A Sequence Stratigraphic Analysis of the Allegheny Group (Middle Pennsylvanian), Southeast Ohio A thesis presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Master of Science Dreadnaught G. Stubbs May 2018 © 2018 Dreadnaught G. Stubbs. All Rights Reserved. 2 This thesis titled A Sequence Stratigraphic Analysis of the Allegheny Group (Middle Pennsylvanian), Southeast Ohio by DREADNAUGHT G. STUBBS has been approved for the Department of Geological Sciences and the College of Arts and Sciences by Gregory C. Nadon Associate Professor of Geological Sciences Robert Frank Dean, College of Arts and Sciences 3 ABSTRACT STUBBS, DREADNAUGHT G. M.S., May 2018, Geological Sciences A Sequence Stratigraphic Analysis of the Allegheny Group (Middle Pennsylvanian), Southeast Ohio (253 words) Director of Thesis: Gregory C. Nadon This study examined a complete section of the Allegheny Group near Nelsonville in southeastern Ohio. The study site is located in the backbulge region of the Alleghanian Orogeny where total accommodation was low. Facies analysis of six detailed measured sections concluded that the Allegheny Group was deposited by a fluvially dominated delta system, which can be divided into ten sequences that vary from 2 to 15 m in thickness. Sequence boundaries were placed at the top of paleosol profiles and base of incised fluvial sandstones. Fluvial incision that occurred during the Falling Stage and Lowstand Systems Tracts resulted in the erosion of some, or all, of an underlying sequence, the formation of paleosols on interfluves, and the amalgamation of some fluvial sandstones. Transgressive Systems Tract deposits include coals, marine and lacustrine prodelta mudstones, and fluvial sandstones. Highstand Systems Tract deposits consist primarily of interbedded laminated mudstones, siltstones. Vertical grain size pattern and fossil content were used to infer locations of the Maximum Flooding Surfaces. The composition of individual sequences varies from a single fluvial sandstone body to a complex assemblage of marine to lacustrine mudstones, sandstones, and coal. The variation in facies patterns and sequence thickness within the section, and between this location and other locales along strike reported in the literature, is interpreted to be primarily a function of allogenic glacial-eustatic sea level changes. The allogenic driver was modified to varying degrees by autogenic processes, 4 such as channel avulsion during deposition of the Highstand Systems Tract, that shifted channel locations between sequences. 5 ACKNOWLEDGMENTS My most genuine thanks to Dr. Greg Nadon for his supreme generosity in the form of wisdom, mentorship and kindness. I am honored and proud to have worked with you on these projects. Many thanks to my committee members Dr. Dan Hembree, Dr. Dina Lopez and Dr. Craig Grimes for their patience and for sharing their expertise. Thanks to the Ohio Geological Survey and especially Frank Fugitt. The field work in this study would have taken twice as long if it weren’t for Frank who was in the field with me every humid, Summer day. Thanks to Trey Hedrick who assisted me in the field. Massive thank you to Cheri Sheets who helped me on almost a daily basis during my 4 years in the department. I owe countless thanks to the faculty and staff of the Dept. of Geol. Sciences at OU. I hope to stay in touch with you all. Lastly, I would like to thank my family. I would not be in the position I am today if it wasn’t for your unwavering support. Funding for this research is greatly appreciated and was provided by the Ohio Department of Natural Resources ‘Ohio Rocks’ Grant and the Ohio University Department of Geological Sciences Graduate Alumni Research Grant. 6 TABLE OF CONTENTS Page Abstract ............................................................................................................................. 3 Acknowledgments ............................................................................................................. 5 List of Tables ..................................................................................................................... 8 List of Figures .................................................................................................................... 9 CHAPTER 1 .................................................................................................................... 11 INTRODUCTION ............................................................................................................. 11 CHAPTER 2 .................................................................................................................... 16 PREVIOUS WORK ......................................................................................................... 16 CHAPTER 3 .................................................................................................................... 26 METHODOLOGY ............................................................................................................ 26 3.1 Introduction ......................................................................................................... 26 3.2 Measured Sections ............................................................................................. 26 3.3 Petrography ........................................................................................................ 26 3.3 X-Ray Fluorescence (XRF) Analysis .................................................................. 27 CHAPTER 4: ................................................................................................................... 29 LITHOFACIES AND FACIES ASSOCIATIONS .............................................................. 29 4.1 Introduction .......................................................................................................... 29 4.2 Lithofacies ........................................................................................................... 29 4.2.1 Facies 1: Black Shale ................................................................................. 32 4.2.2 Facies 2: Mudstone .................................................................................... 35 4.2.3 Facies 3: Siltstone ...................................................................................... 64 4.2.4 Facies 4: Sandstone ................................................................................... 64 4.2.5 Facies 5: Coal ............................................................................................ 74 4.3: Facies Associations ............................................................................................ 76 4.3.2 Facies Association 2: Subaqueous Delta ................................................... 79 4.3.3 Facies Association 3: Delta Plain Interfluve ............................................... 83 4.4 Fluvial Channel Deposits ..................................................................................... 85 4.4.1 FA-4a Single Story Sandstone ................................................................... 85 4.4.2 FA-4b Multistory Sandstone ....................................................................... 86 4.4.3 FA-4c Abandoned Channel ........................................................................ 87 4.5 Depositional Model – Fluvially Dominated Delta ................................................. 89 CHAPTER 5 .................................................................................................................... 94 SEQUENCE STRATIGRAPHIC FRAMEWORK ............................................................. 94 7 5.1 Introduction .......................................................................................................... 94 5.2 Sequence Stratigraphy Terminology ................................................................... 94 CHAPTER 6 .................................................................................................................. 104 CONCLUSIONS ............................................................................................................ 104 REFERENCES .............................................................................................................. 107 APPENDIX 1: DETAILED MEASURED SECTIONS ..................................................... 117 APPENDIX 2: PALEOCURRENT DIRECTIONS .......................................................... 123 APPENDIX 3: POINT COUNTING ................................................................................ 124 APPENDIX 4: XRD ....................................................................................................... 125 XRD Sample Preparation ........................................................................................ 125 Brookville XRD Data ................................................................................................ 127 Lower Kittanning XRD Data .................................................................................... 128 Upper Freeport Paleosol XRD Data ........................................................................ 129 APPENDIX 5: XRF DATA ............................................................................................. 130 XRF Data Normalized to Total Mass ....................................................................... 132 XRF Standards .......................................................................................................