaving little or no evidence of the pre-existing sediment transport mechanism. However, it is qrising that no siliciclastic filled channel systems have been reported Erom the subdace Blue Ridge or equivalent outcrop Simla carbonate shelves.

5.22 Ellesmerian Orogenic Terrane

Although the Ellesmerian orogenic terrane is interpreted to be the source for the underlying Mount Hawmeton Formations, it seems uniikely that coarse siltstone to fine-grained sandstones of the uppermost Mount Hawk or Sassenach Formations codd have been sourced/transported fiom the Ellesmerian orogenic belt for severai reasons: 1) at the end of Frasnian the, the East Shale Basin and most of the West Shale Basin were filled and it is unlikely that coarse siliciclastics could have been transported across these sediments; 2) there is no evidence of coarse siliciclastics northeast of the Jasper Basin; 3) the Sassenach Formation lacks the characteristic westward dipping, downlapping clinoforming relationships dernonstrated in the underlying Mount Hawk (Ireton) Formation which support an Ellesmerian source (Stoakes 1980, etc.); 4) the Sassenach Formation siltdsands coarsen and thicken to the west-southwest (Figs. 1.2, 3.1, 3.2, 4.1, 4.2 and 4.3, Geldsetzer and Upitis, 1993); 5) Nd/Sm isotopes suggest Sassenach Formation siliciclastics have a younger, less evolved source terrane than the underlying Mount Hawk Formation (see section 5.3, Fig. 5.3).

Alternatively, it is possible that siliciclastics were transported around the western side of the WCSB, west of the Peace River Arch (Fig. 5.1, Switzer et al. 1994). Unfortunately, most of the Devonian dong the western side of the WCSB has been eroded during the Laramide Orogeny or remains buried. There is a paucity of stratigraphie data for the transport of coarse siliciclastics fiom the no&. The only evidence for coarse siliciclastics that has been discussed in the literature is the distribution of a few small, isolated pods of Earn Group congbmerate in northwestem Alberta and northeastem British Colombia (Fig. 5.2, Savoy 1992 and Savoy and Mountjoy 1995). Therefore there is stili no evidence of a direct link to the Jasper Basin for the transport of coarse siliciclastics from the Ellesmenan orogenic highlands. Figure 5.2 Major tectonic features of western North America in Late Devonian and Early Mississippian the (hm Savoy 1992). The Eam Group and Imperia1 sequence are Devonian-Mississippian clastic assemblages derived fiom ororgenic or uplified regions. EQ1 is the approximate Tournaisian position of the paleoequator based on lithic paleoclimatic data of Witzke (1990). EQ2 is the approximate Famennian position of the paleoequator based on data of Scotese and McKerrow ( 1 990). EARN GROUP 5.23 WesterdSouthwestem Source Terrane

A westedsouthwestern source terrane is interpreted to be the most likely provenance for famennian Sassenach siliciclastics. The upwards and westwards coanening and thickening and apparent distal horizontal climbing downlap relationship of the Sassenach Formation dong the northeast margin of the Jasper Basin are interpreted as a lowstand wedge of eastwadnortheastward progradhg siliciclastics sourced fiom the West or southwest (Figs. 1.2 and 5.2). One possibility for a source terrane in this direction is the Upper Devonian-Carboniferous AntIer Orogenic highlands in the northem United States (Fig, 52)- Coarse siliciclastics occur in Montana and Idaho (Saadberg et al, 1988) in what has been interpreted to be the Antler Orogenic foreland basin (Fig. 5.2). Siliciclastics in the Sassenach Formation would therefore represent a distal part of this foreland basin.

