Geological Note 14 High-Resolution Subsurface Correlation of Late Ordovician–Wenlock (Silurian) Strata in Southeastern Ohio by Christopher B. T. Waid STATE OF OHIO DEPARTMENT OF NATURAL RESOURCES DIVISION OF GEOLOGICAL SURVEY Michael P. Angle, Interim Chief Columbus 2018 ODNR DIVISION OF GEOLOGICAL SURVEY (614) 265-6576 2045 MORSE RD., BLDG. C-1 (614) 447-1918 (FAX) [email protected] COLUMBUS, OHIO 43229-6693 www.OhioGeology.com SCIENTIFIC AND TECHNICAL STAFF OF THE DIVISION OF GEOLOGICAL SURVEY Administration Michael P. Angle, MS, Interim State Geologist and Division Chief May Sholes, MBA, Financial Analyst Supervisor Geologic Mapping & Industrial Minerals Group J. D. Stucker, MS, Geologist Supervisor Douglas J. Aden, MS, Geologist Mohammad Fakhari, PhD, Geologist Franklin L. Fugitt, BS, Geologist Melinda Higley, PhD, Geologist T. Andrew Nash, MS, Geologist Brittany D. Parrick, BS, Geology Technician Christopher E. Wright, MS, Geologist Ground Water Resources Group James M. 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Peter, MS, Paleontologist An Equal Opportunity Employer - M/F/H High-Resolution Subsurface Correlation of Late Ordovician– Wenlock (Silurian) Strata in Southeastern Ohio by Christopher B. T. Waid Geological Note 14 STATE OF OHIO DEPARTMENT OF NATURAL RESOURCES DIVISION OF GEOLOGICAL SURVEY Michael P. Angle, Acting Chief Columbus 2018 Disclaimer: The statements, findings conclusions and recommendations are those of he author and do not necessarily reflect the view of the Ohio Department of Natural Resources. Editing: Charles R. Salmons Graphic design and layout: David S. Orr Front cover: Exposure of the thin-bedded Brassfield Formation along Lick Fork Creek in Adams County, Ohio. Photo by Charles Salmons Recommended bibliographic citation: Waid, C.B.T., 2018, High-resolution subsurface correlation of Late Ordovician– Wenlockian (Silurian) strata in southern and southeastern Ohio: Columbus, Ohio, Department of Natural Resources, Division of Geological Survey Geological Note 14, 34 p., 5pl. CONTENTS Abstract .......................................................................................................................................................................1 Introduction .................................................................................................................................................................1 Geological and environmental background .........................................................................................................4 Sequence stratigraphy ..........................................................................................................................................5 Silurian stratigraphy of Ohio ................................................................................................................................6 Previous work: Overview of surface and subsurface stratigraphy ..................................................................................7 Surface units........................................................................................................................................................7 Drakes Formation ..........................................................................................................................................7 Centerville Formation ....................................................................................................................................7 Brassfield Formation ......................................................................................................................................7 Belfast Member .......................................................................................................................................7 Lower massive, thin bedded, and upper shaly Brassfield .........................................................................8 Upper massive Brassfield (Rose Run iron ore) ..........................................................................................8 Drowning Creek Formation ...........................................................................................................................9 Plum Creek Shale Member ......................................................................................................................9 Oldham Member ....................................................................................................................................9 Alger Formation ............................................................................................................................................9 Lulbegrud Member ..................................................................................................................................9 Waco Member ......................................................................................................................................10 Estill Member ........................................................................................................................................11 Noland Formation .......................................................................................................................................11 Bisher Formation .........................................................................................................................................11 Subsurface units ................................................................................................................................................11 Medina sand ...............................................................................................................................................11 “Clinton sands” ...........................................................................................................................................12 Packer Shell .................................................................................................................................................12 Cabot Head Shale .......................................................................................................................................12 Rochester Shale ...........................................................................................................................................12 Methodology and results ...........................................................................................................................................12 Building the Adams County composite gamma-ray curve ..................................................................................12 Cross sections ...................................................................................................................................................14 Discussion .................................................................................................................................................................14 Comparison of Adams County and Aristech core gamma curves........................................................................14 Regional correlation ..........................................................................................................................................16 Proposed nomenclature revisions ......................................................................................................................19 Conclusions ...............................................................................................................................................................21 Acknowledgements ...................................................................................................................................................22 References cited ........................................................................................................................................................22 Appendix A Spectral gamma-ray data from Adams County ........................................................................................27 FIGURES 1. Correlation and nomenclature chart for exposed Silurian of southern Ohio ...........................................................2 2. Nomenclature chart for the subsurface of Ohio and surrounding regions ...............................................................2 3. Paleogeographic and study area maps ...................................................................................................................3 4. Generalized correlation diagram of Silurian strata in Adams, Scioto, and Athens Counties ....................................4 5. Chronostratigraphic diagram of the lower part of the Silurian System