LINK<\/strong><\/a><\/p>\n“Magnesium\u2010rich spinel assemblages occur in the two lunar vitric breccia meteorites\u2014Dhofar (Dho) 1528 and Graves Nunataks (GRA) 06157. Dho 1528 contains up to ~0.7 mm cumulate Mg\u2010rich spinel crystals associated with Mg\u2010rich olivine, Mg\u2010 and Al\u2010rich pyroxene, plagioclase, and rare cordierite. Using thermodynamic calculations of these mineral assemblages, we constrain equilibration depths and discuss an origin of these lithologies in the upper mantle of the Moon. In contrast, small, 10 to 20 \u03bcm spinel phenocryst assemblages in glassy melt rock clasts in Dho 1528 and GRA 06157 formed from the impact melting of Mg\u2010rich rocks. Some of these spinel phenocrysts match compositional constraints for spinel associated with \u201cpink spinel anorthosites\u201d inferred from remote sensing data. However, such spinel phenocrysts in meteorites and Apollo samples are typically associated with significant amounts of olivine \u00b1 pyroxene that exceed the compositional constraints for pink spinel anorthosites. We conclude that the remotely sensed \u201cpink spinel anorthosites\u201d have not been observed in the collections of lunar rocks. Moreover, we discuss impact\u2010excavation scenarios for the spinel\u2010bearing assemblages in Dhofar 1528 and compare the bulk rock composition of Dho 1528 to strikingly similar compositions of Luna 20 samples that contain ejecta from the Crisium impact basin.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Axel Wittmann, Randy L. Korotev, Bradley L. Jolliff, Paul K. Carpenter Meteoritics & Planetary Science First Published: 28 November 2018 LINK “Magnesium\u2010rich spinel assemblages occur in the two lunar vitric breccia meteorites\u2014Dhofar (Dho) 1528 and…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[41,115],"tags":[4757,4756,4755,1827,1340,1857],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16828"}],"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=16828"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16828\/revisions"}],"predecessor-version":[{"id":16829,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/16828\/revisions\/16829"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16828"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16828"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16828"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}