REE AND OTHER TRACE ELEMENT CHEMISTRY OF CaS IN QINGZHEN CHONDRITE (EH3) AND THEIR ORIGIN IMPLICATIONS

INAA of 14 single oldhamite grains extracted from the Qingzhen chondrite (EH3) for refractory (La,Ce,Sm,Eu,Yb,Lu,Ca,Sc,Hf,Th),volatile (Na,Cr,Zn,Se,Br etc.) and siderophile elements (Fe,Ni,Co,Ir,Au,As) reveals that oldhamite is highly enriched in refractory elements,acting as the principal carrier of REE and contains about 80% of all REE in the bulk rock of the Qingzhen enstatite chondrite.Furthermore,LREE has larger enrichment relative to HREE in the Qingzhen oldhamite.In general,the oldhamite form metal-sulfide as-sembleges is more enriched in REE than that from the matrix,i.e.the earlier the oldhamite grains condensed,the more they are enriched in REE.Meanwhile,it is also enriched in volatile elements such as Se,Br etc.In terms of the trace element distribution of the Qingzhen oldhamite it is a high-temperature condensate from the nebula with the solar composition and its condensate origin are suggested.