潮坪沉积韵律与沉积间断

Tidal Flat Depositional Rhythm and Diastem

浙西及长江三角洲南翼潮坪剖面均显示，微型层序和小型层序是潮坪沉积的基本组成单元．潮汐说认为，潮坪层序中砂质单层是在大潮期间形成的，而泥质单层是在小潮期间形成的．潮坪观测证明，砂质单层是风暴沉积，而泥质单层是正常天气的沉积单元．砂、泥质单层共同组成一个小型层序（风暴序列）．风暴沉积在潮坪层序中占重要地位，大小潮沉积旋回的概念不适合于长江三角洲一类的非潮道潮坪．

The research of the tidal flat deposits in the southern flank of the Yangtse Delta and in the paleozoic section of Zhejiang Province shows that micro sequence and small sequence are the fundamental units of tidal flat.Concepts of tidal bundle and neap-spring tidal cycle deposition are widelyprevalent. By these concepts, the sand-layer is deposited in the period of spring tide, and the clay layer is deposited in the period of neap-tide.The observations in the Nanhui tidal flat demonstrate that sand layer is deposited by storms, and clay layer is deposited during normal weather. They compose small sequence which is a storm sequence. Storm sediments account for the majority of tidal nat sequence. The concept of neap-spring tidal cycle is not suitable for tidal flat in the Yangtse Delta.