Banca de DEFESA: ALINE CRISTINE TAVARES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ALINE CRISTINE TAVARES
DATA : 31/07/2017
HORA: 08:30
LOCAL: Auditório do LGGP II
TÍTULO:

The evolution of Romanche fracture zone in the Equatorial margin of Brazil

PALAVRAS-CHAVES:

Equatorial Atlantic, Northeastern Brazil, Transform margin, Fracture Zone, Romanche.

PÁGINAS: 79
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

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-W-trending, ~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 continentaloceanic 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 Pará-Maranhão, Ceará, and mainly the Barreirinhas basin.

MEMBROS DA BANCA:
Presidente - 1315614 - DAVID LOPES DE CASTRO
Externo à Instituição - FRANCISCO CEZAR COSTA NOGUEIRA - UFCG
Interno - 2042405 - MOAB PRAXEDES GOMES