Cincinnatian Series

Cincinnatian Series is a Late Ordovician stratigraphic succession notable for extensive carbonate and shale beds exposed around Cincinnati, Ohio. It has been central to nineteenth- and twentieth-century studies by institutions such as Yale University, Ohio State University, and the United States Geological Survey and has hosted field work by figures associated with Benjamin Franklin, James Hall, and later researchers from Smithsonian Institution. The succession informs correlation frameworks used by regional surveys including the Indiana Geological and Water Survey, Kentucky Geological Survey, and Tennessee Division of Geology.

Geology and Stratigraphy

The succession consists of interbedded limestones and shales deposited in a shallow epicontinental sea during the Ordovician and is a classic example used in studies by the Geological Society of America and the Paleontological Research Institution. Stratigraphic subdivisions historically invoked names applied by early workers such as Eli Whitney, Louis Agassiz, and Charles Lyell and are tied to lithostratigraphic units mapped by the Ohio Division of Geological Survey. The series includes marker beds exploited in correlation with sections investigated by researchers associated with Harvard University, University of Cincinnati, and field parties from the Royal Society and the American Museum of Natural History.

Paleontology and Fossil Content

Fossil assemblages are exceptionally rich, preserving benthic and nektonic faunas studied by paleontologists at Yale Peabody Museum, University of Michigan Museum of Paleontology, and the Field Museum of Natural History. Common taxa include brachiopods comparable to those cataloged in works by James Hall and E. O. Ulrich, trilobites discussed in monographs from Lehigh University collections, bryozoans examined in publications from Cornell University, and cephalopods paralleled in holdings of the American Museum of Natural History. Trace fossils and microbialites from exposures cited by researchers at Princeton University and Columbia University contribute to paleoecological reconstructions used in studies by the National Academy of Sciences.

Age and Correlation

Biostratigraphic and conodont data tie the succession to the late Katian and possibly early Hirnantian stages of the Ordovician Period, as integrated in regional chronologies maintained by the International Commission on Stratigraphy and referenced by the British Geological Survey. Correlations have been drawn between these strata and contemporaneous successions in the Appalachian Basin, the Michigan Basin, and Laurentian sequences studied by teams from University of Toronto and McGill University. Isotope stratigraphy and chemostratigraphic work by groups at Scripps Institution of Oceanography and Lamont–Doherty Earth Observatory have been used to compare climatic signals against global events recorded in archives at the Natural History Museum, London and the Muséum national d'Histoire naturelle.

Regional Distribution and Lithology

Exposures are widespread across southwestern Ohio, southeastern Indiana, and northern Kentucky, extending into northeastern Tennessee where strata are logged by personnel from the Tennessee Division of Geology and mapped in collaboration with the Indiana Geological Survey. Lithologies range from oolitic and bioclastic limestones to calcareous shales; sedimentological studies by teams from University of Chicago and University of Illinois Urbana-Champaign document cyclicity comparable to rhythms reported by investigators at the Massachusetts Institute of Technology. Dolomitization, stylolitization, and diagenetic fabrics have been interpreted in isotopic studies produced with support from National Science Foundation grants and in petrographic work connected to the Carnegie Institution for Science.

Economic and Scientific Significance

Locally the succession has been a source of building stone and aggregate used historically by municipalities such as Cincinnati, Ohio and industries documented by the U.S. Bureau of Mines; quarrying histories intersect with industrial archives at the Library of Congress and regional historical societies. Scientifically, the succession has served as a teaching and research locale for generations of geologists from Ohio State University, University of Cincinnati, and Miami University (Ohio), and continues to supply type material to museums including the Cincinnati Museum Center, Yale Peabody Museum, and the Smithsonian Institution. Ongoing research linked to projects at National Oceanic and Atmospheric Administration and the American Geophysical Union uses the succession to address questions of Ordovician paleoecology, sea-level change, and mass-extinction dynamics examined in syntheses by the International Union of Geological Sciences.

Category:Ordovician geology of the United States