Record details

Title
    Metamorphic chlorite and "vermiculitic" phases in mafic dikes from the Maláguide Complex (Betic Cordillera, Spain)
Statement of responsibility
    María Dolores Ruiz Cruz, Jiří K. Novák
Author
    Novák, Jiří K.
    Ruiz Cruz, María Dolores
Language
    anglicky
Source title - serial
    European journal of mineralogy
Vol./nr.
    Vol. 15, no. 1
Pages
    p. 67-80
Year
    2003
Notes
    5 obr., 7 fot., 6 tab., 2 s. bibl.
    il.
    Zkr. název ser.: Eur. J. Mineral.
Subject group
    chemismus minerálů
    dajka
    fylosilikáty
    geotermometrie
    metamorfóza nízkostupňová
    mikroanalýza elektronová
    mikroskopie elektronová transmisní
    minerály smíšených struktur
    vermikulit
    vrásnění alpinské
Geographical name
    Španělsko-Andalusie
Keyword
    Betic
    Chlorite
    Complex
    Cordillera
    Dikes
    Mafic
    Maláguide
    Metamorphic
    Phases
    Spain
    Vermiculitic
Abstract (in english)
   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/venniculite mixed-layers +1:1 regular chlorite/vermiculite mixed-layers + vermiculite (or Na-biotite). Chemical changes observed from chlorite to vermiculitic 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
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    15. 8. 2007
Import date
    8. 8. 2012