Oxygen isotope systematics of chondrules in the Paris CM2 chondrite: indication for a single large formation region across snow line.

ABSTRACT: In-situ oxygen three-isotope analyses of chondrules and isolated olivine grains in the Paris (CM) chondrite were conducted by secondary ion mass spectrometry (SIMS). Multiple analyses of olivine and/or pyroxene in each chondrule show indistinguishable Δ¹⁷O values, except for minor occurrences of relict olivine grains (and one low-Ca pyroxene). A mean Δ¹⁷O value of these homogeneous multiple analyses was obtained for each chondrule, which represent oxygen isotope ratios of the chondrule melt. The Δ¹⁷O values of individual chondrules range from -7‰ to -2‰ and generally increase with decreasing Mg# of olivine and pyroxene in individual chondrules. Most type I (FeO-poor) chondrules have high Mg# (~99) and variable Δ¹⁷O values from -7.0‰ to -3.3‰. Oth

SUBMITTER: Chaumard N 

PROVIDER: S-EPMC8588000 | biostudies-literature | 2021 Apr

REPOSITORIES: biostudies-literature