Mn-Cr dating of carbonates in meteorites and preparetion for a synthetic cabonate standard.

Abstract

Carbonaceous chondrites often contain carbonates to which Mn-Cr dating are applicable. However, formation ages of carbonates obtained in previous studies are not necessarily consistent with ages calculated by other chronometers. In this study, we prepared a synthetic Mn and Cr bearing caltite and evaluated a Mn/Cr relative sensitivity factor. As a result, we obtained formation ages about 3 My younger than those obtained in previous studies.