LINK<\/strong><\/a><\/p>\n\n\n\n“15N\/14N ratios of meteorites are a powerful tool for tracing the journey of life-essential volatiles like nitrogen (N), carbon and water from nebular solids to the present-day rocky planets, including Earth. The utility of 15N\/14N ratios of samples originating from differentiated protoplanets (e.g., iron meteorites) and planets (e.g., Earth\u2019s mantle) for tracing this journey could be affected by the fractionation of N isotopes during core-mantle differentiation, which would overprint their primitive compositions. The extent of N isotopic fractionation during core-mantle differentiation and its effect on the 15N\/14N ratios of resulting metallic and silicate reservoirs is, however, poorly understood. Using high pressure-temperature experiments, here we show that N isotopic fractionation between metallic and silicate melts (\u039415Nalloy\u2013silicate = \u03b415Nalloy \u2013 \u03b415Nsilicate = \u20133.3\u2030 to \u20131.0\u2030) is limited across a wide range of oxygen fugacity and is much smaller than previous estimates. Also, we present ab initio calculations based on the relevant N speciation in metallic and silicate melts confirming both the magnitude and direction of N isotopic fractionation predicted by our experimental results. Limited N isotopic fractionation during core-mantle differentiation suggests that the core and mantle relicts largely preserve the N isotopic compositions of their bulk bodies. Based on the \u03b415N values of non-carbonaceous iron meteorites (as low as \u201395\u2030), we predict that the extent of variations in the N isotopic compositions of inner solar system protoplanets was larger than that recorded by enstatite chondrites (\u03b415N = \u201329\u2030 to \u20136\u2030). As most of the Earth grew primarily via the accretion of similar inner solar system protoplanets, a relatively high \u03b415N value of present-day Earth\u2019s primitive mantle (\u20135\u2030) cannot be explained by the accretion of enstatite chondrite-like materials alone and necessitates a significant contribution of 15N-rich materials to the Earth\u2019s interior.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Damanveer S. Grewal, Tao Sun, Sanath Aithala, Taylor Hough, Rajdeep Dasgupta, Laurence Y. Yeung, Edwin Schauble Geochimica et Cosmochimica ActaAvailable online 19 October 2022 LINK “15N\/14N ratios of meteorites are a powerful tool for tracing…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[131,74,75,112,17,214,73],"tags":[1471,2219,2001,3218,1874,654,4289,2587,239,814,4187,369],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31396"}],"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=31396"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31396\/revisions"}],"predecessor-version":[{"id":31397,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31396\/revisions\/31397"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=31396"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=31396"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=31396"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}