16 From Thin Section to Outcrop: Exploration of Undergraduate Research (Posters)

This session is designed to showcase undergraduate research across all disciplines. All submissions should be written by the student(s) and include a faculty co-author. Categories: Cross-Disciplinary, all topics welcome

Sunday, 22 March 2026
1:30 PM - 5:30 PM
CCC, Ballroom C

Neoproterozoic chemical weathering trends in Death Valley, California

Paper number: 16-6
Program: Technical Sessions
Time: 1:30 PM – 1:30 PM

Authors

Abstract

Two episodes of global glaciation, the Sturtian and Marinoan, followed by non-glacial greenhouse intervals, occurred during the Cryogenian Period of the Neoproterozoic Era, supported by sequences of low-latitude glacial deposits overlain by carbonate-bearing strata. These glaciations are hypothesized to have been triggered by increases in silicate weathering during the fragmentation of the supercontinent Rodinia. After millions of years of glaciation, the snowball Earth hypothesis posits the climate transitioned from icehouse to greenhouse climate states due to the build-up of CO₂ from volcanic activity accompanied by reduced silicate weathering sinks. Post-glacial super greenhouse climates were subsequently stabilized by increased silicate weathering and CO2 drawdown. Cryogenian successions deposited within Death Valley, CA locally record both cryochrons and their post-glaciation aftermaths. Here, we test the hypothesized changes in continental weathering associated with these dramatic climate transitions through geochemical analyses of carbonate and mudrock units within late Tonian, Cryogenian, and early Ediacaran strata. Major-element compositions of shale were used to calculate the Chemical Index of Alteration (CIA) and quantify changes in local chemical weathering intensity in the tropics. Leached carbonate samples were analyzed for strontium isotope ratios to provide constraints on global continental weathering relative to hydrothermal influx, while also enabling chemostratigraphy. Carbon isotope data provide further chemostratigraphic correlation and constraints on carbon cycling. Together, these proxies help to constrain secular changes in continental silicate weathering during the Neoproterozoic, a critical factor in the global carbon cycle and climate regulation.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411316

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