Silurian) in Western Ohio and Eastern Indiana
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Conodont Biostratigraphy and δ13C Chemostratigraphy of the Salina Group (Silurian) in Western Ohio and Eastern Indiana Master’s Thesis Presented in Partial Fulfillment of the Requirements for the Degree of Master of Science in the Graduate School of The Ohio State University By Robert James Anthony Swift, B.A. Graduate Program in Geological Sciences The Ohio State University 2011 Master’s Committee: Dr. Mark A. Kleffner, Advisor Dr. William I. Ausich Dr. Matthew R. Saltzman Copyright by Robert James Anthony Swift 2011 Abstract The Salina Group type area in New York State is well defined, but strata assigned to the Salina Group in Ohio and Indiana may not actually correlate in age or depositional equivalence with the New York units. The integrated tools of bio- and chemostratigraphy, with the well-studied lithostratigraphy, are enabling Paleozoic workers around the world to better constrain regional units in time and space. For the Wenlock and Ludlow, the Mulde and Lau δ13C excursions can be used as correlative tools. A well developed conodont biozonation has also been applied successfully in North America. Four localities were sampled and processed for conodont biostratigraphy and δ13C stratigraphy. Two localities were sampled on the eastern flank of the Cincinnati Arch, one was sampled on the western flank of the Arch, and the fourth was a core drilled in northern Indiana that penetrates the Salina Group some 800 ft underground. The strata from two Ohio localities contained conodonts that can be used as age indicators. Duff Quarry (Huntsville, Ohio) yielded a fauna comprised of Ozarkodina species of O. confluens affinity and Oulodus species. In each case, comparisons to previous work indicate an age of late Ludlow to early Pridoli. Con Ag Quarry (St. Mary’s, Ohio) yielded Pseudooneotodus linguicornis, and also the Mulde δ13C excursion in the Greenfield Dolomite, which leads to a conclusive age for the Greenfield Dolomite of Homerian. The Waldron Member of the Pleasant Mills Formation in Indiana contains ii the Mulde δ13C excursion, as expected due to its stratigraphic position and reports of the Mulde in the Waldron Member outside Indiana. Salina Group strata in northeastern Indiana have an age of Homerian and younger, according to the excursion and conodonts from the HA7 Core. This is supported by the positioning of the Mulde excursion within the oldest anhydrite-hosting portion of that core as well as zonal conodonts appearances including Ozarkodina bohemica longa and Ozarkodina snajdri. iii Acknowledgments My thanks go out to my advisor, Dr. Mark Kleffner, for the assistance and mentoring that introduced me to this project and enabled me to complete it. Dr. Jim Barrick at Texas Tech University was responsible for all isotopic analyses, and I owe him huge thanks for processing all samples in an extremely timely manner. I would like to thank The School of Earth Sciences at The Ohio State University for granting me with a Graduate Teaching Associateship and the Carman Fellowship for support in the summer of 2011. Funds from National Science Foundation Grants EAR-0517976 and EAR- 0517929 were used for laboratory materials and procedures. Lastly, my thanks go out to all faculty and students who have assisted me in the completion of my Master’s degree. These people include (but are not limited to): Dr. Matt Saltzman, Dr. Peter Webb, Dr. Larry Krissek, Alyssa Bancroft, Dr. Brad Cramer, Alexa Sedlacek, Cole Edwards and, certainly not least, Dr. Bill Ausich. iv Vita 2004................................................................Eton College, Windsor, United Kingdom 2009................................................................B.A. Geology, Trinity College Dublin, Ireland 2009 to present ..............................................Graduate Teaching Associate, School of Earth Sciences, The Ohio State University Fields of Study Major Field: Geological Sciences v Table of Contents Abstract __________________________________________________________________ ii Acknowledgments __________________________________________________________ iv Vita ______________________________________________________________________ v Table of Contents ___________________________________________________________ vi List of Figures ____________________________________________________________ viii List of Tables ______________________________________________________________ ix Introduction _______________________________________________________________ 1 Stratigraphic Summary _____________________________________________________ 4 Methods _________________________________________________________________ 12 Results ___________________________________________________________________ 18 