The interplay between event and background sedimentation and the origin of fossil-rich carbonate concretions: a case study in Permian rocks of the Paraná Basin, Brazil - Bondioli, João Guedes; Matos, Suzana Aparecida; Warren, Lucas; Assine, Mario Luis; Riccomini, Claudio; Simões, Marcello Guimarães (Lethaia, 2015)