LINK<\/strong><\/a><\/p>\n“Highlights<\/p>\n
\u2022 We studied 3 lithologies of the Chelyabinsk meteorite in the mid-infrared.
\n\u2022 Features change with increasing impact shock.
\n\u2022 Characteristic is a loss of features with increasing shock.
\n\u2022 Impact melt lithology shows the simplest spectrum.”<\/p>\n
“In order to provide spectral ground truth data for remote sensing applications, we have measured mid-infrared spectra (2-18 \u00b5m) of three typical, well-defined lithologies from the Chelyabinsk meteorite that fell on February 15, 2013, near the city of Chelyabinsk, southern Urals, Russia. These lithologies are classified as (a) moderately shocked, light lithology, (b) shock-darkened lithology, and (c) impact melt lithology. Analyses were made from bulk material in four size fractions (0-25 \u00b5m, 25-63 \u00b5m, 63-125 \u00b5m, and 125-250 \u00b5m), and from additional thin sections.<\/p>\n
Characteristic infrared features in the powdered bulk material of the moderately shocked, light lithology, dominated by olivine, pyroxene and feldspathic glass, are a Christiansen feature (CF) between 8.5 and 8.8 \u00b5m; a transparency feature (TF) in the finest size fraction at \u223c13 \u00b5m, and strong reststrahlen bands (RB) at \u223c9.1 \u00b5m, 9.5 \u00b5m, 10.3 \u00b5m, 10.8 \u00b5m, 11.2-11.3 \u00b5m, 12 \u00b5m, and between 16 and 17 \u00b5m. The ranges of spectral features for the micro-FTIR spots show a wider range than those obtained in diffuse reflectance, but are generally similar.<\/p>\n
With increasing influence of impact shock from \u2018pristine\u2019 LL5 (or LL6) material (which have a low or moderate degree of shock) to the shock-darkened lithology and the impact melt lithology as endmembers, we observe the fading\/disappearing of spectral features. Most prominent is the loss of a \u2018twin peak\u2019 feature between 10.8 and 11.3 \u00b5m, which turns into a single peak. In addition, in the \u2018pure\u2019 impact melt \u201cendmember lithology\u201d features at \u223c9.6 \u00b5m and \u223c9.1 \u00b5m are also lost. These losses are most likely correlated with decreasing amounts of crystal structure as the degree of shock melting increases. These changes could connect mid-infrared features with stages for shock metamorphism (St\u00f6ffler et al., 1991): Changes up to shock stage S4 would be minor, the shock darkened lithology could represent S5 and the impact melt lithology S6 and higher.<\/p>\n
Similarities of the Chelyabinsk spectra to those of other LL chondrites indicate that the findings of this study could be related to this group of meteorites in general.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Andreas Morlok, Addi Bischoff, Markus Patzek, Martin Sohn, Harald Hiesinger Icarus In Press, Accepted Manuscript, Available online 25 November 2016 LINK “Highlights \u2022 We studied 3 lithologies of the Chelyabinsk meteorite in the mid-infrared. \u2022…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[48,24,7,47],"tags":[1833,1816,262,1631,1807],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/10657"}],"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=10657"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/10657\/revisions"}],"predecessor-version":[{"id":11108,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/10657\/revisions\/11108"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10657"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10657"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10657"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}