Abstract

The Precambrian of Ceara (northeast Brazil) includes the reactivated Archean basement and Proterozoic metasediments that have gone through one single stage of metamorphism and deformation during the Brazilian orogeny that culminated at about 600 Ma. Preliminary petrostructural studies show that crystalline nappes with associated Himalayan-type reverse metamorphism have been thrust westward to southwestward over more than 150 km. Geometrical relationships indicate that some steep shear zones could be lateral ramps to the nappes. Thus, this Precambrian segment of the Brazilian belt has the petrostructural signature of a former overthickened continental crust similar to that generated by Himalayan-type continent-continent collisions.

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