Sedimentation of Aptian-Albian plant particles (Phytoclasts) in sedimentary rocks of Taquari Member, Riachuelo Formation, Sergipe Basin, Brazil

Authors

  • Marcelo de Araujo Carvalho
  • David de Castro de Oliveira
  • Luciano Gandin Machado
  • João Graciano Mendonça Filho

Keywords:

Phytoclasts, Palynofacies, Aptian-Albian, Riachuelo Formation, Sergipe Basin

Abstract

The Aptian-Albian sedimentation occurred in the Sergipe Basin is directly related to the progressive separation of the South American and African continents, resulting in the formation of the South Atlantic Ocean. This work aims the paleoenvironment interpretation based in the distribution and the processes of sedimentation of the phytoclasts in the marine environment. For this study were used 118 samples of well GTP-24-SE of Taquari Member, Riachuelo Formation of Sergipe Basin. The slides were analyzed under the light white transmitted microscopy, where the components of the phytoclasts group were classified and counted. Moreover, to access information about the stratigraphical distribution of the phytoclasts, parameters and ratio were used, such as: % of phytoclasts of the total kerogen, opaque: translucent ratio and % of cuticle of the total of phytoclasts. Seven types of components of the phytoclasts were recognized: equidimensional opaque, lath opaque, cuticles, translucent without pits, translucent with pits, fungal hyphae, and membrane. The lath opaque is the most abundant phytoclast particles (average=49.6%) suggesting a strong transport of terrigenous components on the marine paleoenvironment. The stratigraphical distribution of the phytoclast frequencies decreases progressively upward. This reflects an estrangement from the source area as consequence of the shoreline shift in direction to the continent. Two types of depositional environment are indicated by the kerogen for the Taquari Member: transition of shelf to basin in time and distal shelf.

Published

2021-12-13

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