137 Joint SGD-SEPM-IAS Focus on the Sedimentary Record of Climate Change
Explore how sedimentary records reveal Earth's climatic history and processes driving environmental change. This session highlights proxies, stratigraphy, and emerging technologies, advancing understanding of past climates and informing predictions of future climate dynamics through interdisciplinary collaboration.
Monday, 20 October 2025
1:30 PM - 5:30 PM
HBGCC, 303C
Donath Medal | Young Scientist Award: When and How Does Soil Carbonate Form? Using Clumped and Triple Oxygen Isotopes to Decode Terrestrial Paleoclimate Archives
Paper number: 137-1
Program: Technical Sessions
Time: 1:35 PM – 1:55 PM
Authors
Abstract
Soil carbonates provide a valuable record of terrestrial response to (paleo-)climate change. However, our ability to fully leverage their carbon and oxygen stable isotope records to reconstruct terrestrial paleoclimate hinges upon understanding the proxy: when and how do soil carbonates form? Clumped and triple oxygen isotopes are providing new insights. Clumped isotopes constrain growth temperatures, giving the "when." I will discuss the emerging consensus that soil carbonates typically form in the warm season, with significant aberrations best explained by soil grain size and rainfall patterns. The clumped isotope evidence suggests that the timing of soil carbonate formation is set by soil drying and provides a means to predict seasonal bias in paleosols. We are probing the "how" with triple oxygen isotopes. Triple oxygen isotopes record the evaporative state of soil water when carbonate forms and thus constrain the relative importance of evaporative drying versus biological factors (transpiration, respiration) in driving soil carbonate formation. I will describe results of a recent study in dryland critical zones that tests the soil-drying-paradigm in pedogenic carbonates and their parent waters. These geochemical tools were initially developed for paleoclimate but are yielding new insights into modern process, which is in turn enhancing paleoclimatic interpretations.
Geological Society of America Abstracts with Programs. Vol. 57, No. 6
doi: 10.1130/abs/2025AM-412194
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