Ricardo a Valls P Geo

Petrographic and Correlation Study of the San Jose de las Malezas Quartz-Gold Deposit Ricardo a Valls P Geo

A series of nine full petrological descriptions were made from the main host rocks at San José de Las Malezas quartz -gold deposit in Santa Clara, Villa Clara, Cuba. These main petrological groups include leucocratic gabbros, "fresh" (less altered) massive serpentinites, quartz veins and altered (iron and carbonatic alterations) serpentinites. The mafic rocks contain chiefly plagioclase and clinopyroxene as the principal components, with less frequently olivine and a relative large variety of secondary and accessory minerals. Felsic rocks are composed mainly by quartz with different accessory minerals. The inductively coupled plasma optical emission spectroscopy (ICP-EOS) of the global composition of these two main petrological groups allowed the determination of their characteristic correlation coefficients. This study suggests that gold was contributed not by the hydrothermal process itself, but by the remobilization of this element from the host rocks. The presence of zeolites within the quartz bodies is interpreted as an indicator of their low-temperature character. It is proposed that quartz veins were formed as a result of the listwaenitization of the serpentinites, combined with the hydrothermal-metasomatic fluids that altered the host rocks after their obduction onto the surface.