自1983年在西沙石岛首次发现风成灰岩以来,相继报道了一些研究情况。石岛风成灰岩基底明确,侵蚀面清楚,经氧同位素地层学推断,基底年代为7万年,而铀系法测定为13.1万年,差异较大。鉴于这种情况,选择另一种独立的方法确定其基底年龄,十分必要。为此我们用ESR方法对基底样品进行了年龄测定,同时还进一步检验了样品的化学封闭情况。 Since the first limestone was discovered in the island of Sai Sang in 1983, a number of studies have been reported one after another. The Shiqi Island limestone basement is clear and its erosion surface is clear. Based on the oxygen isotope stratigraphy, the basal age is 70,000 years, while the uranium series method is 131,000 years, with a big difference. Given this situation, it is necessary to choose another independent method to determine its basal age. For this reason, we measured the age of the basal samples by the ESR method, and further examined the chemical blocking of the samples.