Publication
A calibration equation between Δ48 values of carbonate and temperature
Publisher:
Wiley
Date:
07-07-2021
DOI:
10.1002/RCM.9147
Abstract: Information on the temperature of formation or alteration of carbonate minerals can be obtained by measuring the abundance of the isotopologues 47 and 48 (Δ 47 and Δ 48 values) of CO 2 released during acid dissolution. The combination of these two proxies can potentially provide a greater insight into the temperature of formation, particularly if the carbonate minerals form by non‐equilibrium processes. We have precipitated calcium carbonates at seven temperatures between 5 and 65°C and measured their δ 48 values using a Thermo‐253 plus isotope ratio mass spectrometer. The values were transformed to Δ 48 values in the conventional manner and then converted to the carbon dioxide equilibrium scale. Using the Δ 48 values, we have established an empirical calibration between temperature and Δ 48 values: urn:x-wiley:09514198:media:rcm9147:rcm9147-math-0001 The calibration line produced allows the determination of the temperature of natural carbonates using the Δ 48 values and agrees with the measurements of the Δ 47 and Δ 48 values of some carbonates assumed to have formed under equilibrium conditions.