Neoproterozoic granitoid suites in southeastern Brazil.

Abstract

Neoproterozoic granitoid suites in southeastern Brazil are closely related to the different tectonic events. Petrography, geochemistry and structural features allow to separate these rocks into pre-, syn-, late and post-tectonic granitoids. The whole emplacement process lasted less than 100 Ma: from 595 Ma for the pre-tectonic granitoids, to 500 Ma for the post-tectonic ones. During this interval a 45 Ma magmatic quiet period (from 582 to 537 Ma) can also be characterized. Detailed field observations and mapping, coupled with petrological and geochemical observations, indicate an important role of the Archaean and Paleoproterozoic crust in the genesis of these granitoids, showing even evidences of some mantle interactions.