The Cincinnati Arch region of Ohio, Kentucky, and Indiana is an icon of North American Paleozoic stratigraphy, as it exposes strata ranging from Ordovician to Pennsylvanian in age. In particular, the highly fossiliferous Ordovician, Silurian, and Middle Devonian successions have been extensively studied since the nineteenth century, and continue to serve as a crucial proving ground for new methods and models of biostratigraphy, chemostratigraphy, and sequence stratigraphy in mixed clastic-carbonate depositional settings. These strata are locally capped by Middle Devonian limestones with their own diverse fauna and unique depositional history. Outcrops near Louisville, Kentucky, provide an excellent opportunity to examine these strata firsthand and discuss sequence stratigraphy, chemostratigraphy, sedimentary environments, and paleoecology. A series of new roadcuts south of Mount Washington, Kentucky, exposes the lower to middle Richmondian Stage (Upper Ordovician, Cincinnatian) and presents a diverse suite of marine facies, from peritidal mudstones to offshore shoals, coral biostromes, and subtidal shales. These exposures are well suited for highlighting the revised sequence stratigraphy of the Cincinnatian Series, presented herein. Nearby outcrops also include much of the local Silurian succession, allowing an in-depth observation of Llandovery and Wenlock strata, including several chemostratigraphically important intervals that have improved regional and international correlation. Supplementary exposures east and north of Louisville provide context for subjacent and superjacent Ordovician-Silurian strata, as well as examples of lateral facies changes and unconformities. Additionally, the Falls of the Ohio at Clarksville, Indiana, features an exceptional outcrop of the overlying Middle Devonian succession, including an extensive and well-preserved biostrome of corals, sponges, and other marine fauna. These fossil beds, coupled with significant exposures in local quarries, are critical for understanding the paleoecology and stratigraphy of the Middle Devonian of the North American midcontinent.
|Title of host publication||GSA Field Guides|
|Number of pages||59|
|State||Published - Dec 10 2018|
|Name||GSA Field Guides|
Bibliographical noteFunding Information:
We acknowledge fieldwork assistance and valuable discussions with C.D. Aucoin, G.C. Baird, A.J. Bartholomew, M.K. DeSantis, A. Goldstein, T.J. Malgieri, G.C. McIntosh, T.J. Schramm, C.E. Schwalbach, A.L. Young, and J.J. Zambito IV, among others. Special thanks go to C.E. Schwalbach for help with certain illustrations. CEB also acknowledges the help and support of B.L. Brett; his past research on Ordovician was supported by grants from the Petroleum Research Fund, American Chemical Society, from NSF grant 0819715, and a grant from the Hess Corporation. KVB would like to thank her undergraduate research students at Bellarmine University (most notably A. Burman, S. Hall, Z. Laughlin, K. Sadler, T. Summerlin, and A. Wilcox) for dedicating many hours to fieldwork, data processing, and data analysis as a part of their undergraduate research projects. Their curiosity, drive, and dedication have pushed this research effort in many novel directions, and it is a daily privilege to work alongside these enthusiastic future scientists. Our sincere appreciation to our reviewers, J.J. Zambito IV and A.M. Bancroft, for their constructive comments. Finally, this field trip and guide was co-sponsored by the Indiana Geological and Water Survey, the Ohio Department of Natural Resources Division of Geological Survey, and the North American Commission on Stratigraphic Nomenclature; we appreciate their support of our efforts. This publication is a contribution to International Geoscience Programme (IGCP) projects 591 and 653.
© 2018 The Geological Society of America.
ASJC Scopus subject areas
- Earth-Surface Processes