洛川黄土地层定年的一个模式及其初步应用

A Dating Model of Loess Stratigraphy in the Central Chine se Loess Plateau and Its Prelrminary Application

选择黄土中２～１６μｍ的颗粒作为沉积速率相对稳定的大气粉尘沉降组分，根据黄土粒度变化与沉积速率变化的相关性，设计了以下的年代学模型：Ｔｍ＝Ｔ１＋（Ｔ２－Ｔ１）（∑ｍｉ＝１ＣｉＨｉ）／（∑ｎｉ＝１ＣｉＨｉ）以黄土地层中根据热释光和古地磁极性倒转点获得的绝对年代作为时间控制点，利用上面的模式对洛川第四纪黄土地层的年代进行了计算，结果表明该模式可以用于黄土高原中部黄土地层的精细定年。

The 2￣6 μm particle fractions of loess were employed as the relatively stable dust depositional flux. On the basis of the relationship between grain size fluctuation and depositional flux variation of loess, the following dating model was used to calculate ages of loess stratigraphy in the central Chinese loess plateau:Tm=T1+(T2-T1)(∑mi=1CiHi)/(∑ni=1CiHi)\ \ Abosolute ages calibrated by thermoluminescence and palaeomagnetic reversal boundary were served as the time controlling points to obtain detail ages of the Luochuan loess profile, the results showed that our dating model is useful in calibrating detail ages of loess stratigraphy in the central Chinese loess plateau.