Distribuição sedimentar da lagoa rodrigo de freitas através de sísmica de alta resolução

Abstract

The Rodrigo de Freitas Lagoon (Rio de Janeiro State) sediments and bottom characteristics were analyzed using high-resolution (10 kHz) sub-bottom profles associated with particle size analyses of 44 bottom sediment samples. Four types of echo-characters were identifed revealing the strong relation with the particle size distribution and bottom morphology. In areas of acoustic penetration, the basement delineates buried sugar-loaf hills and inflled-valley features. The total sediment thickness can reach as much as 16 meters along the paleovalleys, which are aligned in a NE-SW direction, parallel to the regional basement orientation observed on the coastal massifs. There is a predominance of organic rich muddy sediments, inflling the paleovalleys which are the main sites of shallow gas occurrences within the lagoonal sediments. © 2011 Sociedade Brasileira de Geofísica.