5.3 Neodyrnium/Somarium Isotope Analyses

Neodymium~somarium isotopes have been used to indicate both sediment transport routes and provenance in conjunction with regional paleogeographic, stratigraphic and petrological evidence typically used for provenance analyses, (Stevenson et al. in prep.). In the study area &Nd values fiom the Sassenach Formation decrease up-section and decrease with increasiug Zr content. (Fig. 5.3). The increase in Zr content is likely due to an increased sorting and coarsenhg of sediments up-section. Lower sNd values suggest that the zircons are inherited fkom an older source than the underlying Mount Hawk and Perdrix sediments (Stevenson et al. 1996). in addition, the coarsening upwards succession implies that the Sassenach Formation was progradational Le. the distance between the basin and the source was decreasing. These data illustrate important changes in the sources of sedimentary material supplied to the Jasper Basin as a result of tectonic changes along the Western margin of North Amenca during Devonian time (Stevenson et al. 1996). Figure 5.3 a) &Ndvalues for the Mount Hawk, Perdrix and Sassenach formations (fiom Stevenson et al. 1995). Decreasing values for the Sassenach Formation illustrate important changes in the sources of sedimentary material supplied to the Jasper basin as a result of tectonic changes dong the Western margin of North America during Late Devonian the. b) Negative correlation between decreasing &Nd values and increasing zircon content for the Sassenach Formation (fkom Stevenson et ai. 1995). Decreasing &Nd values suggest suggest that zircons are inhented fiom an older source. Increasing zircon content reflects increasing sorting and coarsening of sediments upsection.

The data from the Mount Hawk and Perdrix formations (Fig. 5.3 b) Lie within the range of values (-9 to -6.5) for post-Devonian strata of the Rocky Mountains (Bogossian et al. 1996). A decrease in the &Ndvalues €or the Sassenach Formation is interpreted as evidence for tectonic uplift and the subsequent erosion of older suata to the West. The Mdvalues for the Sassenach Formation overlap with those of late Proterozoic formations (- 10 to -20, Frost and ONions 1984, Frost and Winston 1987 and Boghossian et al. 1996) from the Belt-Purcell Supergroup and the Windermere Supergroup and also overlap with values (- 10 to - 20, Ghosh and Lambert 1989) from thst strata of the Kootenay Arc that Lie to the West of the study area (Fig. 5.2, Smith and Gehrels 1992, Smith et al. 1993).

5.4 Summary

More Sm/Nd isotope analyses from the Graminia Formation silts and upper Mount Hawk silts are necessary to demonstrate whether they have a common source with the Sassenach siliciclastics dong the eastemhonheastem margin of the Jasper Basin. In addition. a more regional study of the stratigraphy and biostratigraphy of Sassenach Formation in the Jasper Basin, and of the Graminia silts in the subsurface would aiso help to suggest potential source areas and transport routes for the siliciclastics. Table 5 Summary of stratigraphie and petrographic observations of source terranes for Sassenach Formation siliciciastics. Table 5 Stratigraphie and Petrographic Observations

Enesmerian Pdambrian Antier Orogenic Orogenic Temne Shield Highland

PRO

Possible vansponation rouie Sasscnach siliciclastics dong the western sidt of lhe coarscn and lhickm up- Alberta Basin via the section and wcstward Richardsoo trough Szsrcnach sna~aform an apparent d-trial ctimbing downlap againn the NE margin of the Jasper Basin

Petrology of Sassenach Fm.: 5-1 0°/0 têIdspar content. subround ro well rounded quartz,

EN^ idicaic that the source for the Sasscnach Fm. siliciclastics was older Ihan for the underlying Fonnm-ons.

Jasper Basin could connecl southwvd with Ader Forcland Basin,

CON

Southwardlwesrward dipping Lack of coarse siliciclastics No direct cvidence of a clinofom, e.g. "2 market' or channclization in the Bluc westcdy source. in the undcrlying lmon Ridge CO tht east (Mount Hawk) Formation not observed in the Sassenach Formation.

The East ShaIe Basin and NdlSm isotopes values for northern portion of thc West ShieId source are consinent Shaie Basin were fillcd by with thc undtriying Mount the end of the late Frasnian. Hawk and Pcrdnx fomations. Chapter 6

Discussion and Conclusions 6.1 Discussion

The sequence stratigraphic relationships across the Frasnian-Famennian boundary in the study area provided an opportunity to consider the relative effects of the three components which contribute to or cause sequence geometries: 1) rate of sea-level change (eu-); 2) sedimentation rate; and 3) tectonics (rate of subsidenceluplift). Udortunately, even though the Simla Member, Mount Hawk and Sassenach formation facies and their respective depositionai processes were relatively easy to ident% and class*, it was not possible to determine a unique solution for the combination of factors that could create these facies and stratigraphie relationships. It was also not possible within the Iimits of this study, to consider every possibilility, so two end-member sequence stratigraphic and their respective depositional models were chosen to represent the greatest and the least amunts of relative sea-level change.

