中国早更新世考古遗址电子自旋共振-铀系联合法牙齿化石测年问题研究

THE COMBINED ESR/U-SERIES DATING OF FOSSIL TOOTH FROM EARLY PLEISTOCENE ARCHAEOLOGICAL SITES IN CHINA

电子自旋共振与铀系联合法测定动物牙齿化石年代是目前我国早期人类活动遗址年代学研究中一种比较可行的测年手段。本文简单介绍了这一方法并探讨了其在测年中的一些基本问题,研究显示:1)对于早更新世地点的牙齿样品,采用双饱和指数函数拟合古剂量优于目前普遍采用的单饱和指数拟合;2)计算样品内部剂量时,在没有铀析出的情况下,US模式与早期(EU)和线性(LU)模式相比可以更客观的重建样品中铀的吸收历史;3)对于外部剂量在总剂量中所占比重较大的样品,在无法采用等时线法测年的情况下,野外γ剂量率的实地准确测量至关重要。电子自旋共振与铀系联合法有望应用于我国早更新世考古遗址的测年,但方法本身还需不断完善和发展。

The combined ESR/U-series dating of fossil tooth is one of the dating methods with potential values to study the chronology of Early Pleistocene archaeological sites in China. This paper makes a brief introduction of this method and several problems regarding this method are discussed as well. Our study shows that ： （ i ） To determine the paleodose of fossil tooth from Early Pleistocene sites, a fitting with double saturation exponential function is more accurate than a conventional single saturation exponential function ; （2） To calculate the internal dose of fossil tooth, the US model is more objective for reconstructing the uranium uptake history of the sample than the conventional Early Uptake （EU） and Linear Uptake （LU） models in the case of no uranium leaching ; （3） For the samples with the external dose taking a great percentage in the total dose, a detailed T in situ dose rate measurement is essential if isochron dating method is not available. With the development of combined ESR/U-series dating method, it will become the routine technique for dating Early Pleistocene sites in China.