X-ray studies on crystalline rocks of the Ófalu Group, Mecsek Mountains, Hungary

Plagioclase, chlorite, biotite and muscovite component minerals have been separated from the metamorphic rock members of the Ófalu Group, Mecsek Mountains, S-Hungary. The mineral fractions were studied by X-ray powder diffraction methods. The plagioclases have composition of (low) albite to oligocla...

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Bibliographic Details
Main Authors: Ghoneim Mohamed Ahmed F.
Viczián István
Format: Article
Published: University of Szeged, Department of Mineralogy, Geochemistry and Petrology Szeged 1977
Series:Acta mineralogica-petrographica 23 No. 1
Kulcsszavak:Kőzettan, Ásványtan, Földtan
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Online Access:http://acta.bibl.u-szeged.hu/24616
Description
Summary:Plagioclase, chlorite, biotite and muscovite component minerals have been separated from the metamorphic rock members of the Ófalu Group, Mecsek Mountains, S-Hungary. The mineral fractions were studied by X-ray powder diffraction methods. The plagioclases have composition of (low) albite to oligoclase (peristerites). Chlorites and biotites were separated from greenstones derived from basic volcanic rocks. Chlorite formula corresponds to the composition of ripidolites according to the classification of HEY (1954). Biotites contain 2.7 (Fe + Mn) and 2.9 (Mg + Al) in six octahedral positions. Micas separated from mica schists revealed special characteristics: there is a double 060 reflection at 1.503 and 1.522 Á, respectively, probably due to a mixture of muscovite with a transitional dioctahedral-trioctahedral type mica similar to that, which was synthetized by CROWLEY and ROY [1964]. According to the authors' knowledge, no natural analogoues of this letter phase which have been reported so far. Standard mixtures of the separated minerals were prepared for the purposes of a quantitative X-ray diffraction analysis. Determinative graphs were constructed for hornblende, biotite, chlorite, plagioclase and quartz using metallic Cu as internal standard. Results of the application of the present method for the quantitative analysis of the Ófalu Group greenstones were compared with -those of the application of the BRISTOL [1967] method and with chemical mesonorm of the rocks.
Physical Description:29-39
ISSN:0365-8066