ESR and U-series ages of coral reef samples from shallow drill holes in the South China Sea

The ages of coral reef samples from several shallow drill holes in the South China Sea are determined by ESR and U-series (²³⁰Th/²³⁴U) methods. The experimental results show ideal agreement between ESR and U-series ages and that the coral reefs were formed in the early Holocene. In the determination of natural total dose of coral reef by use of the additive dose method good results can be obtained by exponential fitting, no matter how the effect of dose saturation is. It was found that the ratio of the natural ESR signal intensity (I0) to the ESR signal intensity at dose saturation (I_max) of sample can reflect the significance of a irradiation efficiency-k value. Using the k value of sample determined by the formula given in this paper, the precision of ESR dating of marine carbonates can be improved.