Banca de QUALIFICAÇÃO: KHALIL BOW LTAIF GARCIA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : KHALIL BOW LTAIF GARCIA
DATE: 18/10/2023
TIME: 14:00
LOCAL: Videoconferência / Canal Youtube PPGG
TITLE:

GEOMORPHOLOGY OF RIO GRANDE DO NORTE OUTER AND QUATERNARY SEA LEVEL FLUCTUATIONS

KEY WORDS:

Sea Level Fluctuations, Açu Reef, Quaternary

PAGES: 50
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

Modern outer shelves are transitional environments between the continental shelf and ocean basins. Sea level fluctuations directly affect this region, shaping it and creating geomorphological records. The study area is located on the northern outer shelf of Rio Grande do Norte adjacent to Macau City. Numerous evidences of paleo sea level are found on the shelf such as: the Açu Incised Valley, submerged dunes, beachrocks, terraces and reefs. The goal of this work is to map a field of reefs called Açu Reef that populated both west and east banks of the Açu Incised Valley, covering an area of 100 km². The present work aims to understand the role of the shelf's physiography, the antecedent lithology, the role of the Incised Valley in the distribution and formation of the Açu Reefs and the correlations between the reefs and the last deglacial event in the Holocene. Through multibeam bathymetry data, it was possible to map an area of 33 km² with the occurrence of reefs between 25-50 m isobaths. The patch reefs are on average 4 m high and are positioned in two well-marked terraces: T1 at 30 m and T2 at 40 m. Both located behind to barrier reef lineaments that provide the formation of a lagoon for their development. Correlating its distribution and sea level curves at low latitudes, it is observed that the best conditions for reef formation occurred between 11-9 kyr BP. This Period represents the final phase of the Meltwater Pulse 1B which is characterized by a slowdown in sea level rise. A large difference in formation is noted between the reefs on the west bank and east bank of the Açu River, possibly due to tidal, current, wind and even structural influences. Thus, three sectors can be identified, a dune field to the west of the incised valley, an estuary at the old river mouth and a barrier island system to the east of the valley, which brings complexity to this area.

COMMITTEE MEMBERS:
Externo à Instituição - ALEX CARDOSO BASTOS - UFES
Interna - 2218779 - HELENICE VITAL
Presidente - 2042405 - MOAB PRAXEDES GOMES
Externo à Instituição - RUY KENJI PAPA DE KIKUCHI - UFBA