{"id":21284,"date":"2020-01-23T15:11:35","date_gmt":"2020-01-23T14:11:35","guid":{"rendered":"http:\/\/karmaka.de\/?p=21284"},"modified":"2020-01-23T15:11:36","modified_gmt":"2020-01-23T14:11:36","slug":"atmospheric-co2-levels-from-2-7-billion-years-ago-inferred-from-micrometeorite-oxidation","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=21284","title":{"rendered":"Atmospheric CO2 levels from 2.7 billion years ago inferred from micrometeorite oxidation<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>O. R. Lehmer, D. C. Catling, R. Buick, D. E. Brownlee and S. Newport<\/p>\n\n\n\n<p>Science Advances  22 Jan 2020:<br>\nVol. 6, no. 4, eaay4644<br>\nDOI: 10.1126\/sciadv.aay4644 <\/p>\n\n\n\n<p><a href=\"https:\/\/advances.sciencemag.org\/content\/6\/4\/eaay4644\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br>\n<a href=\"https:\/\/advances.sciencemag.org\/content\/advances\/6\/4\/eaay4644.full.pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;Earth\u2019s atmospheric composition during the Archean eon of 4 to 2.5 billion years ago has few constraints. However, the geochemistry of recently discovered iron-rich micrometeorites from 2.7 billion\u2013year\u2013old limestones could serve as a proxy for ancient gas concentrations. When micrometeorites entered the atmosphere, they melted and preserved a record of atmospheric interaction. We model the motion, evaporation, and kinetic oxidation by CO2 of micrometeorites entering a CO2-rich atmosphere. We consider a CO2-rich rather than an O2-rich atmosphere, as considered previously, because this better represents likely atmospheric conditions in the anoxic Archean. Our model reproduces the observed oxidation state of micrometeorites at 2.7 Ga for an estimated atmospheric CO2 concentration of &gt;70% by volume. Even if the early atmosphere was thinner than today, the elevated CO2 level indicated by our model result would help resolve how the Late Archean Earth remained warm when the young Sun was ~20% fainter.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>O. R. Lehmer, D. C. Catling, R. Buick, D. E. Brownlee and S. Newport Science Advances 22 Jan 2020: Vol. 6, no. 4, eaay4644 DOI: 10.1126\/sciadv.aay4644 LINK (OPEN ACCESS) PDF (OPEN ACCESS) &#8220;Earth\u2019s atmospheric composition&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[112,3157],"tags":[5396,2090,2821,2457,327],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/21284"}],"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=21284"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/21284\/revisions"}],"predecessor-version":[{"id":21285,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/21284\/revisions\/21285"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21284"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21284"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21284"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}