AbstractsChemistry

The silicate phases of 11 pallasites were analyzed instrumentally to determine the concentrations of some major, minor, and trace elements. The silicate phases were found to contain about 98% olivine with 1 to 2% accessory minerals such as lawrencite, schreibersite, troilite, chromite, and farringtonite present. The trace element concentrations, except Sc and Mn, were found to be extremely low and were found primarily in the accessory phases rather than in the pure olivine. An unusual bimodal Mn distribution was noted in the pallasites, and Eagle Station had a chondritic normalized REE pattern enrichedin the heavy REE. The silicate phases of pallasites and mesosiderites were shown to be sufficiently diverse in origin such that separate classifications are entirely justified.