In collaboration with Drs. Schwartz and Grun at McMaster University, Dr. Clark Howell will work to improve the ESR dating technique, apply it to tooth enamel, and determine the ages of a series of significant archaeological sites. The ESR dating technique is based on the measurement of energy stored in crystal lattices which result from the bombardment by environmental radioactivity. The amount of stored energy can be determined by electron spin resonance (ESR) spectroscopy. The age of the crystal is then determined from the ratio of the accumulated energy dose to the dose rate, which is a function of the concentration of radioactive elements in the environment. This method can be applied to the tooth enamel of large mammals and is thus applicable to most Pleistocene prehistoric sites for ages up to a few million years. The project includes two stages. The first will consist of a series of experiments to increase the accuracy and reliability of the technique. In the second, the investigators will continue to date samples from anthropologically significant sites. This research is important for two reasons. Reliable and widely applicable dating techniques are lacking for most archaeological sites over 40,000 years in age (this is the effective time limit for radiocarbon dating). If ESR can be established as a workable technique, many archaeological sites could then be dated and the information derived from them would be greatly increased. The technique would also be useful to geologists, paleontologists, and other scientists concerned with the past. Secondly, the specific sites which Drs. Howell, Schwartz, and Grun plan to examine are important in their own right.
