Electron Spin Resonance Dating

Abstract Electron spin resonance (ESR) dating is one of a family of ‘trapped charge’ dating methods that use the damage produced by radioactivity in a material to determine age. Others include optically stimulated luminescence (OSL) and thermoluminescence (TL). ESR dating exceeds both of these in utility due to longer time range and greater variety of suitable sample types. In the nearly 50 years since the first published paper on ESR dating, the method has been used to date a variety of materials over a time range, from ~ 10 Ka to 3 Ma depending on sample type. Most frequently used materials are fossil teeth, carbonate deposits such as stalagmites, and quartz. The former is found in paleontological sites since tooth enamel is the hardest substance in the body. The latter two are common constituents of geological sites. There are difficulties that interfere with accurate and precise results, most often due to changes in the ambient environment. Despite this, ESR has been used to determine the details of physical changes in the landscape, periods of climate change, and the tempo and mode of human evolution. This article describes the physical background to ESR dating, the selection of samples, and the treatment of results. A number of case studies show the versatility of the method within subfields of geology.