158 Redox-Driven Nutrient and Contaminant Dynamics in Terrestrial Systems

Redox sensitive environments and nutrient and metalloid cycling in natural waters.

Tuesday, 21 October 2025
8:00 AM - 12:00 PM
HBGCC, 210AB

Characterizing uranium speciation in pedogenic carbonates shows strong heterogeneity

Paper number: 158-7
Program: Technical Sessions
Time: 9:38 AM – 9:53 AM

Authors

Abstract

Understanding the behavior of uranium (U) has significant implications for nuclear energy, remediation, paleoclimate, and geochronology. The U – carbonates interactions were mostly examined in marine systems. However, our comprehension of the geochemical redox behavior and burial pathways of U within pedogenic carbonate remains limited. More specifically, studies exploring the speciation and phases of U in soil systems are significantly less common. The critical zone often displays fluctuating redox conditions that affect reactivity and transport of U in soils. Therefore, soil systems offer a unique opportunity to explore the behavior of U in a dynamic redox environment.

Synchrotron-based spectrometric techniques were used to collect elemental maps and U L-III edge spectra within pedogenic carbonates. Our preliminary data show a significant heterogeneity in both the spatial distribution and speciation of U. For the first time, we present results showing the occurrence of mixed oxidation states in terrestrial carbonate systems. Taken together, our new data suggest the U geochemistry in pedogenic carbonates is more complex than anticipated. Yet once the geochemical controls will have been fully characterized, it will unlock interesting applications regarding paleoclimate and remediations initiatives.  

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

doi: 10.1130/abs/2025AM-414026

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