LINK<\/strong><\/a><\/p>\n\n\n\n“Petrologic investigations of martian meteorite Northwest Africa (NWA) 13227 indicate it is an olivine-gabbroic shergottite, a relatively new shergottite group, which differs from previously described gabbroic shergottites due to relatively high quantities of olivine. NWA 13227 is comprised of phenocrystic, oscillatory-zoned pyroxene and olivine, set in a matrix of maskelynite, Fe-Cr-Ti oxides, phosphates, and sulfides. It displays gabbroic and poikilitic textures in 2D from back-scattered electron images, and in 3D from X-ray Computed Tomography (XCT) imaging, suggesting affinities to both poikilitic and gabbroic shergottites. Measured \u03b5Hf and \u03b5Nd values of bulk rock (-19.7 and \u22125.9, respectively) and its chondrite-normalized La\/Yb ratio of 1.13 indicate the specimen is derived from a mantle reservoir relatively enriched in incompatible trace elements and is similar to that which produced most \u2018enriched shergottites.\u2019 Based on the Ti\/Al ratio of pyroxene, phosphorous zoning in olivine, and minor components in phosphates and oxides, we infer that NWA 13227 began crystallizing under reducing conditions of QFM\u20132.6 and temperatures of\u202f\u223c\u202f1100\u202f\u00b0C, consistent with conditions in Mars\u2019 lower crust\/upper mantle. The sample finished crystallizing at or near the surface under redox conditions between QFM\u20130.5 to QFM\u20130.1 and temperatures of\u202f\u223c\u202f850\u202f\u00b0C. The volatile element compositions in apatite indicate that NWA 13227 experienced degassing during the last stages of crystallization. The timing of crystallization is estimated at 225\u202fMa\u202f\u00b1\u202f50\u202fMa using a Lu-Hf and Sm-Nd source versus age model.”<\/p>\n","protected":false},"excerpt":{"rendered":"
S. Benaroya, J. Gross, P. Burger, M. Righter, T.J. Lapen, S. Eckley Geochimica et Cosmochimica ActaIn Press, Journal Pre-proof, Available online 16 February 2024 LINK “Petrologic investigations of martian meteorite Northwest Africa (NWA) 13227 indicate…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[43],"tags":[6613,6614,1829],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/35458"}],"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=35458"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/35458\/revisions"}],"predecessor-version":[{"id":35459,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/35458\/revisions\/35459"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=35458"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=35458"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=35458"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}