Incised valley paleoenvironments interpreted by seismic stratigraphic approach in Patos Lagoon, Southern Brazil

Eduardo Calixto Bortolin, Jair Weschenfelder, Andrew Cooper

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The Rio Grande do Sul (RS) coastal plain area (33,000 km2) had its physiography modified several times through the Quaternary,
responding to allogenic and autogenic forcings. The Patos Lagoon covers a significant area of RS coastal plain (10,000 km2), where incised valleys were
identified in previous works. About 1,000 km of high resolution (3.5 kHz) seismic profiles, radiocarbon datings, Standard Penetration Test (SPT) and
gravity cores were analyzed to interpret the paleoenvironmental evolution as preserved in incised valley infills. Seismic facies were recognized by seismic
parameters. The sediment cores were used to ground-truth the seismic interpretations and help in the paleoenvironmental identification. Key surfaces
were established to detail the stratigraphical framework, and seismic facies were grouped into four seismic units, which one classified in respective system
tracts within three depositional sequences. The oldest preserved deposits are predominantly fluvial and estuarine facies, representing the falling stage and
lowstand system tracts. The Holocene transgressive records are dominated by muddy material, mainly represented by estuarine facies with local variations.
The transgression culminated in Late Holocene deposits of Patos Lagoon, representing the highstand system tract. The depositional pattern of the vertical
succession was controlled by eustatic variations, while the autogenic forcing (paleogeography and sediment supply) modulated the local facies variation.
LanguageEnglish
Article number10.1590/2317-4889201820170133
Pages533-551
JournalBrazilian Journal of Geology
Volume48
Issue number3
DOIs
Publication statusPublished - Sep 2018

Fingerprint

incised valley
paleoenvironment
lagoon
systems tract
coastal plain
Holocene
penetration test
depositional sequence
highstand
radiocarbon dating
infill
paleogeography
transgression
sediment core
sediment

Keywords

  • incised valley
  • seismic facies
  • Quaternary
  • system tracts

Cite this

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title = "Incised valley paleoenvironments interpreted by seismic stratigraphic approach in Patos Lagoon, Southern Brazil",
abstract = "The Rio Grande do Sul (RS) coastal plain area (33,000 km2) had its physiography modified several times through the Quaternary,responding to allogenic and autogenic forcings. The Patos Lagoon covers a significant area of RS coastal plain (10,000 km2), where incised valleys wereidentified in previous works. About 1,000 km of high resolution (3.5 kHz) seismic profiles, radiocarbon datings, Standard Penetration Test (SPT) andgravity cores were analyzed to interpret the paleoenvironmental evolution as preserved in incised valley infills. Seismic facies were recognized by seismicparameters. The sediment cores were used to ground-truth the seismic interpretations and help in the paleoenvironmental identification. Key surfaceswere established to detail the stratigraphical framework, and seismic facies were grouped into four seismic units, which one classified in respective systemtracts within three depositional sequences. The oldest preserved deposits are predominantly fluvial and estuarine facies, representing the falling stage andlowstand system tracts. The Holocene transgressive records are dominated by muddy material, mainly represented by estuarine facies with local variations.The transgression culminated in Late Holocene deposits of Patos Lagoon, representing the highstand system tract. The depositional pattern of the verticalsuccession was controlled by eustatic variations, while the autogenic forcing (paleogeography and sediment supply) modulated the local facies variation.",
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Incised valley paleoenvironments interpreted by seismic stratigraphic approach in Patos Lagoon, Southern Brazil. / Bortolin, Eduardo Calixto; Weschenfelder, Jair; Cooper, Andrew.

In: Brazilian Journal of Geology, Vol. 48, No. 3, 10.1590/2317-4889201820170133, 09.2018, p. 533-551.

Research output: Contribution to journalArticle

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