{"id":7006,"date":"2016-01-23T10:06:46","date_gmt":"2016-01-23T09:06:46","guid":{"rendered":"http:\/\/karmaka.de\/?p=7006"},"modified":"2016-01-23T10:08:24","modified_gmt":"2016-01-23T09:08:24","slug":"the-chlorine-isotope-composition-of-martian-meteorites-2-implications-for-the-early-solar-system-and-the-formation-of-mars","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=7006","title":{"rendered":"The chlorine isotope composition of Martian meteorites 2. Implications for the early solar system and the formation of Mars"},"content":{"rendered":"<p>Sharp, Z., Williams, J., Shearer, C., Agee, C. and McKeegan, K.<\/p>\n<p>Meteoritics &#038; Planetary Science.<br \/>\ndoi: 10.1111\/maps.12591<br \/>\nArticle first published online: 22 JAN 2016<\/p>\n<p><a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.12591\/abstract\" target=\"_blank\"><strong>LINK<\/strong><\/a><\/p>\n<p>&#8220;We determined the chlorine isotope composition of 16 Martian meteorites using gas source mass spectrometry on bulk samples and in situ secondary ion microprobe analysis on apatite grains. Measured \u03b437Cl values range from \u22123.8 to +8.6\u2030. The olivine-phyric shergottites are the isotopically lightest samples, with \u03b437Cl mostly ranging from \u22124 to \u22122\u2030. Samples with evidence for a crustal component have positive \u03b437Cl values, with an extreme value of 8.6\u2030. Most of the basaltic shergottites have intermediate \u03b437Cl values of \u22121 to 0\u2030, except for Shergotty, which is similar to the olivine-phyric shergottites. We interpret these data as due to mixing of a two-component system. The first component is the mantle value of \u22124 to \u22123\u2030. This most likely represents the original bulk Martian Cl isotope value. The other endmember is a 37Cl-enriched crustal component. We speculate that preferential loss of 35Cl to space has resulted in a high \u03b437Cl value for the Martian surface, similar to what is seen in other volatile systems. The basaltic shergottites are a mixture of the other two endmembers. The low \u03b437Cl value of primitive Mars is different from Earth and most chondrites, both of which are close to 0\u2030. We are not aware of any parent-body process that could lower the \u03b437Cl value of the Martian mantle to \u22124 to \u22123\u2030. Instead, we propose that this low \u03b437Cl value represents the primordial bulk composition of Mars inherited during accretion. The higher \u03b437Cl values seen in many chondrites are explained by later incorporation of 37Cl-enriched HCl-hydrate.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Sharp, Z., Williams, J., Shearer, C., Agee, C. and McKeegan, K. Meteoritics &#038; Planetary Science. doi: 10.1111\/maps.12591 Article first published online: 22 JAN 2016 LINK &#8220;We determined the chlorine isotope composition of 16 Martian meteorites&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[122,42,43],"tags":[2369,1828],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/7006"}],"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=7006"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/7006\/revisions"}],"predecessor-version":[{"id":7008,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/7006\/revisions\/7008"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7006"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7006"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7006"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}