The environment of deposition of the Ohio Shale of the Appalachian Basin has been studied extensively using various geochemical proxies for each of its members. The accumulation of organic matter (OM) and its preservation in the Late Devonian-Early Mississippian black shales of central Kentucky have been studied extensively, especially the possible correlations between trace metal contents and water-column oxygenation. Previous work has centered on geochemical, petrographic, and isotopic analysis of samples collected throughout the central Appalachian Basin. Mechanisms for OM preservation include high productivity, enhanced preservation due to dysoxic or anoxic bottom waters, and a feedback loop due to high productivity that creates enhanced preservation through the periodic cycling and scavenging of essential nutrients. Usually, a combination of these factors results in the accumulation of enough OM to produce these black shales. This research shows the relationships between trace metal data and the environment of deposition of several cores taken along the eastern side of the Cincinnati Arch in the central Appalachian Basin. Whereas the indices do not all agree in every instance across the breadth of the study area, analyzed together a predominant environment of deposition has been inferred for the shales. The Sunbury Shale and upper part of the Cleveland Member of the Ohio Shale were deposited under euxinic conditions, the lower part of the Cleveland Member was likely euxinic in the northern study region and anoxic throughout the central and southern study areas, whereas the Huron Member of the Ohio Shale was deposited under a range of conditions, from oxic, to dysoxic, to anoxic.

The Late Devonian-Early Mississippian-age New Albany Shale is both a source rock and reservoir rock for hydrocarbons in the Illinois Basin. Previously suggested models for organic carbon enrichment consider productivity, anoxia, and the interdependent roles of sedimentation, primary production, and microbial metabolism. This study attempts to reconstruct paleoenvironmental conditions during deposition and re-evaluates these models using geochemical data from multiple cores across the eastern edge of the Illinois Basin in west-central Kentucky. Geochemical methods utilizing redox-sensitive major elements (C, S, Fe, P, K, Ti, and Si), trace elements (V and Mo), and ratios (Ni/Co, V/Cr, and V/(V+Ni) are used. Analysis of paleo-redox indicators suggests variable bottom-water conditions during accumulation of the New Albany Shale members including: anoxic to possibly euxinic conditions for the Clegg Creek Member, anoxic to periodically dysoxic conditions for the Camp Run, and dysoxic to oxic (normal marine) for the Morgan Trail and Blocher Members. Variability in redox proxy results suggests that multiple parameters should be utilized in such studies rather than relying on a single proxy. High C/P ratios observed in these members may be controlled by regeneration of P, enhanced productivity, and sequestration of organic carbon (the productivity-anoxia feedback (PAF) mechanism) under anoxic conditions. The lack of correlation between organic carbon content and clastic-influx proxies suggests that organic matter (OM) accumulation was not controlled by sedimentation rate or increased nutrient supply associated with increased sediment influx.