2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 21
Presentation Time: 8:00 AM-4:45 PM

Updates to the Taphonomy of the Aaron Scott Dinosaur Site (Jurassic, Morrison Formation) in Central Utah


DONALDSON, Kevin1, BISSELL, Corrina1, HESTER, William1, O'BRYAN, Alice1, ROBINSON, Rath1, BERTOG, Janet L.2, JEFFERY, David L.3 and BISHOP, John R.3, (1)Physics and Geology, Northern Kentucky University, SC 104, Nunn Dr, Highland Heights, KY 41099, (2)Physics and Geology, Northern Kentucky Univ, Highland Hts, KY 41099, (3)Department of Petroleum Engineering and Geology, Marietta College, 215 Fifth Street, Marietta, OH 45750, donaldsonk@nku.edu

The Aaron Scott Site is a rich accumulation of vertebrate remains in the Jurassic Morrison Formation of central Utah. The site is dominated by a partially articulated skeleton of a Diplodocid sauropod, including cervical and caudal vertebrae. In addition to the sauropod, disarticulated remains of Allosaurus, Ceratosaurus, and an ornithopod dinosaur as well as a rich accumulation of microfauna including turtle, crocodile and sphenodonts are found.

The majority of the bones in the quarry, aside from the sauropod, are fragmented. Although the sauropod shows little directional orientation, the disarticulated remains of the other animals show exhibit orientation that is consistent with both river current and wave activity.

Stratigraphy and sedimentology suggest that the bones accumulated on a delta plain during a period of drought. The bones were disarticulated and broken by wreathing processes and possibly by trampling. Bones were then reworked and oriented in distributary channels or by wave activity along the lake margin. Following the drought, the lake level rose and the bones are capped by a mudstone containing molluscs from the lake.