GRANITOS PALEOPROTEROZÓICOS NO ESCUDO PRÉ-CAMBRIANO BOLIVIANO: AS ROCHAS MAGMÁTICAS DA CORRERECA DE 1,92-1,89 GA E IMPLICAÇÕES TECTÔNICAS

Paleoproterozoic granites in Bolivian Precambrian Shield: the 1.92-1.89 Ga Correreca Intrusion magmatic rocks and tectonic implications

Abstract

The Pb-Pb isotope results in zircons presented in this work define an important change in the chronostratigraphy of the units in the Bolivian Precambrian. In this sense, Correreca granite has an age variation between 1.92 and 1.89 Ga and was probably generated in a Paleoproterozoic magmatic event not yet reported in the pre-Cambrian Bolivian. The units described here as basements correspond to the oldest rocks in relation to the San Ignacio orogeny. In this way, these rocks older than the Lomas Manechis event, reported here as Correreca granite, which occurs in the southern part of the San Diablo shear zone and indicate a geological history distinct from other areas of the Precambrian basement in Bolivia. In the Santo Corazon region and south of the San Diablo front, the Correreca intrusion has a mostly granodioritic composition suggesting the San Diablo front may be interpreted as a suture zone between the southeastern of Paraguá and Sunsás blocks composed of a shear zone generated by the collision between both blocks with distint geologic evolution