{"id":4446,"date":"2015-04-21T16:26:42","date_gmt":"2015-04-21T14:26:42","guid":{"rendered":"http:\/\/karmaka.de\/?p=4446"},"modified":"2015-04-21T16:29:00","modified_gmt":"2015-04-21T14:29:00","slug":"chemical-characteristic-of-r-chondrites-in-the-light-of-p-rees-th-and-u-abundances","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=4446","title":{"rendered":"Chemical characteristic of R chondrites in the light of P, REEs, Th and U abundances"},"content":{"rendered":"<p>Rahat Khan, Naoki Shirai, Mitsuru Ebihara<\/p>\n<p>Earth and Planetary Science Letters<br \/>\nVolume 422, 15 July 2015, Pages 18\u201327<br \/>\ndoi:10.1016\/j.epsl.2015.04.008<\/p>\n<p><a href=\"http:\/\/www.sciencedirect.com\/science\/article\/pii\/S0012821X15002204\" target=\"_blank\"><strong>LINK<\/strong><\/a><\/p>\n<div class=\"su-quote su-quote-style-default\"><div class=\"su-quote-inner su-u-clearfix su-u-trim\">Rare earth elements (REEs), Th, U and P were determined in 15 Rumuruti (R)-type chondrites and the Allende CV chondrite. Repeated analyses of Allende for REEs, Th and U by ICP-MS and P by ICP-AES, and comparisons of these data with literature values ensure high reproducibility (precision) and reliability (accuracy) of acquired data. CI-normalized REE abundances in R chondrites are slightly enriched in heavy REEs with a small, positive Ce anomaly, in contrast to Allende. CI-normalized Pr\/Tm and Nd\/Yb ratios show a positive correlation, suggesting the heterogeneous mixing of two components (CI-like and refractory-rich materials) during the accretion of the R chondrite parent body. A Ce anomaly, however, was likely homogeneously present in the nebula. A mean Th\/U ratio of R chondrites is View the MathML source3.81\u00b10.13(1\u03c3), which is 5.1% higher than the CI ratio. Probably, the Th\u2013U fractionation was inherited from the nebula from which the R chondrite parent body formed. Besides the Th\u2013U fractionation, REEs and Th\u2013U are heterogeneously fractionated in R chondrites, for which parent body processing is assumed to be the cause. A mean P content of R chondrites (1254 \u03bcg\/g) is higher than for any ordinary chondrite and is close to the EL mean. There appears to be a negative correlation between P and REEs contents in R chondrites. It is probable that REEs were diluted by extraneously supplied, REEs-depleted and P-containing materials (schreibersite or metal). This process must have occurred heterogeneously during accretion so that the heterogeneity of P-containing materials was preserved in the R chondrite parent body and individual R chondrites.<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Rahat Khan, Naoki Shirai, Mitsuru Ebihara Earth and Planetary Science Letters Volume 422, 15 July 2015, Pages 18\u201327 doi:10.1016\/j.epsl.2015.04.008 LINK<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14,27],"tags":[108,1807,1311,1312,678,1187,1309,896,133,1310,132],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/4446"}],"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=4446"}],"version-history":[{"count":3,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/4446\/revisions"}],"predecessor-version":[{"id":4449,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/4446\/revisions\/4449"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4446"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4446"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4446"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}