{"id":9425,"date":"2016-04-01T22:18:12","date_gmt":"2016-04-01T20:18:12","guid":{"rendered":"http:\/\/karmaka.de\/?p=9425"},"modified":"2016-07-15T13:29:09","modified_gmt":"2016-07-15T11:29:09","slug":"in-situ-observation-x-ray-diffraction-and-raman-analyses-of-carbon-minerals-in-ureilites-origin-and-formation-mechanisms-of-diamond-in-ureilites","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=9425","title":{"rendered":"In situ observation, X\u2013ray diffraction and Raman analyses of carbon minerals in ureilites: Origin and formation mechanisms of diamond in ureilites<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"<p>Yoshihiro NAKAMUTA, Fumio KITAJIMA, Kazuhiko SHIMADA<\/p>\n<p>Journal of Mineralogical and Petrological Sciences<\/p>\n<p><a href=\"https:\/\/www.jstage.jst.go.jp\/article\/jmps\/advpub\/0\/advpub_150906\/_pdf\" target=\"_blank\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n<p>&#8220;Carbon minerals in sixteen monomict ureilites which are variable in shock features in olivine were observed in situ by optical microscopy, scanning electron microscopy, X\u2013ray powder diffraction, and Raman analyses. Euhedral blade\u2013like shaped or amoeboid shaped graphite crystals occur in the very low\u2013shock ureilites, not associated with diamond. In the low, medium, and high\u2013shock ureilites, diamond occurs together with graphite. X\u2013ray diffraction and Raman analyses reveal that crystallinity of diamond is relatively well in the low\u2013shock ureilites, although it varies in a wide range in the high\u2013shock ureilites. Diamond formation in the low\u2013shock ureilites occurred as a result of solid\u2013state catalytic transformation of graphite at a pressure lower than 10 GPa, with metallic iron as the catalyst, while diamond in the high\u2013shock ureilites formed by spontaneous transformation of graphite together with the catalytic transformation at a pressure higher than 12 GPa. The relative crystal\u2013axes orientations between graphite (Gr) and diamond (Di) determined by EBSD analyses in the low\u2013shock Y\u20138448 ureilite is the same as that observed for graphite and diamond in a carbon grain from the high\u2013shock Goalpara ureilite. The metallic iron catalyst promoted the sliding and puckering of the hexagonal carbon planes of graphite in the solid\u2013state transformation processes of graphite to diamond after intercalating into its interplanar spaces. It is shown that noble gas systematics in ureilites can be matched with the shock formation origin of diamond in ureilites. &#8220;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Yoshihiro NAKAMUTA, Fumio KITAJIMA, Kazuhiko SHIMADA Journal of Mineralogical and Petrological Sciences PDF (OPEN ACCESS) &#8220;Carbon minerals in sixteen monomict ureilites which are variable in shock features in olivine were observed in situ by optical&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[28,39],"tags":[1328,3057,423,3058,245],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/9425"}],"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=9425"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/9425\/revisions"}],"predecessor-version":[{"id":9426,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/9425\/revisions\/9426"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9425"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9425"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9425"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}