Banca de QUALIFICAÇÃO: FLÁVIA VALÂNEA SOUZA BELCHIOR

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : FLÁVIA VALÂNEA SOUZA BELCHIOR
DATA : 26/07/2018
HORA: 10:00
LOCAL: Sala 1 - PPGG
TÍTULO:

MORPHOLOGY AND DISTRIBUTION OF SUBMERGED DUNES OF THE POTENGI-RIVER ESTUARY (NATAL-RN) 

PALAVRAS-CHAVES:

Sediment dynamics; estuary; Potengi; bedforms; subaqueous dunes

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

The Potengi River extends for more than 170 km and flows into the eastern coast of Rio Grande do Norte, its estuarine region being surrounded by the metropolitan region of the city of Natal. The main channel has suffered periodic dredging and its margins with intense urbanization. Such interferences directly influence the estuarine sedimentary dynamics, resulting in redistribution of erosion and silting zones. Due to the semi-diurnal regime of mesotidal, the circulation of the estuary is dominated by currents of ebb and flood which, in different zones of the estuarine channel, form patterns of bottom forms and subaquatic dunes that show the transport of sediments and the modifications in the morphology of the channel. The main objective of this work is to analyze the spatialization and morphology of the bottom features, to investigate the morpho-sedimentary processes and the possible anthropic impacts. Sonographic and bathymetric data were acquired in the main channel of the estuary in August of 2017 by means of an interferometric sonar (Edgetech 4600), operating in the frequency of 540 KHz, with lateral reach of 125 m per sensor. The sonographic data were processed using the software SonarWiz 6 that allowed to generate the mosaic and the interpretation of the zones and bedforms, maps and 3D models. The bathymetric data were filtered using Hypack 2014 software and are in the modeling phase. The estuary has an asymmetrical main channel with depths ranging from 3 m to 20 m upstream and downstream, respectively. Bottom shapes were mapped along the estuary as 2D dunes, 3D dunes, small, medium and large dunes, flat bottom, rough bottom, anthropized regions. The flat and rough bottoms are common on the margins of the channel with depth varying from 2 to 6 m. In addition, they are found in the central region surrounding 2D dunes. Both 2D and 3D dunes are asymmetric dunes and vary according to the spacing between them: from 0 to 5 m (small size), 5 to 10 m (medium size) and from 10 to 100 m (large size). Both have depths ranging from 6 to 12 m. Although these dunes are well distributed throughout the channel, the 2D predominates in relation to 3D. Preliminary results based on bedforms indicate different direction and speed of tidal currents controlling the morphology of the channel and the irregular distribution of the sedimentary features.

MEMBROS DA BANCA:
Interno - 1161652 - FRANCISCO PINHEIRO LIMA FILHO
Externo à Instituição - LEAO XAVIER DA COSTA NETO - IFRN
Presidente - 2042405 - MOAB PRAXEDES GOMES