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Equilibrated gas and carbonate standard-derived dual (Δ47 and Δ48) clumped isotope values

February 1, 2023

Carbonate clumped isotope geochemistry has primarily focused on mass spectrometric determination of m/z 47 CO2 for geothermometry, but theoretical calculations and recent experiments indicate paired analysis of the m/z 47 (13C18O16O) and m/z 48 (12C18O18O) isotopologues (referred to as Δ47 and Δ48) can be used to study non-equilibrium isotope fractionations and refine temperature estimates. We utilize 5,448 Δ47 and 3,400 Δ48 replicate measurements of carbonate samples and standards, and 183 Δ47 and 195 Δ48 replicate measurements of gas standards from 2015 to 2021 from a multi-year and multi-instrument data set to constrain Δ47 and Δ48 values for 27 samples and standards, including Devils Hole cave calcite, and study equilibrium Δ4748, Δ47-temperature, and Δ48-temperature relationships. We compare results to previously published findings and calculate equilibrium regressions based on data from multiple laboratories. We report acid digestion fractionation factors, Δ*63-47 and Δ*64-48, and account for their dependence on the initial clumped isotope values of the mineral.

Publication Year 2023
Title Equilibrated gas and carbonate standard-derived dual (Δ47 and Δ48) clumped isotope values
DOI 10.1029/2022GC010458
Authors Jamie K Lucarelli, Hannah M. Carroll, Robert N. Ulrich, Ben M. Elliott, Tyler B. Coplen, Robert A. Eagle, Aradhna K. Tripati
Publication Type Article
Publication Subtype Journal Article
Series Title Geochemistry, Geophysics, Geosystems
Index ID 70245098
Record Source USGS Publications Warehouse
USGS Organization WMA - Laboratory & Analytical Services Division