Sediments from silicoclastic strata of Pleistocene age cropping out in North Calabria, near Castrovillari (CS) were examined. We have examined three stratigraphic sections of which one is made up of grey silty clays with a thickness of about 50 m which show intercalations and sandy lenses, while the others two, with a thickness of about 20 m, can be classified as silty sands. Mineralogical, grain size, chemical and micropaleontological analyses have been carried out. Optical microscopy shows that the biogenic component represents about 10% of the total framework in the > 63 μm size fraction and is essentially made up of Foraminifera in a well-preserved state. The examined sediments are referred to the middle Pleistocene age due to the presence of Hyalinea balthica. The terrigenous framework is essentially made up of grains and polycrystalline calcite grains, feldspars, micas (muscovite and biotite) and opacified quartz by the wear with rounded edges. Chemical and X-ray diffraction (XRD) analyses were carried out on size fractions smaller than 4 μm. The study carried out both on the bulk samples and on decarbonated samples has shown that the main components are represented, in order of abundance, by quartz, carbonates and clay minerals. The clay mineral association consists of illite, ferrous-type chlorite, kaolinite and smectite (especially montmorillonite). In addition, Fourier Transform Infrared spectroscopy (FTIR) studies also showed the presence of muscovite and dolomite. Based on chemical analyses, the main components are SiO2 (x–=48.55%), which is present within both quartz and clay minerals, and Al2O3 (x–=21.65%). The presence of illite, identified by X-ray diffraction, accounts for the K2O content (x–=3.85%), whereas Fe2O3 might be related to the presence of chlorite. The K/Rb ratio is low, indicating a high degree of sediment evolution. The V/Cr, U/Th, Ni/Co ratios indicate a discreetly oxygenated environment.

Mineralogia e geochimica di peliti pleistoceniche del Bacino di Castrovillari (Calabria, Italia meridionale).

SACCA', Carmelo;SACCA', Domenica;NUCERA, PREZIOSA;
2007

Abstract

Sediments from silicoclastic strata of Pleistocene age cropping out in North Calabria, near Castrovillari (CS) were examined. We have examined three stratigraphic sections of which one is made up of grey silty clays with a thickness of about 50 m which show intercalations and sandy lenses, while the others two, with a thickness of about 20 m, can be classified as silty sands. Mineralogical, grain size, chemical and micropaleontological analyses have been carried out. Optical microscopy shows that the biogenic component represents about 10% of the total framework in the > 63 μm size fraction and is essentially made up of Foraminifera in a well-preserved state. The examined sediments are referred to the middle Pleistocene age due to the presence of Hyalinea balthica. The terrigenous framework is essentially made up of grains and polycrystalline calcite grains, feldspars, micas (muscovite and biotite) and opacified quartz by the wear with rounded edges. Chemical and X-ray diffraction (XRD) analyses were carried out on size fractions smaller than 4 μm. The study carried out both on the bulk samples and on decarbonated samples has shown that the main components are represented, in order of abundance, by quartz, carbonates and clay minerals. The clay mineral association consists of illite, ferrous-type chlorite, kaolinite and smectite (especially montmorillonite). In addition, Fourier Transform Infrared spectroscopy (FTIR) studies also showed the presence of muscovite and dolomite. Based on chemical analyses, the main components are SiO2 (x–=48.55%), which is present within both quartz and clay minerals, and Al2O3 (x–=21.65%). The presence of illite, identified by X-ray diffraction, accounts for the K2O content (x–=3.85%), whereas Fe2O3 might be related to the presence of chlorite. The K/Rb ratio is low, indicating a high degree of sediment evolution. The V/Cr, U/Th, Ni/Co ratios indicate a discreetly oxygenated environment.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/1675444
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