Delimitação de blocos estruturais de diferentes escalas em seqüências mezosóicas do Estado do Rio Grande do Sul: implicações bioestratigraficas

Authors

  • Átila Augusto Stock da Rosa
  • Ubiratan Ferrucio Faccini

Abstract

Photolineaments and stream alignments, visible on radar and satellite images and on aerial photos of varied scales, define structural blocks in sedimentary rocks, characterized by a certain stratigraphic homogeneity, allowing the possibility of correlation on heavily vegetated areas. At the central portion of the Rio Grande do Sul State (Southern Brazil), six structural blocks were recognized (Santa Maria, São João do Polêsine, Faxinal do Soturno, Agudo, Paraíso do Sul and Candelária), based on fault displacements on the order of 100 m, which is more than the average thickness of some lithostratigraphic units. At the Santa Maria block, groundwater wells and field data allowed to recognize five structural subblocks (Cabeceira do Raimundo, Tancredo Neves, Cidade, Km 3, Camobi), with fault displacements averaging 30 m. The identified fault displacements, in lithofaciologically similar deposits, lead to a biostratigraphic discontinuity, from block to block, produced by the lateral juxtaposition of different biozones. The main alignments show distinct cenozones on each side, leading to difficulties on litho- and biostratigraphic correlations, at the regional scale. This study seeks to demonstrate that the advance on the comprehension of stratigraphic correlations at the central portion of the Rio Grande do Sul State must consider the structural compartmentalization of the region.

Keywords: Triassic, Santa Maria Formation, Caturrita Formation, post-depositional tectonics.

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Published

2021-06-08

Issue

Vol. 1 No. 1 (2005): jan/jun

Section

Artigos

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