TRACE-ELEMENT GEOCHEMISTRY OF VOLCANIC GLASS FROM THE OBSIDIAN CLIFFSFLOW, 3 SISTERS WILDERNESS, OREGON

This study was undertaken to investigate potential intrasource trace e lement variability in the Obsidian Cliffs flow, Three Sisters Wilderne ss, Oregon. Geologic samples of artifact-quality volcanic glass (obsid ians) were collected from twelve locations around the flow, and 80 of these (ten each from eight locations) were subjected to non-destructiv e energy dispersive x-ray fluorescence analysis. Concentration abundan ces of eleven minor, trace, and rare earth elements were determined fo r each collection location. The results show that all locations repres ent obsidian of the same (Obsidian Cliffs) geochemical type, and they contribute to the long-term goal of establishing a geochemical data ba se against which artifacts from Oregon archaeological sites can be com pared.