Tide‐influenced depositional system recorded in southern Gondwana during the Early Permian: Post‐glacial infill of the Capané palaeovalley

ABSTRACT Mixed‐energy coastal systems produce complex depositional records that can obscure the predominant processes controlling sediment deposition. This occurs mainly when the interpretation of the primary sedimentary structures is non‐unique. The Rio Bonito Formation succession infilling the Capané palaeovalley in the southern Paraná Basin exhibits records of the depositional influence of tides and waves, in which tidal deposits are predominant. However, the depositional environment has not been completely elucidated, and little is known about the significance of tides in the depositional environment. To identify the physical processes responsible for sediment deposition and reconstruct the depositional system, sedimentary facies and stratigraphic analyses of drilled cores and outcrops from the Capané palaeovalley were performed. Fourteen sedimentary facies, four facies associations and three types of sand bodies are described (tidal point bars, compound tidal dunes and offshore tidal sand ridges). The sedimentary succession records an incised valley infill comprising lowstand and transgressive systems tracts. In the deepest part of the palaeovalley, an inner portion of a fluvial‐tidal transitional environment is preserved. The lower succession along the valley is marked by the establishment of an estuarine system, which is replaced by an offshore tidal system in the upper succession, and culminates with a coastal marine environment. This interpretation differs from the wave‐dominated model previously described for this area. This study contributes to the understanding of the evolution and distribution of coal‐forming depositional systems of the Rio Bonito Formation.