海南岛万宁小海的障壁海岸沉积

Barrier Coast Deposition in Wanning Xiaohai of Hainan Island

对万宁小海障壁海岸进行了野外考察和室内研究．从沉积物的成分、结构、沉积构造等方面阐述了障壁沙坝、泻湖和潮坪、潮道及潮汐三角洲的沉积特征，认为小海障壁海岸具海退型沉积层序，潮道侧向迁移是入潮口附近重要的动力学机制，障壁沙坝、潮道、潮汐三角洲砂体通过潮道侧向迁移在时空上共生、连片分布．小海障壁海岸发育主要取决于海平面的相对下降和中低潮差，并与海岸地形、风浪作用、沉积物供给有关．

The barrier coast in Wanning Xiaohai of Hainan Island is investigated in both field and laboratory. The sedimentary characteristics of barrier sand bar, lagoon tidal flat, tidal channel and tidal delta in the aspects of components, texture and structure of sediments are introduced. The barrier coast in Xiaohai has a regressive depositional sequence and the barrier sand bar which has a low maturity includes a fixed tie bar and an active sand mouth. The lateral removal of tidal channel is the main dynamic mechanics near lagoonal tidal inlet, which controlls the expansion of the delta. The sandy bodies of barrier sand bar, tidal channel and tidal delta are paragenetic and sheet distributed to form important sandy sedimentary body. The development of barrier coast in Xiaohai is determined mainly by relative eustasy of sea level, middle to low tidal range and correlated with coastal landform, wind and wave action and the supply of sediments.