Comparison of clumped isotope signatures of dolomite cements to fluid inclusion thermometry in the temperature range of 74-180 °C

Abstract:

Widespread application of the novel clumped isotope paleothermometer (Δ₄₇) using carbonate samples from shallow crustal settings has been hindered by a lack of knowledge about clumped isotope systematics in carbonate minerals forming at temperatures greater than 50ºC. Furthermore, the utility of the Δ₄₇ proxy in the mineral dolomite is limited because calibration data for dolomites that formed at any temperature are lacking. Consequently, applications involving diagenetic temperatures have required extrapolations beyond the range of most Δ₄₇-temperature calibrations. Here we compare Δ₄₇ values in dolomite cements to temperatures independently determined using fluid-inclusion microthermometry, and compare this rock-based “calibration” to previously published laboratory-derived calibrations for synthetic carbonates. This combination of approaches yields results that are consistent with the shallow calibration slope that has been reported from some laboratory experiments.