Paleocanais na plataforma continental interna do Rio Grande do Sul: evidências de uma drenagem fluvial pretérita

• Autor(a) principal: Abreu, José Gustavo Natorf de
• Data de Publicação: 2005
• Outros Autores: Calliari, Lauro Júlio
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da FURG (RI FURG)
• Texto Completo: http://repositorio.furg.br/handle/1/2859
• topic: Seismic survey; Inner continental shelf; Rio Grande do Sul State; Levantamentos sísmicos; Plataforma continental interna; Rio Grande do Sul

Subsurface structures mapped by the Sparker R acoustic system on the inner continental shelf of Rio Grande do Sul State, in southern Brazil were interpreted as paleochannels which developed over a coastal plain environment during the upper Pleistocene and lower Holocene. Two major reflectors displaying expressive lateral continuity were identified. The first reflector, which is shallower, is buried at depths ranging from 10 to 12m and its surface is relatively homogeneous displaying few irregularities associated that channeled structures. The second reflector mapped on depths ranging from 14 a 32m is more discontinuous and irregular and display erosive structures. The overall interpretation of the shallow seismic reflection profiles indicates that this preterit drainage display an N/NE-SE/SW orientation increasing its width and decreasing its depth towards offshore. The presence of paleochannels in the inner continental shelf of RS state supports the paleogeographic models of the area proposed by early studies.