{"id":19812,"date":"2019-06-18T06:45:19","date_gmt":"2019-06-18T04:45:19","guid":{"rendered":"http:\/\/karmaka.de\/?p=19812"},"modified":"2019-06-18T06:46:15","modified_gmt":"2019-06-18T04:46:15","slug":"shock-physics-mesoscale-modeling-of-shock-stage-5-and-6-in-ordinary-and-enstatite-chondrites","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=19812","title":{"rendered":"Shock physics mesoscale modeling of shock stage 5 and 6 in ordinary and enstatite chondritesOPEN ACCESS<\/span> "},"content":{"rendered":"\n

Juulia-Gabrielle Moreau, Tomas Kohout, Kai W\u00fcnnemann, Patricie Halodova, Jakub Haloda<\/p>\n\n\n\n

Icarus
\nIn Press, Accepted Manuscript, Available online 18 June 2019<\/p>\n\n\n\n

LINK (OPEN ACCESS)<\/strong><\/a>
\nPDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n

“Highlights<\/p>\n\n\n\n

\u2022 Shock metamorphism numerical modeling correlated with chondrite shock classification
\n\u2022 Porosity\/pre-heating creates conditions for higher shock stages at lower pressures.
\n\u2022 Shock-darkening in ordinary chondrites occurs from 40\u202fGPa to 60\u202fGPa.
\n\u2022 Crack orientation to the shock wave controls heating and melting of silicates.
\n\u2022 Real SEM-BSE images converted to numerical meshes in the iSALE shock physics code”<\/p>\n\n\n\n

“Shock-darkening, the melting of metals and iron sulfides into a network of veins within silicate grains, altering reflectance spectra of meteorites, was previously studied using shock physics mesoscale modeling. Melting of iron sulfides embedded in olivine was observed at pressures of 40\u201350\u202fGPa. This pressure range is at the transition between shock stage 5 (CS5) and 6 (CS6) of the shock metamorphism classification in ordinary and enstatite chondrites. To characterize CS5 and CS6 better with a mesoscale modeling approach and assess post-shock heating and melting, we used multi-phase (i.e. olivine\/enstatite, troilite, iron, pores, and plagioclase) meshes with realistic configurations of grains. We carried out a systematic study of shock compression in ordinary and enstatite chondrites at pressures between 30 and 70\u202fGPa. To setup mesoscale sample meshes with realistic silicate, metal, iron sulfide, and open pore shapes, we converted backscattered electron microscope images of three chondrites. The resolved macroporosity in meshes was 3\u20136%. Transition from shock CS5 to CS6 was observed through (1) the melting of troilite above 40\u202fGPa with melt fractions of ~0.7\u20130.9 at 70\u202fGPa, (2) the melting of olivine and iron above 50\u202fGPa with melt fraction of ~0.001 and 0.012, respectively, at 70\u202fGPa, and (3) the melting of plagioclase above 30\u202fGPa (melt fraction of 1, at 55\u202fGPa). Post-shock temperatures varied from ~540\u202fK at 30\u202fGPa to ~1300\u202fK at 70\u202fGPa. We also constructed models with increased porosity up to 15% porosity, producing higher post-shock temperatures (~800\u202fK increase) and melt fractions (~0.12 increase) in olivine. Additionally we constructed a pre-heated model to observe post-shock heating and melting during thermal metamorphism. This model presented similar results (melting) at pressures 10\u201315\u202fGPa lower compared to the room temperature models. Finally, we demonstrated dependence of post-shock heating and melting on the orientation of open cracks relative to the shock wave front. In conclusion, the modeled melting and post-shock heating of individual phases were mostly consistent with the current shock classification scheme (St\u00f6ffler et al. 2018, 2019).”<\/p>\n","protected":false},"excerpt":{"rendered":"

Juulia-Gabrielle Moreau, Tomas Kohout, Kai W\u00fcnnemann, Patricie Halodova, Jakub Haloda Icarus In Press, Accepted Manuscript, Available online 18 June 2019 LINK (OPEN ACCESS) PDF (OPEN ACCESS) “Highlights \u2022 Shock metamorphism numerical modeling correlated with chondrite…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1221,48,17,6,24,7,63],"tags":[1222,1833,2203,1807,1976,3176,260,1844,606],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/19812"}],"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=19812"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/19812\/revisions"}],"predecessor-version":[{"id":19814,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/19812\/revisions\/19814"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19812"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}