LINK<\/strong><\/a><\/p>\n“Here we report in situ secondary ionization mass spectrometry Ca\u2010phosphate U\u2010Pb ages for an L\u2010impact melt breccia (NWA 7251), which are integrated with petrological and mineral chemical studies of this meteorite. NWA 7251 is a heavily shocked rock that is composed mainly of the chondrite host, impact melt portion, and melt veins (crosscutting and pervasive type). The host is an L4 chondrite that has been shocked to S4. The impact melt portion has a fine\u2010grained igneous texture, and is composed mainly of olivine, low\u2010Ca pyroxene, high\u2010Ca pyroxene, and albitic glass. The impact melt was generated at pressure of >30\u201335 GPa and temperature of >1300\u20131500 \u00b0C during an impact event. The Ca\u2010phosphate grains in the host were affected by a shock heating event. Most of the Ca\u2010phosphate grains in the melt were neocrystallized, but relatively large grains enclosed by or adjacent to metal veins or melt globules are likely inherited. The U\u2010Pb isotopic systematics of Ca\u2010phosphates in NWA 7251 yield an upper intercept age of 4457 \u00b1 56 Ma and a lower intercept age of 574 \u00b1 82 Ma on the normal U\u2010Pb concordia diagram. The age of 4457 \u00b1 56 Ma is interpreted to be related to an early shocking event rather than the thermal metamorphism of the parent body. The impact melt and veins in NWA 7251 were generated at 574 \u00b1 82 Ma, resulting from disruption of the L chondrite parent body. “<\/p>\n","protected":false},"excerpt":{"rendered":"
Meteoritics & Planetary Science First published: 24 March 2018 https:\/\/doi.org\/10.1111\/maps.13061 LINK “Here we report in situ secondary ionization mass spectrometry Ca\u2010phosphate U\u2010Pb ages for an L\u2010impact melt breccia (NWA 7251), which are integrated with petrological…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23,7,337],"tags":[2207,1815,2370,1457,4431,1807,2887,1844],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14515"}],"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=14515"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14515\/revisions"}],"predecessor-version":[{"id":14516,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14515\/revisions\/14516"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14515"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14515"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14515"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}