Mode1 1 suggests that the sequence stratigraphic relationships can be explained by a small, < 25 m (Fig. 4.7 a), late Frasnian relative sea-level fdl generated by some combination of eustasy and subsidence. In the latest Frasnian, there was an initial influx of allochthonous debris overlain of an early Famennian, lowstand fan or wedge which provided an oversupply of sediments that gradually filled the existing accomodation space within the Jasper Basin (Figs 3.1,3 .2,4.1 & 4.4). During the deposition of the early Famennian strata, the rates of subsidence and eustasy (rate of relative sea-level change) were insignificant compared to the rate of sediment supply-

Mode1 2 suggests that the sequence stratigraphic relationships cmbe explained by a large 100- 150 m (Fig. 4-7 b), late Frasnian relative sea-level fdl and a ?rapid, continuous transgression followed by a stillstand- In this model, a thin, latest Frasnian, lowstand wedge was preserved. Transgression began during the earliest Famennian and progressed to a stillstand that ailowed sediments to shallow up to sea- level and caused them to prograde across the Jasper Basin in the upper member of the Sassenach Formation (Figs 3.1,3.2,4.1 & 4.5). During the deposition of the earliest Famennian strata, some combination of the rates of subsidence and eustasy (rate of relative sea-level change) controlled the rate of accomodation. The rate of sediment supply was insignificant. in the upper member of the Sassenach the rate of relative sea-level was still the dominant factor; a lower rate of relative sea-level rise increased the relative rate of sedimentation and caused the subsequent progradation. There are difficulties inherent in the interpretation of both sequence stratigraphic models because both are limited by similar data constraints. Firstiy, for both models, the full extent of the stratigraphic relatioaships cannot be observed because most of the Jasper basin was eroded during uplift. This meam that the regionai extent of the source tenane and sediment supply routes and the proximal portion of the depostional environment can not be observed.

Secondly, in Mode1 2, the earliest Famennian transgression is based on the iderred existence of a transgressive oncolite facies (Facies 9, Fig. 3.1, Appendix A, base of Thornton Creek & Mount Haultain), that tracked the transgression up the basin margin, (Figs- 3.1,4.l & 4.5). However, the fidl extent of the lateral relationships of the shoreface carbonates cannot be observed because the basin margin is covered in Thomton Creek (Figs. 2.4 & 3. l), and occurs on an inaccessible cliff face (Fig. 2.5 & 3 -2) in the Colin and Chetamon thrust sheets respectively.

Finally, it is also difficult to interpret the boundùig surfaces for Mode1 2, For exarnple, there is no clear evidence of a Maximum Flooding Surface (MFS) between the transgressive and high/stillstaad systems tracts (Figure 4.1 b & d). It is possible that this surface may have ken obscwed by the mixture of carbonate/siiiciclastic deposition in the study area. In addition, the bounding surface between the HST Sassenach sediments and the TST Palliser carbonates must be a Type II (non- erosional) sequence boundary (Van Wagoner et al. 1988, Van Wagoner 1990). However, Type II sequence boundaries are now thought to be marine flooding surfaces that form parasequence set boundaries. Therefore, until the correlative exposure horizon is obsewed, it is not yet acceptable to interpret this sdace as a sequence boundary .

From a geologic/tectonic perspective, it becomes difficult to envision a geologic mechanism that could induce 100-150+ m of rapid, relative sea-level fall. Further, to only generate a paraconformity, sea-level must have nsen very rapidly in the early Famennian. This reqksa geologic/tectonic mechanism that couid create a significant (1 00-1 50 m) and rapid relative sea-level rise. Thus, for model 2 to be favoureà, a MaxFS, an erosional unconformity associated with the Sassenach - Palliser contact should be observed and the tectonic mechanism for such large, rapid relative sea-level changes must be identified. T'herefore, Model 1 is the preferred interpretation for the shidy area because it requires no drarnatic changes in relative sea-level, and does not rely on Merred stratigraphic relationships. However, in Model 1, the extent of the stratigraphic relationships of the carbonate shoreface cannot be seen and this model ignores the possibility of additional shoreface associations.

Similarly, data constraints and a lack of regional information makes it impossible to conclusively identie the probable sources of Sassenach siliciclastics. The source may be fiom the West or north, or may be some combination of these sources. NdSm coosrraints indicate that the source terrane differs fiom the source for the underlying Mount Hawk and Perdrix formations, but does not pinpoint one source conclusively.

