PRELIMINARY OSL AGES FOR PREHISTORIC POTTERY SHERDS FROM TWO SHOSHONEAN SITES

Optically stimulated luminescence (OSL) is gaining popularity as a reliable chronometric dating technique in archaeology. The Boulder Ridge Locality and High Rise Village, two late period (<1500 years ago) high-altitude (>3000 meters asl) archaeological sites in northwest Wyoming provide an ideal setting to use the technique. Radiocarbon dates at both sites have proven problematic due to an old wood problem near upper treeline and radiocarbon calibration issues. Sherds from Intermountain Ware ceramic vessels were recovered from both sites after wildfires swept through the area. OSL dating is the only practical alternative to yielding an absolute age, as the quartz-rich temper of the recovered sherds lends itself to the technique. Resulting ages provide a date for when the vessels were fired and the sites likely occupied. Single-grain dating allows for grains potentially reset in recent wildfires to be identified and removed from contributing to the final age. These results are part of a larger study aimed at developing a methodology to apply and refine OSL dating to prehistoric Intermountain Ware sherds, common throughout the Greater Yellowstone Ecosystem.