TAPHONOMIC STUDIES OF THE AARON SCOTT SITE QUARRY (MORRISON FORMATION, JURASSIC) NEAR FERRON, UTAH

The Aaron Scott Site (Emery County, Utah) is in the Jurassic Morrison Formation. The Aaron Scott Site quarry has been under excavation for the past five years and has yielded excellent dinosaur fossil samples. The vertebrate samples range from an articulated skeleton of a sauropod to disarticulated and broken samples of crocodile, turtle, and allosaurus. The Morrison Formation is located in the Western Interior of the United States across New Mexico to Montana and South Dakota to Utah and Oklahoma. The paleoenvironmental conditions have been related to that of an African savannah; semi-arid with local areas of dunes, wetlands, and flood plains. However, research has suggested that the Aaron Scott site is a delta deposit along the margins of a large lake.

Previous research has used rare earth elements (REE) of fossil bones to determine the environment where the animal was deposited shortly after. The REE characteristics trends are compared to that of modern day water environmental conditions. Because REE signatures are stable in fossil bone post recrystallization and uptake, REE signatures of fossil bone reflect the signature of the fluids during initial diagenesis and are not affected by alteration at later dates. Non-sauropod bones showed REE trends suggesting a fluvial environment. The

bones are broken and disarticulated, supporting a fluvial transport. The bones broke during transportation of the river and accumulated at the end of the river. Sauropod bones suggest REE trends similar to a lake. These bones are articulated and show no signs of being carried by fluvial environments or carried far from the non-sauropod bones. This interprets that the sauropod died and lake levels rose, bringing sediments to deposit the remains. These interpretations are consistent with the stratigraphy of the area around the Aaron Scott Site.