{"id":22186,"date":"2020-06-01T17:45:00","date_gmt":"2020-06-01T15:45:00","guid":{"rendered":"http:\/\/karmaka.de\/?p=22186"},"modified":"2020-06-04T17:50:11","modified_gmt":"2020-06-04T15:50:11","slug":"shock-metamorphism-in-plagioclase-and-selective-amorphization","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=22186","title":{"rendered":"Shock metamorphism in plagioclase and selective amorphization<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Lidia Pittarello, Luke Daly, Annemarie E. Pickersgill, Ludovic Ferri\u00e8re, Martin R. Lee<\/p>\n\n\n\n<p>Meteoritics &amp; Planetary Science<br>Version of Record online:30 May 2020<\/p>\n\n\n\n<p><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.13494\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/onlinelibrary.wiley.com\/doi\/epdf\/10.1111\/maps.13494\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;Plagioclase feldspar is one of the most common rock\u2010forming minerals on the surfaces of the Earth and other terrestrial planetary bodies, where it has been exposed to the ubiquitous process of hypervelocity impact. However, the response of plagioclase to shock metamorphism remains poorly understood. In particular, constraining the initiation and progression of shock\u2010induced amorphization in plagioclase (i.e., conversion to diaplectic glass) would improve our knowledge of how shock progressively deforms plagioclase. In turn, this information would enable plagioclase to be used to evaluate the shock stage of meteorites and terrestrial impactites, whenever they lack traditionally used shock indicator minerals, such as olivine and quartz. Here, we report on an electron backscatter diffraction (EBSD) study of shocked plagioclase grains in a metagranite shatter cone from the central uplift of the Manicouagan impact structure, Canada. Our study suggests that, in plagioclase, shock amorphization is initially localized either within pre\u2010existing twins or along lamellae, with similar characteristics to planar deformation features (PDFs) but that resemble twins in their periodicity. These lamellae likely represent specific crystallographic planes that undergo preferential structural failure under shock conditions. The orientation of preexisting twin sets that are preferentially amorphized and that of amorphous lamellae is likely favorable with respect to scattering of the local shock wave and corresponds to the \u201cweakest\u201d orientation for a specific shock pressure value. This observation supports a universal formation mechanism for PDFs in silicate minerals.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Lidia Pittarello, Luke Daly, Annemarie E. Pickersgill, Ludovic Ferri\u00e8re, Martin R. Lee Meteoritics &amp; Planetary ScienceVersion of Record online:30 May 2020 LINK (OPEN ACCESS)PDF (OPEN ACCESS) &#8220;Plagioclase feldspar is one of the most common rock\u2010forming&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1598,59,90,63],"tags":[1416,1447,334,3176,1844],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/22186"}],"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=22186"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/22186\/revisions"}],"predecessor-version":[{"id":22188,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/22186\/revisions\/22188"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=22186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=22186"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=22186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}