Geoacoustic properties of submarine polymetallic crusts

Marine mining is the ocean´s new exploration frontier. The Exclusive Economic Zone (EEZ) is the region over which the respective coastal states hold sovereign rights for exploration, exploitation, conservation and management of natural, living or non-living, resources. The Brazilian EEZ has a rough oceanic area of 4.5 million square kilometers and is consecrated by the word "Blue Amazon", an area adjacent to the Brazilian mainland, which corresponds to 52% of the country´s land area. Knowing the resources of such a large area is a strategic issue concerning the country´s development. This work aims to determine the physical and geoacoustic properties (Vp, density, acoustic impedance) of polymetallic crusts from different areas along the Brazilian coast and to correlate with its chemical analysis. The first were measured in two different directions, parallel and orthogonal to the layering of the samples, in order to determine anisotropic effects related to the sample´s framework. The correlation of the data will allow the analysis of the acoustic response of the samples to different frequencies indicating how the sample´s chemical composition affects its acoustic response. Since the investigation of the seafloor is basically conducted using acoustic geophysical methods, the results of this research will allow deciding for the best procedure and technique to be used for future exploration of this resource.