LINK<\/strong><\/a><\/p>\n\n\n\n“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 \u039417O values, except for minor occurrences of relict olivine grains (and one low-Ca pyroxene). A mean \u039417O value of these homogeneous multiple analyses was obtained for each chondrule, which represent oxygen isotope ratios of the chondrule melt. The \u039417O values of individual chondrules range from \u20137\u2030 to \u20132\u2030 and generally increase with decreasing Mg# of olivine and pyroxene in individual chondrules. Most type I (FeO-poor) chondrules have high Mg# (\u223c99) and variable \u039417O values from \u20137.0\u2030 to \u20133.3\u2030. Other type I chondrules (Mg# \u226497), type II (FeO-rich) chondrules, and two isolated FeO-rich olivine grains have host \u039417O values from \u20133\u2030 to \u20132\u2030. Eight chondrules contain relict grains that are either 16O-rich or 16O-poor relative to their host chondrule and show a wide range of \u039417O values from \u201313\u2030 to 0\u2030.<\/p>\n\n\n\n
The results from chondrules in the Paris meteorite are similar to those in Murchison (CM). Collectively, the \u039417O values of chondrules in CM chondrites continuously increase from \u20137\u2030 to \u20132\u2030 with decreasing Mg# from 99 to 37. The majority of type I chondrules (Mg# >98) show \u039417O values from \u20136\u2030 to \u20134\u2030, while the majority of and type II chondrules (Mg# 60-70) show \u039417O values of \u20132.5\u2030. The covariation of \u039417O versus Mg# observed among chondrules in CM chondrites may suggest that most chondrules in carbonaceous chondrites formed in a single large region across the snow line where the contribution of 16O-poor ice to chondrule precursors and dust enrichment factors varied significantly.”<\/p>\n","protected":false},"excerpt":{"rendered":"
No\u00ebl Chaumard, C\u00e9line Defouilloy, Andreas T. Hertwig, Noriko T. Kita Geochimica et Cosmochimica ActaIn Press, Journal Pre-proof, Available online 18 February 2021 LINK “In-situ oxygen three-isotope analyses of chondrules and isolated olivine grains in the…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,56,148,18,65],"tags":[1839,1864,105,3037,1845,304],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26299"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=26299"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26299\/revisions"}],"predecessor-version":[{"id":26300,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26299\/revisions\/26300"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=26299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=26299"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=26299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}