Hopefidly, with firrther work in adjacent thrust sheets, it will be possible to narrow the possibilities towards one end-member depositionaVsequence stratigraphic model and to gain a more regionai understandhg of bot.the relative sea-level changes across the Frasnian-Famennian boundary and the source(s) for the Sassenach siliciclastics. 6.2 Conclusions

Stratigraphy

1. The F-F boundary represents a major paraconformity in the fiont ranges of the Rocky mountains, Jasper Basin. This paraconfomity is interpreted based on the folIowing: a) major faunal gap; b) late Frasniao, "initial lowstand or lowstand siltstone slump and debris beds containing iron stained peloidal intraclasts; c) darkened and reddened lirnestone "breccia" clasts within carbonate debrites d) downlap of ?latest Frasnian Simla sediments and euncation of the Simla platforni margin (Chetamon thrut sheet); and e) the abrupt contact between the underlying late Frasnian and overlying Famennian sediments.

2. The uppermost Mount Hawk Formation and Simla Member comprise four facies types: 1) Siltstone Debntes; 2) FoldedlDeformed Interbedded Limestone and siltstone; 3) Bioclastic/Lithoclastic Wackestone to Packstone; and 4) SiltstonelFine-grained Sandstone.

The Sassenach Formation comprises eight facies types; 5) Calcareous Shale, 6) Bioclastic Packstone-Grainstone, 7a) Siltstone/Limestone/Mudstone Interkds, 7b) Coarse Siltstone-Fine- Grained Sandstone Interbeds, 8) Stromatolite Bafflestone, 9) Oncoid Wac kestone to Grainstone, 10) Limestone; Wackestone to Packstone (Brachiopod, Crinoid, Peloid), 4/11) Siltstone to Fine-Grained Sandstone

3. The Sassenach Facies have ken grouped into Lower (5,6,7a) and Upper (7b, 8, 9, 10,4/118) Memben based on an upwards ùicrease in coarseness and bed thickness and their stratigraphie position. 4. Eight Facies Associations were identifted: 3 for the uppermost Sida Member and Mount Hawk Formation (SMH-A, SMH-B and SMH-CLMS-C); 3 for the Iower member Sassenach Formation (LMS-A, SMH-B and SMH-C/LMS-C); and 3 for the upper rnember Sassenach Fonnation (UMS-A, UMS-B and UMS-C).

Sequence Stratigraphy

Latest Frasnian Simla plaâom sediments represent a sea-level Kighstand bounded above by a Type 1 Sequence Bomdary based on the following evidence: a) depositionai facies in the Iate Frasnian Simla Member represent a shallow, peritidai environment deposited near or at sea-level; b) late Frasnian Simla Member carbonates prograde basinward (Colin th- sheet and downlapfprograde (Chetamon thnist sheet). c) the uppennost Simla platfonn displays erosional relief of 5 to 30 cm; and d) the uppermost Simla platform is locally overlain by a bioclastic debrite comprising erosionaVreddened bioclasts and blackened lithoclasts.

Parasequences were difficult to define; facies associations were used to define stacking patterns within the systems tracts.

Sassenach Formation parasequences fonn an apparent distal, horizontal or distal climbing dowdap (Handford 1995) against the eastem Jasper Basin Margin.

There are several possible sequence stratigraphie interpretations for the Sassenach Formation. Two end-members were considered:

INITIAL LST; Uppermost Mount Hawk Formation and Simla Member interbedded siltstone debrites and bioclasticAiùioclastic carbonate facies associations. LST; Sassenach Formation progradational, distal basin plain facies associations (Lower Member and lowermost Upper Member), including lowstand shoreface carbonates suggested by the presence of lower member oncolite units at the Type Section. TST; uppermost Upper Member Sassenach progradationai, proximal and shoreface carbonate facies association continuing upwards into the Paiiiser Formation.

Interpretation problems; 1) Cannot see the extent of the stratigraphie relationships of the shoreface carbonates because the basin margin is covered in Thornton Creek Valley. 2) Sediment transport and proximal depositional system have not been mapped.

LST; Uppermost Mount Hawk Fomation and Simla Member interbedded siltstone debrites and bioclastic~ithoclastic carbonate facies association, prev. basai Sassenach. TST to HST; Sassenach Formation distal (TST) to strongly progradational, proximal and shoreface carbonate facies associations (HST); includes the Lower and lowermost Upper Members. TST; Uppermost Upper Member Sassenach progradational, proximal facies associations continuing upwards into the Palliser Formation.

