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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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/24030 |
| Date | 31 July 2017 |
| Creators | Tavares, Aline Cristine |
| Contributors | 40623742420, Nogueira, Francisco Cezar Costa, 81236751353, Gomes, Moab Praxedes, 01252122403, Bezerra, Francisco Hilario Rego, Castro, David Lopes de |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM GEODIN?MICA E GEOF?SICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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