Tsuyoshi Iizuka, Yi-Jen Lai, Waheed Akram, Yuri Amelin, Maria Sch\u00f6nb\u00e4chler<\/p>\n
Earth and Planetary Science Letters
\nAvailable online 11 February 2016
\ndoi:10.1016\/j.epsl.2016.02.005<\/p>\n
Updated: February 11, 2016<\/p>\n
PDF (open access)<\/strong><\/a> “Niobium-92 is an extinct proton-rich nuclide, which decays to 92Zr with a half-life of 37 Ma. This radionuclide potentially offers a unique opportunity to determine the timescales of early Solar System processes and the site(s) of nucleosynthesis for p-nuclei, once its initial abundance and distribution in the Solar System are well established. Here we present internal Nb-Zr isochrons for three basaltic achondrites with known U-Pb ages: the angrite NWA 4590, the eucrite Agoult, and the ungrouped achondrite Ibitira. Our results show that the relative Nb-Zr isochron ages of the three meteorites are consistent with the time intervals obtained from the Pb-Pb chronometer for pyroxene and plagioclase, indicating that 92Nb was homogeneously distributed among their source regions. The Nb-Zr and Pb-Pb data for NWA 4590 yield the most reliable and precise reference point for anchoring the Nb-Zr chronometer to the absolute timescale: an initial 92Nb\/93Nb ratio of $(1.4 \\pm 0.5) \\times 10^{-5}$ at $4557.93 \\pm 0.36$ Ma, which corresponds to a 92Nb\/93Nb ratio of $(1.7 \\pm 0.6) \\times 10^{-5}$ at the time of the Solar System formation. On the basis of this new initial ratio, we demonstrate the capability of the Nb-Zr chronometer to date early Solar System objects including troilite and rutile, such as iron and stony-iron meteorites. Furthermore, we estimate a nucleosynthetic production ratio of 92Nb to the p-nucleus 92Mo between 0.0015 and 0.035. This production ratio, together with the solar abundances of other p-nuclei with similar masses, can be best explained if these light p-nuclei were primarily synthesized by photodisintegration reactions in Type Ia supernovae. ”<\/p>\n","protected":false},"excerpt":{"rendered":" Tsuyoshi Iizuka, Yi-Jen Lai, Waheed Akram, Yuri Amelin, Maria Sch\u00f6nb\u00e4chler Earth and Planetary Science Letters Available online 11 February 2016 doi:10.1016\/j.epsl.2016.02.005 Updated: February 11, 2016 PDF (open access) abstract “Niobium-92 is an extinct proton-rich nuclide,…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[28,1598,37,523,72,35,68,71,507],"tags":[1819,759,1825,1823,478,2424,2423,1069,2508,2323,184],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/7108"}],"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=7108"}],"version-history":[{"count":5,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/7108\/revisions"}],"predecessor-version":[{"id":7451,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/7108\/revisions\/7451"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7108"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7108"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7108"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nabstract<\/strong><\/a><\/p>\n