LINK<\/strong><\/a><\/p>\n\n\n\n“Highlights<\/p>\n\n\n\n
\u2022 A novel methodology for understanding surface-rock interactions.
\n\u2022 Multiple surface reservoirs sampled by martian meteorites.
\n\u2022 Perchlorate surface chemistry recorded in martian phosphates.”<\/p>\n\n\n\n
“The triple oxygen isotope compositions of phosphate grains in six martian meteorites have been measured by Secondary Ion Mass Spectrometry (SIMS) and combined together with their chlorine isotope and halogen concentrations have been used to constrain hydrosphere-lithosphere interactions on Mars. These samples include three enriched shergottites (Zagami, Roberts Massif 04262 and Larkman Nunatak 12011), one depleted shergottite (Tissint), an orthopyroxenite (Allan Hills 84001), and a regolith breccia (Northwest Africa 7533). The phosphates measured here have a range in \u03b418O [(18O\/16O)sample\/(18O\/16O)Standard-1] \u00d7 103] from +1.0 to +6.8\u2030 and could be a result of indigenous mantle values, mixing with martian water, or replacement reactions taking place on the surface of Mars. Three samples have a \u039417O [\u03b417O-1000(1 + \u03b418O \/1000)0.528-1] in equilibrium with the martian mantle (ALH 84001, Tissint, and Zagami), while three samples (LAR 12011, RBT 04262, and NWA 7533) have an elevated positive \u039417O outside of analytical uncertainty of the martian fractionation line (MFL). The phosphates in the latter group also have positive and negative \u03b437Cl [(37Cl\/35Cl)sample\/(37Cl\/35Cl)standard \u2013 1] \u00d7 103] and enrichments in halogens not seen in the rest of the sample suite. Perchlorate formation on Earth fractionates Cl in both positive and negative directions and generates a correlated positive \u039417O. Further, perchlorate has been detected in wt% amounts on the martian surface. Thus, these results strongly suggest the presence of multiple Cl isotope reservoirs on the martian surface that have interacted with the samples studied here over the last ca. 2 Ga of geologic time. The weighted average of \u039417O measurements from phosphate grains (n = 13) in NWA 7533, which are the explicit result of exchange reactions on the martian surface, yields a statistically robust mean value of 1.39 \u00b1 0.19\u2030 (2\u03c3, MSWD = 1.5, p = 0.13). This value likely represents an accurate estimate for an oxidized surface reservoir on Mars.”<\/p>\n","protected":false},"excerpt":{"rendered":"
J.J. Bellucci, M.J. Whitehouse, A.A. Nemchin, J.F. Snape, G.G. Kenny, R.E. Merle, P.A. Bland, G.K.Benedix Earth and Planetary Science Letters In Press, Corrected Proof, Available online 27 November 2019 LINK “Highlights \u2022 A novel methodology…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3180,122,42,46,65,43],"tags":[2795,4975,2612,5297,1858,1006,352,3443,5296,5086,1829,1885,1142],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20740"}],"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=20740"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20740\/revisions"}],"predecessor-version":[{"id":20741,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20740\/revisions\/20741"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=20740"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=20740"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=20740"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}