COMPARING TRANSPORT-INDUCED ABRASION OF FRESH AND FOSSILIZED SKELETAL REMAINS

Understanding the susceptibility of skeletal remains to damage via various taphonomic processes is central to correctly interpreting the depositional history of fossil assemblages. Organic/biologic influences and macrovertebrate specimens have comprised the majority of previous taphonomic studies, whereas physical transport, especially of microvertebrate specimens, has received less attention. Ongoing experiments to determine the effects of bedload transport on skeletal remains assess the importance of bone morphology, sediment size, weathering state, and taxonomic affinity on abrasion damage of small bones. Under simulated fluvial conditions, preliminary results from microvertebrate green bones have shown broad compatibility of abrasion-induced damage across taxa despite the unique bone structure of birds. Sediment size and weathering state influence the degree of damage to a greater extent.

As a next step, analogous green and fossilized bones are being analyzed to determine the effects of fossilization on the susceptibility of bone to damage through interaction with sediment during transport. Initial results suggest that fossilized bones may be more readily abraded during transport than green bone. This finding has important implications for identifying reworked fossil assemblages. Additional experiments underway will clarify the parameters controlling the susceptibility of fossil bone to transport-induced abrasive damage. Work to date highlights the importance of understanding reworked or degraded bones as important contributors to the fossil record.