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Revista Brasüeir» de Geociências

22(4):493-499, dezembro de 1992

ESTRATIGRAFIA E SEDIMENTOLOGIA DO PROTEROZÓICO MÉDIO E SUPERIOR
DA REGIÃO SUDESTE DO CRÁTON AMAZÔNICO
CARLOS J.S. ALVARENGA* & GERSON S. SAES**

ABSTRACT
STRATIGRAPHY A>TOSEDIMENTOLOGY OF THE MIDDLE AND LATE PROTEROZOIC
IN THE SOUTHEAST OF THE AMAZONIAN CRATON.
The southeastern part of the Amazonian Craton is

made up of Archean and Lower Proterozoic sequences including gneiss, greenstone belts and a huge granitic suite.
During the Middle Proterozoic this craton was affected by an exteasional regime, during which fult zones of the cratonic basement were reactivated. Basins formed during this episode were nUed byte sediments of the Aguapei,
Sunsás and Huanchaca groups. These sedimente are interpreted as the product of deposition as a platform cover, with extensive shallow marine by-passing to deeper marine deposition ends with fluvial sediments. In the Sunsás and
Aguapef belt these middle Proterozoic sediments were affected by the Sonsas Orogeny, whereas in the Huanchaca,
Santa Barbara and Rio Branco regions, they are spared of the deformation. Late Proterozoic sediments and metasediments are present along the trasition zone between the Amazonian Craton ande the Paraguay Belt.Three Major
Glaciomarine sediments deposited on shelf domain (Puga Formation) and slope environments (Cuiabá Group). In this
Last enviroment the glaciomarine sediments were strongly reworked by turbidites currents. The midle unit inclues
Carbonate (Araras Formation) deposited directly on top of glaciomarine sediment, which the changes laterally towards the border of the Craton to muddy limestones (Guia Formation). The upper unit consists of siliciclastic sediments
(Raizama and Diamantino formations).
Keywords: Stratigraphy, Mid-Late Proterozok, Paraguay Belt, Aguapef Group, Mato Grosso.
RESUMO O sudeste do Cráton Amazônico é formado por seqüências do Arqueano ao Proterozóico Inferior, que apresentam gnaisses, rochas verdes