水成沉积物释光测年研究进展与展望

A review of OSL dating for water-laid deposits:progress and prospect

石英光释光(OSL)测年方法对于蕴藏着丰富区域气候环境变迁、古洪水、古地震及构造信息的冲积、洪积、湖积等水成沉积物组成的沉积地层,面临许多难题。水成沉积物矿物颗粒在搬运和沉积过程中,先前积存的释光信号能否被晒退,晒退是否均匀?残留水平如何?如何准确测定这些沉积物的天然释光信号强度的等效剂量(De)?环境剂量率怎样才能准确测定等问题,是几十年来国内外释光测年研究者普遍关注的问题。本文通过对水成沉积物研究成果的梳理、存在问题及研究现状分析,探讨了光释光测年方法在水成沉积物方面的应用前景。

OSL dating method has been widely used for dating sediments, most of which are wind-laid. There are many difficulties to use OSL dating method for dating water-laid deposits, such as alluvial, fluvial and lacustrine deposits, which need more chronological data support and contain abundant information of regional climate and environment change, ancient flood, ancient earthquake and geological structure. Therefore, application of the OSL dating method in water-laid deposits has been baffled to some extent. Can optical signal preserved in mineral particles of water-laid deposits be bleached in the process of transportation and deposition？ Is that bleaching even？ How is the residual level？ How to determine the equivalent dose of nature optical signal intensity of the water-laid deposits？ How to mensurate the equivalent dose accurately？ These are decades-long problems concerned by OSL dating researchers home and abroad. In this paper, progresses in this field of research are reviewed, the recent research status and problems are discussed, and prospect of applying the OSL dating method to water-laid deposits is given.