INSIGHTS TO THE GENETICS, AGE AND CRYSTALLIZATION OF GROUP IC AND IIC IRON METEORITES

Abstract

Siderophile element isotopic compositions and abundances were determined for the IC and IIC iron meteorite groups to assess whether the members of each group can be related by crystal-liquid fractionation models, constrain timing of metal-silicate segregation and parent body accretion, and characterize the chemical characteristics of the parent bodies.

Collectively, the IC and IIC group meteorites sample two genetically distinct reservoirs that were nevertheless chemically similar with respect to HSE absolute and relative abundances. Further, the relative core sizes of the IC and IIC parent bodies were similar, consistent with similar states of planetesimal oxidation. The distinct chemical trends between within the two groups originated as a result of their unique formation histories, revealing that mixing and impact processes were important mechanisms in the early protoplanetary disk.