Metallogenic aspects of Itu intrusive suite

The integrated use of geological, geochemical, geophysical and remote sensing data is providing interesting new information on the metallogenic characteristics of the Itu Intrusive Suite. During World War II, up to 1959, a wolframite deposit was mined near the border of the northernmost body (Itupeva Granite). This deposit is formed by greisen veins associated with cassiterite and topaz, clearly linked with later phases of magmatic differentiation. Generally those veins are related to hydrothermal alteration of the granites and the above mentioned shear zone. U, Th and K determinations by field and laboratory gammaspectrometry were used for regional distribution analysis of those elements and its ratios and calculation of radioactivity heat production. In this aspects, the Itupeva Granite is the hottest and presents several anomalies in the Th/U ratio, indicative of late or post magmatic oxidation processes. (author)