Carbonate paleothermometry based on abundances of ^(13)C-^(18)O bonds

Abstract

Urey’s carbonate oxygen isotope paleothermometer is a milestone of paleoclimate research but constrains temperature only if the oxygen isotope composition of water from which carbonate grew is known. Moreover, difficulty in recognizing diagenetic overprinting has confounded the interpretation of carbonate oxygen isotope compositions for much of the geological record. We pesent a carbonate paleothermometer based on the formation of bonds between ^(13)C and ^(18)O. This ordering of rare isotopes can be described by the reaction: Ca^(13)C^(16)O_3 + Ca^(12)C^(18)O^(16)O_2 = Ca^(12)C^(16)O_3 + Ca^(13)C^(18)O^(16)O_2 rxn 1