Počet záznamů: 1
A rapid and precise quantitative electron probe chemical mapping technique and its application to an ultrahigh-pressure eclogite from the Moldanubian Zone of the Bohemian Massif (Nové Dvory, Czech Republic)
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SYSNO ASEP 0498537 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název A rapid and precise quantitative electron probe chemical mapping technique and its application to an ultrahigh-pressure eclogite from the Moldanubian Zone of the Bohemian Massif (Nové Dvory, Czech Republic) Tvůrce(i) Yasumoto, A. (JP)
Yoshida, K. (JP)
Kuwatani, T. (JP)
Nakamura, D. (JP)
Svojtka, Martin (GLU-S) SAI, RID, ORCID
Hirajima, T. (JP)Celkový počet autorů 6 Zdroj.dok. American Mineralogist - ISSN 0003-004X
Roč. 103, č. 10 (2018), s. 1690-1698Poč.str. 9 s. Forma vydání Tištěná - P Jazyk dok. eng - angličtina Země vyd. US - Spojené státy americké Klíč. slova Bohemian Massif ; compositional map ; electron probe ; eclogite ; pyroxenite ; ultrahigh pressure ; X‑ray map Vědní obor RIV DB - Geologie a mineralogie Obor OECD Mineralogy Institucionální podpora GLU-S - RVO:67985831 UT WOS 000445855200015 EID SCOPUS 85049513321 DOI 10.2138/am-2018-6323CCBY Anotace Quantitative X‑ray mapping using an electron probe enables quantitative evaluation of inhomogeneities within rocks. Recent studies have proposed methods to construct quantitative chemical maps by combining X‑ray maps with referential spot analyses within a mapped area. These approaches address matrix effects by assuming each pixel in the mapped area represents a single phase. In such cases, the spatial resolution of the X‑ray maps must be sufficiently high to separate mineral phases.This study proposes a new procedure to reliably quantify centimeter-scale X‑ray maps even if the maps contain an ineligible number of pixels analyzing multiple phases because of a large mapping probe diameter. Such multi-phase pixels are statistically classified into their constituent phases by introducing a distribution-based clustering analysis. Furthermore, based on referential spot analyses, we implemented corrections for matrix effects and the backgrounds of single- and multi-phase pixels. Our technique, termed QntMap, was developed as an open source R package and distributed on a social coding platform, GitHub (https://github.com/atusy/qntmap).
We applied QntMap to calculate local bulk compositions within an ultrahigh-pressure eclogite from Nové Dvory, Czech Republic. The studied sample is a garnet-rich bimineralic eclogite that includes a 3 mm thick pyroxene-rich layer. A mapped area is approximately 3 × 1 cm in size and oriented normal to the layer. A profile normal to the layer shows increases in Cr2O3 (0.0 to 0.3 wt%) and XMg [Mg/(Fe+Mg) = 0.5 to 0.8] from the garnet-rich matrix toward the pyroxene-rich layer. A large variation in XMg and high-Cr2O3 contents in the pyroxene-rich layer are inconsistent with a cumulate origin. We suggest that the pyroxene-rich layer was derived from a pyroxenitic melt that intruded the eclogite.Pracoviště Geologický ústav Kontakt Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Rok sběru 2019
Počet záznamů: 1