Banca de QUALIFICAÇÃO: VANESSA COSTA FONTES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : VANESSA COSTA FONTES
DATA : 05/12/2017
HORA: 17:30
LOCAL: Sala 1 - PPGG
TÍTULO:

Sonographic mapping of the Tamandaré continental shelf (PE)

PALAVRAS-CHAVES:

Sonography, reefs, continental shelf

PÁGINAS: 25
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

The Tamandaré-PE continental shelf has mixed carbonatic and siliciclastic sedimentation, is narrow and shallow up to -60 m at the shelfbreak, and has a wide distribution of reef bodies parallel to the coast. Coral reefs development is controlled by sea level and they contribute significantly to the evolution of mixed sedimentation of the platform. Thus, we mapped the reef environments of the inner shelf environments of the Tamandaré coast. An interferometric sweep system (EdgeTech 4600) was used to identify sedimentary zones and bioconstructed structures, as well as the collection of five samples along the area. We processed and interpreted the acoustic images using the software SonarWiz6 and ArcGIS 10.3, and the samples were treated in laboratory and classified using the SAG software. Seven distinct backscattering patterns (from P1 to P7), were observed. The pattern P1, P2 and P3 are associated to different forms of reef occurrences. P1 displays rugged homogeneous texture with high amplitude of backscatter. This pattern is associated with proximal reef bodies that present north-south orientation. P2 is characterized moderate backscatter with a heterogeneous texture (rough-smooth) and a preferred orientation NE-SW. This is related to the farthest reef field mapped. P3 shows moderate backscatter and smooth homogeneous texture, with NE-SW orientation. These reefs are associated with reef bodies possibly covered by calcareous algae or with building organisms different of those related with the patterns P1 and P2. P4 displays smooth and flat textural aspect and high backscatter strength. This patter is associated with a gravelly bottom, identified from the analysis of the grab sediment sample. P5 presents low backscatter and homogeneous texture of flat pattern, interpreted as sandy bottom. P6 is a soft and moderate textural pattern return signal, interpreted as gravel-sand bottom. And P7 presents a pattern with low return signal, homogeneous and flat texture, being interpreted as a mudy bottom. According to the acoustic map, we found two reef fields, separated by a wide muddy belt N-S oriented. A paleovalley may be seen in deeper parts of the study area. The spatial distribution of the sediments appear to be controlled by shelf relief and hydrodynamics. Further study for shelf morphology and the pattern and extension of reef occurrence are in development

MEMBROS DA BANCA:
Presidente - 2042405 - MOAB PRAXEDES GOMES
Interno - 2218779 - HELENICE VITAL
Externo à Instituição - ANDRE GISKARD AQUINO DA SILVA - CAU