{"id":38795,"date":"2025-07-26T10:11:30","date_gmt":"2025-07-26T08:11:30","guid":{"rendered":"https:\/\/karmaka.de\/?p=38795"},"modified":"2025-07-26T10:11:31","modified_gmt":"2025-07-26T08:11:31","slug":"mineralogical-and-isotopic-constraints-on-early-high-temperature-events-and-reservoirs-recorded-in-the-interior-of-a-type-b-ca-al-rich-inclusion-from-the-reduced-cv3-chondrite-vigarano","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=38795","title":{"rendered":"Mineralogical and isotopic constraints on early, high-temperature events and reservoirs recorded in the interior of a Type B Ca-Al-rich inclusion from the reduced CV3 chondrite Vigarano<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Jangmi Han, Changkun Park, Ming-Chang Liu, Nozomi Matsuda, Justin I. Simon, Lindsay P. Keller<\/p>\n\n\n\n<p>Geochimica et Cosmochimica Acta<br>In Press, Journal Pre-proof, Available online 24 July 2025<\/p>\n\n\n\n<p><a href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0016703725003825\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK + PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;A coordinated mineralogical and oxygen and Al-Mg isotopic study of a Type B Ca-Al-rich inclusion (CAI) from the reduced CV3 chondrite Vigarano was carried out using electron microprobe analysis, transmission electron microscopy, and secondary ion mass spectrometry. This CAI, a once molten igneous object, shows heterogeneous oxygen isotopic compositions among its constituent mineral phases. Spinel is uniformly 16O-rich with \u039417O \u2264 \u221223\u202f\u2030. The \u039417O values of Al,Ti-diopside in the CAI core range from\u202f\u221211\u202f\u2030 to\u202f\u221218\u202f\u2030, which are positively correlated with its TiO2 contents, whereas diopside in the Wark\u2013Lovering (WL) rim is 16O-rich with \u039417O = \u221223\u202f\u2030. Melilite in the CAI mantle shows \u039417O values\u202f\u2264\u202f\u221210\u202f\u2030 only when \u00c5k&lt;15 but becomes more 16O-poor (\u039417O\u202f=\u202f\u22123\u202f\u2030 to\u202f\u22129\u202f\u2030) when \u00c5k&gt;15. These correlated chemical and oxygen isotopic variations were likely established during crystallization of melilite and Al,Ti-diopside from a partial melt, while spinel preserves the original 16O-rich composition of the CAI precursor. We infer that a partial melt was isotopically evolving from 16O-rich to 16O-poor during melilite crystallization, then back to 16O-rich during Al,Ti-diopside crystallization via exchange with different gas reservoirs of 16O-poor and 16O-rich compositions during heating event(s). Our Al-Mg isotopic measurements of the CAI core and mantle define a single isochron with an inferred initial 26Al\/27Al ratio of (4.93\u202f\u00b1\u202f0.18)\u202f\u00d7\u202f10\u22125, indistinguishable from that of the WL rim. This indicates that multiple high-temperature events and oxygen isotope exchange with isotopically distinct gas reservoirs occurred rapidly during the CAI formation.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Jangmi Han, Changkun Park, Ming-Chang Liu, Nozomi Matsuda, Justin I. Simon, Lindsay P. Keller Geochimica et Cosmochimica ActaIn Press, Journal Pre-proof, Available online 24 July 2025 LINK + PDF (OPEN ACCESS) &#8220;A coordinated mineralogical and&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[66,9,14,22,2532],"tags":[5708,2404,448,2669,1718,3830,3315,3273,1812,5053,2778,2960,727,482,1832],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/38795"}],"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=38795"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/38795\/revisions"}],"predecessor-version":[{"id":38796,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/38795\/revisions\/38796"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=38795"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=38795"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=38795"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}