Banca de QUALIFICAÇÃO: ALINE CRISTINE TAVARES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : ALINE CRISTINE TAVARES
DATA : 12/07/2016
HORA: 14:30
LOCAL: PPGG
TÍTULO:

Evolution of the Romanche Fracture Zone in the Equatorial Margin of Brazil

PALAVRAS-CHAVES:

Neotectonics, plate lithosphere tectonics, Romanche fracture zone

PÁGINAS: 23
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

The oceanic Romanche fracture zone (RFZ) was formed during the breakup between South America and Africa. The process started in an extensional stress regime with graben generation, but later evolved into a strike-slip stress regime during the opening of the South Atlantic Ocean. The RFZ is the second largest oceanic fracture zone with more than 950 km of horizontal offset. It extends to the Brazilian equatorial margin and shows evidence of continuation in the continent shelf and inland. Despite being one of the largest structures on earth, the RFZ and their influence in adjacent sedimentary basins are still poorly known. Oceanic fracture zones divide the equatorial margin of Brazil into several segments, where sedimentary basins developed independently one from another. Therefore, the possibility that these oceanic fracture zones still have a role in the evolution of the sedimentary basins have been increasingly questioned by recent studies. This research focus on the integration of geophysical methods through the joint inversion of 2D gravity, magnetic, and reflection seismic data. These methods are also integrated with bathymetry and borehole data. The objectives of this study are (1) to identify and analyze the deformation caused by the RFZ in the oceanic and continental crusts and in the sedimentary basins; (2) to identify possible tectonic activity in the RFZ in its intraplate evolutionary stage; (3) and to identify thermal or tectonic subsidence and inversion in the sedimentary basins across the fracture zone. Several task have been carried out to achieve this goal: (a) identify and analyze the tectonic regional framework; (b) mark the boundaries between the oceanic and continental crusts and the Mohovicic discontinuity; and (c) identify the continuity of the RFZ as far as the Brazilian continental margin. The preliminary results indicate that the RFZ marks the boundary between the continental and oceanic crusts in the area of the Barreirinhas and Ceará basins. The altitude of the oceanic basins, which are more elevated to the south than to the north of the RFZ is another point of investigation. This unexpected behavior is against the predictions of the thermal subsidence model, which may indicate tectonic inversion. This fracture zone is difficult to identify in bathymetric maps because it is capped by a thick sedimentary sequence, but is well marked on aeromagnetic and gravity maps. In addition, there are evidence of neotectonic deformation of near surface sediments close to the RFZ.

MEMBROS DA BANCA:
Presidente - 1315614 - DAVID LOPES DE CASTRO
Interno - 350640 - FRANCISCO HILARIO REGO BEZERRA
Interno - 2042405 - MOAB PRAXEDES GOMES