Chemical studies of the Mundrabilla iron meteorite by neutron activation

Abstract

We report on trace and minor element contents in the large 6.1 ton mass of the Mundrabilla iron meteorite as determined by non-destructive and radiochemical neutron activation analysis. Mundrabilla is a medium octahedrite and is classified as a anomalous member of group IA. Its structure is very exceptional, consisting of about 75% ironnickel and around 25% sulfide inclusions, mainly troilite (FeS). Most samples for analysis were taken as drill samples, and metal and sulfide portions were carefully separated to avoid cross contamination. In pure metal samples, the elements Mn, Co, Ni, Cu, Ga, Ge, As, Ir and Au are remarkably uniformly distributed over large areas of the meteorite. Most elements analyzed in the different sulfide samples exhibit a larger range in concentration, except Se and Cr which are very uniform and strongly chalcophile. Implications of element abundances are discussed.