38 ka以来海南岛东海岸风成沙的粒度特征及其反映的沉积环境演变过程

 木堆地层剖面是海南岛东海岸沙丘与丘间地沉积过程的典型记录。在对该剖面地层高密度采样和光释光定年的基础上,对风成沙及相关沉积物的粒度组成、粒度参数和概率累积曲线及粒度敏感指标（SC/D值）的分析表明,风成沙、弱沙质古土壤、风水两相沉积物和泻湖相沉积物的粒度特征各异,反映38 ka BP来海南岛东海岸沉积环境经历了阶段Ⅰ（38～22 ka BP）、阶段Ⅱ（22～17 ka BP）、阶段Ⅲ（17～10 ka BP）、阶段Ⅳ（10 ka BP至今）等4个演变阶段,气候环境经历了暖湿-暖干-暖湿-暖干-暖湿-干凉-温湿-波动-暖湿的演变,沉积环境也经历了泻湖沉积-沙丘与丘间地沉积-沙丘固定成壤-流沙沉积的演变过程。

Grain-size Features of Aeolian Sands on Eastern Coast of Hainan Island and the Reflected Sedimentary Environment since 38 ka BP

The Mudui stratigraphic section is a typical record of the sedimentary process of sand dunes and the inter-lowland in the eastern parameters, cumulative probability curve and sensitive indexes (SC/D value) were conducted based on high-resolution sampling and OSL age determination. Results show that the grain-size features of eolian sands, immature sandy paleosol, sediments of Aeolian-water and lacustrine facies are different from each other. The sedimentary environment evolution in eastern coast of Hainan Island can be divided into four phases: 38～22 ka BP ;22～17 ka BP ;17～10 ka BP ;10 ka BP to present. Correspondingly, climate followed changes of hot-wet-hot-dry-hot-wet-hot-dry-hot-wet-dry-cool-warm-wet-fluctuation-hot-wet;semimetal environment followed changes of lagoon-dune and inter-dune-dune fixed for pedogenic environment-shifting sand deposit.