New structural data collected along the type-section of the Araguaia Belt provides the basis for a new tectonic model of the region. We propose that two deformational phases affected the region: the first involves north-trending foliation dipping E and recording oblique sinistral thrusting, with structural vergence towards the Amazonian Craton. This phase is well displayed in the metasedimentary rocks of the Estrondo Group in the inner zone of the Araguaia Belt and was accompanied by amphibolite facies metamorphism. The second deformational phase is represented by orogen-parallel wrench tectonics leading to the development of vertical north-south trending shear zones. This second set of structures overprints the thrust fabric of the Estrondo Group and is responsible for the development of a retrograde metamorphism in the inner zone. An intervening phase of doming is inferred due to the existence of extensional fabric around the domes.
This tectonic model does not answer some questions regarding the tectonic evolution of the Araguaia Belt. For example, the reasons for the abrupt metamorphic contrast and difference in structural style between the inner and outer zones. Likewise, the significance of the Tocantins-Araguaia shear zone, the significance of the mafic-ultramafic bodies situated towards the foreland and finally the mechanism of dome generation are unclear.
The age of the strike-slip overprint has not been determined. But considering the tectonic framework of Congo-São Francisco, Amazonian and West African block interaction and the extension of the West African Craton limits to the south, we propose that strike-slip faults connect with the east-west trending dextral strike-slip faults in the Borborema Orogen on the northern margin of the São Francisco Craton through the Transbrasilian lineament buried under the Parnaíba cover sequence.
In summary, the Araguaia Belt, described as part of the Tocantins orogen, records two events. The older event, possibly Paleoproterozoic resulted in a fold and thrust belt verging towards the Amazonian craton. We postulate that by the end of the Brasiliano/Pan-African orogeny, the Araguaia Belt accommodated northward lateral escape of terranes wedged between the Amazonian and West African Cratons, overprinting its inner zone and deforming the younger Neoproterozoic strata of the Couto de Magalhães and Pequizeiro Formations in its outer zone.