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Sedimentology and Stratigraphy of the Eocene

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Sedimentology and Stratigraphy of the Eocene FACIES ARCHITECTURE AND STRATIGRAPHY OF TIDAL RIDGES IN THE EOCENE RODA FORMATION, NORTHERN SPAIN BY KAIN J. MICHAUD A THESIS SUBMITTED TO THE DEPARTMENT OF GEOLOGICAL SCIENCES & GEOLOGICAL ENGINEERING IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE QUEEN’S UNIVERSITY KINGSTON, ONTARIO, CANADA APRIL, 2011 COPYRIGHT © KAIN J MICHAUD, 2010 It doesn't matter if the water is cold or warm if you're going to have to wade through it anyway. ~Teilhard de Chardin i ABSTRACT The Eocene Roda Formation in northern Spain documents the deposits from a range of coastal depositional environments. These include alluvial plains, distributary channels, mouth bars, upper to lower-shorefaces, and tidal shelf ridges. Eighteen progradational sand tongues that are interpreted as parasequences compose two third-order sequences. Sequence 1 accumulated in an environment with strong tidal currents and high rates of progradation, while Sequence 2 was deposited under relatively weaker currents and higher rates of aggradation, which produced a higher mudstone:sandstone ratio. The stratigraphy highlights the transgressive origin of six tidal shelf ridges, three in each sequence, that overlie regressive deltaic tongues. Sequence 1 shelf ridges are composed almost entirely of cross-bedded sandstones, whereas Sequence 2 ridges are composed of a mixture of cross-bedded and ripple-laminated deposits. Ridges in both sequences contain bioturbation that is typical of the Cruziana Ichnofacies, and that indicates a marine origin. The tidal ridges are stratigraphically located at or near the point of maximum third-order regression, and are not found within early highstand or late transgressive deposits― times of high relative sea level when the deltaic shoreline did not protrude significantly. Tidal currents were accentuated at the coast when the delta complex had prograded several kilometres into the basin, while during times of high relative sea level, the basin was wider and tidal currents were weaker, consequently leading to a lack of tidal deposits. The tidal ridges are, thus, interpreted as being headland-associated deposits. ii ACKNOWLEDGEMENTS My time at Queen’s University has been both exciting and rewarding, and it gives me great pleasure to express my appreciation to all of you who have supported me. Dr. Robert Dalrymple provided insightful guidance while patiently awaiting the completion of the project. I thank him for developing my geologic skills, our pleasant insightful discussions and for sending me to Spain, Bermuda, New York and Quebec (Ft. McMurray excluded). Bob let me find my own way through scientific problems, encouraging out-of-the-box thinking, which inevitably led to numerous fruitful debates. While he won most of those debates (or all depending on who you ask), I like to think I came out the victor with a strong education and a resilient thesis. Fellow graduate students provided much needed distractions and discussions, resulting in the improvement of the thesis content alongside my foosball and ping pong skills. Few days went by without discussions with Duncan Mackay, Aitor Ichaso, Cody Miller, Geoff Reith, Meg Seibal, Pim Van Geffen, Nick Riordan and Laura O’Connell. I would like to thank all of you for the great company and insightful conversations. Bryce Jablonski deserves special mention for his hard work in Spain. Thanks again for not complaining about the long hikes, carrying the heavy pack, and constantly reminding me to take what I had forgotten. I would also like to thank Allard Martinius, Cornel Olariu, and Ron Steel for introducing me to the study area. My time spent there would have been exponentially more confusing without your guidance. Local Spaniard, Jose Antonio Naval, treated me like a family member during my stay and I am especially grateful to his family for sharing their home and culture. iii Also my family’s contributions must be recognized. Continued support and guidance from my parents over the last 7 years of my education made this thesis possible and I cannot thank them enough for that. My wife deserves pages upon pages of credit for her patience and motivation; however, for the sanity of readers I will conclude with a simple— thank you Linda. This project would not have been possible without funding which was graciously provided by NSERC grants to Robert Dalrymple and by Queen’s University. STATEMENT OF ORIGINALITY The following thesis is a compilation of my own field work, literature review and insight. Nevertheless, Dr. Robert Dalrymple’s contributions must be recognized as he has provided invaluable guidance and revisions that greatly improved the scientific and grammatical quality of the thesis. This study is unique as it 1) is the first to document the detailed sedimentology and stratigraphy of the Eocene Esdolomada Member, a 180 m thick mixed siliciclastic/carbonate succession, and also 2) illustrates the range of facies present within tidal shelf ridges and documenting the distribution of facies, stratigraphic location and variability of 6 ridges. iv TABLE OF CONTENTS Abstract ..................................................................................................................................... ii Acknowledgments ................................................................................................................... iii Statement of Originality .......................................................................................................... iv Table of Contents ...................................................................................................................... v List of Figures ......................................................................................................................... vii List of Tables ......................................................................................................................... viii CHAPTER 1 INTRODUCTION 1.1: General Introduction .................................................................................................... 1 1.2: Geologic Setting ........................................................................................................... 3 1.3: Stratigraphic Background ............................................................................................ 4 1.4: Methods ........................................................................................................................ 6 CHAPTER 2 THE FACIES , SEQUENCE-STRATIGRAPHIC FRAMEWORK AND COMPARISON OF SHELF RIDGES IN THE RODA FORMATION, NORTHERN SPAIN 2.1: Introduction .................................................................................................................. 8 2.2: Facies Analysis ............................................................................................................. 8 2.3: Stratigraphic Framework ............................................................................................ 21 2.4: A Comparison between the Upper and Lower Sequences ........................................ 25 2.5: Conclusions ................................................................................................................ 29 v CHAPTER 3 FACIES ARCHITECTURE OF THE TRANSGRESSIVE TIDAL RIDGES 3.1: Introduction ................................................................................................................ 31 3.2: Facies Analysis ........................................................................................................... 33 3.3: Facies Distributions, Isopach Patterns and Paleocurrents ......................................... 45 3.4: Ridge B ....................................................................................................................... 48 3.5: Ridge F ....................................................................................................................... 53 3.6: Origin of Tidal Ridges ............................................................................................... 55 3.7: Comparison between Roda and Esdolomada members ............................................ 59 3.8: Variation between Ridges .......................................................................................... 60 3.9: Conclusions ................................................................................................................ 62 CHAPTER 4 CONCLUSIONS 4.1 Concluding Remarks .................................................................................................... 65 REFERENCES ..................................................................................................................... 68 APPENDIX A.1 Measured Sections ....................................................................................................... 89 A.2 Outcrop Photographs and Uninterpreted Figures from Previous Chapters ............. 112 vi LIST OF FIGURES CHAPTER 1 Figure 1.1: Regional Geology .............................................................................................. 2 Figure 1.2: Stratigraphic Section ......................................................................................... 5 Figure 1.3: Outcrop Outline ................................................................................................. 6 Figure 1.4: Study Location ................................................................................................... 7 CHAPTER 2 Figure 2.1: Facies A Channels and Facies B Alluvial Plain ............................................
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