Obsidian hydration dating dating ithaca ny
INTRODUCTION | PREPARATION METHODS | REFERENCES The obsidian hydration dating method was introduced to the archaeological community in 1960 by Irving Friedman and Robert Smith of the U. When a new surface of obsidian is exposed to the atmosphere, such as during the manufacture of glass tools, water begins to slowly diffuse from the surface into the interior of the specimen.
The potential of the method in archaeological chronologic studies was quickly recognized and research concerning the effect of different variables on the rate of hydration has continued to the present day by Friedman and others. In Chronometric Dating in Archaeology, edited by R.
The hydration rate is typically established empirically through the calibration of measured samples recovered in association with materials whose cultural age is known or whose age can be radiometrically determined, usually through radiocarbon dating methods (Meighan 1976).
The hydration rate can also be determined experimentally, an approach that has shown increasing promise in recent years (Friedman and Trembour 1983; Michels et al. An appropriate section of each artifact is selected for hydration slide preparation.
These cuts produce a cross-section of the artifact approximately one millimeter thick which is removed from the artifact and mounted on a petrographic microscope slide with Lakeside thermoplastic cement. A New Dating Method Using Obsidian: Part I, The Development of the Method.
The mounted specimen slide is ground in a slurry of 600 grade optical-quality corundum abrasive on a plate glass lap.
Progress and Prospects in Obsidian Hydration Dating.
University of California Institute of Archaeology Monograph No.
The prepared slide is measured using an Olympus BHT petrographic microscope fitted with a video micrometer unit and a digital imaging video camera. In Archaeological Investigations, PGT-PG&E Pipeline Expansion Project, Idaho, Washington, Oregon, and California, Volume V: Technical Studies, by Robert U. Report prepared for Pacific Gas Transmission Company, Portland, Oregon, by INFOTEC Research, Inc., Fresno, California, and Far Western Anthropological Research Group, Davis, California. Considerations of Hydration-rind Dating of Glass Artifacts: Alteration Morphologies and Experimental Evidence of Hydrogeochemical Soil-zone Pore Water Control. In Current Directions in California Obsidian Studies, edited by Richard E. 48, University of California, Berkeley, California.
The location of the section is determined by the morphology and the perceived potential of the location to yield information on the manufacture, use, and discard of the artifact.