Bioturbation and trace fossils in deep sea sediments of the Walvis Ridge, southeastern Atlantic, Leg 74

Trace fossil distribution present in pelagic carbonates cored on the Walvis Ridge during Deep Sea Drilling Project Leg 74 are described. A characteristic deep-sea trace fossil assemblage comprising the cosmopolitan ichnogenera Planolites, Chondrites, Zoophycos, and Teichichnus was found at paleo-water-depths ranging from a few hundred to about 4500 m. Paleodepth distribution indicates that Zoophycos has changed its environmental preference from relatively shallow water in the Cretaceous into deeper water in the late Paleocene. Thus Zoophycos can be used as a paleodepth indicator in the bathyal environment if its stratigraphic age is known.