Molybdenum-isotope signals and cerium anomalies in Palaeoproterozoic manganese ore survive high-grade metamorphism.

ABSTRACT: Molybdenum (Mo) and its isotopes have been used to retrieve palaeoenvironmental information on the ocean-atmosphere system through geological time. Their application has so far been restricted to rocks least affected by severe metamorphism and deformation, which may erase or alter palaeoenvironmental signals. Environmental Mo-isotope signatures can be retrieved if the more manganese (Mn)-enriched rocks are isotopically depleted and the maximum range of δ⁹⁸Mo values is close to the ~2.7‰ Mo-isotope fractionation known from Mo sorption onto Mn oxides at low temperature. Here, we show that the Morro da Mina Mn-ore deposit in Minas Gerais, Brazil, contains Mn-silicate-carbonate ore and associated graphitic schist that likely preserve δ⁹⁸Mo of Palaeoproterozoic seawater, d

SUBMITTER: Cabral AR 

PROVIDER: S-EPMC6418314 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature