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

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 Δ₄₇-Δ₄₈, 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.