HIGH FREQUENCY SEQUENCE STRATIGRAPHIC CONTROLS ON STRATAL ARCHITECTURE OF AN UPPER PENNSYLVANIAN “REGRESSIVE LIMESTONE” (BETHANY FALLS LIMESTONE), MIDCONTINENT, USA By GRAHAM J. BUTLER, B.S. A THESIS IN GEOSCIENCES Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE Approved Dr. Peter Holterhoff Chairperson of the Committee Dr. James E. Barrick Dr. George Asquith Dr. Peggy Gordon Miller Interim Dean of the Graduate School December, 2010 Copyright 2010, Graham James Butler All Rights Reserved Texas Tech University, Graham Butler, December 2010 ACKNOWLEDGEMENTS I would like to thank Dr. Peter Holterhoff, Dr. Jim Barrick, and Dr. George Asquith for standing on my committee and for being not only mentors but friends. Special thanks are due to Dr. Steven Rosscoe for sacrificing many of his valuable weekends to share his expertise on Mid-Pennsylvanian conodonts. To the Texas Tech Geosciences Department I would like to thank everyone for their assistance and specifically James Browning for his cutting of thin sections. Lastly, I would like to thank my friends, family, and fiancée for their endless support and assistance in every way possible. Without you all, it may never have been finished. ii Texas Tech University, Graham Butler, December 2010 TABLE OF CONTENTS ACKNOWLEDGEMENTS ii ABSTRACT vi LIST OF TABLES viii LIST OF FIGURES ix CHAPTER I. INTRODUCTION 1 II. BACKGROUND INFORMATION 4 2.1 The Cyclothem Model 4 2.2 Sequence Stratigraphy 8 2.2.1 The Falling Stage Systems Tract 12 2.2.2 Clarification of Common FSST Terms 15 2.3 Sequence Stratigraphy vs. the Cyclothem Model 17 2.4 Geologic Setting and Paleogeography 19 2.5 Previous Research 25 III. METHODOLOGY 29 3.1 Sampling 29 3.2 Sample Processing 30 3.3 Data Analysis 31 IV. LITHOFACIES AND MAJOR LITHOFACIES TYPES (MFT) 33 4.1 MFT – 01: Skeletal Mudstone Facies 35 4.1.1 Major Lithofacies Description: Skeletal Mudstone 37 4.2 MFT – 02: Skeletal Wackestone Facies 39 4.2.1 Major Lithofacies Description: Skeletal Wackestone 41 iii Texas Tech University, Graham Butler, December 2010 4.3 MFT – 03: Skeletal Packstone 42 4.3.1 Major Lithofacies Description: Skeletal Packstone 43 4.4 MFT – 04: Coated Grain Facies 44 4.4.1 MFT – 04a: Ooid Grainstone (porous) 44 4.4.2 MFT – 04b: Ooid Grainstone (tight) 48 4.4.3 MFT – 04c: Ooid Wackestone-Packstone 50 4.4.4 MFT – 04d: Peloid-Ooid Grainstone-Packstone (tight) 53 4.5 Major Lithofacies Description: Coated Grainstone Facies 55 4.5.1 Ooid Grainstone Subfacies (porous) Discussion 57 4.5.2 Ooid Grainstone Subfacies (tight) Discussion 58 4.5.3 Ooid Packstone-Wackestone Subfacies Discussion 58 4.5.4 Peloid-Ooid Grainstone-Packstone Subfacies Discussion 59 4.6 MFT – 04: Shale Facies 60 4.6.1 Major Lithofacies Description: Shale Facies 61 V. CONODONT PALEOCOLOGY AND DISTRIBUTION 63 5.1 Introduction 63 5.2 Conodont Environment Interpretation 64 5.3 Conodont Results 66 5.4 Conodont Discussion 68 VI. DISCUSSION 70 6.1 HFSB vs. SB 70 6.2 Flooding events vs. Galesburg Shale 72 iv Texas Tech University, Graham Butler, December 2010 VII. SYNTHESIS 73 REFERENCES 80 APPENDICES A. MEASURED SECTIONS 87 B. OUTCROP PHOTOS 103 C. RESEARCH PHOTOS 118 D. GPS COORDINATES OF OUTCROPS 122 E. CONODONT RAW DATA 124 F. CROSS SECTION I Back Pocket G. CROSS SECTION II Back Pocket v Texas Tech University, Graham Butler, December 2010 ABSTRACT The Early Missourian (Upper Pennsylvanian) Bethany Falls Limestone (BFL) is the highstand–falling stage carbonate member of the Swope high frequency sequence as developed on the northern platform of the Mid-continent Basin. It is underlain by the condensed Hushpuckney Shale (maximum flooding surface) and is overlain by the Galesburg Shale (lowstand of the Dennis sequence). The Swope sequence is a significant hydrocarbon reservoir in the subsurface of western Kansas with outcrops of excellent reservoir analog lithofacies exposed in eastern Kansas and adjacent states. Although the BFL is often considered a uniform shallowing-upward carbonate system, we hypothesize that traceable flooding and erosion surfaces can be recognized within the BFL and that these surfaces define basinward–stepping carbonate clinothems. Recognizing this internal architecture is critical for understanding the potential controls on the deposition and diagenesis of oolite facies developed across the region within the BFL. Flooding surfaces within the BFL are recognized by mudrock (clay-rich shale) partings throughout the carbonate succession. Distinctive conodont biofacies collected from these mudrocks aid in correlation and provide some confidence in mapping these surfaces across the region, although not without some ambiguity. Correlations indicate that basinward stepping clinothem packages can be recognized within the BFL. Conodont abundances and species occurrences also aid in the determination of the depositional environments of the flooding surfaces. Proximal occurrences of the mudrock partings contain