Density functional theory and ab initio molecular dynamics reveal atomistic mechanisms for carbonate clumped isotope reordering.

ABSTRACT: Carbon (¹³C) and oxygen (¹⁸O) isotopes in carbonates form clumped isotope species inversely correlated with temperature, providing a valuable paleothermometer for sedimentary carbonates and fossils. However, this signal resets ("reorders") with increasing temperature after burial. Research on reordering kinetics has characterized reordering rates and hypothesized the effects of impurities and trapped water, but the atomistic mechanism remains obscure. This work studies carbonate-clumped isotope reordering in calcite via first-principles simulations. We developed an atomistic view of the isotope exchange reaction between carbonate pairs in calcite, discovering a preferred configuration and elucidating how Mg²⁺ substitution and Ca²⁺ vacancies lower

SUBMITTER: Perez-Beltran S 

PROVIDER: S-EPMC10306293 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature