Host: Abstracts of Annual Meeting of the Geochemical Society of Japan
Name : Abstracts of Annual Meeting of the Geochemical Society of Japan
Number : 71
Date : September 18, 2024 - September 20, 2024
Pages 188-
In an attempt to understand the late accretionary history of Earth, we investigated Archean rocks from Acasta complex. The Acasta Gneiss complex hosts the oldest rocks preserved on Earth with a crystallization age of 4.03 Ga (1). Molybdenum isotopes provide important insights into the late accretionary history of our planet. Due to its moderately siderophile character, Mo partitioned largely into the core and the present day bulk silicate Earth Mo isotope composition is an integration of the original and late accreted material (2). Mass independent (nucleosynthetic) Mo isotope anomalies are a valuable tool in constraining genetic relationship among meteorites and planetary materials. However, a recent study reported the spurious Mo mass independent anomalies resulting from a mass dependent fractionation of Mo isotopes in terrestrial samples (3). We have conducted a Mo isotopic investigation (mass independent and mass dependent) of several mafic and intermediate rocks from the Acasta Complex, that have been least affected by later events involving widespread migration of fluid mobile elements (4). References (1) Reimink et al. (2019) Earth s Oldest Rocks. (2) Dauphas (2017) Nature 541,. (3) Budde et al. (2023) Geochemistry, 83. (4) Koshida et al. (2016) Precambrian Res. 283.
