Delaney Leigh McCarthy ’21 Examines Devonian Organic Matter Variability within the Appalachian Basin
The Devonian Plant Explosion, when plants increased in diversity and abundance during the Middle to Late Devonian, is known to have had a wide range of effects on Earth systems. Terrestrial floral ecosystems went from rock-covering moss to multi-storied forests with trees reaching up to 30 meters high. This shift, which increased nutrient flux into nearby oceans, resulted in a global increase in black shale deposition.
This project aims to better characterize Middle-Late Devonian (Givetian-Fransian) terrestrial to marine organic matter flux by analyzing the geochemical composition of the marine black shale. Total Organic Carbon (TOC), δ13C, and biomarker analysis of samples from two localities in the Appalachian Basin will be used to test the hypotheses that terrestrial biomass input decreases as proximity to open-ocean settings increases, and terrestrial biomass input to marine settings increases through time.
Humans today are drastically changing the carbon cycle and are thought to have initiated the next mass extinction. This project will allow a better understanding of carbon cycle changes during the Devonian, therefore providing a baseline for large-scale changes to the Earth System that can provide context for the unprecedented Anthropogenic changes occurring today.