LINK<\/strong><\/a><\/p>\n\n\n\n“Here we present petrographic, O isotope, and C isotope data on calcite and petrographic and O isotope data on magnetite in Aguas Zarcas (CM2) and Miller Range (MIL) 13005 (CM1\/2) in an effort to test CM aqueous alteration models. Our O and C isotope data for Aguas Zarcas and MIL 13005 are within the ranges reported in previous work for calcite in CMs. Using O isotope data from \u039417O-matched calcite and magnetite grains in our samples, we calculated equilibrium-model formation temperatures for the analyzed calcites in each meteorite. Combining our isotopic and temperature data with literature data, we sort the data into less altered (CM2) and more altered (CM1\/2 and CM1) categories, and examine that data for differences between the categories by analyzing the \u03b418O-\u03b417O, \u03b418O-\u03b413C, and model formation temperature data of the categories. We find potential differing cluster patterns between \u03b418O and \u03b413C in calcites between our two CM alteration categories, and find that sparse extant temperature data imply that more altered CMs (types 1 and 1\/2) may have undergone alteration at a lower average temperature than CM2s. We also find that the O isotopic compositions between CM1s, CM2s, and CM1\/2s do not differ significantly. Through use of a novel mass-balance model, we infer a pre-alteration ice \u039417O within the range of 5.3\u201313.3\u2030. We find two generations of calcite formation in MIL 13005 with different proportions of their O being sourced from ices and anhydrous silicates, and one generation of calcites within Aguas Zarcas. We created concentration mixing models through an original machine-learning-based analytical approach, which show that the calcite data can be readily explained using three optimally determined C- and O-bearing sources.”<\/p>\n","protected":false},"excerpt":{"rendered":"
S.P. Goudy, M. Telus, K. Nagashima, G.R. Huss Geochimica et Cosmochimica Acta, In Press, Journal Pre-proof, Available online 12 April 2026 LINK “Here we present petrographic, O isotope, and C isotope data on calcite and…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5001,61,9,18,47],"tags":[5708,3965,4965,1842,1241,250,3273,105,2224,2990,295,994,6599,1845,1832,5727,5728,7117,7116],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41343"}],"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=41343"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41343\/revisions"}],"predecessor-version":[{"id":41344,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41343\/revisions\/41344"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=41343"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41343"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41343"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}