ESRdatering

ESRdatering, or ESR-datering, is a dating method that estimates the age of certain archaeological and geological materials by measuring trapped electronic charges produced by ionizing radiation. The technique relies on the buildup of stable paramagnetic centers in minerals and biogenic materials after burial or heating.

The basic principle is that ionizing radiation from natural sources gradually creates trapped electron defects in minerals such as tooth enamel, bone apatite, quartz, and calcite. The amount of trapped charge is proportional to the total absorbed dose since the event of burial or last heating, known as the paleodose. In the laboratory, the natural electron spin resonance (ESR) signal is measured and compared to signals produced by controlled laboratory irradiation to determine the paleodose. The age is then calculated as the paleodose divided by the annual dose rate, which is the rate at which the sample collects radiation from its environment.

Common materials dated with ESR include fossil teeth (enamel and dentin), fossil bones (apatite in bone), and certain carbonate minerals like quartz and calcite. Quartz and calcite ESR dating have been applied to cave sediments, speleothems, and other geological settings, while dental enamel is a primary target in archaeological contexts.

ESR dating complements radiocarbon and luminescence methods, offering an age range that can extend beyond radiocarbon limits and into hundreds of thousands to a few million years in suitable materials. Limitations include dependence on undisturbed samples, accurate dose-rate estimation, and potential signal saturation or diagenetic alteration.