Evolução estrutural do Sinclinório de Rio Maria, limite SE do Cráton Amazônico, Província Mineral de Carajás

Abstract

The Rio Maria Sinclinorium overlies the Rio Maria Granite-Greenstone Terrain at the SE Amazonian Craton limit, where is covered by the Araguaia Fold Belt. Displays landforms in mountains, plains, hills and plains, and structural lineaments show distinct deformation patterns. Mylonites, synforms and antiforms axial traces indicate NNE-SSW to NNW-SSE shortening, which are affected by brittle, semi-brittle and ductile structures (faults, fractures, tension gashes, kink folds, asymmetric folds, foliation and lineation stretching and mineral lineations), thus this relationship indicates shortening WNW-ESE to ENE-WSW late to NNE-SSW to NNW-SSE. Three evolution stages of this tectonic feature could be established based on structural and stratigraphic data: F1- includes the craton edge subsidence, epicontinental sea implantation and Rio Maria Fm. (Cachoeirinha and São Roque Members) deposition, F2 - involves the development of ENE-WSW ductile shear zones, placement of dykes swarms and Jamon suite, located metamorphism, the Rio Maria Basin uplift, inversion and its southern portion folding. This event is interpreted as a result of lithospheric extension, and as other worldwide Cratonic Nucleous (North China Craton, Hearne Craton in Canada and Cratons Pilbara and Yilgarn in Australia), involved passive rifts production among Orosiriano and Ectasiano; and F3 - NW tectonic transport and sinistral kinematics related to Araguaia Belt to Amazonian Craton collage.