Absolute speleo-thermometry, using clumped isotope measurements to correct for kinetic isotope fractionations induced by CO_2 degassing

Abstract

Assuming that a given speleothem precipitates near thermodynamic equilibrium, quantitative interpretation of its ^(18)O record in terms of physical parameters is generally hampered by the lack of robust methods for separating isotopic variations due to paleo-temperatures and those reflecting source water composition. Moreover, in many settings it appears likely that speleothems form out of equilibrium, due to kinetic isotopic fractionation caused by rapid CO_2 degassing, which further detracts from the reliability of paleo-environmental reconstructions