关键词: 沉积层序, 埋藏潮沙体, 沉积特征, 形成机制, 发育演化, 黄海南部陆区

Abstract: Based mainly upon anlysing of eight drill-holes and upon other several dozens ofis paper. It is non-marine facies of Pleistocene that under lay the sediments of Holocene with an unconformity between them. The Holocene sedimentary sequences can be divided into the lower transgressive and the upper regressive ones, consisting of beach facies (contains estuary-bay facies in some part of the studied area), nearshore neritic facies (tidal sand body facies) and tidal flat facies. It is obvious that facies change horizontally. It merits notice that the nearshore neritic facies is composed of fine sands or silty fine sands in all drill-holes. Characteristics of the sand bands have been researched about their textures, structures, minerals and microfossils etc. Through comparative sedimentological study with the modern tidal sand ridges in Jianggang, it is found that the buried sand bodies belong to the type of tidal sand body.Tidal sand body refers to the sand body of geomorphological bedform formed by the tide current.Along with the changes in current power and sand source, the bedform appears diffenent shapes, and forms different types of tidal sand bodies.According to the differences in their sedimentological characteristics and microfossils, the buried tidal sand bodies can be distiguished into three types: Ⅰ) nearshore tidal sand bars, Ⅱ ) tidal sand waves. and Ⅲ ) nearshore tidal sand ridges. They correspond respectively to the sand banks discribed by Stride (1982) and Caston (1972), the sand waves discribed by Stride (1982) and Belderson (1966) and the sand ribbons discribed by Stride (1982),Kenyon (1970) and Off (1963) or sand ridge discribed by Swift ( 1975 ).

Key words: coasral sedimentary sequences, buried tidal sand bodies, sedimentary characteristics, South Yellow Sea coastal land