Mineralogical Evidence of Hydrothermal Alteration in Cabeço de Vide Mafic – Ultramafic Complex, Central Portugal☆

Abstract Mineralogical and geochemical studies were carried out on hydrothermally altered rocks from the Cabeco de Vide ultramafic complex. Samples from a borehole ascribed to mineral water exploitation showed mineralogical composition dominated by antigorite, lizardite, amphiboles (inc. anthophyllite), and calcite, the clay fractions being dominated by serpentines and chlorite. The mineralogical zoning along the sampled borehole may be a result of hydrothermal signatures of the system, reflecting different evolution stages.