Paleochannels related to late quaternary sea-level changes in Southern Brazil

  • Jair Weschenfelder Universidade Federal do Rio Grande do Sul; Instituto de Geociências; Centro de Estudos de Geologia Costeira e Oceânica
  • Iran Carlos Stalliviere Corrêa Universidade Federal do Rio Grande do Sul; Instituto de Geociências; Centro de Estudos de Geologia Costeira e Oceânica
  • Salvador Aliotta Instituto Argentino de Oceanografia
  • Ricardo Baitelli Universidade Federal do Rio Grande do Sul; Instituto de Geociências; Centro de Estudos de Geologia Costeira e Oceânica
Keywords: seismic survey, coastal evolution, incised valleys, Patos Lagoon

Abstract

The geological evolution of the continental shelf and in the coastal zone of southern Brazil during the Quaternary period is addressed in this study. High-resolution seismic records obtained at the Patos Lagoon revealed the presence of channels that deeply dissected the coastal zone before the formation of the modern, low-relief, coastal plain. Two periods of channel incision are inferred, based mainly on seismic records. The paleodrainage paths mapped from the seismic records can be connected with those recognized by previous studies on the adjacent continental shelf and slope. Upstream, the drainage incised mainly into the coastal prism deposited during previous sea-level highstand events. The paleodrainage network, recognized on the coastal plain and continental shelf, represents a river-shelf system, linking the drainage basin to the depositional settings on the marginal basin, bypassing the continental shelf exposed during a forced regression event. The drainage incised into the coastal plain and continental shelf of Rio Grande do Sul played an important role in the basin-margin architecture, facies distribution and accommodation during the Quaternary sea-level fluctuations.

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Published
2010-01-01
How to Cite
Weschenfelder, J., Corrêa, I., Aliotta, S., & Baitelli, R. (2010). Paleochannels related to late quaternary sea-level changes in Southern Brazil . Brazilian Journal of Oceanography, 58(spe2), 35-44. https://doi.org/10.1590/S1679-87592010000600005
Section
naodefinida