Geological Society of America

121 Caves and Karst Through Space and Time: Biogeochemistry, Climate, and Astrobiology

We welcome submissions on the biogeochemistry, astrobiology, and historical records in of caves and karst features.

Monday, 20 October 2025
1:30 PM - 5:30 PM
HBGCC, 211

Quantifying Cave-Internal Alterations in Speleothems using Triple Oxygen Isotopes

Paper number: 121-11
Program: Technical Sessions
Time: 4:15 PM – 4:35 PM

Authors

Annabel Wolf Presenting Author
University of Michigan, Ann Arbor, MI
Julia Cole
University of Michigan, Ann Arbor
Michael Griffiths
William Paterson University, Environmental Science, Wayne, NU
Matthew Allen
University of Michigan, Ypsilanti, MI
Jie Geng
University of Michigan, Ann Arbor, MI
Jada Langston
University of Michigan, Ann Arbor, MI
Benjamin Passey
University of MichiganEarth and Environmental Sciences, Ann Arbor, MI
Elizabeth Patterson
Lafayette College, Pennsylvania
Jonathan Baker
University of Innsbruck, Innsbruck
Kathleen Johnson
UC Irvine, Dept. of Earth System Science, Irvine, CA
David McGee
MIT, Earth, Atmos. and Planetary Sciences, Cambridge, MA

Abstract

Monsoons consist of local hydrology and large-scale monsoonal circulation, which can vary independently. This is a challenge for paleo-monsoon reconstructions, requiring careful consideration of various proxies. While stable oxygen isotopes (δ¹⁸O) in carbonates serve as one of the primary proxies for reconstructing large-scale monsoon circulation, they can be influenced by cave-internal processes, creating a bias towards local hydrological conditions. Current methods cannot separate the large-scale climate signal from localized (cave-specific) influences. This creates unexplained between-site discrepancies and leaves large uncertainties in our understanding of past climate variability. Theoretical frameworks suggest that triple oxygen isotopes (Δ'¹⁷O) can be used as a new tool to quantify nonclimatic cave-internal effects on δ¹⁸O. To evaluate the effects of strong cave-internal alterations on Δ'¹⁷O, we are using an ideal set of samples that have previously been interpreted as having altered δ¹⁸O. Although more data are needed, preliminary results suggest a positive slope caused by cave-internal processes, such as prior carbonate precipitation and/or degassing, consistent with model predictions. Triple oxygen isotopes will provide new insights into speleothem oxygen isotopes, improving our interpretation of past climate conditions. This is a crucial step in for our understanding of past climate variability, especially in monsoonal regions, where speleothems are commonly used.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-414140

© Copyright 2025 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.