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Mechanical Stratigraphy of the Utica Shale, Eastern New York State

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Mechanical Stratigraphy of the Utica Shale, Eastern New York State Graduate Theses, Dissertations, and Problem Reports 2014 Mechanical Stratigraphy of the Utica Shale, Eastern New York State John Brockman Follow this and additional works at: https://researchrepository.wvu.edu/etd Recommended Citation Brockman, John, "Mechanical Stratigraphy of the Utica Shale, Eastern New York State" (2014). Graduate Theses, Dissertations, and Problem Reports. 5260. https://researchrepository.wvu.edu/etd/5260 This Thesis is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. Mechanical Stratigraphy of the Utica Shale, Eastern New York State John Brockman Thesis submitted to the Eberly College of Arts and Sciences at West Virginia University in partial fulfillment of the requirements for the degree of Master of Science in Geology Dr. Ryan Shackleton, Ph.D., Chair Dr. Kathleen Benison, Ph.D. Dr. Timothy Carr, Ph.D. Department of Geology and Geography Morgantown, West Virginia 2014 Keywords: Utica Shale; Mechanical Stratigraphy; Fractures; Flat Creek Shale; Dolgeville Formation; New York; Ordovician Copyright 2014 John Brockman ABSTRACT Mechanical Stratigraphy of the Utica Shale, Eastern New York State John Brockman The mechanical stratigraphy of the Upper Ordovician Utica Shale is characterized by studying outcrops and core located in Montgomery County, eastern New York State. Previous studies of the Utica Shale in New York State have focused on characterizing fracture orientations, distinguishing fracture generations, and establishing a relationship between fracture density and proximity to faults, but fractures in outcrops of the Utica Shale have not been studied in the context of mechanical stratigraphy. The composition, sedimentary texture, strength, and thickness of individual beds within the Flat Creek Shale and Dolgeville Formation are studied to better understand the nature of fracture propagation in thinly- bedded mudrocks. The Flat Creek Shale and Dolgeville Formation are fine- grained clastic rocks containing varying amounts of detrital carbonate grains. There are also multiple bentonite layers within both members. A fracture bedding termination analysis is conducted at three outcrops of the Flat Creek Shale to identify mechanical interfaces in the vertical section. A Schmidt Hammer is used to measure rock strengths approximately every .2 vertical meters, and samples are collected throughout the section to be analyzed with XRD. Utica Core 74 NY-05 is described in terms of bedding thicknesses, lithofacies, and sedimentary texture. Three thin sections are analyzed with multiple petrographic microscopes to identify common textures and mechanical flaws associated with individual lithofacies. The combination of the fracture bedding termination analysis, rock strength measurement, core description, petrographic investigation, and XRD analysis assist with characterizing the mechanical behavior of these rocks. The fracture bedding termination analysis indicates that bentonites are responsible for approximately 51% of identifiable fracture terminations in the Flat Creek Shale; therefore bentonites act as mechanical barriers to fracture propagation. The bentonites exhibit significantly lower present day rock strength values and are primarily composed of clay minerals. While the remaining 49% of vein-filled fracture terminations occur in shale layers, there are few shale mechanical interfaces identified. The observation that bentonite horizons form significant mechanical barriers to fracture propagation has important implications for modeling subsurface fracture networks, because bentonites are widespread in basins, and are easily distinguished on gamma ray logs. Acknowledgements I am a dwarf standing on the shoulders of giants. This project would still be in its infancy if it weren’t for the guidance I’ve received from faculty, my committee, my peers, and a lot of intelligent and helpful people. I would first like to thank my advisor Dr. Shackleton for providing funding, direction, and an overall pleasant experience throughout this process. I’d also like to thank the rest of my committee, Dr. Carr and Dr. Benison, for offering their expertise and valuable advice. Your input, especially during my thesis proposal, has helped me to focus on the subjects that are most pertinent to my study. There are quite a few people who have gone out of their way to help me with this project: Jim Leone, Aaron Evelsizor, Matt Erenpreiss, Dr. Carlton Brett, Dr. Bob Jacobi, Frank Karmanocky, and Lucas Hinegardner. Jim Leone, I can’t thank you enough for giving Dr. Shackleton and I a tour, for getting me set up with Utica Core 74NY-05, and for introducing all of the literature and geologic concepts related to the Utica Shale. We would literally have gotten stuck up the wrong creek without your help. Speaking of Utica Core 74NY-05, I owe thanks to Aaron Evelsizor and Matt Erenpreiss. Thank you for being so flexible with your schedules, for willingly assisting me whenever I requested something, and for preparing the core every session. I hope all is going well at the survey. Dr. Brett, I may not have ended up working in the Cincinnati arch, but at the very least I now know a lot of really good fossil hunting localities! Thanks! Dr. Jacobi, thank you for all of your help, and I’m sorry Dr. Shackleton and I never got to stop by Buffalo. Frank, thanks for your help with the thin section photography. Lucas, I wouldn’t have had the time to finish my thesis this semester had you not shown the initiative to help me and Dr. Shackleton with this research. I wish you the best of luck with grad school or wherever you end up working. I’d also like to thank Dr. Brian Currie for many things, of which there are too many to list. Mom and Dad, thank you for letting me play in the gravel driveway. Kari, thank you for listening to me talk about my thesis every day for the past year or so. Lastly, I’d like to thank Dr. Ding and the WVU Shared Research Facilities for providing training and access to XRD. ii Table of Contents PAGE LIST OF FIGURES.................................................................................................................................iv LIST OF TABLES.........................................................................................................................v 1. Introduction................................................................................................................................1 2. Background................................................................................................................................3 2.1 Stratigraphy....................................................................................................................3 2.2 Tectonics........................................................................................................................5 2.3 Rock Mechanics.............................................................................................................7 2.4 Burial Depth Estimation & Vein-Fill Origin Theories................................................13 3. Methods.....................................................................................................................................18 3.1 Core Methods...............................................................................................................18 3.2 Field Methods..............................................................................................................19 3.3 XRD Methods..............................................................................................................20 4. Observations.............................................................................................................................21 4.1 Core Observations........................................................................................................21 4.2 Thin Section Observations...........................................................................................26 4.3 Field Observations.......................................................................................................30 5. Results.......................................................................................................................................33 5.1 Flat Creek Field Results...............................................................................................33 5.2 Canajoharie Creek Field Results..................................................................................40 5.3 Fracture Bedding Termination Analysis......................................................................43 5.4 XRD Results................................................................................................................55 6. Discussion.................................................................................................................................60
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