A Coastal Dune Overwash Record of Typhoon Storm Events from Southeastern Hainan Island
- 海洋环境－已发表论文 
通过海南岛东南部海岸详细的古风暴学考察,在尖岭海岸发现了含有风暴冲越沉积物的海岸沙丘剖面,分别命名为JL-1和JL-2剖面,试图从海岸沙丘沉积记; 录中提取历史上的风暴事件信息。沉积物粒度、磁化率等参数的指标分析表明,这两个剖面含有典型的风暴冲越沉积物,利用放射性核素AMS~(14)C测年、; OSL测年分析,并结合历史文献记载,确定这些风暴沉积层是多次台风作用的产物,其形成机制与风暴浪越过海岸沙丘的堆积有关,风暴流越过沙丘顶部后不能回; 流,导致风暴流携带的沉积物迅速沉积。此外,依据Stockdon经验公式计算结果,该地点沉积记录所代表的最大风暴事件相当于100到200年一遇的重; 现期。研究表明,该处海岸沙丘冲越沉积含有南海台风强度与重现期的重要信息。In the present study, coastal dune deposits are analyzed to derive the; information on historical storm events. Paleotempestology investigations; were carried out for the southeastern part of Hainan Island. The storm; deposits identified are interbedded within the aeolian coastal dune; profiles on the Jianling coast. They are characterized by coarse-grained; overwash deposits during the extreme storm events, as revealed on the; basis of detailed stratigraphic division, grain size and magnetic; susceptibility analyses. The age of the storms events was determined; using the ~(14)C and OSL dating methods, in combination with historical; documents. When a storm surge hits the coast, the coastal dune may be; overtopped or breached, and a low-lying dune associated with a large,; flat terrain at the backshore is suitable for trapping the storm; sediment to form a thick-bedded, sandy washover deposit. The Stockdon; empirical equation was used to calculate the overwash height, indicating; that the storm record at the Jianling site represents the product formed; by several storms, with their return periods being 100 to 200 years. The; result obtained implies that the coastal dune here contain important; information on the intensity and frequency of occurrence of the South; China Sea typhoons.