GSA Connects 2023 Meeting in Pittsburgh, Pennsylvania

Paper No. 105-8
Presentation Time: 8:00 AM-5:30 PM

IS THERE EVIDENCE OF THE CARNIAN PLUVIAL EVENT WITHIN CENTRAL NEVADA? SEARCHING FOR NEGATIVE CARBON-ISOTOPIC EXCURSIONS IN THE CARNIAN STAGE (UPPER TRIASSIC) STAR PEAK GROUP, NEVADA


JORGENSEN, Maren, Department of Geological Sciences, California State University, Fullerton, 800 N. State College Blvd., Fullerton, CA 92831, BONUSO, Nicole, Geological Sciences, California State University, Fullerton, Department of Geological Sciences, MH-254, 800 N. State College Blvd, Fullerton, CA 92831 and LOYD, Sean, Department of Geological Sciences, California State University, Fullerton, Fullerton, CA 92831

The Carnian Pluvial Event (CPE) demonstrates major climatic alteration during the Late Triassic Carnian age (~235 MYA). Multiple negative carbon isotopic excursions (NCIEs) throughout the CPE produced environmental conditions oscillating between humid and arid. This shift in climate caused a significant loss of biodiversity and restructuring of ecosystems. Most Late Triassic NCIE studies focus on the Tethys region of Pangea (Arabian plate, North Africa, and parts of Southern Eurasia). Still, data are lacking for the Panthalassa region (North America, South Africa, and some of Northern Eurasia).

This research aims to find more evidence of the CPE by analyzing carbon-13 isotopes (𝜹13C) from three newly measured sections within central Nevada: East Range, Mill City, and Fossil Hill. 𝜹13C was measured using Cavity-Ringdown spectroscopy. Preliminary results for this study show a 2.8‰ NCIE occurring in the East Range, 2.5‰ NCIE in Mill City, and 2.7‰ NCIE in Fossil Hill within the timeframe of the CPE. These data correspond with the 2.4‰ NCIE previously recorded in South Canyon, NV by Bonuso et al. in 2018 - one of the first studies to find a NCIE in the Panthalassa region.