Depositional Environment and Facies Analyses of the Owl Mountain Province, Fort Hood Military Installation, Bell and Coryell Counties, Texas
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Stephen F. Austin State University SFA ScholarWorks Electronic Theses and Dissertations 12-2018 DEPOSITIONAL ENVIRONMENT AND FACIES ANALYSES OF THE OWL MOUNTAIN PROVINCE, FORT HOOD MILITARY INSTALLATION, BELL AND CORYELL COUNTIES, TEXAS Jacob Meinerts [email protected] Follow this and additional works at: https://scholarworks.sfasu.edu/etds Part of the Geology Commons, Geomorphology Commons, Hydrology Commons, and the Sedimentology Commons Tell us how this article helped you. Repository Citation Meinerts, Jacob, "DEPOSITIONAL ENVIRONMENT AND FACIES ANALYSES OF THE OWL MOUNTAIN PROVINCE, FORT HOOD MILITARY INSTALLATION, BELL AND CORYELL COUNTIES, TEXAS" (2018). Electronic Theses and Dissertations. 222. https://scholarworks.sfasu.edu/etds/222 This Thesis is brought to you for free and open access by SFA ScholarWorks. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of SFA ScholarWorks. For more information, please contact [email protected]. DEPOSITIONAL ENVIRONMENT AND FACIES ANALYSES OF THE OWL MOUNTAIN PROVINCE, FORT HOOD MILITARY INSTALLATION, BELL AND CORYELL COUNTIES, TEXAS Creative Commons License This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License. This thesis is available at SFA ScholarWorks: https://scholarworks.sfasu.edu/etds/222 DEPOSITIONAL ENVIRONMENT AND FACIES ANALYSES OF THE OWL MOUNTAIN PROVINCE, FORT HOOD MILITARY INSTALLATION, BELL AND CORYELL COUNTIES, TEXAS By Jacob Allan Meinerts, B.S Presented to the Faculty of the Graduate School of Stephen F. Austin State University In Partial Fulfillment Of the Requirements For the Degree of Masters of Science STEPHEN F. AUSTIN STATE UNIVERSITY December 2018 Depositional Environment and Facies Analyses of the Owl Mountain Province, Fort Hood Military Installation, Bell and Coryell Counties, Texas By JACOB ALLAN MEINERTS, B.S. APPROVED: ___________________________________ Dr. Melinda S. Faulkner, Thesis Director ___________________________________ Dr. Kevin W. Stafford, Committee Member ___________________________________ Dr. LaRell Nielson, Committee Member ____________________________________ Dr. Joseph A. Musser, Committee Member _____________________________ Pauline M. Sampson, Ph.D. Dean of Research and Graduate Studies ABSTRACT The Owl Mountain Province is a plateaued, karst landscape located in the eastern section of the Fort Hood Military Installation and is characterized by Lower Cretaceous Fredericksburg Group carbonates. The topography is capped by thick sequences of the Edwards limestone; steep scarps and incised valleys along the edges of the plateaus host inter-fingering outcrops of the Edwards and Comanche Peak limestones, and the lower valleys are covered by alluvial sediments and intermittent outcrops of the Walnut Clay. These formations were deposited to the north and west of the main Edwards trend, and are thought to be part of a series of complex carbonate mounds that developed as backreef deposits in a restricted environment on the Comanche Shelf, associated with the western flank of the Belton High. The purpose of this study is to describe the microfacies within the Fredericksburg Group and characterize the depositional environment of the study area. Field observations and laboratory analyses were used to investigate the microfacies in greater detail to provide evidence relating to the compositional makeup and diagenetic processes of the Lower Cretaceous strata. Sixteen lithostratigraphic sections were measured in the Comanche Peak and Edwards formations, identifying microfacies through field descriptions based on allochems, matrix, bioturbation, bedding style, and other distinct features. After thin section i analyses, 11 microfacies were identified, characterized, and used to create a diagenetic model to provide an accurate depiction of the Lower Cretaceous middle shelf depositional environment of the Owl Mountain Province. ii ACKNOWLEDGEMENTS I would like to thank all of the people that have helped make this project a reality, mainly my advisor on this journey, Dr. Mindy Faulkner. If she hadn’t convinced me to come to graduate school I don’t know where I would be or what I would be doing, her guidance throughout this project has been unparalleled. I would also like to thank Dr. Kevin Stafford for all of his help on this project as well, I know I annoyed him with all of my diagenesis and thin section questions. Many of my friends and fellow graduate students helped in the field collecting samples and data, thank you to Colby Reece, Jessica Shields, Kaleb Henry, and Heather Dailey. I would also like to thank Charles Pekins, who was our liaison on the base, none of this