English: Shales over carbonates in the Devonian of Kentucky, USA.

The outcrop seen here consists of the basal-preserved beds of the New Albany Shale unconformably overlying carbonates of the Duffin Limestone - both are Devonian in age. The shales are dolomitic and are part of the Trousdale / Blocher Member. A lag unit is present between the Trousdale and the Duffin. The top of the lag unit is subplanar at outcrop scale and the bottom of the lag unit has outcrop-scale paleotopography (see figure 2.3.3 of Schieber & Lazar, 2004). The lag consists principally of a mix of detrital dolomite, quartz sand, and silicified / chertified fossil fragments. The Duffin rocks underlying the lag are calcareous-dolomitic sandstones with some crystal-lined vugs. Duffin sediments are probably reworked from the Boyle Formation, which occurs underneath the Duffin.

Stratigraphy: Trousdale / Blocher Member (New Albany Shale / Ohio Shale / Chattanooga Shale, Givetian Stage, upper Middle Devonian) over the Duffin Limestone (Givetian Stage, upper Middle Devonian)

Locality: roadcut on the eastern side of Route 127, just south of Bowens Road intersection & just north of bridge over Harris Creek, ~3 miles south of Junction City, northwestern Lincoln County, central Kentucky, USA (37˚ 32.619’ North latitude, 84˚ 48.135’ West longitude) (= Stop 3A of Schieber & Lazar, 2004, pp. 24-29)

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Synthesized from:

Schieber, J. & R. Lazar (eds.). 2004. Devonian black shales of the eastern U.S. New insights into sedimentology and stratigraphy from the subsurface and outcrops in the Illinois and Appalachian Basins. Field Guide for the 2004 Annual Field Conference of the Great Lakes Section of SEPM. Indiana Geological Survey Open-File Study 04-05. 90 pp.