Feições fisiográficas submarinas da plataforma continental do Rio Grande do Norte visíveis por imagens de satélite / Underwater physiography of the continental shelf of Rio Grande do Norte visible through satellite imagery

AUTOR(ES)
DATA DE PUBLICAÇÃO

1989

RESUMO

This work introduces visible TM-Landsat imagery as an effective tool for the investigation of underwater physiography on a regional scale, down to 35 m depth, with a resolution of 30 m, on highly reflective seabed on continental shelves with highly transparent waters. The choice of the State of Rio Grande do Norte, Brazil, as the main survey area was dictated by the richness in geomorphological units and benthic ecosystems not recorded on charts or previus literature, which could be seen in the imagery. Most of the large-scale physiography could be recognized by comparing these images with digital charts obtained from smooth sheets, and nautical charts, while some of the geomorphology was only recognized by image assisted "in situ" work. Field work involved echosounder profiling, surficial sediment sampling by diving and underwater photography. Four important geomorphological units, related to holocene sedimentation processes are reported: 1) The discovery of a great lineament limiting a terrace at 20 m depth, shown to correspond to an ancient shore-face; 2) The location and field study of a "beach-rock" reef over this lineament; 3) The identification and field study of large-scale transverse bedforms (dunes), and 4) The location of a large field of longitudinal bedforms. The ocurrence of ancient submerged river-beds, tidal bedforms, and a conspicuous lineament, probably related to a tectonic event are also reported.

ASSUNTO(S)

thematic mappers (landsat) water resources mapeador tematico (landsat) continental shelves spot (satelite frances) ecossistemas sensors and remote sensing techniques geomorfologia imagens de satelites image interpretation interpretacao de imagens oceanography satelites landsat geomorphology spot (french satellite) oceanografia rio grande do norte (estado)cabo galcanhar (rn) satellite imagery integrated environmental studies marine resources recursos marinhos landsat satellites plataforma continental ecosystems

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