LINK<\/strong><\/a><\/p>\n\n\n\n“Apatite has been widely used for assessing the volatile inventory and hydrothermal fluid compositions of asteroidal and planetary bodies. We report the OH, F, and Cl abundances, as well as the hydrogen isotope composition, of apatite in the CM1\u20102 chondrite Boriskino and in the C1\u2010ungrouped Bench Crater meteorite. Apatite in both meteorites is halogen\u2010poor, close to the hydroxylapatite endmember composition, and characterized by average \u03b4DSMOW values of \u2212226 \u00b1 59% and 233 \u00b1 92%, respectively. Compared to apatite, the matrix in Bench Crater is depleted in D with a \u03b4DSMOW value of \u221216 \u00b1 119\u2030. Comparing apatite and water H isotope compositions yields similar apatite\u2010water D\/H fractionation \u0394DApatite\u2010Water of approximately 120\u2013150\u2030 for both chondrites, suggesting that apatite formed at similar temperatures. Combining a lattice strain partitioning model with apatite F and Cl abundances in Boriskino and Bench Crater yields low F and Cl abundances <300 \u03bcg g\u22121 in apatite\u2010forming fluids, and fluid F\/Cl ratios that are roughly consistent with the bulk F\/Cl ratios of other CI and CM chondrites. This suggests that hydrothermal alteration on these meteorite parent bodies took place under closed\u2010system conditions. Based on the OH abundance estimates for the apatite\u2010forming fluids, we estimated the pH values of alteration fluids to be of approximately 10\u201313. Such alkaline fluid compositions are consistent with previous modeling and suggest that apatite formed late, toward the end of completion of hydrothermal alteration processes on the Boriskino and Bench Crater parent bodies.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Maxime Piralla, Romain Tart\u00e8se, Yves Marrocchi, Katherine H. Joy Meteoritics & Planetary ScienceVersion of Record online: 26 March 2021 LINK “Apatite has been widely used for assessing the volatile inventory and hydrothermal fluid compositions of…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[61,9,10,18,335],"tags":[658,5522,1392,3275,105,2180],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/27186"}],"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=27186"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/27186\/revisions"}],"predecessor-version":[{"id":27187,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/27186\/revisions\/27187"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=27186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=27186"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=27186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}