LINK<\/strong><\/a><\/p>\n\n\n\n“The NWA 11004 ordinary chondrite (OC) can provide insights into the complex petrogenetic processes of the early solar system. Although originally classified as an L7 chondrite, it is reclassified as LL based on kamacite Ni (4.9 \u00b1 0.3 wt.%) and Co (3.6 \u00b1 0.5 wt.%) and bulk O\u2010isotopic composition (\u03b417O = 3.76\u2030; \u03b418O = 5.39\u2030). NWA 11004 is characterized by (1) the occurrence of 3\u2010 to 5\u2010mm\u2010sized poikilitic pyroxene, (2) scattered low\u2010Ca pyroxene data in a TiO2 versus Al2O3 diagram, (3) relatively magnesian olivine and low\u2010Ca pyroxene (Fa25.4, Fs21.3), (4) low abundances of high\u2010Ca pyroxene, plagioclase, troilite and Ca\u2010phosphate, and (5) low rare earth element contents in low\u2010Ca pyroxene. The geochemical features of olivine and low\u2010Ca pyroxene in NWA 11004 differ from literature data for grains that crystallized from a melt in an OC impact melt breccia. We suggest that in NWA 11004, a plagioclase\u2010phosphate high\u2010Ca pyroxene\u2010troilite melt migrated away during partial melting. Some high\u2010Ca pyroxene grains crystallized from the residual melt, as indicated by a positive linear trend in a TiO2 versus Al2O3 diagram. Whereas poikilitic low\u2010Ca pyroxene in NWA 11004 exhibits undulose\u2010to\u2010weak mosaic extinction, the olivine chadacrysts exhibit sharp optical extinction; this implies that NWA 11004 experienced a late\u2010stage shock event (S4) followed by annealing. The Ca\u2010phosphate 207Pb\/206Pb age of 4546 \u00b1 34 Ma most likely dates this late\u2010stage shock event. We suggest that the presence of type 7 OC in the early solar system may be attributable to impacts on warm chondritic asteroids that were initially heated by the decay of 26Al.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Y. Li, A. E. Rubin, W. Hsu, K. Ziegler JGR: Planets LINK “The NWA 11004 ordinary chondrite (OC) can provide insights into the complex petrogenetic processes of the early solar system. Although originally classified as…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24,7],"tags":[5572,1807],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/22109"}],"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=22109"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/22109\/revisions"}],"predecessor-version":[{"id":22110,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/22109\/revisions\/22110"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=22109"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=22109"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=22109"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}