ESR dating of subfossil Holocene shells in Estonia

Different subfossil shells (Limnea peregra, Cardium, Littorina sp., etc.) of known age, 4000–9000 years, were dated from six localities. ESR spectra were measured using ESR-221 (D.D.R.) equipment. Prior to measurements shells were etched in 0.3 N HCl for 3–5 min in order to remove α-activated surface and crushed. Special precautions were not applied against the activities of light. Accumulated dose was determined using the method of added doses. It is shown that one of the lines of ESR spectrum, g = 2.0020, may be applied to ESR dating. The factors having an impact on the value of annual dose are analyzed. Graphical method is suggested for dating the shells over 10,000 years old. The ESR method proved fruitful for the study area. Our results indicate that the ESR method shows promise for dating of shells. Both detailed physical studies and investigation of representative geological collections from profoundly studied regions are of urgent necessity