LINK<\/strong><\/a><\/p>\n\n\n\n“Fe-rich relict olivine grains are found in a small percentage of cosmic spherules, which are studied here to determine the nature of their precursors. We examined 128 Fe-rich relict olivine grains with Fa >10\u2009mol% from 53 cosmic spherules of different types collected from Antarctica (Antarctica micrometeorites [AMM]) and deep-sea sediments (DSS) of the Indian Ocean. Fe-rich olivines identified in cosmic spherules are close analogs of type II chondrule olivines formed in the early solar system. The olivine analysis shows well-defined trends in molar Fe\/Mn versus Fe\/Mg with an affinity for ordinary and carbonaceous chondrites. The minor oxides in olivine are in ranges such as MnO ~0.1\u20130.8\u2009wt%, Cr2O3 ~0\u20130.7\u2009wt%, CaO ~0\u20130.6\u2009wt%, and Al2O3 ~0\u20130.2\u2009wt%, respectively. The chemical composition suggests that the precursors for these Fe-rich olivine-bearing cosmic spherules consist of ordinary chondrites (~21%\u201323%, AMM-DSS), carbonaceous chondrites (~17%\u201336%, AMM-DSS), and a large fraction overlapping both carbonaceous and ordinary chondrites (~41%\u201362% AMM-DSS). The elemental ratios Fe\/Si\/CI and Mg\/Si\/CI for the Fe-rich relict olivines ranging between the values 0.5\u20131.0 and 1.1\u20131.7 are compatible with IDPs, Comet 81P\/Wild 2 as well as the Asteroid Itokawa and Ryugu, which are indistinguishable from carbonaceous and ordinary chondrites. In addition, pyroxene and olivine assemblages in their Fa versus Fs mol% show strong similarities to EOC chondrites. Our results on Fe-rich relict olivines show that these grains in cosmic spherules are less common than Mg-rich olivines, which show a narrow range of chemical compositions identical to those from ordinary chondrites and carbonaceous chondrites, indicating a supplementary contribution of an ordinary chondritic component to the micrometeorite source of dust.”<\/p>\n","protected":false},"excerpt":{"rendered":"
D. Fernandes, N. G. Rudraswami, M. Pandey, V. P. Singh MAPS, Version of Record online: 06 February 2024 LINK “Fe-rich relict olivine grains are found in a small percentage of cosmic spherules, which are studied…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,7],"tags":[3273,1381,3037,1807,4792],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/35347"}],"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=35347"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/35347\/revisions"}],"predecessor-version":[{"id":35348,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/35347\/revisions\/35348"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=35347"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=35347"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=35347"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}