INSTITUTO SUPERIOR DE CORRELACION GEOLOGICA
Unidad Ejecutora - UE
Pegmatitas y depósitos hidrotermales de la Sierra de Velasco, La Rioja: Revisión mineralógica.
SARDI, F.G.; RICCI, H.I.; ROMANOS, C.; GROSSE, P.; BELLOS, L.I.; BÁEZ, M.A.
Acta Geológica Lilloana
Fundación Miguel Lillo
Lugar: Tucumán; Año: 2008 vol. 20 p. 54 - 54
A mineralogical review of some pegmatitic and hydrothermal deposits from Velasco range (Sierra de Velasco), La Rioja province, Argentina, is presented. Physical properties, mocroscopic descriptions, chemical tests and density of the different minerals have been realized. The pegmatites belong to Velasco district (or field) located in the central-sector of this range. Pegmatites from south of the range are studied also. However, the first one has both the greatest mineral concentrations and important mining possibility due to the gemological qualities of the some beryls. The studied hydrothermal deposits are El Cantadero on the flank of the range and Las Diaguitas which is probably a hydrothermal stage of homonymous pegmatite of the Velasco district. Muscovite, biotite, beryl, triplite, apatite, tourmaline and topaz are accessory minerals of Velasco district. The pegmatite from south of the Velasco Range contain magnetite, martite, and scarce biotite. Wolframite associated with apatite and garnet has been determined in Las Diaguitas, and iron-bearing mineral, azurite and malaquite have been recognized in El Cantadero. In this deposit, white mica and topaz have been determined in the border of the quartz-veins.