Banca de DEFESA: ISABELLE ROSSELYNE FERREIRA DE ARAÚJO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ISABELLE ROSSELYNE FERREIRA DE ARAÚJO
DATA : 31/08/2018
HORA: 15:00
LOCAL: Sala 1 - PPGG
TÍTULO:

Ceara Plateau: an isolated and drowned carbonatic platform in Brazilian Equatorial Margin

PALAVRAS-CHAVES:

Ceará Plateau; Isolated carbonatic platform; Drowned platform; Brazilian Equatorial Margin

PÁGINAS: 102
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

Studies about the Brazilian Equatorial Margin (BEM) have always been concentrated in the continental shelf, supported by oil and gas industry. Deep-waters are vast, unknown and economically unexplored. In this way, there is a great data lack of the BEM's deep portion. Ceará Plateau (CeP) is a seamount and a significant feature of BEM, located 100 km offshore Fortaleza (Brazil) and east of Fortaleza High (limit of Potiguar and Ceará Basins). Its origin supposed to be volcanic based in its steep flanks and collected samples (olivine basalt) in others surrounding seamounts, associated with the Fernando de Noronha Fracture Zone. The GEBCO's grid bathymetry suggests that the isobaths of 1,600 m define the CeP base and its top is average 280 m depth. Its coverage is limestone enriched with phosphorite (~18%). The aim of this work is to define CeP evolution as an isolated carbonatic platform and then its demise. We used 2D multichannel seismic reflection data associated with lithology and biostratigraphy of exploratory wells. In the seismic profiles, the shape and pattern of reflectors termination was interpreted, as well as their external and internal sequences geometry. Seven seismic patterns and four seismic sequences were recognized on the volcanic CeP top. Our results indicate that during the Rupelian/Chattian transition, the substrate was in the photic zone and partially emerged, leading to the development of carbonate wedges on the flanks. The development has become progradational (Chattian-Burdigalian) and then aggradational (Burdigalian/ Tortonian). Carbonate production ceased during the Tortonian, probably when the Antarctic ice sheet began to melt. Tectonics, subsidence and eustatic changes on a global and regional scale acted as control factors in the platform growth. This platform can be used as a model for the stratigraphic development of adjacent MEB seamounts.

MEMBROS DA BANCA:
Presidente - 2218779 - HELENICE VITAL
Interno - 1149363 - VALERIA CENTURION CORDOBA
Externo à Instituição - Pedro Xavier Neto - PETROBRAS