Granulados litoclásticos

Abstract

Marine terrigenous elastics aggregates are composed of sand and gravel, of continental origin, deposited on the continental shelf and reworked by the combined effect of waves and coastal currents. Most deposits are associated with fluvial and glacial systems, which extended to the outer continental shelf during low-stands of the sea level. These deposits were further reworked during the subsequent marine transgression, remaining as relict drowned deposits on the present continental shelf. Today, they constitute important mineral source for industrial use and coastal restoration projects. The exploitation of these marine mineral deposits has experienced a significant increase during the last decades, in association with decreasing continental reserves. Today it represents an active mineral extraction activity in many continental shelves around the world, such as in Japan, United States, United Kingdom, France and Denmark, which are leading the world marine aggregates exploitation. The reconnaissance of the reserves in Brazilian waters is still very regional, and the use of marine aggregates is localized on metropolitan areas, associated with beach replenishment projects in severely eroded coasts.