Resumo

MOSCOTE DAZA, Yesica Paola et al. Mineralogical and geochemical evidence of the iron manifestations hosted in The Rhyodacite of Tabanos Unit, sector of Corral de Piedras, San Juan del Cesar, La Guajira. Prospect. [online]. 2018, vol.16, n.1, pp.67-75. ISSN 1692-8261.  https://doi.org/10.15665/rp.v16i1.1129.

In Corral de Piedras town, (San Juan de Cesar, La Guajira), there are important iron manifestations inside The Rhyodacite of Tabanos Unit, without references and geochemical classification. Four samples were randomly taken along the mineralization with the purpose of identifying the present minerals, morphologies, microtextures, percentage concentration of the iron oxides and to determine their possible origin. Samples were characterized by three laboratory tests, (1) X-ray diffraction (XRD) analysis corroborated the presence of hematite, magnetite, quartz and heated actinolite as major crystals; The iron oxides have a concentration in the rocks between 72,7 and 58,1%, (2) the samples were described microtextural and morphologically with the application of the scanning electron microscope and energy dispersion spectroscopy (SEM/EDS), presents a great variety of microstructural, morphological and textural characteristics, the hematite was characterized by well-defined polyhedral shapes with a slightly rough texture, the magnetite was observed with a rough texture and sinuous edges, the quartz and the actinolite presented a smooth texture, compact and dense surface, (3) X-ray fluorescence (XRF) for the chemical characterization of the minerals, the XRF showed concentrations of Fe2O3 between 64,21 and 78,35%. The iron manifestations are associated to the volcanic activity that between the Triassic and early Cretaceous affected the zone, were originated as a product of the hydrothermal activity and metasomatic substitution of the flows of lava riodaciticas by dissolution and precipitation of fluid magnetite at high temperatures.

Palavras-chave : Iron oxides; SEM/EDS; X-ray fluorescence; Magnetite.

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