Interpretation problems: 1) No evidence of a MaxFS between the TST and HST. This may be dificult to observe due to the mixture of carbonate/siliciclasticdeposition. 2) No evidence of exposure within the upper member Sassenach Fm., ie. the bounding surface between the Sassenach HST and TST is a Type II SB.

Depositional Models

8. Uppermost Mount Hawk Formation FoldecVDeformed Limestone and Siltstone Interbeds and Lithoclastic Siltstones were deposited by slumping and debris flow mechanisms respectively. Uppermost Simla Member BioclastidLithoclasbic carbonates represent erosional debris derived fiom the Simla Platform, deposited by debris flows dong the basin matgin and siope. 9. Lower Member Sassenach Siltstone/Lirnestone/Mudstone interbeds represent distal basin (ABC) turbidites and background suspension deposition.

10. Upper Member Sassenach Coarse Siltstone-Fine Grained Samistond Limestone/Mudstone interbeds represent lower to ?middle shoreface (ABC) turbidi tes and background suspension deposition.

11. Basin margin carbonate deposits represent higher energy, shallow, subtidal shoreface deposits.

Magnitude of Relative Sea-Level FaU

12. The magnitude of relative sea-Ievel drop at the end of the Frasnian cm be roughly estirnated based on stratigraphic relationships as minimum and maximum amounts of relative sea-level fall;

Mode1 1) (Minimum case) c 25 m, and

Mode1 2) (Maximum case) approximately 100 to 150 m.

Source Terrane

13. The most likely source for the Sassenach siliciclastic sediments is interpreted to be the Antler orogenic beit to the southwest based on the following critena:

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Mount Hawk Formation/ Simla Mcmber Facies

Biwliuiic/Li~hoclasiic FoldcJ/Dçfomd Wackcsionc IO Packsionc Intchldcd Limcsionc and Silistona

Sasscnach Formation Facies

Oncoid Wackcriono IO Uninstone ' W 10 Lirncstow-Waclrcsionc 10 Packstonc

*N,B, Façics 411 1 also occun in the Mount Hawk Fomtion Colin Thrust Sheet SB.

PSB

PSB

PSB l'se Type Section A

PSB

PSB

PSB

PSB

Mom Pak D

abni -

7- -

60m-

Som -

4am-

PSB

Chetamon Thmst Sheet GIS.ESÇlot/grMst~baf,kwh~*~h~odry oppr sPnjce. cbipnducdl piocha out dofiWIa9~

61~usmu&ttffnhsiIrym~ntiPttrbcdr, bcddiog ipdiaiacr, biamrhim ma 00 top ofbodding s4Zmacdbnchs

PSB

PSB

~E3ty*prp~*-*IIM.drkipcyIML GLKON. GS, Gd,CIlcrcoor mdst. piaey. We, pyrifc & chut nodiiles G19CON. Caüawe dcbrir, wackdpodra? saomr,cwrIir, amis ~orMrkcfiar.~t SimlaMcmbaCrboolit ador kcs CquinlcPt GI6, Ribbao rock di^ prka 5-7 an iorckds ad thian~~2-3cmsiùsr/ti5stiorakdr.sane dlatifictiae, lrnrl Gap Lake C

Eh-

Ilom -

PSB

lm-

9Om-

PSB

8ûm - Gap Lake D -. bais =O1

wz

POE

PSB

PSB

FS, Shy prbZ PSB

PSB

PSB UOm-

PI-

n -

L -

b Mount Stnagt A

] &.&.A S.... m... AmAm&

œœ PSB S. sn. S~IY-ad nrtn intakd* M Jrat~?drar.bi~~al~oatopi dkdsdumpedintcrrJtSm Mount &ange C

PSB Mount Strangt D Mount Sbrage E Mount Sbrngc F

I Cl!ha

4-10 m iora6ds of sihy pwkst ami dtsd f&sr.bukhns,~~-~C;LCIQO~OOI dabasesotbah

Appendix B Location Meters Above Fauna Probable Range Sample # Base of Section

Type Section

N55CON 0-4 m Belodelia sp. A Late F~.rwalla (AD. McCracken) Palnntolepis rrhea~ Lower to Upper Bischoff rhenana Zone Po&gnathtrs planannanus aapper Poiygnathrrs spp. (non platforni elements)

Paimatoiepis boogaardi Mn Zone 13 PaImutoZepis rhemnu Late Frrwiiian Palmatoiepis winchelli AncyrodeIIa ioides ("homeomorph") AncyrodeIJa nodosa Poïygnathtrs br&cmiM Poiygnatthus lodinenris Poljgnathzis impwilis Pelekysgnathus planus Mehiina sp. Belodella sp.

