PALEOPEDOLOGY AND FLUVIAL SEDIMENTOLOGY OF THE UPPER DEVONIAN CATSKILL FORMATION, CENTRAL PENNSYLVANIA: A TEST OF THE DISTRIBUTIVE FLUVIAL SYSTEM MODEL A Thesis Submitted to the Temple University Graduate Board In Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE By Christopher Oest July 2015 Advisors Dr. Dennis O. Terry, Jr., Department of Earth and Environmental Science Dr. Alexandra E. Krull-Davatzes, Department of Earth and Environmental Science Dr. David E. Grandstaff, Department of Earth and Environmental Science ABSTRACT …… The Upper Devonian Catskill Formation represents marginal marine and alluvial sediments which prograded into the Appalachian Basin during the Acadian Orogeny. Distributive fluvial systems (DFS) are prevalent in modern actively aggrading basins in all tectonic and climatic regimes and may be common in the rock record. In this study, I reinterpret the Catskill Formation as a prograding distributive fluvial system (DFS) on the basis of up-section variability in paleosols, channel sandstone textural trends, and alluvial architecture. At least three distinct pedotypes representative of prevailing soil forming conditions are identified during deposition of the Irish Valley, Sherman Creek, and Duncannon Members of the Catskill Formation. Increased paleosol drainage is inferred from an up-section transition from hydromorphic aqualfs within the Irish Valley Member to non-calcareous, uderts within the Duncannon Member. Qualitative field observations of channel sandstone morphology show an increase in channel size up-section. Channels occur as small isolated bodies at the base of the section, transitioning to relatively larger, amalgamated channels, and finally, large isolated channel bodies up-section. Sandstones are litharenites and coarsen-upward throughout the Catskill Formation overall. This coarsening upward trend results from increasing paleo-flow competency in larger channels up-section. These results are consistent with deposition of the Catskill Formation by DFS processes and demonstrate the utility of paleopedological analysis in interpreting alluvial depositional processes. Identifying DFS in the rock record has implications for paleosol-based paleoclimatic studies, as paleosols forming on prograding DFS have increased paleosol drainage up-section, which could potentially be misinterpreted as a shift from prevailing humid to arid paleoclimatic conditions. I Recognition of DFS in the rock record also has implications for basin analysis and exploration of fluvial aquifers and hydrocarbon reservoirs, as the stratigraphic architecture of DFS are fundamentally different from tributary systems at the basin scale. II ACKNOWLEDGEMENTS The majority of the funding for this project was provided by the Society of Sedimentary Geology (SEPM) Foundation Student Assistance Grant. Temple University Department of Earth and Environmental Science provided laboratory supplies and travel support. DT – You’re responsible for getting me into this business. Thank you for giving me ample freedom to allow me to dive into a project that I was genuinely interested in. Alix – I can’t recall how many times I’ve come into your office in a mild panic asking “if you had a minute” and you still took the time to talk with me even though you were clearly in the middle of something. Thank you for your guidance. G – I know every time I bring a manuscript to you, I’ll get it back torn to shreds. But it always turns out for the best. Thank you for constantly keeping me on my toes. Ilya – You’re name might not be on the cover page, but I still consider you a mentor. The ideas that you planted in my head were great contributions to this project. Nick – Whether you realize it or not (or believe me), I genuinely loved both of your classes. Thank you for taking the time to entertain my random questions about all things structural geology and making me a better scientist. Many, many thanks to my fellow graduate students, especially Haley and Paul. You were always there to unwind at the end of a long day/week. May there be many dollar taco nights ahead for us. Steve, Jesse, and Tim – You all have wisdom beyond your years in geology and in life. Thanks for imparting that onto me and keeping me cool on rough days. III The Valentine Lab - Thanks for the fun times at lunch and helping me remember basic chemistry. To my undergraduate field assistants (donkeys/wolves) – Phil, Wes, Zach, Chris – the field work for this project literally could not have been completed in time without your help. I am in your debt. Aaron, Chris, Chris, and Jess – Your help with preparing my thin sections was huge. To all my students – Thank you for not accepting everything I said at face value. You made me a better geologist. And remember, we like to have fun here at Temple Geology. Thanks to my family (Mom, Dad, Patrick, Gran) for you overwhelming support (both emotional and financial). You got me through this. IV TABLE OF CONTENTS ABSTRACT …… .............................................................................................................. I ACKNOWLEDGEMENTS .............................................................................................. III LIST OF FIGURES ......................................................................................................... VII LIST OF TABLES ............................................................................................................ IX CHAPTER 1. INTRODUCTION ....................................................................................... 1 1.2 Distributive Fluvial Systems ........................................................................... 7 1.3 Stratigraphy, Paleogeography, Tectonic Setting, and Paleoclimate ................ 8 1.4 Methods ......................................................................................................... 17 CHAPTER 2. RESULTS .................................................................................................. 27 2.1 Paleopedology ............................................................................................... 27 2.1.1 Pedotype 1 ..................................................................................................... 27 2.1.2 Pedotype 2 ..................................................................................................... 35 2.1.3 Pedotype 3 ..................................................................................................... 38 2.2 Channel Sandstone Petrography .................................................................... 41 2.2.1 Mineralogy .................................................................................................... 41 2.2.2 Grain Size Analysis ....................................................................................... 47 2.3 Channel Morphology ..................................................................................... 52 2.4 Decompaction................................................................................................ 52 CHAPTER 3. DISCUSSION ............................................................................................ 54 v 3.1 Paleoenvironmental Factors of Soil Formation ............................................. 54 3.1.1 Paleoclimate .................................................................................................. 54 3.1.2 Effect of Land Plants ..................................................................................... 57 3.1.3 Landscape Gradient and Base Level ............................................................. 58 3.1.4 Parent Material .............................................................................................. 61 3.1.5 Time of Pedogenesis ..................................................................................... 62 3.2 Sandstone Provenance ................................................................................... 64 3.3 Up-section Variability in Channel Grain Size and Morphology ................... 65 3.4 Flow Competency Analysis .......................................................................... 67 3.5 A Note on Diagenesis .................................................................................... 70 CHAPTER 4. CONCLUSIONS ....................................................................................... 72 REFERENCES CITED ..................................................................................................... 76 APPENDIX A. STUDY SITE LOCATIONS AND DESCRIPTIONS ....................... 85 APPENDIX B. GRAIN SIZE DISTRIBUTIONS ....................................................... 86 vi LIST OF FIGURES Figure 1: Hydrofacies variability on DFS. ..................................................................4 Figure 2: Study sites relative to the Devonian outcrop belt in Pennsylvania. .............6 Figure 3: Paleogeography and hypothetical cross section of the Appalachian Basin during the Late Devonian ................................................................12 Figure 4: Generalized stratigraphic section of the Catskill Formation in Central Pennsylvania. ................................................................................13 Figure 5: Key to symbols used in Figure 4, Figure 8, and Figure 9. .........................14 Figure 6: Outcrop photographs showing various lithologic characteristics of the Irish Valley and Sherman Creek Members. .........................................15 Figure 7: Outcrop photographs showing various