Glossifungites suites and tubular tempestites in Devonian shallow-marine deposits from Paraná Basin

The Glossifungites ichnofacies can be a signature of allogenic processes that demark omission, exhumation and ravinement, or indicate autogenic processes impacting several depositional scenarios such as incised valleys, submarine gullies and canyons, erosive shorefaces, tidal channels and dewatered muddy substrates. Comparatively, autogenic surfaces demarked by the Glossifungites ichnofacies have been less studied than allogenic surfaces. In this study case, we interpret the examples from the transitional offshore to offshore deposits of the Devonian Ponta Grossa Formation (Paraná Basin, southern Brazil) as tubular tempestites. They are commonly associated with the initial phase of the transgressive systems tract when the shallow-marine environment becomes starved of sediment supply. Those occurrences are mostly characterized by Thalassinoides and less frequently by Palaeophycus, Skolithos and Rhizocorallium, with sharp to irregular walls, passive filling and descending from an erosive surface. In offshore deposits, the erosive surface can be obliterated, making the Glossifungites suite the unique evidence of storm processes (e.g. tubular tempestites). The results also highlight some differences between autogenic and allogenic Glossifungites from the Ponta Grossa Formation and demonstrate that the few levels with allogenic Glossifungites suites represent coplanar surfaces coupling sequence boundaries and transgressive surfaces developed in the early stages of transgressive systems tracts.