LINK<\/strong><\/a><\/p>\n\n\n\n“We report the results of a detailed study of the basaltic eucrite Northwest Africa (NWA) 7188, including its mineralogical and bulk geochemical characteristics, oxygen isotopic composition, and 147,146Sm\u2010143,142Nd mineral isochron ages. The texture and chemical composition of pyroxene and plagioclase demonstrate that NWA 7188 is a monomict eucrite with a metamorphic grade of type 4. The oxygen isotopic composition and the Fe\/Mn ratios of pyroxene confirmed that NWA 7188 belongs to the howardite\u2013eucrite\u2013diogenite meteorite suite, generally considered to originate from asteroid 4 Vesta. Whole\u2010rock TiO2, La, and Hf concentrations and a CI chondrite\u2010normalized rare earth element pattern are in good agreement with those of representative Stannern\u2010group eucrites. The 147,146Sm\u2010143,142Nd isochrons for NWA 7188 yielded ages of 4582 \u00b1 190 and 4554 +17\/\u221219 Ma, respectively. The closure temperature of the Sm\u2010Nd system for different fractions of NWA 7188 was estimated to be >865 \u00b0C, suggesting that the Sm\u2010Nd decay system has either been resistant to reheating at ~800 \u00b0C during the global metamorphism or only partially reset. Therefore, the 146Sm\u2010142Nd age of NWA 7188 corresponds to the period of initial crystallization of basaltic magmas and\/or global metamorphism on the parent body, and is unlikely to reflect Sm\u2010Nd disturbance by late reheating and impact events. In either case, NWA 7188 is a rare Stannern\u2010group eucrite that preserves the chronological information regarding the initial crustal evolution of Vesta.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Saya Kagami, Makiko K. Haba, Tetsuya Yokoyama, Tomohiro Usui, Richard C. Greenwood Meteoritics & Planetary Science First Published: 29 August 2019 LINK “We report the results of a detailed study of the basaltic eucrite Northwest…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35,33],"tags":[1823,5154,5155],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20339"}],"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=20339"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20339\/revisions"}],"predecessor-version":[{"id":20340,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20339\/revisions\/20340"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=20339"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=20339"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=20339"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}