Petrografia e zonas de alteração hidrotermal do furo PDH 18-03 projeto de cobre do alvo planalto, província mineral de Carajás (Pa)

Abstract

The Planalto prospect is located West from the Sossego iron oxide-copper-gold deposit in the Carajás Mineral Province. Geological studies aim description of mineralogical assembly and caracterization of hydrothermal alteration patterns which was included, scapolitization (bioitite- k-feldpsar) magnetite formation, chloritization, copper mineralization. With the data obtained it was possible to determine the sequence of hydrothermal alteration stages for Planalto prospect whereas was take account others genetic models of IOCG deposits in Carajás Province with hydrotermal alteration controlled by to two distinct E–Wand WNW–ESSE trending regional shear zones. With early scapolitization poorly represent marked by high salinity and temperature fluids (> 500ºC), superimposed by potassic alteration in lower temperature conditions, followed by late mineralization associated with chloritization, formed at temperatures (<350ºC) with decreasing salinity and pH and increasing oxygen fugacity, favoring the deposition of the sulphites, which chalcopyrite was the main mineral of copper ore associated with pyrite and sphalerite, and hydrothermal alteration veins relatively colder and later ,near to mineralization. The Planalto prospect has hydrothermal alteration sequence with characteristics that allow its classification as deposit IOCG.