Sedimentary structures and composition in the New Albany and Chattanooga Shales (Devonian) along the western flank of the Cincinnati arch in Kentucky help define seven lithofacies. These lithofacies, recognized by x-radiography, are: (1) organic-rich laminated shale, (2) bioturbated greenish-gray shale, (3) indistinctly laminated greenish-gray shale, (4) siltstone, (5) fine-grained sandstone, (6) carbonate, and (7) authigenic mineral phases. The organic-rich laminated shale is dominant and can be divided into three subfacies: (a) organic-rich thinly laminated shale, (b) organic-rich thickly laminated shale, and (c) organic-rich laminated shale with current stratification. This current stratification is in the form of discontinuous laminae, ripples, cross-beds, and scour s rfaces. The carbonate and authigenic mineral phases refer to early (diagenetic?) formation of carbonates, sulfates, sulfides, and phosphates.

Areal and vertical distribution of these lithofacies in the New Albany and Chattanooga Shales in western-central Kentucky are interpreted to show the influence of the paleo-Cincinnati arch. The organic-rich, thinly laminated shale is dominant in the basins on the flanks of the arch and occurs on the arch. This facies records episodic deposition in quiet, anaerobic waters. The organic-rich thinly laminated shale with current stratification is dominant on the arch and is interpreted as evidence of episodic deposition in an anaerobic environment with weak bottom currents. Indistinctly laminated, greenish-gray shale and bioturbated greenish-gray shale facies are representative of a dysaerobic environment. Siltstone and fine-grained sandstone facies are also present in small amounts, mainl near the base of the section. Carbonate and authigenic minerals are indicators of paleosalinity, oxygen content, and conditions of Eh, and support interpretations of the other associated lithofacies.

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