{"id":39946,"date":"2025-11-30T21:09:00","date_gmt":"2025-11-30T20:09:00","guid":{"rendered":"https:\/\/karmaka.de\/?p=39946"},"modified":"2025-12-20T21:12:17","modified_gmt":"2025-12-20T20:12:17","slug":"northwest-africa-4269-a-metal-rich-eucrite-from-the-algerian-sahara","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=39946","title":{"rendered":"Northwest Africa 4269: a metal-rich eucrite from the Algerian Sahara"},"content":{"rendered":"\n<p>Abdelmadjid Seddiki, Bertrand Moine, J\u00e9r\u00f4me Bascou, Ratiba Kared, Jean Yves Cottin, Marguerite Godard, Fran\u00e7ois Faure, Richard C. Greenwood, Ian A. Franchi<\/p>\n\n\n\n<p>Geochemistry<br>Volume 85, Issue 4, December 2025, 126363<\/p>\n\n\n\n<p><a href=\"https:\/\/www.sciencedirect.com\/science\/article\/abs\/pii\/S0009281925001187\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;Northwest Africa (NWA) 4269 is an anomalous monomict eucrite that is characterized by a very high content of metallic iron (~ 3 %). It shows various textures (relict magmatic sub-ophitic, granulitic areas as coarse and fine-grained). NWA 4269 also shows petrographic evidence of secondary sub-solidus reheating events. Pyroxenes have homogeneous compositions and are iron-rich. NWA 4269 is metamorphosed type 5. It has a normal HED oxygen isotope composition. The chemical composition of NWA 4269 has characteristics similar to that of Nuevo-Laredo trend eucrites. Metal is extremely abundant in the fine-grained areas (~ 10 %). Metal also has a very low Ni content (Ni &lt; 0.1 %) that excludes a direct origin from a chondrite-like impactor. Origin of the pure-Fe groundmass metal remains enigmatic. The high metal content in NWA 4269 can be interpreted as having formed via the reduction of FeO and probably also by desulfidation of pre-existing troilite. Iron metal could have formed by deposition from a Fe-rich fluid that, probably after an event that triggered sudden reduction. NWA 4269 has normal HED oxygen isotope compositions and interpreted as belonging to the 4-Vesta asteroid.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Abdelmadjid Seddiki, Bertrand Moine, J\u00e9r\u00f4me Bascou, Ratiba Kared, Jean Yves Cottin, Marguerite Godard, Fran\u00e7ois Faure, Richard C. Greenwood, Ian A. Franchi GeochemistryVolume 85, Issue 4, December 2025, 126363 LINK &#8220;Northwest Africa (NWA) 4269 is an&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35,33],"tags":[3576,1823,212,7027],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39946"}],"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=39946"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39946\/revisions"}],"predecessor-version":[{"id":39947,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39946\/revisions\/39947"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=39946"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=39946"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=39946"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}