Interpretação morfoestrutural a partir de dados de batimetria multifeixe, à NW do Arquipélago São Pedro e São Paulo (ASPSP)

Abstract

About 70% of the Earth's surface is below the water column, and is relatively understudied due to the significant challenges of conducting research in the marine environment. Despite roughly two-thirds of the Earth's surface being covered by oceans, our understanding and exploration of the marine depths remain limited. In fact, to date, less than a quarter of the ocean floor is known. Understanding the depths of the seafloor (bathymetry) is of vital importance for a growing variety of fundamental uses that contribute to the understanding of the Earth's functioning. The aim of this study was map the seafloor northwest of the São Pedro and São Paulo Archipelago (ASPSP), through multibeam bathymetry. Data acquisition was carried out aboard the Hydro-Oceanographic Research Vessel Vital de Oliveira (NPqHOc Vital de Oliveira), using a Kongsberg EM-122 multibeam echosounder operating at a frequency of 12 kHz. Raw data processing was performed using Caris HIPS & SIPS software version 11.4.24. The study area until this work had not been mapped, that is, mapping a previously unexplored area on the ocean floor represents a crucial advance, highlighting the importance of understanding the complexity of the marine environment. From the results obtained, it was possible to generate maps of bathymetric surfaces and acoustic backscatter mosaics (RA). As well as backscatter map, aspect map, slope map and elevation profile; the association and comparison of these products allowed for the morphostructural interpretation of the area based on the bathymetric map and interpretation of the main structures. From the analysis and integration of the results, the morphology of mid-ocean ridges with a slow spreading axis was identified, which results in the development of an axial valley delimited by very steep edge faults; A discontinuity classified as non-transforming displacement, or second order offset, was interpreted along the valley. Additionally, the occurrence of some neovolcanic mounds was identified. Finally, it was possible to interpret that the study area is situated between the South American and African tectonic plates.