{"id":34483,"date":"2023-11-02T06:49:34","date_gmt":"2023-11-02T05:49:34","guid":{"rendered":"https:\/\/karmaka.de\/?p=34483"},"modified":"2023-11-02T06:49:35","modified_gmt":"2023-11-02T05:49:35","slug":"petrogenesis-of-the-dar-al-gani-dag-1-1%e2%80%89ma-ejection-paired-olivine-phyric-shergottites-and-implications-for-470%e2%80%89ma-martian-volcanism","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=34483","title":{"rendered":"Petrogenesis of the Dar al Gani (DaG) 1.1\u2009Ma ejection-paired olivine-phyric shergottites and implications for ~470\u2009Ma Martian volcanism<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Tarryn Aucamp, Geoffrey H. Howarth, Chad J. Peel, Gelu Costin, James M. D. Day, Petrus le Roux, James M. Scott, Ansgar Greshake, Rainer Bartoschewitz<\/p>\n\n\n\n<p>MAPS<br> Version of Record online: 01 November 2023<\/p>\n\n\n\n<p><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.14090\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/epdf\/10.1111\/maps.14090\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;The Dar al Gani (DaG) olivine-phyric shergottites share mineralogical and geochemical characteristics, which confirm that these meteorites are derived from a single source. Bulk trace elements (La\/Yb\u20140.12), in situ maskelynite 87Sr\/86Sr (~0.7014) and redox estimates (FMQ\u2009~\u2009\u22122) indicate derivation from a depleted, reduced mantle reservoir; identical to all ~470\u2009Ma shergottites ejected at 1.1\u2009Ma. The DaG shergottites have been variably affected by terrestrial alteration, which precipitated carbonate along fractures and modified bulk-rock fluid mobile (e.g., Ba) elements. Nonetheless, sufficient data are available to construct a multi-stage formation model for the DaG shergottites and other 1.1\u2009Ma ejection-paired shergottites that erupted at ~470\u2009Ma. First, partial melting of a depleted mantle source occurred at 1540\u2009\u00b1\u200920\u00b0C and 1.2\u2009\u00b1\u20090.1\u2009GPa, equivalent to &gt; ~100\u2009km depth. Then, initial crystallization in a staging chamber at ~85\u2009km depth at the crust\u2013mantle boundary took place, followed by magma evolution and variable incorporation of antecrystic olivine\u2009\u00b1\u2009orthopyroxene. Subsequently, crystallization of olivine phenocrysts and re-equilibration of olivine antecrysts occurred within an ascending magma. Finally, magmas with variable crystal loads erupted at the surface, where varied cooling rates produced a range of groundmass textures. This model is similar to picritic flood basalt magmas erupted on Earth.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Tarryn Aucamp, Geoffrey H. Howarth, Chad J. Peel, Gelu Costin, James M. D. Day, Petrus le Roux, James M. Scott, Ansgar Greshake, Rainer Bartoschewitz MAPS Version of Record online: 01 November 2023 LINK (OPEN ACCESS)PDF&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[523,122,43],"tags":[3389,1858,2794,1829,3126],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/34483"}],"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=34483"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/34483\/revisions"}],"predecessor-version":[{"id":34484,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/34483\/revisions\/34484"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=34483"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=34483"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=34483"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}