A central concept in evolution is the escalation of biotic interaction over geologic time. Among the most testable of escalation hypotheses is the "bulldozing hypothesis:" accelerating bioturbation caused a commensurate decline of non- locomotive taxa living on unconsolidated substrata. The changing intensity of bioturbation can change the rock record, altering taphonomy, sedimentology and stratigraphic resolution. PI will test the bulldozing hypothesis for a critical interval of geologic time. Data covers 7 time intervals (formations) and 3 shelf environments. PI will gather quantitative data on lighology, ichnology and body fossils from >1200 samples via bed by bed logging of 400-500 m of Silurian and Devonian carbonates and siliciclastics in New York and Pennsylvania during 6 person-months of field work. The interval (Wenlockian-Eifelian) spans some 40 million years, during which preliminary work indicates that ecologically significant bioturbation first affected the Appalachian Basin. This is the first study to test the association between bioturbation and vulnerable body fossils. These data will also document cross- shelf environmental trends of bioturbation during the study interval.
