Banca de QUALIFICAÇÃO: FRANCISCO CORDEIRO DO NASCIMENTO NETO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : FRANCISCO CORDEIRO DO NASCIMENTO NETO
DATA : 14/06/2017
HORA: 16:00
LOCAL: Auditório do DGEF
TÍTULO:

SUBAQUEOUS DUNE OF NORTHERN TROPICAL SHELF OF RIO GRANDE DO NORTE (NE BRAZIL)

PALAVRAS-CHAVES:

Ceará Subaqueous dunes; Marine geomorphology; Shelf dynamic

PÁGINAS: 22
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

Subaquatic dunes are important morphological seabed features found on several continental shelves around the world. Their deposits in the geological record are used as indicative parameters of the local dynamics such as the current direction. The Northern Tropical Shelf of Rio Grande do Norte is known for its mixed siliciclastic-bioclastic composition, exposure to high-energy processes and the presence of several features. Among these features, a large dune field stands out on the adjacent inner shelf. The aim of this work is the dynamics, geomorphology and sedimentology of this extensive dune field. For this, previous bathymetric and sonographic data acquired in March 2015 were reprocessed and a new hydroacoustic data collection cruise was acquired in May 2017. In this last cruise, punctual sediments samples were collected and scientific diving was performed for filming and for collection of samples. These samples will be used to characterize the different backscatter patterns recognized in the sonographic mosaic. Small and large dunes were identified in the study area, separated by a 1 meter step at 8-meter isobath. The dunes are oblique to the coastline and present crests in SW-NE direction. Seven backscatter patterns were characterized. The P1 pattern refers to the oil industry pipelines installed in the region. Patterns P2 and P3 have high intensity backscatter. However, P2 presents ripples, while P3 is homogeneous. P4 and P5 have medium intensity backscatter, with P4 being homogeneous and P5 being rough. Finally, the patterns P6 and P7 have low intensity backscatter, with the first homogeneous and the latter very rough. The collected samples indicate a heterogeneity of the sediments, even within a certain pattern. The rough aspect of backscatter appears to be related to the presence of bioclastic gravel.

MEMBROS DA BANCA:
Presidente - 2218779 - HELENICE VITAL
Interno - 2042405 - MOAB PRAXEDES GOMES
Externo à Instituição - ANDRE GISKARD AQUINO DA SILVA - CAU
Externo à Instituição - LUIZ ANTONIO PEREIRA DE SOUZA - IPT-SP