摘要
REE （Rare Earth Element） signatures in fossil vertebrates from different stratigraphic units are sufficiently distinctive to allow identification of the original unit or location in which fossilization occurred. Our field studies at the classic Pleistocene site of Fossil Lake, Oregon, reveal at least nine exposed depositional packages, most separated by disconformities. Bones analyzed from eight of the defined packages have distinctly different REE signatures. By accruing an extensive REE data library, samples with nebulous origin can be compared to this data library to determine the best stratigraphic context of the fossil. The research involves an articulated horse from the Ferruginous Sandstone unit at Fossil Lake. This unit shows subtle lithological changes which may indicate differences in depositional environment. The recovered specimen transected these subtle variations of this unit. Since REE reflect depositional environment this specimen offers a unique opportunity to investigate the possible variations in a signature due to subtle changes in lithology. This was accomplished by collecting bone and sediment material from 1 cm increments. By relating subtle changes in lithology to possible variations in REE signature, this study will offer a better resolution for application of REE signatures to Paleoenvironmental interpretations, fossil provenience and stratigraphic correlation.
