Ichnology of rhythmically bedded Demopolis Chalk (Upper Cretaceous, Alabama); implications for paleoenvironment, depositional cycle origins, and tracemaker behavior

bioturbation Demopolis Chalk carbon chalk clastic rocks burrows Cretaceous Alabama Campanian biogenic structures carbonate rocks Chondrites ichnofossils rhythmic bedding sedimentation ichnofossils lebensspuren marl Planolites Mesozoic sedimentary rocks Marengo County Alabama Selma Group United States Upper Cretaceous planar bedding structures sedimentary structures Thalassinoides organic carbon Senonian Teichichnus Zoophycos