Origin of heterogeneous isotope distribution for heavy elements in the early solar system

点击翻译按钮获取中文摘要

We have investigated the origin of heterogeneous isotope distribution for heavy elements in the early solar system. Highly precise isotope analyses of Sr, Nd, Te, and Mo were conducted using TIMS for bulk rocks of chondrites and nonchondrites, as well as for chondrite components (e.g., CAIs, chondrules, acid leachates). We found that planetary scale isotope heterogeneities exist only for moderately refractory elements with 50% condensation temperature between 1300K to 1600K (e.g., Cr, Mo, Sr). This implies that isotope heterogeneities for moderately refractory elements were created by a dynamical history of dust grains related to thermal processing, material transportation, and mixing in the protoplanetary disk prior to planetesimal formation, rather than assuming processes such as supernova injection and/or grain-size sorting.