{"id":13097,"date":"2017-06-29T17:37:13","date_gmt":"2017-06-29T15:37:13","guid":{"rendered":"http:\/\/karmaka.de\/?p=13097"},"modified":"2017-06-29T17:38:18","modified_gmt":"2017-06-29T15:38:18","slug":"coordinated-mineralogical-and-isotopic-analyses-of-a-cosmic-symplectite-discovered-in-a-comet-81pwild-2-sample","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=13097","title":{"rendered":"Coordinated mineralogical and isotopic analyses of a cosmic symplectite discovered in a comet 81P\/Wild 2 sample."},"content":{"rendered":"<p>Nguyen, A. N., Berger, E. L., Nakamura-Messenger, K., Messenger, S. and Keller, L. P.<\/p>\n<p>Meteoritics &#038; Planetary Science. doi: 10.1111\/maps.12905<\/p>\n<p><a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.12905\/full\" target=\"_blank\"><strong>LINK<\/strong><\/a><\/p>\n<p>&#8220;We have discovered in a Stardust mission terminal particle a unique mineralogical assemblage of symplectically intergrown pentlandite ((Fe,Ni)9S8) and nanocrystalline maghemite (\u03b3-Fe2O3). Mineralogically similar cosmic symplectites (COS) have only been found in the primitive carbonaceous chondrite Acfer 094 and are believed to have formed by aqueous alteration. The O and S isotopic compositions of the Wild 2 COS are indistinguishable from terrestrial values. The metal and sulfide precursors were thus oxidized by an isotopically equilibrated aqueous reservoir either inside the snow line, in the Wild 2 comet, or in a larger Kuiper Belt object. Close association of the Stardust COS with a Kool mineral assemblage (kosmochloric Ca-rich pyroxene, FeO-rich olivine, and albite) that likely originated in the solar nebula suggests the COS precursors also had a nebular origin and were transported from the inner solar system to the comet-forming region after they were altered.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Nguyen, A. N., Berger, E. L., Nakamura-Messenger, K., Messenger, S. and Keller, L. P. Meteoritics &#038; Planetary Science. doi: 10.1111\/maps.12905 LINK &#8220;We have discovered in a Stardust mission terminal particle a unique mineralogical assemblage of&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,179,335],"tags":[1329,3958,568,972],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13097"}],"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=13097"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13097\/revisions"}],"predecessor-version":[{"id":13098,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13097\/revisions\/13098"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13097"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13097"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13097"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}