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Late Pennsylvanian aridification in Gondwana mid-latitudes contemporaneous to high-latitudes ice cap expansion, upper Piauí Formation, Brazil

2022; Elsevier BV; Volume: 117; Linguagem: Inglês

10.1016/j.jsames.2022.103840

1873-0647

Carrel Kifumbi, Claiton Marlon dos Santos Scherer, Ezequiel Galvão de Souza, Adriano Domingos dos Reis, João Pedro Formolo Ferronatto, Rossano Dalla Lana Michel,

Paleontology and Stratigraphy of Fossils

The Pennsylvanian Epoch was marked by a well-known glaciation period documented in several basins across the Gondwana . However, stratigraphic data from the Parnaíba Basin suggest that drier climate conditions dominated mid-paleolatitudes simultaneously to the glaciation. To investigate the possible time equivalence and the causes of aridification in mid-paleolatitudes, high-resolution stratigraphic analysis of the upper Piauí Formation were conducted in the eastern margin of the Parnaíba Basin. As a result, three stratigraphic intervals separated by key stratigraphic surfaces were identified: The first stratigraphic interval is dominantly composed of fluvial deposits progressively overlain by eolian facies ; the second stratigraphic unit is essentially composed of lacustrine deposits and represent a regional flooding related to a period of lake expansion and finally, the third stratigraphic unit is characterized by three eolian genetic units and depicts cyclic expansion and contraction of a dune field . The overall vertical stratigraphic succession represents a progressive change from original fluvial sedimentation to essentially eolian accumulation and constitutes a drying upward trend that reflects an increasing aridification in the Parnaíba Basin during the Late Pennsylvanian age. The detailed analysis of the paleoclimatic conditions and the atmospheric circulation during the Late Pennsylvanian Epoch evidenced that the waning and waxing of the ice sheets controlled the development, expansion and contraction of the upper Piauí Formation dune-field. • High-latitudes glaciation contemporaneous to mid-latitudes aridification. • The Gondwana aridification registered in the Piauí Formation of the Parnaíba Basin. • Shift from fluvial to eolian deposits caused by growing arid conditions. • Eolian genetic units controlled by water-table fluctuations. • Waning and waxing of the ice sheets controlled the dune field dynamics.