Revised Telychian-Sheinwoodian (Silurian) stratigraphy of the Laurentian mid-continent: building uniform nomenclature along the Cincinnati Arch

 

Authors: Brett CE, Cramer BD, McLaughlin PI, Kleffner MA, Showers WJ, Thomka JR

Published in: Bulletin of Geosciences, volume 87, issue 4; pages: 733 - 753; Received 22 August 2011; Accepted in revised form 31 May 2012; Online 2 October 2012

Keywords: Indiana, Ohio, Kentucky, Silurian, chronostratigraphy, correlation,

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Abstract

Recent detailed studies of the physical, bio-, and chemostratigraphy of upper Llandovery to middle Wenlock strata of the Cincinnati Arch area, primarily SW Ohio and SE Indiana and to a lesser extent west-central Kentucky, indicate a regionally extensive pattern of units, correlatable in detail over more than 30,000 sq. km. This relatively simple stratigraphy has been obscured by the development of local names and by different usage of the same name in different areas. Herein we review and update this stratigraphical succession to provide uniform nomenclature and correlation of these units throughout the study area. The units as redefined and/or extended in this study include the Lee Creek, Dayton, Osgood, Lewisburg, Massie, and Laurel formations. Extension of the unit name Salamonie Dolomite is herein discouraged south of the Salamonie type area in NE Indiana. The term Dayton Dolostone is herein redefined; it is overlain by the Osgood Formation, which is also redefined here as equivalent to Foerste’s (1897) ‘Lower Osgood Clay’. The Lewisburg Limestone/Dolostone is reintroduced here as a formal name at the rank of formation to include a thin interval of pelmatozoan-brachiopod dolomitic pack- to grainstone formerly termed ‘Middle Osgood Limestone’ in Indiana and ‘Laurel of Ohio’ (in part) in SW Ohio. The term Massie Shale, defined in SW Ohio, is extended at formation rank throughout the study area as equivalent to the ‘Upper Osgood Clay’ and unnamed shale unit of the lower part of the Laurel (subunit 2) in Kentucky.