ESR dating of spring deposited travertines

ESR dating of spring deposited travertines is complicated by the presence of acid insoluble minerals, which contain concentrations of radioactive elements that differ from those of the secondary calcite which is to be dated, and the fact that most samples do not display ESR signals which are suitable for dating. However, sampling of synsedimentarily formed crusts significantly increases the probability that the ESR spectrum of the samples contains the signal at g = 2.0007 which can be used for a dating attempt. Additionally, the concentration of acid insoluble minerals in those crusts is normally negligible.