Banca de QUALIFICAÇÃO: DANIELA DE ANDRADE MOREIRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : DANIELA DE ANDRADE MOREIRA
DATE: 22/12/2025
TIME: 08:00
LOCAL: Sala 1 - PPGG
TITLE:

Geomorphology of the Continental Slope on the Eastern Brazilian Margin Adjacent to Rio Grande do Norte (Natal to Rio do Fogo, NE Brazil))

KEY WORDS:

multibeam bathymetry; submarine canyons; continental slope; submarine geomorphology

PAGES: 15
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The Brazilian Continental Margin adjacent to the State of Rio Grande do Norte remains one of the least characterized sectors of the South Atlantic, particularly regarding the geomorphological and sedimentary context of the continental slope. This study presents the preliminary characterization of the continental slope between Natal and Rio do Fogo, seeking to understand its development based on hydroacoustic data (multibeam bathymetry and MBES backscatter) acquired during the 2023 survey aboard the Hydroceanographic Research Vessel Vital de Oliveira – H39, using a Kongsberg EM 122 multibeam echosounder (dual-swath mode) operating at 12 kHz. Data processing was conducted in four main stages: (a) pre-processing (patch test), (b) processing (project creation, bathymetry georeferencing, surface generation, quality control, and creation of the final DTM), (c) products generation (production of profiles, thematic maps, and backscatter mosaic), and (d) interpretation. The integrated analysis of these data allowed the identification of key features such as submarine canyons, large ravines, unincised areas, and significant variations in morphological gradients. The resulting bathymetry reveals depths ranging from –71 to –3014 m, extending from the shelf break (–71 m), across the upper slope (–100 m), and down to its most distal portion toward the deep ocean basin (–100 m to –3014 m). The continental slope is narrow, with a width of approximately 16.5–22 km (E–W) and a length of ~50 km (N–S). Based on the spatial distribution of the founded features, the region was subdivided into upper (100 to 800–1000 m), middle (800–1000 to 2000 m), and lower (> 2000 m) slope zones. Two major submarine canyons were identified: Canyons 1 and 2. Canyon 1 is characterized by high continuity, an average slope of 7.7°, moderate sinuosity (1.12), a length of ~21,710 m, and a thalweg ranging from 800 to 2760 m depth; its cross-sectional shape is U shaped. Canyon 2 has an amphitheater-like shape head (SW–NE) incised by negative features such as ravines. It exhibits a slope of 9°, high continuity, and moderate sinuosity (1.18), with a concave profile and V-shaped cross-section on the upper slope that transitions to a U-shaped morphology on the middle and lower slope. In its lower segment, a southern ridge bifurcates the canyon path. The results contribute to advancing scientific understanding of the geomorphological evolution of the Eastern Brazilian Margin, enhance knowledge of the sedimentary processes acting on the continental slope, and provide essential support for future assessments of geological hazards (geohazards) and the potential installation of offshore structures. This study reinforces the importance of detailed mapping of the Amazônia Azul and its integration into contemporary agendas of sustainability, the blue economy, and marine spatial planning

COMMITTEE MEMBERS:
Interno - 1451214 - ADERSON FARIAS DO NASCIMENTO
Presidente - 2218779 - HELENICE VITAL
Externa à Instituição - JÚLIA CARVALHO LANNES GALVÃO FONSECA
Externa ao Programa - 1226434 - MARY LUCIA DA SILVA NOGUEIRA - null