河流阶地砾石埋藏年龄的光释光测年方法研究

河流阶地砾石层沉积年代框架的建立对于全面理解阶地的形成和发育过程，反演流域内古环境演变、构造活动等相关信息具有重要意义，但砾石埋藏年代的直接测定一直是第四纪研究中一个难题。本课题拟通过测试分析一系列河流阶地砾石表层光释光信号特征，在对比测试有年龄控制样品及试图了解光线在岩石中穿透过程及对光释光信号晒退机制的基础上，分析砾石在沉积埋藏前光释光信号晒退状况及与砾石形状特征、沉积产状的关系，遴选出适于年龄测定的研究对象、剂量计矿物及其稳定的光释光信号，发展和构建适于阶地砾石埋藏年龄测定的光释光测年方法。

A reliable numerical chronology is central to understanding environment changes, geomorphological processes, and major hazards. However, because of lacking of a wildly-used dating method, the dating of fluvial cobbles has been a bottleneck problem in the study of fluvial geomorphology. While, robust rock surface dating techniques are essential for this purpose, and luminescence provides an exciting new approach to this. The main purpose of this project is to test and develop this new surface burial dating method used on fluvial cobbles. The reliability of the new method will be calibrated and tested against a series of known ages samples, including modern river cobble samples, archaeological rock samples of historically known age and buried fluvial cobble samples with OSL ages of overlying sediments. Two key problems will be addressed by this project. The first purpose is to investigate the daylight OSL signal bleaching characteristics in buried fluvial cobbles and address the relation with cobble shape or deposit occurrence before deposition or burial. And then, we will determine the most appropriate target cobble samples and mineral (quartz, K-feldspar or Na-feldspar) to provide the most appropriate stable dosimetric signal for dating. The main outcome of this project will be the testing and proving of a novel rock-surface burial dating method with broad application in many fields in Quaternary geology, geomorphology and archaeology.