A Potůčky fragment of the Steinbach IVA-an meteorite: Implications from the trace-element composition of the constituent phases

Abstract

We have analyzed in situ mineral phases in a Potůčky fragment of the stony-iron IVA-an meteorite Steinbach for trace-element compositions. The studied fragment contains silicate grains (pyroxene and tridymite) interspersed with grains of metal (kamacite, plessite, and taenite) displaying Widmanstätten pattern and troilite. Multiple inclusions of chromite, troilite, and bi-mineral troilite + taenite assemblages were observed within some pyroxene grains. The data on variations in trace-element compositions in different meteorite phases are consistent with a number of models, suggesting the involvement of several processes in the generation of the lithologies presently observed in the Potůčky meteorite. These processes might have involved fractional crystallization of silicate liquid, collision, impact, shock melting, and cooling. As a result of such processes, specific trace-element composition of different mineral phases was formed. Trace-element compositions of metals and sulfides from the Potůčky meteorite are very similar to those for minerals from the LL ordinary chondrite, suggesting LL-like asteroid as a parent body for the Potůčky (IVA-an) precursor material.