LASER ABLATION ICP-MS ANALYSIS OF FOSSIL BONE: PRELIMINARY RESULTS ON RARE EARTH ELEMENT DISTRIBUTION IN DIFFERENT TYPES OF FOSSIL BONE APATITE

Inductively couple plasma mass spectrometry (ICP-MS) with Nd:YAG laser ablation is a powerful tool for high resolution chemical analysis of fossil bone. Laser ablation allows for continuous line measurements or small spot analysis (ca. 30 micron diameter) of solid samples. Up to 40 elements can be determined nearly simultaneously, with at least one of those used as an internal standard to correct for differences in ablated mass. This study focused on the REE distribution from core to edge of bone found in the late Early Cretaceous Yellow Cat Member of the Cedar Mountain Formation. This project tests recent work that suggests total REE diffuse through the bone with little to no fractionation. Differences types of bone (such as compact versus trabecular) were tested and results provide the basis for designing a companion test of bone from different geologic time periods. Because REE patterns from whole-bone dissolution are used as discriminates in identifying bone populations, and because redox-sensitive REE are used to interpret paleoenvironments, establishing that the bone REE have not been altered by diffusion-driven fractionation is important to validating REE as a tool for interpreting depositional environment, taphonomic reworking, and post-depositional alteration of these macrofossils