{"id":39885,"date":"2025-12-04T15:54:39","date_gmt":"2025-12-04T14:54:39","guid":{"rendered":"https:\/\/karmaka.de\/?p=39885"},"modified":"2025-12-04T15:54:40","modified_gmt":"2025-12-04T14:54:40","slug":"modeling-enstatite-chondrites-reduced-rocks-with-a-pinch-of-oxidized-material-affected-by-varying-h2og-derived-from-planetesimals-shocked-during-the-epoch-of-giant-planet-migration","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=39885","title":{"rendered":"Modeling enstatite chondrites: Reduced rocks with a pinch of oxidized material (affected by varying H2O(g)) derived from planetesimals shocked during the epoch of giant\u2013planet migration<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Alan E. Rubin<\/p>\n\n\n\n<p>MAPS, Version of Record online: 04 December 2025<\/p>\n\n\n\n<p><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.70080\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/epdf\/10.1111\/maps.70080\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;The O-, N-, Mo-, Ru-, Os-, Cr-, Ti-, Ni-, Fe-, Nd-, Ca-, Zn-, Sr-, and Mg-isotopic compositions of enstatite chondrites are essentially identical to those of the Earth and Moon. These correspondences suggest enstatite chondrites formed at \u22481\u2009AU as the only known chondrite groups that accreted in the vicinity of a major planet. Bulk Earth has a higher Mg\/Si weight ratio (1.09) than enstatite chondrites (0.63\u20130.76) and aubrites (0.84). Earth could have accreted from a mixture of these materials along with forsterite (Mg\/Si\u2009=\u20091.73) and niningerite [(Mg,Fe)S] from the lower mantles of aubritic parent asteroids whose crusts and upper mantles were stripped off by hit-and-run collisions. The highly reducing conditions in which enstatite chondrites formed resulted from the dehydration of the inner regions of the nebula caused by outward diffusion of water vapor; this lowered the H2O\/H2 ratio of the gas. The minor fraction of oxidized material in enstatite chondrites formed earlier\u2014when the H2O\/H2 ratio was briefly enhanced by inward-migrating ice particles. Enstatite chondrites are the most shocked chondrite groups, exhibiting a large variety of shock features\u2014for example, deformed silicate lattices; petrofabrics; brecciation; shock veins; metal globules; coesite; impact-melt textures; impact-produced phases (keilite, sinoite, graphite and F-rich minerals); and fractionated bulk REE patterns. The Ar-Ar, Rb-Sr and I-Xe ages of enstatite chondrites indicate many of these rocks were shocked early in Solar System history, 4520\u20134563\u2009Ma ago. This interval stretches back to the period of giant-planet migration, when the 1\u2009AU region became dynamically excited.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Alan E. Rubin MAPS, Version of Record online: 04 December 2025 LINK (OPEN ACCESS)PDF (OPEN ACCESS) &#8220;The O-, N-, Mo-, Ru-, Os-, Cr-, Ti-, Ni-, Fe-, Nd-, Ca-, Zn-, Sr-, and Mg-isotopic compositions of enstatite&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[74,17,73],"tags":[2001,1813,4265,5138,257],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39885"}],"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=39885"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39885\/revisions"}],"predecessor-version":[{"id":39886,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39885\/revisions\/39886"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=39885"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=39885"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=39885"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}