福建长乐海岸沙丘记录的小冰期晚期风沙气候与海岸环境演变

摘要

对福建长乐东海海岸沙丘进行光释光测年(OSL)分析,并根据毗邻海岸沙丘的光释光年代以及环境考古年代校验,初步确定了长乐海岸带近300 a来的海岸沙丘发育的时段.在光释光年代学确定的统一时间标尺基础上,采用粒度参数作为环境代用指标,讨论分析了不同空间尺度下影响长乐海岸沙丘发育的主要因素.研究表明:1)长乐海岸沙丘砂粒度特征表现出典型风成砂的特征:以中砂为主,分选较好,近对称,中等峰态,粒级较集中;2)长乐东海海岸沙丘发育于1714年以来,长乐海岸带海岸沙丘发育可划分为3个时期,AD1800以前、AD1800—1868、AD1896年至今;3)近300 a来东海沙丘发育主要受到东亚冬季风强度的影响,冬季风较强的时期海岸风沙活动频繁,但人类活动的影响也不容忽视.%Dating the age of Donghai dune in Changle by OSL,basing the OSL age of adjacent coastal dune and environmental archaeology,this study fundamentally determines the period of dunes growth in Changle during recent 300-year.The study takes grain-size parameters as environmental proxy and dis-cusses the main factors that affect the dunes'growth of different spatial-scale based on unified time scale confirmed by OSL.The result showed that:1)The grain-size characteristics of dune sand in Changle coast is typically Aeolian, mainly comprised of medium sand, fairly well sorted, nearly sym-metrical,medium skewness,concentrated particle distribution;2)the dunes were formed since 1714, and its coastal Aeolian sand activity can be divided into three periods,before AD1800,AD1800—1868 and AD1896 till now; and,3)the development of the dunes were mainly influenced by the winter monsoon intensity,and Aeolian activity is frequent with strong wind in winter,at the same time the in-fluence of human activity can not be ignored.