{"id":39858,"date":"2025-11-25T21:38:08","date_gmt":"2025-11-25T20:38:08","guid":{"rendered":"https:\/\/karmaka.de\/?p=39858"},"modified":"2025-11-25T21:38:09","modified_gmt":"2025-11-25T20:38:09","slug":"physicochemical-controls-on-the-compositions-of-the-earth-and-planets","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=39858","title":{"rendered":"Physicochemical Controls on the Compositions of the Earth and Planets<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Paolo A. Sossi, Remco C. Hin, Thorsten Kleine, Alessandro Morbidelli &amp; Francis Nimmo<\/p>\n\n\n\n<p>Space Science Reviews, Volume 221, article number 118, Published: 25 November 2025<\/p>\n\n\n\n<p><a href=\"https:\/\/link.springer.com\/article\/10.1007\/s11214-025-01243-w\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/link.springer.com\/content\/pdf\/10.1007\/s11214-025-01243-w.pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;Despite the fact that the terrestrial planets all formed from the protoplanetary disk, their bulk compositions show marked departures from that of material condensing from a canonical H2-rich solar nebula. Metallic cores fix the oxygen fugacities (fO2s) of the planets to between \u223c5 (Mercury) and \u223c1 log units below the iron-w\u00fcstite (IW) buffer, orders of magnitude higher than that of the nebular gas. Their oxidised character is coupled with a lack of volatile elements with respect to the solar nebula. Here we show that condensates from a canonical solar gas at different temperatures (T0 ) produce bulk compositions with Fe\/O (by mass) ranging from \u223c0.93 (T0 = 1250 K) to \u223c0.81 (T0 = 400 K), far lower than that of Earth at 1.06. Because the reaction Fe(s) + H2O(g) = FeO(s) + H2(g) proceeds only below \u223c600 K, temperatures at which most moderately volatile elements (MVEs) have already condensed, oxidised planets are expected to be rich in volatiles, and vice-versa. That this is not observed suggests that planets i) did not accrete from equilibrium nebular condensates and\/or ii) underwent additional volatile depletion\/f O 2 changes at conditions distinct from those of the solar nebula. Indeed, MVE abundances in small telluric bodies (Moon, Vesta) are consistent with evaporation\/condensation at \u0394IW-1 and \u223c1400\u20131800 K, while the extent of mass-dependent isotopic fractionation observed implies this occurred near- or at equilibrium. On the other hand, the volatile-depleted elemental- yet near-chondritic isotopic compositions of larger telluric bodies (Earth, Mars) reflect mixing of bodies that had themselves experienced different extents of volatile depletion, overprinted by accretion of volatile-undepleted material. On the basis of isotopic anomalies in Cr- and Ti in the BSE, such undepleted matter has been proposed to be CI chondrites, which would comprise 40% by mass if the proto-Earth were ureilite-like. However, this would result in an overabundance of volatile elements in the BSE, requiring significant loss thereafter, which has yet to be demonstrated. On the other hand, 6% CI material added late to an enstatite chondrite-like proto-Earth would broadly match the BSE composition. However, because the Earth is an end-member in isotopic anomalies of heavier elements, no combination of existing meteorites alone can account for its chemical- and isotopic composition. Instead, the Earth is most likely made partially or essentially entirely from an NC-like missing component. If so, the oxidised-, yet volatile-poor nature of differentiated bodies in the inner solar system, including Earth and Mars, is a property intrinsic to the NC reservoir.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Paolo A. Sossi, Remco C. Hin, Thorsten Kleine, Alessandro Morbidelli &amp; Francis Nimmo Space Science Reviews, Volume 221, article number 118, Published: 25 November 2025 LINK (OPEN ACCESS)PDF (OPEN ACCESS) &#8220;Despite the fact that the&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[74,131,112,73],"tags":[80,2001,5802,4453,239,1761,1009,2992],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39858"}],"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=39858"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39858\/revisions"}],"predecessor-version":[{"id":39859,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39858\/revisions\/39859"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=39858"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=39858"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=39858"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}