LINK<\/strong><\/a><\/p>\n\n\n\n“Chondrites are meteorites from undifferentiated parent bodies that provide fundamental information about early Solar System evolution and planet formation. The element Cr is highly suitable for deciphering both the timing of formation and the origin of planetary building blocks because it records both radiogenic contributions from 53Mn-53Cr decay and variable nucleosynthetic contributions from the stable 54Cr nuclide. Here, we report high-precision measurements of the mass-independent Cr isotope compositions (\u03b553Cr and \u03b554Cr) of chondrites (including all carbonaceous chondrites groups) and terrestrial samples using for the first time a multi-collection inductively-coupled-plasma mass-spectrometer to better understand the formation histories and genetic relationships between chondrite parent bodies. With our comprehensive dataset, the order of decreasing \u03b554Cr (per ten thousand deviation of the 54Cr\/52Cr ratio relative to a terrestrial standard) values amongst the carbonaceous chondrites is updated to CI = CH \u2265 CB \u2265 CR \u2265 CM \u2248 CV \u2248 CO \u2265 CK > EC > OC. Resolvable \u03b554Cr (with 2SE uncertainty) differences between CV and CK chondrites rule out an origin from a common parent body or reservoir as has previously been suggested. The CM and CO chondrites share common \u03b554Cr characteristics, which suggests their parent bodies may have accreted their components in similar proportions. The CB and CH chondrites have low-Mn\/Cr ratios and similar \u03b553Cr values to the CI chondrites, invalidating them as anchors for a bulk Mn-Cr isochron for carbonaceous chondrites. Bulk Earth has a \u03b553Cr value that is lower than any chondrite group, including enstatite chondrites. This depletion may constrain the timing of volatile loss from the Earth or its precursors to be within the first million years of Solar System formation and is incompatible with Earth\u2019s accretion via any of the known chondrite groups as main contributors, including enstatite chondrites.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Ke Zhu \u6731\u67ef, Fr\u00e9d\u00e9ric Moynier, Martin Schiller, Conel M. O’D. Alexander, Jemma Davidson, Devin L. Schrader, Elishevah van Kooten, Martin Bizzarro Geochimica et Cosmochimica ActaAvailable online 27 February 2021 LINK “Chondrites are meteorites from undifferentiated…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[131,9,584,583,15,18,11,19,582,14,13,20,21,22,72,112,127,71],"tags":[671,121,3273,1426,1887,2932,1124,105,2907,1814,1356,1810,2268,234,2491,3122,1779,2001,1813,1066,1807,2992,683],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26546"}],"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=26546"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26546\/revisions"}],"predecessor-version":[{"id":26548,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/26546\/revisions\/26548"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=26546"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=26546"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=26546"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}