T50 Geology in the National Parks; Research, Mapping, Education, and Interpretation

Monday, 5 November 2001
1:30 PM - 5:30 PM

PALEOPEDOLOGY AND TAPHONOMY OF THE BRIAN MABIUS SITE, BADLANDS NATIONAL PARK, SOUTH DAKOTA

Paper number: T50-12
Program: Technical Sessions
Time: 1:30 PM – 5:30 PM

Authors

Abstract

The Brian Mabius Site (BM) in Badlands National Park is located in the lower/middle Scenic Member of the Brule Formation of the White River Group. The BM Site is a collection of fluvially reworked volcaniclastic and epiclastic sediments of mudstones, channel sands, silts, and vertebrate fossils. Paleosols are prevalent and consist predominantly of weakly developed Haplustalfs, Haplustepts, and one pervasive, strongly developed Paleustalf, which is informally referred to as the Hay Butte Marker Bed. Based on microscopic, macroscopic, and geochemical data, these paleosols indicate sub-humid to semi-arid and semi-forested to savanna paleoenvironments within an anastomosing floodplain region.

Taphonomically, the BM Site contains many various specimens of weakly to moderately weathered, disarticulated, carnivore processed, and mostly random oriented vertebrate fossils that are adjacent and laterally traceable to the Haplustalfs and Haplustepts. These taphonomic indicators imply that drought and/or predators proximal to a lacustrine (oxbow) setting terminated these Orellan taxa where periodic seasonal flooding events transported and buried faunal remains. This is different than the Pig Dig Site, where faunal accumulation is due to drought.

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 derive models to predict new sites and to interpret the effect of basin dynamics on bone bed genesis which will aid in protecting them from poaching.