REE-bearing sulfide in Bishunpur (LL3.1), a highly unequilibrated ordinary chondrite

This is a report of the first unambiguous discovery of rare earth elements (REE) in iron sulfide (FeS) in an ordinary chondrite. The content and the pattern of REE as well as the reduced state of the chondrules with the REE-containing sulfide suggest that the sulfide inside the Bishunpur (LL3.1) chondrules is of igneous origin, formed during crystallization of the chondrule melts. The similarities in the content and the pattern of REE between chondrule sulfide and matrix sulfide in Bishunpur indicate a genetic relationship. The presence of igneous sulfide inside chondrules provides constraints on the ambient nebular temperature and the duration of chondrule formation. The results of this study allow, on the basis of REE content and pattern, discrimination of igneous sulfide from condensate and secondary sulfide in chondrites and other interplanetary materials.