a lower abundance, lower diversity fauna compared to more distal locations along a clinoform profile. Unexpected faunas with the presence of “deepwater” vi Texas Tech University, Graham Butler, December 2010 genera and high overall abundances in the lower BFL are noted at some locations. These occurrences appear to coincide with structural highs and may represent transitional facies with the underlying condensed horizon. Distinctive lithofacies offsets and internal exposure surfaces indicate the presence of high frequency sequence boundaries within the BFL. These offsets are mappable and, like the flooding surfaces, define clinothem packages. The distribution of carbonate lithologies within these stratal packages is consistent with basinward progradation of facies throughout clinothem deposition. Using this combined knowledge it is possible to identify high frequency sequence boundaries (HFSB) within this forced regressive package. vii Texas Tech University, Graham Butler, December 2010 LIST OF TABLES 1 Research Localities' GPS Coordinates 123 2 Conodont Count Numbers (Raw Data) 125 viii Texas Tech University, Graham Butler, December 2010 LIST OF FIGURES 1.1 Stratigraphic Column of the Kansas Missourian Stage (Late Pensylvanian) (Wilke, 2000; after Miller, 1966). 3 1.2 Relationship of current continents to Pennsylvanian Midcontinent paleogeography, landmasses, and oceans (Scotese, 2002). 3 2.1.1 Ideal Kansas Cyclothem with sea-level curve (Heckel, 1986). 4 2.2.1 Chronostratigraphic vs lithostratigraphic (“layer-cake”) correlation methods. (Bashore et al., 1994). 9 2.2.2 Depositional sequence model displaying parasequences and systems tracts. (French, 1993). 9 2.2.3 Diagrams displaying aggradational and progradational clinoform packages. (Emery, 1999). 11 2.2.4 Diagram displaying the Falling Stage Systems Tract. 13 2.4.1 Close up of Midcontinent during Missourian continental flooding (Blakely, 2005). 20 2.4.2 NE Kansas and surrounding states overlaid with facies belts. (Modified after Heckel, 1978). 22 2.4.3 Base map showing outcrop localities with major regional features (Modified after Lee, 2005). Refer to Appendix V for GPS coordinates. 24 4.0.1 Typical Pennsylvanian cyclothem stratigraphy with sea level and environmental associations (Heckel, 1999). 33 4.02 Depositional facies model of Pennsylvanian low angle ramp geometries with ooid shoals. (Markello, 2008). 34 4.03 Thin section image of skeletal mudstone facies LC-KS-B4 sampled from bed four the 17mi S. of Louisburg KS outcrop. Note large brachiopod fragment. (Scale bar = 500um). 35 4.04 Polished Slab of skeletal mudstone sample LC-KS-B4. 36 ix Texas Tech University, Graham Butler, December 2010 4.05 Thin section of skeletal mudstone sample U-MO-10b collected from the base of bed 10 at the Utica, Mo outcrop. (Scale bar = 500um) 36 4.06 Cut and polished hand sample of skeletal mudstone collected from bed 10 at Utica, Mo (U-MO-B10). (Scale bar = 500um) 37 4.07 Thin section of skeletal wackestone sample LC-KS-B3-lwr collected from lower bed 3 at the outcrop 17mi S. of Louisburg, KS. Note brachiopod spine at top and ostracod near bottom. (Scale bar = 500um). 39 4.08 Hand sample of skeletal wackestone LC-KS-B3-lwr collected from the lower bed 3 at the 17mi S. of Louisburg, KS outcrop. Note the burrow-mottled fabric. 40 4.09 Thin section of skeletal wackestone sample #U-MO-B5 collected from bed 5 at the Utica, MO outcrop. Note: the fossil constituent is a brachiopod spine. (Scale bar = 500um). 40 4.10 Thin section of a brachiopod-dominated skeletal packstone collected from bed 9 at the Utica, MO outcrop (U-MO-B9). (Scale bar = 500um). 42 4.11 Cut and polished skeletal packstone slab from bed 9 Utica, MO outcrop (U-MO-B9). 43 4.12 Thin section of porous ooid-grainstone unit at Xenia, NW locality sample # XNW02. The blue epoxy = porosity. (Scale bar = 500um). 45 4.13 Cut and polished handsample of XNW02. Note bedding and porosity visible as shadows. 45 4.14 Thin section from the base of the upper ooid package at Jingo, KS. Sample # Jingo_base-top02 with porosity highlighted by blue epoxy. (Scale bar = 500um). 46 4.15 Handsample cut and polished from the lower portion of the upper ooid unit at Jingo, KS. Note the dead oil in the lower (black) portion of the handsample. 47 x Texas Tech University, Graham Butler, December 2010 4.16 Thin section from the uppermost ooid package from within a few inches of the sequence boundary. All ooids from within sample U- MO-TOPb are completely replaced with calcite contain no porosity. (Scale bar = 500um). 48 4.17 Polished handsample of the slab cut for thin section U-MO-TOP. 49 4.18 Photograph of reverse side of U-MO-TOP hand sample to show filled root casts. 49 4.19 Thin section of XNW-02 showing well preserved ooids and the minimal oomoldic porosity in a ooid wackestone-packstone. (Scale bar = 500um). 50 4.20 Close up of ooid wackestone-packstone XNW-01a showing ooid preservation.