ABSTRACT
This chapter reviews major constituents of the Early Proterozoic and of the Archean. The Amazonian craton is completely different Cover rocks consisting of lavas and continental sediments generally overlie the infrastructure or basement with a clear angular unconformity. Basement exposures in the region of Asuncion represent either the southern end of the Amazonian craton or a western fragment of the Rio de la Plata craton. The chapter describes in succession the Archean basement, the cratonic covers, whose age varies between Late Archean and Middle Proterozoic, and the rare metasediments exposed in the mobile zones of Namaqua and Natal, which mainly reactivated the Archean and a portion of its cover sequences around 1200-1000 Ma. In the Dom Feliciano fold belt in southern Brazil a succession composed of back arc metavolcanics and metasediments, together with diorites, quartz diorites, tonalites, granodiorites and granites, is interpreted as the roots of a magmatic arc.
