During the Middle to Late Devonian, increased forest evolution was a catalyst for an array of environmental changes. This idea, known as the Devonian Plant Hypothesis, proposed that the abundance of root systems in terrestrial forests enhanced extraction of nutrients in the soil at an accelerated rate and led to their flux to marine settings which caused marine eutrophication, biotic crises, and global climate change. The organic matter would either decay or be preserved (as black shale) based on the conditions of the marine environment (oxic vs. anoxic). In the resulting black shale succession, elemental abundance should correspond to the degree of oxygenation of the seafloor and correspondingly organic matter preservation, meaning that elemental abundances can be used to infer paleoredox conditions and organic matter concentration. Identification of trace metal relationships can then be used as proxies or future studies of similar strata.

Samples were collected from the L-14 core in Allen County, KY, which is on the edge of the Cincinnati Arch and margin of the Illinois Basin. The samples were collected and powdered using a shatter box. The powdered samples were analyzed by pXRF to collect data for different elements. The elements that are hypothesized to help with constraining paleoredox and organic matter concentrations are Potassium, Thorium, Molybdenum, and Uranium. These elements are indicators of different types of marine environments. The next steps will be creating elemental profiles for each of these elements to figure out if there is any correspondence with Total Organic Carbon and Gamma Ray Log data. Different element proxies will either be validated or invalidated based on the results of this study.