光释光技术在我国海岸晚第四纪沉积测年中的应用

位于陆地与海洋交界的海岸系统，对环境变化反应敏感，海岸沉积是记录区域及全球环境变化的重要载体。但海岸沉积动力环境复杂，多存在沉积物的侵蚀、搬运与再沉积现象，或缺乏¹⁴C测年所需的有机质材料，因此年代问题是海岸第四纪地层研究的难点。光释光测年技术（OSL）主要通过石英或长石矿物的释光信号，确定沉积物的埋藏年龄，测年范围从近百年到几十万年。OSL的快速发展为海岸第四纪地层年代确定提供了有利条件，特别是单片再生剂量法的提出，提高了光释光测年结果的准确度和精度。OSL测年需要根据样品的年龄与性质，进行测年矿物、测量程序条件及粒级的选择。文章基于近年来石英和长石光释光测年技术的发展，结合我国海岸第四纪地层断代中已发表的500多个光释光年代数据，探讨光释光测年技术在海岸第四纪沉积物定年中遇到的常见问题及应对策略，包括测年矿物的选择（石英vs.长石）、样品的晒退、剂量率、石英信号的组分、长石包裹体等。对这些问题的认识有助于对光释光测年结果准确度的评估，可以更好地服务于海岸晚第四纪沉积研究。

Application of optically stimulated luminescence dating to Late Quaternary coastal deposits in China

The coastal system, lying at the interface between the land and the ocean, is sensitive to environmental changes. Coastal deposits are archives of regional and global environment changes. However, due to the complex sedimentary processes, such as sediment reworking and redeposition, and lack of suitable material for 14C dating, accurate age determination remains a challenge for Quaternary stratigraphic study in coastal system. Optically stimulated luminescence(OSL) dating, which normally uses quartz and feldspar as the dating minerals, can be applied to obtain depositional age or burial age of the sediments in a variety of sedimentary environments. The technique provides a wide age range from nearly a hundred years to several hundred thousand years. Recent development in the luminescence methodology has led to great improvement in the applicability and precision of luminescence dating, especially the improved single-aliquot regenerative-dose(SAR) protocol for OSL, and its rapid development has offered an invaluable technique for dating late Quaternary coastal deposits.