{"id":36417,"date":"2024-07-09T23:39:55","date_gmt":"2024-07-09T21:39:55","guid":{"rendered":"https:\/\/karmaka.de\/?p=36417"},"modified":"2025-05-03T08:48:48","modified_gmt":"2025-05-03T06:48:48","slug":"corundum-%c2%b1-magnesium-deltalumite-%c2%b1-hibonite-bearing-objects-in-the-ch-chondrite-sayh-al-uhaymir-290","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=36417","title":{"rendered":"Corundum\u2009\u00b1\u2009magnesium-deltalumite\u2009\u00b1\u2009hibonite-bearing objects in the CH chondrite Sayh al Uhaymir 290"},"content":{"rendered":"\n<p>Konstantin M. Ryazantsev, Alexander N. Krot, Chi Ma, Marina A. Ivanova, Cyril A. Lorenz, Vasiliy D. Shcherbakov<\/p>\n\n\n\n<p>MAPS, Version of Record online: 09 July 2024<\/p>\n\n\n\n<p><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.14238\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;solated corundum grains and corundum\u2009\u00b1\u2009Mg-deltalumite [(Al,Mg)(Al,\u25fb)2O4]\u2009\u00b1\u2009hibonite assemblages were investigated in the CH3.0 metal-rich carbonaceous chondrite Sayh al Uhaymir (SaU) 290. Although very refractory inclusions containing abundant Zr- and Sc-rich oxides and silicates, hibonite, grossite, or perovskite have been previously described in CH chondrites, this is the first discovery of corundum and Mg-deltalumite in CHs and the first discovery of Mg-deltalumite in nature. Magnesium-deltalumite can be indexed by the Fd3m spinel-type structure and gives a perfect fit to the synthetic Al-rich spinel cells. Corundum-Mg-deltalumite grains, 5\u201320\u2009\u03bcm in size, are occasionally rimmed by a thin layer of hibonite replacing corundum. Some corundum grains contain tiny inclusions of ultrarefractory Zr,Sc-rich minerals and platinum-group element (PGE) nuggets. All corundum, hibonite, and Mg-deltalumite grains studied have 16O-rich compositions (average \u039417O\u2009\u00b1\u20092SD\u2009=\u2009\u221222\u2009\u00b1\u20093\u2030). Two corundum grains show evidence for significant mass-dependent fractionation of oxygen isotopes: \u039418O\u2009~\u2009+34\u2030 and\u2009~\u2009+19\u2030. We suggest that the SaU 290 corundum-rich objects were formed by evaporation and\/or condensation in a hot nebular region close to the proto-sun where the ambient temperature was close to the condensation temperature of corundum. A corundum grain with tiny inclusions of Zr- and Sc-rich phases and PGE metal nuggets recorded formation temperatures higher than the condensation temperature of corundum. Two corundum-rich objects with highly fractionated oxygen isotopes must have crystallized from a melt that experienced evaporation. Corundum grains corroded by hibonite recorded gas\u2013solid interaction in this region during its cooling. The Mg-deltalumite\u2009\u00b1\u2009corundum\u2009\u00b1\u2009hibonite objects were formed by rapid crystallization of high-temperature (&gt;2000\u00b0C) refractory melts. The lack of minerals with condensation temperatures below those of corundum and hibonite in the SaU 290 corundum-rich objects suggests that after formation, these objects were rapidly removed from the hot nebular region by disk wind and\/or by turbulent diffusion and disk spreading.&#8221;<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.14364\" target=\"_blank\" rel=\"noreferrer noopener\">Correction to \u201cCorundum\u2009\u00b1\u2009Magnesium-Deltalumite\u2009\u00b1\u2009Hibonite-Bearing Objects in the CH Chondrite Sayh Al Uhaymir 290\u201d<\/a><br>MAPS, Version of Record online: 02 May 2025<\/p>\n\n\n\n<p><strong>Figures 5 and 6 were reversed. The order of the captions was correct.<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Konstantin M. Ryazantsev, Alexander N. Krot, Chi Ma, Marina A. Ivanova, Cyril A. Lorenz, Vasiliy D. Shcherbakov MAPS, Version of Record online: 09 July 2024 LINK &#8220;solated corundum grains and corundum\u2009\u00b1\u2009Mg-deltalumite [(Al,Mg)(Al,\u25fb)2O4]\u2009\u00b1\u2009hibonite assemblages were investigated&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,583],"tags":[3273,4628,997,995],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/36417"}],"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=36417"}],"version-history":[{"count":3,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/36417\/revisions"}],"predecessor-version":[{"id":38191,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/36417\/revisions\/38191"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=36417"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=36417"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=36417"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}