work is possible without his cooperation and his desire for scientific research within the base. The Department of Geology also deserves a big thank you, my work isn’t possible without the department’s help and funding. Lastly I would like to thank my family and friends for their support of me furthering my education these last few years. iii TABLE OF CONTENTS Page ABSTRACT……………………………………………………………… i ACKNOWLEDGEMENTS……………………………………………… iii TABLE OF CONTENTS………………………………………………... iv LIST OF FIGURES……………………………………………………… ix LIST OF TABLES……………………………………………………….. xiii PREFACE……………………………………………………………….. xv DEPOSITIONAL ENVIRONMENT AND FACIES ANALYSES OF THE OWL MOUNTAIN PROVINCE, FORT HOOD MILITARY INSTALLATION, BELL AND CORYELL COUNTIES, TEXAS……. 1 ABSTRACT…………………………………………………...... 1 INTRODUCTION……………………………………………… 2 GEOLOGIC SETTING……………………………………….. 5 STUDY AREA……………………………………………….... 7 iv Page REGIONAL DEPOSITIONAL ENVIRONMENT…………… 10 METHODOLOGY…………………………………………….. 13 MICROFACIES ANALYSES………………………………… 17 PERITIDAL MUD FLAT MICROFACIES…………………… 17 PERITIDAL – BIOHERMAL MICRO FACIES…………….... 20 SUBTIDAL TO LAGOONAL – MOBILE GRAIN FLAT AND BACKREEF LAGOON MICROFACIES……………………… 23 OWL MOUNTAIN PROVINCE DEPOSITIONAL MODEL… 25 DIAGENETIC MODEL………………………………………… 32 CONCLUSIONS……………………………………………….. 36 REFERENCES………………………………………………… 39 APPENDIX (A) EXTENDED PREVIOUS WORKS………………… 42 PREVIOUS MODELS 42 APPENDIX (B) MEASURED SECTIONS …………………………… 48 v Page MAP OF MEASURED SECTION LOCATIONS...…………… 49 SECTION 1………………………………………………........... 50 SECTION 2……………………………………………….......... 51 SECTION 3…………………………………………………...... 52 SECTION 4…………………………………………………...... 53 SECTION 5…………………………………………………….. 54 SECTION 7…………………………………………………….. 55 SECTION 8…………………………………………………….. 56 SECTION 9…………………………………………………….. 57 SECTION 10…………………………………………………… 58 SECTION 11…………………………………………………… 59 SECTION 12…………………………………………………… 60 SECTION 13…………………………………………………… 61 vi Page SECTION 14…………………………………………………… 62 SECTION 15…………………………………………………… 63 SECTION 16…………………………………………………… 64 APPENDIX (C) THIN SECTION ANALYSES……………………… 65 MAP OF THIN SECTION LOCATIONS…………………….. 66 JM01................................................................................... 67 JM02................................................................................... 68 JM03................................................................................... 69 JM04................................................................................... 70 JM05.................................................................................... 71 JM06.................................................................................... 72 JM07.................................................................................... 73 JM08.................................................................................... 74 vii Page JM09................................................................................... 75 JM10................................................................................... 76 JM11................................................................................... 77 JM12................................................................................... 78 JM13................................................................................... 79 JM14................................................................................... 80 JM15................................................................................... 81 VITA.............................................................................................. 82 viii LIST OF FIGURES Page Figure 1: Paleogeographic map of Texas during the Cretaceous. Light blue = shallow water, dark blue = deeper water, green = Kirschberg 4 Lagoon……………………………………………………………............. Figure 2: Map showing Fort Hood Military Installation in green with Owl Mountain Province in light blue, city of Killeen, major highways, and 9 counties labeled, source: ArcGIS online database…………………… Figure 3: Regional depositional model for the greater Killeen area during the Cretaceous, study area outlined in red (modified from Kerr 12 1977 and Brown 1975). .................................................................... Figure 4: Map showing the location of each measured section within the 15 study area, source: ArcGIS online database………………………… Figure 5: Measure section 8 drafted in Adobe Illustrator, showing the 16 vertical transitions between subtidal/lagoonal to peritidal facies….. Figure 6: Microphotographs of the mudflat microfacies……………. 19 Figure 7: Outcrop photo showing nodular chalky beds (zone A) and 20 massive crystalline beds (zone B)……………………………………. Figure 8: Microphotographs of the bioherm microfacies…………… 22 ix Page Figure 9: Microphotographs of the mobile grain flat microfacies….. 25