Mapeamento do Talude Continental adjacente ao Cabo Calcanhar/RN, Margem Equatorial Brasileira

Abstract

The study area is located on the Brazilian Equatorial Margin (MEB), which represents Brazil's most recent exploratory frontier in deep and ultra-deep waters. However, the MEB still requires studies. The study region, in the eastern end of the Potiguar Basin, is one of the least known. The main aim of this work was to map the Brazilian Continental Slope, adjacent to Cabo Calcanhar (RN), between the isobaths of 100 and 2,000. The survey was carried out on board of the Hydroceanographic Research Vessel Vital de Oliveira. Multibeam bathymetry was the method selected, with two echo sounders being used: the EM 122 and the EM 710, respectively for the deepest and the shallowest portion of the study area. Data processing was carried out with the CARIS HIPS & SIPS 12 Software.Analysis and integration of all data resulted in the creation of Digital Terrain Maps (MTD) and profiles, to characterize the seabed. Three submarine canyons were identified along the study area, named A, B and C according to their morphological characteristics. Canyon A had an average length of 18.2 km and width of 1.4 km, whilecanyons B and C extend further towards the ocean basin, with an average length of 19.5 km, greater lateral width and more pronounced depths in the thalvegs. The slopeof the Continental Slope, observed in the bathymetric profiles, varied from 0º to 32º. The canyons were detailed in different parts of thecontinental slope, covering all the depth characteristics and different bottom features found along the course, such as ravines, feeder gullies and grooves in the middle slope, terraces, gorges and landslide scars on the outer slope and ocean basin.