University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies Legacy Theses 2012 A methodology for studying tectonic subsidence variations: insights from the Fernie Formation of west-central Alberta McCartney, Tannis Maureen McCartney, T. M. (2012). A methodology for studying tectonic subsidence variations: insights from the Fernie Formation of west-central Alberta (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/24227 http://hdl.handle.net/1880/48945 master thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY A methodology for studying tectonic subsidence variations: insights from the Fernie Formation of west-central Alberta by Tannis Maureen McCartney A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE DEPARTMENT OF GEOSCIENCE CALGARY, ALBERTA APRIL, 2012 © Tannis Maureen McCartney 2012 The author of this thesis has granted the University of Calgary a non-exclusive license to reproduce and distribute copies of this thesis to users of the University of Calgary Archives. Copyright remains with the author. Theses and dissertations available in the University of Calgary Institutional Repository are solely for the purpose of private study and research. They may not be copied or reproduced, except as permitted by copyright laws, without written authority of the copyright owner. Any commercial use or re-publication is strictly prohibited. The original Partial Copyright License attesting to these terms and signed by the author of this thesis may be found in the original print version of the thesis, held by the University of Calgary Archives. Please contact the University of Calgary Archives for further information: E-mail: [email protected] Telephone: (403) 220-7271 Website: http://archives.ucalgary.ca ii Abstract Tectonic subsidence curves for over 300 subsurface wells in west-central Alberta indicate that the Western Canada Foreland Basin was initiated at the same time the lower units of the Fernie Formation were being deposited. This evidence is further supported by sedimentological data and fits with the timing of the onset of deformation in the Cordillera and the initiation of the foreland basin in Montana. The volume of subsidence curves in this study required an innovative methodology. Subsidence calculations were performed using customized macros in a spreadsheet. The tectonic subsidence variations were displayed in a tectonic subsidence envelope, which showed the total variation in the subsidence curves, and three suites of maps: tectonic subsidence, tectonic subsidence residuals, and tectonic subsidence ratios. Collectively, the maps of the tectonic subsidence in the Fernie Formation show that there was a western influence on subsidence during deposition of the oldest members of the Fernie Formation. iii Acknowledgements There are so many people I want to thank for their support over the last two and a half years that it is almost impossible to know where to begin. Thank you to my supervisor, Dr. Andrew Leier, for believing in me enough to let me take this project in a different direction than we’d originally planned. Thank you to the other professors in CABS (Centre for Applied Basin Studies) for their support and feedback over the years, especially Dr. Stephen Hubbard, Dr. Benoit Beauchamp, and Dr. Bernard Guest. A huge thank you also goes to Dr. Terry Poulton, of the Geological Survey of Canada, for his feedback and support. In my time as a graduate student at the University of Calgary, I have been incredibly lucky to have learned from Dr. Philip Simony and Dr. Ed Ghent—thank you both for your mentorship. To my CABS colleagues, thank you for your support and discussions. In particular, thank you to Dallin Laycock for the Adobe tutorials, to Ross Kukulski and Julianne Fic for the brief but awesome time we spent together in the field, to Kevin Jackson and Erin Pemberton for all the feedback and moral support, and to Kate Zubin- Stathopoulos for teaching me so much, as my TA and in our “Beer and Tectonics Sessions.” Ross, I cannot thank you enough for all of the additional help and discussions—I have learned a lot from you and you’ve been instrumental in helping me understand the Jurassic in west-central Alberta better. iv In the last year or so I have become involved in the geoblogging and geotweeting community. I want to thank them for the support, suggestions, feedback, enthusiasm, and for the constant reminders that geology is really cool. #ThankYouGeoTweeps. None of this would have been possible without the support of my family and friends—thank you for not telling me I was totally crazy to come back to school. In particular, I cannot thank Jennifer Unterschutz enough for the constant reminders that I was smart enough and strong enough to do this, even on the hardest days. And thank you for volunteering to read my thesis! I was lucky enough to spend some time with friends overseas just before the final push to finish writing my thesis. Thank you to Janine and Ben, Annabel and Arend, Krista and Kris, Ailsa and Ray, Linda and Steve, the entire Woodley family, and Mick: the time I spent with you (and your families) was just what I needed. To Andy Owens and Tony England: you are gone, but never forgotten. You believed in me, and gave me so much support while you were alive; I know you both would have been proud of me. Last, but not least, thank you to the staff at the Last Defence Lounge, but especially Charley, for taking such good care of me at my other home. You kept me sane (and fed and watered). v Dedication Toitū he whenua, whatungarongaro he tangata is a Maori proverb stating that man perishes, but the land remains. I dedicate this work to the people of New Zealand. It was in your land, in the raw landscapes of Aotearoa, that I became interested in geology. An earthquake in 1995 started me on this path. Over the last 18 months earthquakes have changed your country, and it nearly broke my heart because I wasn’t prepared for how much so until I visited in late 2011. Kia Kaha New Zealand vi Table of Contents Abstract............................................................................................................................... ii Acknowledgements ............................................................................................................ iii Dedication............................................................................................................................v Table of Contents............................................................................................................... vi List of Tables .......................................................................................................................x List of Figures.................................................................................................................... xi List of Symbols, Abbreviations and Nomenclature ......................................................... xvi Epigraph.......................................................................................................................... xvii CHAPTER ONE: INTRODUCTION..................................................................................1 1.1 Western Canada Foreland Basin ................................................................................1 1.2 Timing Problem .........................................................................................................3 1.3 Preliminary Work ......................................................................................................5 1.4 Objectives ..................................................................................................................6 1.5 Study Area .................................................................................................................6 CHAPTER TWO: BACKGROUND ...................................................................................9 2.1 Foreland Basin ...........................................................................................................9 2.2 Subsidence Analysis ................................................................................................13 2.2.1 Airy Isostasy....................................................................................................17 2.2.2 Decompaction..................................................................................................18 2.2.3 Backstripping...................................................................................................19 2.3 Geological Framework ............................................................................................20 2.3.1 Western margin of North America ..................................................................20 2.3.2 Cordilleran Tectonics ......................................................................................23 2.3.3 Major structural features in west-central Alberta ............................................26 2.3.3.1 Snowbird Tectonic Zone........................................................................26