An?lise estrutural do Sistema de Grabens do Rio Tocantins, borda oeste da Bacia do Parna?ba (Tocantins, Par? e Maranh?o)

• Main Author: Souza, Kau? Seoane
• Other Authors: 06892922449
• Language: Portuguese
• Published: PROGRAMA DE P?S-GRADUA??O EM GEODIN?MICA E GEOF?SICA 2017
• Subjects: CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOFISICA; Bacia do Parna?ba; Sistema de Grabens; Estruturas distensionais
• Online Access: https://repositorio.ufrn.br/jspui/handle/123456789/21575

Submitted by Automa??o e Estat?stica ([e-mail]) on 2017-01-03T19:37:12Z No. of bitstreams: 1 KaueSeoaneSouza_DISSERT.pdf: 7922270 bytes, checksum: 3448befee9f575a57b4d9a011df2972a (MD5) === Approved for entry into archive by Arlan Eloi Leite Silva ([e-mail]) on 2017-01-05T20:39:30Z (GMT) No. of bitstreams: 1 KaueSeoaneSouza_DISSERT.pdf: 7922270 bytes, checksum: 3448befee9f575a57b4d9a011df2972a (MD5) === Made available in DSpace on 2017-01-05T20:39:30Z (GMT). No. of bitstreams: 1 KaueSeoaneSouza_DISSERT.pdf: 7922270 bytes, checksum: 3448befee9f575a57b4d9a011df2972a (MD5) Previous issue date: 2016-06-08 === Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) === A borda oeste da Bacia do Parna?ba apresenta um marcante sistema de fotolineamentos N-S, imediatamente a leste do contato com o embasamento. A distribui??o das unidades litoestratigr?ficas nesta regi?o segue essa orienta??o N-S, diferindo do padr?o de faixa aflorante ovalada da bacia. Esse padr?o N-S corresponde a um sistema de grabens j? abordado nas cartas geol?gicas da CPRM, composto por um graben principal, no interior da bacia, e outro secund?rio, encravado no embasamento cristalino. Nas bordas do graben principal, as faixas aflorantes das forma??es Motuca e Samba?ba s?o balizadas por falhas normais ou normais obl?quas sinistrais, que ocasionam a omiss?o de unidades estratigr?ficas sotopostas. Mais a sul, na regi?o de Palmas-Miracema do Tocantins, o Grupo Serra Grande, a Forma??o Pimenteiras e o embasamento cristalino est?o em contato por falhas normais. O outro graben, localizado a oeste do principal, tamb?m acomoda a Forma??o Motuca e possui a mesma orienta??o. A an?lise de imagens SRTM auxiliou na cartografia dos fotolineamentos e dos limites dos grabens. A orienta??o N-S das falhas envolve uma varia??o de 20?-30? para E ou W, que ? controlada pelas anisotropias do embasamento cristalino nesta borda da bacia, relacionado ? Faixa Araguaia. Falhas de regime normal e normal sinistral evidenciam a uma distens?o NE durante a forma??o do graben. A idade m?nima para a forma??o do graben ? estimada no intervalo Permo-Tri?ssico, baseada nas rela??es estruturais e nas unidades litoestratigr?ficas afetadas por esses eventos. Na regi?o norte do mesmo, fotolineamentos E-W/ENE controlam as ocorr?ncias de basaltos e diab?sios eojur?ssicos da Su?te Mosquito, que interceptam as estruturas do graben principal. A distens?o N/NNW na Su?te Mosquito, e falhas normais ou transcorrentes ainda mais jovens, acomodando distens?o NW, s?o tentativamente correlacionadas aos eventos de abertura do Atl?ntico Central e Sul, respectivamente. === The west border of the Parna?ba Basin displays an outstanding N-S photolineaments pattern. The N-S orientation differs from the oval basin. This N-S pattern corresponds to a graben system, previously identified in CPRM geologic maps, including an eastern main graben inside the basin as well as a western structure isolated in the crystalline basement. Along the borders of the main graben, outcrops of young units (f.e. Motuca and Samba?da formations) are in contact with older units through normal and normal-oblique faults, with omission of stratigraphic sections. Inside of the basin, further south (Palmas and Miracema do Tocantins region), the Serra Grande Group, the Pimenteiras Formation and the crystalline basement appear side-by-side uplifted through normal faults. The other graben, in west of the main graben, also accommodates the Motuca Formation and have the same orientation the main graben. The analysis of SRTM images allowed mapping the photolineaments and the graben borders, beyond cutting relationships present in different photolineaments directions. Starting with geometry and kinematic of structures and the orbital image data, could be suggested three deformational events, D1, D2 e D3. The deformational event D1, it is the pioneer of grabens and responsible for your genesis and structuration, the N-S faults orientation of this event involves a 20? to 30? variation to E or W, which is controlled by basement anisotropies along this basin edge, related to the Araguaia Belt. The deformational event D2, is recognized mainly in north region of main graben, where EW/ENE photolineaments control the eojurassic basalts occurrence Suite Mosquito and intersects the structures of previous event. And the deformational event D3 show normal faults NE direction and strike-slip faults dextral and sinistral. Normal and normal sinistral faults, dominate the graben structuration and control your opening with NE distension. The minimum age for this is estimated in the Permo-Triassic interval, based on structural relations and the mentioned stratigraphic units. The E-W eojurassic distension structures of D2 on Suite Mosquito, and normal faults or strike-slip showing NW distension, are much young and tentatively correlated to the event of Atlantic Central and South opening, respectively.