A PALEOSOL AND TAPHONOMY COMPARISON BETWEEN THE BRIAN MABIUS SITE AND OTHER FOSSIL RICH LOCALITIES IN BADLANDS NATIONAL PARK, SOUTH DAKOTA

The Brian Mabius Site (BM), Jerry`s Bone Bed (JBB), Deer Haven Trail (DHT), and the Pig Dig Site (PD) in Badlands National Park are located in the lower/middle Scenic Member of the Oligocene Brule Formation of the White River Group. The BM Site, JBB, and DHT are a collection of fluvially reworked volcaniclastic and epiclastic sediments, paleosols, and vertebrate fossils. Based on macroscopic field data, paleosols suggest riparian and savanna conditions for BM and DHT, and proximal stream conditions for JBB. This is in contrast to the PD Site, which is suggestive of a watering hole environment.

Taphonomically, the Ossiculum pedotype (BM Site), JBB and DHT all contain weakly to moderately weathered and semi-articulated to disarticulated vertebrate fossils within pedogenically modified mudstone. For the BM Site and DHT, these remains were found adjacent to weakly developed riparian soils. For JBB, remains were adjacent to very poorly developed and sometimes waterlogged, proximal stream soils. These conditions suggest that remains were accumulated proximal to laterally migrating stream channels where periodic flooding events buried faunal remains. This is in contrast to the PD Site where remains were accumulated in an ancient watering hole (Terry, 1996), and the Vetus pedotype (BM Site), which contained highly abraded and disarticulated remains that were accumulated in stream deposits.

This research is apart of a program sponsored by the National Park Service to document and protect fossil resources within Badlands National Park. Detailed analyses of sedimentology, paleopedology, stratigraphic position, and geographic distribution of fossil sites will help to develop models to predict new sites, and to interpret the effects of basin dynamics on bone bed genesis.