Search for nickel-60 excesses in pallasite olivines

Abstract

We have initiated a search in pallasite olivines for possible excesses of ^(60)Ni due to the decay of ^(60)Fe (half-life 1.5 Ma). The search in pallasite olivines was based on the observation of evidence for the in situ decay in pallasite olivine of ^(53)Mn (half-life 3.7 Ma) for Eagle Station and for Omolon; the expectation of high ^(56)Fe/^(58)Ni in pallasite olivines; Re-Os measurements in pallasites that indicate a whole-rock isochron for pallasites consistent with the whole-rock Re-Os isochron for iron meteorites and possibly early formation; and the discovery of evidence for the in situ decay of ^(60)Fe in eucrites.