LINK<\/strong><\/a><\/p>\n\n\n\n“The Fe isotopic compositions of mantles of differentiated inner solar system bodies are similar to, or heavier than those of chondritic meteorites. Core\u2013mantle differentiation is a potential contributor to planetary isotopic fractionation. However, previous metal\u2013silicate experiments provide only equivocal evidence for such fractionation, and have been used to argue that the Ni content of core-forming metal influences the extent of Fe isotopic fractionation. Here, we complement existing data with twenty-two novel metal\u2013silicate equilibrium experiments with varying Ni content to better quantify the effect of Ni on the vector and magnitude of Fe isotopic fractionation during core formation. We find no statistically resolvable effect of the Ni content in the metallic phase on the metal\u2013silicate Fe isotopic fractionation factor over a wide range of Ni concentrations (0 to 70 wt.% in the metal). In particular, the Fe isotopic composition of alloys from two experiments performed with 70 wt.% of Ni (\u03b456Femetal=0.27\u00b10.04\u2030 and 0.32\u00b10.03\u2030, 2 standard deviations \u03c3) are identical to the bulk experimental starting material (\u03b456Febulk=0.27\u00b10.10\u2030, 2\u03c3). Our data across all experiments yield an average isotopic fractionation factor \u039456Femet\u2013sil=0.05\u00b10.22\u2030 (2\u03c3) at 1873 K and 1\u20132 GPa, suggesting that little to no isotopic fractionation of Fe is expected to occur during core formation at low pressures. As such, our data does not support core formation as the main mechanism causing the observed variability in Fe isotope ratios between the silicate Earth, Moon, Vesta and other differentiated asteroids. A combination of multiple accretion-related processes\u2014including condensation from the solar nebula, volatile-depleting events such as giant impacts, and the disproportionation of ferrous iron to ferric iron and iron metal in larger bodies\u2014as well as deep mantle and recycling processes could explain the heavier-than-chondritic signatures in the silicate Earth and Moon. Furthermore, our results support the ideality of mixing among Fe\u2013Ni alloys, as previously demonstrated for physical properties but less conclusively evidenced for chemical properties.”<\/p>\n","protected":false},"excerpt":{"rendered":"
E. Kubik, P.A. Sossi, J. Siebert, E. Inglis, M. Roskosz, E. Siciliano Rego, N. Wehr, F. Moynier Geochimica et Cosmochimica ActaIn Press, Journal Pre-proof, Available online 24 February 2022 LINK “The Fe isotopic compositions of…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77,75,112,115,186],"tags":[462,2219,3679,1243,1928,3681,1872],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/30245"}],"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=30245"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/30245\/revisions"}],"predecessor-version":[{"id":30246,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/30245\/revisions\/30246"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=30245"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=30245"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=30245"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}