2017-02-142017-02-141993-12-17BORGES, Maurício da Silva. Evolução tectono-estrutural da região de Dianópolis-Almas, SE do estado de Tocantins. Orientador: João Batista Sena Costa. 1993. 365 f. Tese (Doutorado em Geologia e Geoquímica) -Centro de Geociências, Universidade Federal do Pará, Belém, 1993. Disponível em: http://repositorio.ufpa.br:8080/jspui/handle/2011/7663. Acesso em: .https://repositorio.ufpa.br/handle/2011/7663Several geological sequences of rocks with distinct ages of evolution were mapped in the Dianopólis-Almas region (southwestern part of the State of Tocantins) in the Brasília block: an extensive segment of an Archean-Lower Proterozoic granite-greenstone terrain, Proterozoic metasediments of the Bambuí Group, Cretaceous continental deposits of the Urucuia Formation, colluvial and alluvial (partially lateritized) and Holocenic fluvial-lacustrine deposits. The granite-greenstone terrains include several strands of supracrustal rocks (Riachão do Ouro Group) and granitoid bodies (Serra do Boqueirão Suite), both developed over migmatized tonalitic gneisses, granulites and amphibolites of the Alto Paranã Complex. The Riachão do Ouro Group is composed of phyllite, schist, meta-rhyolite, meta-dacite, iron formation, quartzite, metaconglomerate and breccia; phyllite, schist and metavolcanic rocks are the dominant lithologies. The Serra do Boqueirão Suite includes granitoids of tonalitic, trondhjemitic, granodioritic and granitic compositions, which were strongly deformed in the border zones and cut by pegmatite and aplite veins. All there lithological units underwent ductile deformation which formed an anastomosed pattern of N10-20E, N45E, and N55W transcurrent shear zones. Along the shear zones there are asymmetric or symmetric transpressive duplexes alternating with straigth segments. These structures can be seen extensively developed at supracrustal rock-granitoid boundaries and are characterized by mylonitic foliation parallel to the tectonic layering; other structures are represented by internal duplexes, shear bands, pods of less deformed rocks, extensional cleavage of C' type (crenulation cleavage) and brittle-ductile shear zones expressed by dilatation structures (tension gashes). The stretching lineation is defined by rods of quartz, axes of agregates of elliptical minerais and elongated micas. Dextral sense of shearing is determined from kinematic criteria. Microfabric investigation suggest that the deformation was accommodated mainly by crystal plasticity and the crystallographic shape fabrics confirm the dextral sense of shearing. Only the N55W shear zones underwent sinistral movement. The observed sets of structures is interpreted as linked to a N20E dextral strike-slip system and, in this case, the N10-20E, N45E, N25W and N55W zones correspond respectively to Y, R, P and R' zones. The Archean-Lower Proterozoic evolution is understood in terms of an oblique collision of continental segments which uplifted the granulitic rocks and was followed by transtension regime which originated several basins in where the supracrustal rocks of the Riachão do Ouro Group were deposited, and the granitoids of the Serra do Boqueirão Suite were emplaced. The progressive deformation involved transpression characterized by ductile shear zones. The Middle to Upper Proterozoic is represented by the Bambuí Group which includes slates, metasiltites, phyllites and carbonate rocks. The tectonic structures linked to the São Francisco Basin inversion in the Upper Proterozoic, are represented by N-S oblique thrusts and NE-SW lateral ramps. During the Mesozoic (Upper Cretaceous) the Alto Sanfranciscana Basin was filled by continental sediments of the Urucuia Formation. The lithostratigraphic sequence is composed of the following lithofacies: 1) conglomeratic facies which represents residual paviments of.deflation and in part interdune deposits and wadifans related to an intermittent drainage system; 2) sandstone facies formed by ortoquartzite, arkose and subarkose which constitute wind deposits; 3) and stratified chert facies which represent chemical lacustrine deposits. The basin architecture includes also NNW-SSE listric normal faults and NE-SW transfer faults related to a N5OE extensional axis. During the Tertiary coluvial and aluvial deposits, which underwent lateritization as an immature profile, were formed. The Quaternary is represented by a lacustrine-fluvial sedimentary system. The drainage system is related to the basin of the Manoel Alves and Araguaia rivers, strongly controlled by NE-SW lineaments and associated to pull-apart structures linked to a dextral system.Acesso AbertoGeologia regionalGeologia estruturalGeologia estratigráficaGranito-GreenstoneRegião de Dianópolis-AlmasTocantins, SudoesteTeseCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::ESTRATIGRAFIACNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::GEOTECTONICACNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIA::GEOLOGIA REGIONAL