A 187Re-187Os, 87Rb-87Sr, highly siderophile and incompatible trace element study of some carbonaceous, ordinary and enstatite chondrite meteorites

New 187Re-187Os, 87Rb-87Sr, triple O-isotope isotope, bulk rock highly siderophile- (HSE: Os, Ir, Ru, Pt, Pd, Re), major- and trace-element abundance data are reported for a variety of carbonaceous, ordinary enstatite chondrite meteorites. In addition, new mineral chemical the Chelyabinsk LL5 fall comparison with existing to investigate element sequestration into metal phases within some chondrites. The focus study is link variations observed in HSE abundances Re-Os isotopes other isotopic elemental explore relative roles sample sizes, terrestrial alteration parent body processes more fully on meteorite compositions. Trace silicate, oxide grains highlight importance geochemical heterogeneity imparted by mineralogical mode effects, as well size. Using range powder aliquot it possible show that this becomes significant at <0.1 g. Variations high field strength elements (HFSE: Ti, Zr, Nb, Ta, Hf) also identified individual aliquots carbonaceous Ivuna, emphasizing complete dissolution refractory phases. find meteorites examined here demonstrates effects revealed trace (e.g., Ba, U, Sr) do not correlate particularly Re/Os variations. Instead, ratios chondrites susceptible disturbance, so than indicated incompatible systematics, Murchison CM2 showing fractionation between aliquots. For measured or appear be largely restricted thermal metamorphism dehydration. Including study, combined published dataset isotope now extends 33 ordinary, 39 27 6 Rumuruti absolute among these groups ?30%, all having, uncertainties, same average Pt Pd abundances. Notably, have long-term ? 8% lower groups. If representative early planetary feedstocks, then 187Os/188Os make them close match composition silicate Earth. Assuming ?0.5% late accretion Earth, would result Rb/Sr ratio ?0.6% higher from chondrites, indicating potentially attractive source moderately volatile enrichment.