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GEOREF RECORD

Metamorphic chlorite and "vermiculitic" phases in mafic dikes from the Malaguide Complex (Betic Cordillera, Spain)

Maria Ruiz Cruz and Jiri K. Novak
Metamorphic chlorite and "vermiculitic" phases in mafic dikes from the Malaguide Complex (Betic Cordillera, Spain)
European Journal of Mineralogy (February 2003) 15 (1): 67-80

Abstract

Low-grade metamorphic mineral associations present in mafic dikes from the Malaguide Complex were examined by X-ray diffraction (XRD) analysis, electron microprobe analysis (EMPA) and transmission-analytical electron microscopy (TEM/AEM). The low-grade phyllosilicates occur both as pseudomorphs after pyroxene and as matrix phases of the rock. The metamorphic phyllosilicate assemblage is formed either by chlorite+muscovite or by the association chlorite+randomly ordered chlorite/vermiculite mixed-layers +1:1 regular chlorite/vermiculite mixed-layers+vermiculite (or Na-biotite). Chemical changes observed from chlorite to vermiculite phases include: 1) increase of the Si/Al ratio; 2) decrease of Mg+Fe; and 3) presence of variable amounts of Ca+alkali. Later alteration of the second assemblage originates Al-smectite, which forms from chlorite-mixed-layers- and low-charge biotite (vermiculite) packets. Excluding the alteration products, the mineral associations observed in dikes are similar, as studied by XRD, to those observed in metaclastites from this Complex, suggesting a common metamorphic event. Nevertheless, both EMPA and TEM/AEM analyses reveal chemical differences, which are probably related to differences in bulk-chemistry between metaclastites and dikes.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 15
Serial Issue: 1
Title: Metamorphic chlorite and "vermiculitic" phases in mafic dikes from the Malaguide Complex (Betic Cordillera, Spain)
Affiliation: Universidad de Malaga, Campus de Teatinos, Departamento de Quimica Inorganica, Malaga, Spain
Pages: 67-80
Published: 200302
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 58
Accession Number: 2003-025997
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 6 tables
N36°00'00" - N38°49'60", W07°30'00" - W00°40'00"
N36°00'00" - N38°45'00", W05°34'60" - E00°15'00"
Secondary Affiliation: Institute of Geology, CZE, Czech Republic
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute.
Update Code: 200309
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