N56CON 10 m Palmatolepis rhem~ (A.D. McCracken) Bischoff Polygnatb spp. (non- Lower to Upper platform elements) rkenano Zone

N59 CON f4m Belodella sp. A Late Frrwnian (A.D. McCracken) Palmatolepis rhenam Upper rhenana Bischoff Zone Po&gnathtrs immlis napper & Lane PoIygnuthzrs ex gr. webbi Stauifér Polygnathus spp. (non- platform elements) indeterminate elements Location & Meters Above Faona Probable Range Sample # Base of Section

NCON2 26 m Pdmatolepis sp. Late Frasnian (A.D. McCracken) Polygrrrrthrcs impmipmillis Upper rhenuna Klapper & Lane Zone PoiygMihur sp. (non- platform elemento)

Late Frasnian

Upper rhenanu Zone Oufodus? sp. A PallltatoIeepis rheMnu Bischoff Poljgnathtu imparilis Klapper & Lane Polygnahs ex gr. brevis Miller & Youngquist Polygnathus sp. A Polygnathus sp. B Poiygnathtrs spp. (non- platfom elements) Indeterxninate cyrtonioifom etement

Pahnutolepis trianguIlais Lower Famenaian Polygnathus breviluminus Lower to Middle Polygnathus precursor? biangularis Zona Iiiohalternaius kri& iowaensis

47.3 m Pa1matoZepi.s sp. Lower Famennian indeterminate (1 6.3 m above FF Polygnathus brevilaminus (not zonaiiy restrieted) Location & Meters Above Fauna Probable Range Sample AT Base of Section

Mount Haultain

HICON Belodella devonica (A.D. McCracken) (StauEef?) Polyguaihus planmius Lower to Upper Kbper rhenana Zone Poiygnathus ex gr. webbi StauEer Poiygnatrhus spp. (non- platform elements)

H2CON Icriodrrs aiternatu Eariy Famemira (A.D. McCracken) altematus Btanson & Mehl Icriodus alternatus helmi Lower triangufaris Sandberg & Dreesen Zone through Middle crepidu Zone Icriodus aitertultus Bnuwn & Mehl ssp. Point~ltolepiscanademis Orchard PoZygnathw ex gr. brevilminus Btanson & Mebi Pol'ygnathus spp. (non- pla$orm elements) Indeterminate acostate cone Ichthyoliths Location & Meters Above Faana Probable Range Sample # Base of Section

Gap Lake Section

G19 Ancyrodeh dosa Late Frrwnian (A.D. McCracken) Ulrich & BassIer BelodeIIa sp. A Upper rkenuna Zone "hrakiu"sp. A Elsonellu rhenana Lincisirom & Ziegler ûuiodus? sp. A Pulrnatolepis rhenana Bischoff Palmatoiepis sp. B Orchard? Pele&sgnathtrs plmus Sannemann Poiygnathus ex gr. brevis Miller & Youngquist Poiygntithus imparilis Klapper & Lane Poiygnathus decorosus Stauffer Poijgnathw ex gr. webbi StaufEer Poiygnathw spp. (non- platfonn elewnts) "condontpearl" Indeterminate zygognathiform element Location & Meters Above Fauna Probable Range Sample # Base of Section

Gl8 Ancyrdellu nodosu Earïy Famennian (A.D. McCracken) ülrich & Bassler "Coelocerodonhis"sp- A Lower aiogrrllcvk Zone tbrough - Middle c~pida Zone "Dvorakia"sp. A Icriodus alfernatushelmsi Sandberg & Dreesen Oulodtis? sp. A Palmatolepis rhenana Bischoff Palmatolepis cf.wolskajue Ovnatanova Palmatolepis spp. Polygnathus imparilis Klapper & Lane Poljgnafhusex gr. webbi StaufXer Pofygnath spp. (non- platform elements) Ichthyoliths "conodoat pearls"