Abstract: A three-dimensional investigation of an aff. Phycosiphon ichnofabric from the Cretaceous Rosario Formation, Cajiloa, Baja California, Mexico (poster presentation)

This study investigates the three-dimensional nature of the ichnofabric produced by a large (1 cm diameter) Phycosiphonlike trace fossil in a turbiditic siltstone. The fossil material comes from a succession of well exposed slide blocks in a slope channel complex from coastal exposures of the Cretaceous Rosario Formation at Cajiloa, close to the town of El Rosario, Mexico. The present material has been investigated by thin sectioning, serial slicing and CT scanning in order to gain a thorough understanding of the ichnofabric produced by the trace-maker. The material is also studied using mini-permeametry to investigate the effect that the aff. Phycosiphon have on the permeability of the siltstone. The 3D morphology of the trace is also compared to pre-existing models for the geometry of Phycosiphon.