{"id":14541,"date":"2018-03-28T19:20:16","date_gmt":"2018-03-28T18:20:16","guid":{"rendered":"http:\/\/karmaka.de\/?p=14541"},"modified":"2018-03-28T19:37:10","modified_gmt":"2018-03-28T18:37:10","slug":"oxygen-isotopic-evidence-for-accretion-of-earths-water-before-a-high-energy-moon-forming-giant-impact","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=14541","title":{"rendered":"Oxygen isotopic evidence for accretion of Earth\u2019s water before a high-energy Moon-forming giant impact<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"<p>By Richard C. Greenwood, Jean-Alix Barrat, Martin F. Miller, Mahesh Anand, Nicolas Dauphas, Ian A. Franchi, Patrick Sillard, Natalie A. Starkey<\/p>\n<p>Science Advances  28 Mar 2018:<br \/>\nVol. 4, no. 3, eaao5928<br \/>\nDOI: 10.1126\/sciadv.aao5928 <\/p>\n<p><a href=\"http:\/\/advances.sciencemag.org\/content\/4\/3\/eaao5928.full\" target=\"_blank\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br \/>\n<a href=\"http:\/\/advances.sciencemag.org\/content\/advances\/4\/3\/eaao5928.full.pdf\" target=\"_blank\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n<p>&#8220;The Earth-Moon system likely formed as a result of a collision between two large planetary objects. Debate about their relative masses, the impact energy involved, and the extent of isotopic homogenization continues. We present the results of a high-precision oxygen isotope study of an extensive suite of lunar and terrestrial samples. We demonstrate that lunar rocks and terrestrial basalts show a 3 to 4 ppm (parts per million), statistically resolvable, difference in \u039417O. Taking aubrite meteorites as a candidate impactor material, we show that the giant impact scenario involved nearly complete mixing between the target and impactor. Alternatively, the degree of similarity between the \u039417O values of the impactor and the proto-Earth must have been significantly closer than that between Earth and aubrites. If the Earth-Moon system evolved from an initially highly vaporized and isotopically homogenized state, as indicated by recent dynamical models, then the terrestrial basalt-lunar oxygen isotope difference detected by our study may be a reflection of post\u2013giant impact additions to Earth. On the basis of this assumption, our data indicate that post\u2013giant impact additions to Earth could have contributed between 5 and 30% of Earth\u2019s water, depending on global water estimates. Consequently, our data indicate that the bulk of Earth\u2019s water was accreted before the giant impact and not later, as often proposed.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>By Richard C. Greenwood, Jean-Alix Barrat, Martin F. Miller, Mahesh Anand, Nicolas Dauphas, Ian A. Franchi, Patrick Sillard, Natalie A. Starkey Science Advances 28 Mar 2018: Vol. 4, no. 3, eaao5928 DOI: 10.1126\/sciadv.aao5928 LINK (OPEN&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[38,112,41,115,65,81],"tags":[4441,1826,4440,1474,4442,80,1109,113,1720,4443,642,1827,4444,1857,3858,4445,4446,1855],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14541"}],"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=14541"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14541\/revisions"}],"predecessor-version":[{"id":14542,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14541\/revisions\/14542"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14541"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14541"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}