Eolian sedimentation record in the western part of the Bauru Basin: Rio Paraná Formation (Upper Cretaceous)

Abstract

The Bauru Supersequence comprises two chronocorrelates groups, namely, Caiuá and Bauru. While substantial efforts have been dedicated to detailed mapping in the eastern portion of the Bauru Basin, the western part, specifically the Caiuá Group, remains unresolved and undivided. The aim of this research was to characterize the occurrence area of the Rio Paraná Formation in the state of Mato Grosso do Sul, which is located in the Midwest region of Brazil, as well as its lithostratigraphic characteristics, and the implications for a better understanding of the paleoclimate and paleogeography of that region during the Cretaceous. The Rio Paraná Formation is constituted by six lithofacies: sandstone with cross-stratification (Sct), sandstone with trough cross-stratification (Sct-t), sandstone with cross-stratification pebbles (Sctp), massive sandstone (Sm), massive sandstone with fragments of basalt (Smb), and sandy mudstone (Fme). It was possible to group three facies associations: large-size eolian dunes, interdunes, and sand sheet deposits. The direction of paleocurrent is southwest, which is similar to those previously recognized in the eastern part of the basin and chronocorrelates basins in Brazil. Based on the results obtained in this research, it was possible to provide evidence for the future paleogeographic reconstruction of the Late Cretaceous in South America.

KEYWORDS:
Group Caiuá; sand sea; eolian systems; Mato Grosso do Sul