Golden olden days of the Ordovician, Silurian Seas, and Pleistocene Ice: An introduction to the geology of the Dayton, Ohio, area
Michael R. Sandy, 2012. "Golden olden days of the Ordovician, Silurian Seas, and Pleistocene Ice: An introduction to the geology of the Dayton, Ohio, area", On and around the Cincinnati Arch and Niagara Escarpment, Michael R. Sandy, Daniel Goldman
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This article is aimed at providing an overview of the geology of the Dayton region to those who seek an introduction to Dayton’s geological story. The oldest rocks exposed in the area are Ordovician (Katian Stage, Cincinnatian Series in local North American usage) in age, and are world famous for the quantity and quality of their fossils. Unconformably overlying the Ordovician strata are Silurian (Llandovery–Wenlock Series) dolomites, limestones, and shales, which represent tropical seas that were at times rich in crinoids, corals, brachiopods, and other invertebrates. A large time gap (unconformity) in the rock record of some 420+ million years occurs between the Silurian and the Pleistocene “Ice Age” deposits of the area. Significant changes to the natural environment in the Dayton area have occurred during the Anthropocene.
A number of localities that can be reached within about 30–40 minutes from downtown Dayton are described. This is effectively Montgomery County and adjacent counties. As such this treatment is brief and not meant as a compendium but as an introduction and outline of Dayton’s geology and geological history. The localities selected illustrate Dayton’s geological heritage, from the Ordovician to the Pleistocene, while several of the area’s distinctive natural landmarks are discussed. A number of the landforms are expressions of the Niagara Escarpment, where resistant Silurian limestones and dolomites overlie less resistant older rocks.
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This volume, produced in conjunction with the GSA North-Central Section Meeting held in Dayton, Ohio, April 2012, has a mix of papers, ranging from stratigraphy, paleontology, and hydrogeology, to geomorphology, drainage basins, and building stones. The geographic spread of the chapters focuses mainly on an area bounded by those counties adjacent to Montgomery County, but also extends beyond-from Paulding County in the north to Georgetown, Kentucky, in the south. Topics include the Silurian stratigraphy of southwestern Ohio, drainage basins of the Mad River and Little Miami River, the relationship between geology and groundwater of the Inner Bluegrass Region, Kentucky (and its connection to the distilling and aging of bourbon), and the building stones of Dayton, as well as an introduction to the geology of the Dayton area.