{"id":21763,"date":"2020-04-02T15:23:54","date_gmt":"2020-04-02T14:23:54","guid":{"rendered":"http:\/\/karmaka.de\/?p=21763"},"modified":"2020-04-02T15:23:56","modified_gmt":"2020-04-02T14:23:56","slug":"the-origin-and-fate-of-volatile-elements-on-earth-revisited-in-light-of-noble-gas-data-obtained-from-comet-67p-churyumov-gerasimenko","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=21763","title":{"rendered":"The origin and fate of volatile elements on Earth revisited in light of noble gas data obtained from comet 67P\/Churyumov-Gerasimenko<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>David V. Bekaert, Michael W. Broadley &amp; Bernard Marty <\/p>\n\n\n\n<p>Scientific Reports, Volume 10, Article number: 5796 (2020)<\/p>\n\n\n\n<p><a href=\"https:\/\/www.nature.com\/articles\/s41598-020-62650-3\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br>\n<a href=\"https:\/\/www.nature.com\/articles\/s41598-020-62650-3.pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;The origin of terrestrial volatiles remains one of the most puzzling questions in planetary sciences. The timing and composition of chondritic and cometary deliveries to Earth has remained enigmatic due to the paucity of reliable measurements of cometary material. This work uses recently measured volatile elemental ratios and noble gas isotope data from comet 67P\/Churyumov-Gerasimenko (67P\/C-G), in combination with chondritic data from the literature, to reconstruct the composition of Earth\u2019s ancient atmosphere. Comets are found to have contributed ~20% of atmospheric heavy noble gases (i.e., Kr and Xe) but limited amounts of other volatile elements (water, halogens and likely organic materials) to Earth. These cometary noble gases were likely mixed with chondritic &#8211; and not solar &#8211; sources to form the atmosphere. We show that an ancient atmosphere composed of chondritic and cometary volatiles is more enriched in Xe relative to the modern atmosphere, requiring that 8\u201312 times the present-day inventory of Xe was lost to space. This potentially resolves the long-standing mystery of Earth\u2019s \u201cmissing xenon\u201d, with regards to both Xe elemental depletion and isotopic fractionation in the atmosphere. The inferred Kr\/H2O and Xe\/H2O of the initial atmosphere suggest that Earth\u2019s surface volatiles might not have been fully delivered by the late accretion of volatile-rich carbonaceous chondrites. Instead, \u201cdry\u201d materials akin to enstatite chondrites potentially constituted a significant source of chondritic volatiles now residing on the Earth\u2019s surface. We outline the working hypotheses, implications and limitations of this model in the last section of this contribution.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>David V. Bekaert, Michael W. Broadley &amp; Bernard Marty Scientific Reports, Volume 10, Article number: 5796 (2020) LINK (OPEN ACCESS) PDF (OPEN ACCESS) &#8220;The origin of terrestrial volatiles remains one of the most puzzling questions&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,179,112,17],"tags":[613,1870,80,2579,369,600],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/21763"}],"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=21763"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/21763\/revisions"}],"predecessor-version":[{"id":21764,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/21763\/revisions\/21764"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21763"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21763"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21763"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}