ESR dating of raised coral reefs from Kish Island, Persian Gulf

Abstract

Electron spin resonance (ESR) dating of raised coral reefs from Kish Island, Persian Gulf, Iran, was used for the calculation of uplift rates. From the methodological point of view, it has been demonstrated that concentrations of uranium, as needed for the calculation of dose rates, determined by instrumental neutron activation analyses were significantly lower than the results of inductively coupled plasma—mass spectrometry and are probably systematically underestimated. The ESR ages for the corals show no increase with elevation as was expected due to field observations. This apparent discrepancy is explained by the dicyclic nature of the palaeo-reef. Average uplift rates for Kish Island are between ∼0.13 and ∼0.24 mm a −1. This is consistent with previous estimates based on 230Th/ 234U dating of raised marine deposits from the nearby Iranian mainland and Qeshm Island, Strait of Hormuz, but contrary to results based on 14C dating that predicted uplift rates as high as 3 mm a −1 in that area. It is once more demonstrated that 14C dates >20 ka from this context often have to be interpreted as minimum ages.