Western Ohio ___________________________________________________________________ 18 Eastern Indiana __________________________________________________________________ 25 Discussion ________________________________________________________________ 32 Western Ohio ___________________________________________________________________ 32 Eastern Indiana __________________________________________________________________ 35 Conclusions ______________________________________________________________ 37 References _______________________________________________________________ 40 Conodont Plates ___________________________________________________________ 44 vi Appendix A: Conodont Taxonomic Discussion and Explanation of Nomenclature ____ 54 Appendix B: Conodont Processing Data _______________________________________ 60 Appendix C: Conodont Distribution Data _____________________________________ 65 Appendix D: Locality Information ___________________________________________ 71 Appendix E: Data Tables and Cross Plots of Isotopic Analysis Data ________________ 73 Appendix F: Details from 10MK3 Core _______________________________________ 85 vii List of Figures Figure 1 - A generalized conodont and δ13C stratigraphy of the study period. .................. 3 Figure 2 - Surface geology map of the North American Midwestern Basins and Arches region .................................................................................................................................. 5 Figure 3 - Stratigraphic positions of Salina Group Cincinnati Arch units. ......................... 6 Figure 4 - Silurian Stratigraphy of the Midwestern Basins and Arches Region ................. 8 Figure 5 - Stratigraphic positions of Cincinnati Arch units on the western flank .............. 9 Figure 6 - δ13C and conodont data from Con Ag Quarry.................................................. 21 Figure 7 - δ13C and conodont data from Duff Quarry....................................................... 24 Figure 8 - δ13C and conodont data from Anderson Falls. ................................................. 27 Figure 9 - δ13C and conodont data from the HA7 Core. ................................................... 31 Figure 10 – Biochemostratigraphy of the Salina Group of western Ohio and eastern Indiana based on the conclusions of this report ................................................................ 39 Figure 11 - Representative portion of 16 m – 12 m depth in the 10MK3 core. ................ 85 Figure 12 - Transition zone (~12m deep in 10MK3 core). ............................................... 86 Figure 13 - 9.3m below ground surface in core. ............................................................... 87 Figure 14 - 8.6m below ground surface in core. ............................................................... 88 Figure 15 - 4.2 m below ground surface in core. .............................................................. 89 Figure 16 - 1.3m below ground surface in core. ............................................................... 90 viii List of Tables Table 1 - Conodont retrieval data from the HA7 Core ..................................................... 60 Table 2 - Conodont retrieval data from Duff Quarry strata .............................................. 63 Table 3 - Conodont retrieval data from Con Ag Quarry strata ......................................... 64 Table 4 - Conodont distribution data from Duff Quarry................................................... 66 Table 5 - Conodont distribution data from Con Ag Quarry .............................................. 67 Table 6 - Conodont distribution data from the HA7 Core ................................................ 68 Table 7 : Locality information for sections featured in this report ................................... 72 Table 8 - Isotopic analysis data and cross plot from 09MK1 - Con Ag Quarry ............... 73 Table 9 - Isotopic analysis data and cross plot from 10MK3 - Con Ag Quarry core ....... 74 Table 10 - Isotopic analysis data and cross plot from 10MK1/2 – Duff Quarry .............. 76 Table 11 - Isotopic analysis data and cross plot from 10MK5 - Duff Quarry .................. 78 Table 12 - Isotopic analysis data and cross plot from 08MK2 - Anderson Falls .............. 79 Table 13 - Isotopic analysis data and cross plot from HA7 Core ..................................... 81 ix Introduction The Silurian Period has attracted attention in recent years as a time of extreme paleoclimate cycles. Successions that were once impossible to subdivide now yield some of the most easily-recognizable stratigraphic markers in the Paleozoic. Thick successions of carbonates and shales were deposited containing abundant bio- and chemostratigraphic markers, and the resolution of Silurian divisions becomes finer as more workers