Petrology,Mineralogy and Stable Isotopic Composition of NWA 13943(CK5)Carbonaceous Chondrite
CK(Karoonda-like)carbonaceous chondrites(CCs)are highly oxidized meteorites,with metal/magnetite ratio close to zero.Unlike other CCs(petrologic type:1-3),most CK chondrites have suffered intense thermal process(550-1270 K)on their parent body with a petrologic type 4 or above.Lines of evidence indicate that CK chondrites could be genetically related to CV(Vigarano-like)chondrites which are mostly type 3 meteorites.However,there are still slight differences in petrographic texture and chemical composition between these two meteorites.Therefore,it is crucial to distinguish their geochemical characteristics for testing the CK-CV single parent body hypothesis.Northwest Africa(NWA)13943,a newly found meteorite which has undergone intense thermal metamorphism,was classified using scanning electron microscopy and electron microprobe.The whole-rock oxygen and chromium isotope composition of NWA 13943 meteorite were also determined by mass spectrometer.Integrating petrology,mineralogy,oxygen isotope anomaly(△17O,where △ represents isotopic fractionation value),and chromium isotope anomaly(ε54Cr,where ε expresses parts per ten thousand mass-independent isotope deviation)data,it is legitimated to infer that CK and CV chondrites may derive from two similar but distinct isotopic reservoirs within the protoplanetary disk.
NETL
NSTL
万方数据
维普
