Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-10-04T19:47:29Z No. of bitstreams: 1 AlineCristineTavares_DISSERT.pdf: 5980937 bytes, checksum: daf398f9ace99aeccba1a757dc2c694d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-10-10T22:51:12Z (GMT) No. of bitstreams: 1 AlineCristineTavares_DISSERT.pdf: 5980937 bytes, checksum: daf398f9ace99aeccba1a757dc2c694d (MD5) / Made available in DSpace on 2017-10-10T22:51:12Z (GMT). No. of bitstreams: 1 AlineCristineTavares_DISSERT.pdf: 5980937 bytes, checksum: daf398f9ace99aeccba1a757dc2c694d (MD5) Previous issue date: 2017-07-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Margens continentais transformantes s?o caracterizadas pela presen?a de falhas transformantes/zonas de fratura de grande rejeito transcorrente, que foram investigadas escassamente quando comparadas ?s margens divergentes e convergentes. Essas falhas influenciaram a segmenta??o e evolu??o das margens transformantes. Este estudo investiga a evolu??o da Zona de Fratura de Romanche (RFZ) na margem equatorial do Brasil, utilizando dados gravim?tricos, magn?ticos, batim?tricos e de s?smica de reflex?o. Os resultados da presente investiga??o indicam que a RFZ ? uma zona de dire??o E-W com ~70 km de largura, marcada por cadeias de at? 2,5 km acima da topografia circundante. As anomalias magn?ticas que marcam a crosta oce?nica mais antiga est?o em um ?ngulo de 26? e 30? no sentido hor?rio a sul e a norte da zona de fratura, respectivamente, indicando que os primeiros centros de espalhamento foram obl?quos ? zona de fratura. As anomalias rotacionaram no sentido hor?rio e passaram de obl?quas para ortogonais em rela??o ? transformante na is?crona 34 (83,5 ? 8 My). Esta rota??o indica que a influ?ncia do limite das crostas continental e oce?nica ? menos pronunciada ? medida que as anomalias tornam-se mais jovens e mais distantes do continente. A RFZ comportou-se como uma barreira topogr?fica, que impediu que parte dos sedimentos do continente e plataforma atingissem a parte norte da cadeia. Falhas normais formam a borda da plataforma continental e as bordas de cadeias e montes submarinos e atingem as camadas mais recentes, indicando que h? reativa??o neotect?nica. A orienta??o e a geometria da RFZ moldaram a geometria atual da margem brasileira, caracterizada por setores de dire??o E-W e NW-SE, e moldaram a evolu??o das bacias Par?-Maranh?o, Cear? e, principalmente, Barreirinhas. / Large-offset transform faults/fracture zones characterize transform continental margins, which have been seldom investigated when compared to divergent and convergent margins. These faults influenced the segmentation and evolution of the transform margins. This study investigates the evolution of the Romanche Fracture Zone (RFZ) in the Equatorial margin of Brazil using bathymetric, magnetic, gravity, and reflection seismic data. The results of the present investigation indicate that the RFZ is an E-Wtrending, ~70-km-wide zone marked by ridges 2.5 km above the surrounding topography. Magnetic anomalies that mark the oldest oceanic crust are at an angle of 26? and 30? clockwise south and north of the fracture zone, respectively, indicate that the first spreading centers were oblique to the main fracture zone. The anomalies rotated clockwise and shift from oblique to orthogonal to the transform at isochron 34 (83.5 ? 8 My). This rotation indicates that the influence of the continental-oceanic crust boundary is less pronounced as the anomalies become younger and a farther away from the continent. The RFZ behaved as topographic barrier, which prevented part of the sediments from the continent and shelf from reaching the northern part of the ridge. Normal faults form the border of the continental shelf and the borders of ridges and seamounts and they reach the upper younger layers, indicating that neotectonic reactivation. The orientation and geometry of the RFZ shaped the present-day geometry of the Brazilian margin, characterized by E-W- and NW-SE-trending sectors, and the evolution of the Par?-Maranh?o, Cear?, and mainly the Barreirinhas basin.