GEOCHEMISTRY OF UPPER DEVONIAN PALEOSOLS FROM THE CATSKILL FORMATION, APPALACHIAN BASIN, NORTH-CENTRAL PENNSYLVANIA

The late Devonian is a dynamic period in earth’s history to study climate—characterized by the apex of the Acadian orogeny, the onset of the Late Paleozoic ice age (LPIA), and the diversification/evolution of terrestrial life prior to major loss of biodiversity at the Devonian-Carboniferous boundary. The Acadian (pre-Appalachian) mountains of Laurentia were close to the equator (0-30°S), making hypotheses of late Devonian glaciation in such paleohighlands controversial.

The upper Devonian (upper Famennian) Catskill Formation redbeds in the Appalachian foreland basin (north-central Pennsylvania) record erosion of the Acadian mountains. These strata have been described in detail and studied with a focus on fluvial architecture and the diverse vertebrates preserved within. We present the stratigraphic context and preliminary geochemical analysis of abundant and well-developed paleosols in the Catskill Formation that preserve evidence of late Devonian terrestrial (to transitional, marginal-marine) climate during this interval. Previous sedimentological studies report glacial deposits within ~20 to ~100 km of the sampled sites, but companion paleoclimate data, including geochemical data from paleosols, are generally lacking. Ten paleosols from outcrop (Tioga County, PA) and four paleosols from core (Lackawanna County, PA) were sampled and processed to remove carbonate prior to complete (whole rock and trace element) geochemical characterization. Using various paleo-weathering indices, we assess whether the paleoclimatic conditions recorded on land (temperature, precipitation, degree of chemical weathering) are consistent with a glaciogenic landscape in the Appalachian hinterland. New geochemical data from Appalachian Basin Catskill Formation paleosols provide insight for understanding the nature of ecological and climatic events on land that may play a role in the lead up to the upper Devonian mass extinction.