'Clumped isotope' thermometry for high-temperature problems

Abstract

Paleothermometers for shallow-crustal environments (50 ≤ T ≤ 300°C) are generally empirical, semi-quantitative, or depend on knowledge of the compositions of pore-fluids. Carbonate clumped isotope thermometry (i.e., paleotemperature estimates based on ordering of ^(13)C and ^(18)O in solid carbonate minerals) potentially provides a means for quantitative, thermodynamically-based temperature estimates in shallow crustal environments, independent of knowledge of or assumptions regarding compositions of co-existing fluids. Application of clumped isotope thermometry at high-temperatures faces several hurdles: limits to precision; relevant calibrations; and preservation (i.e., 'blocking temperature').

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