CV and CM chondrite impact melts

摘要: Abstract Volatile-rich and typically oxidized carbonaceous chondrites, such as CV CM potentially respond to impacts differently than do other chondritic materials. Understanding impact melting of chondrites has been hampered by the dearth recognized melt samples. In this study we identify five chondrite clasts in three host meteorites: a CV3red chondrite, CV3oxA regolithic howardite. The these meteorites respectively formed from protoliths. We identified interpreted their precursors based on texture, mineral chemistry, silicate bulk elemental composition, case clast, situ measurement oxygen three-isotope signatures olivine. These melts contain euhedral–subhedral olivine microphenocrysts, sometimes with relict cores, glassy groundmasses. Based petrography Raman spectroscopy, four exhibit evidence for volatile loss: either vesicles or are depleted H2O relative precursors. Volatile loss (i.e., H2O) may have reduced redox state clast. that more (CV3oxA chondrites) phase compositions consistent higher intrinsic fugacities clast precursor (CV3red chondrite). chemistries assemblages here provide template recognizing surfaces asteroids.