江苏近海辐射状沙脊地貌的发育

本文阐述江苏近海辐射状沙脊的分布和形态特征,划分了沙脊和潮谷的地貌类型,讨论了沙脊地貌的发育规律。

THE GEOMORPHIC DEVELOPMENT OF RADIATING SAND RIDGES IN THE JIANGSU SEASHORE

The Jiangsu radiating sand ridges are distributed in the shallow sea region from the old estuary of Huanghe River (Yellow River) to Qe-Dong cape about 35m in deep water, with the Jionggang harour shallow and palm-like in N.E. and ES direction. These sand ridges extend for about 200km from north to south and 100km from west to east. The highest of them is 5.8m and the deepest of them is 48m on theorical deep base-level. This. hydrody-namic structure of sediment is very complex. It is a seldom seen geomorphic phenomenon.The study of radiating sand ridges can supply scientific evidence in synthetical use of the resources of the sea Recently more than 20 years, foreign scholars have investigated submarine sand ridge in The European North Sea and the eastern coast of U.S.A. The chief reason is to provide for oil formation theory scientific basis.In this paper, we simply analysed the geomorphic development of radiating sand ridges in the Jiangsu sea shore; First, it analysed distribution and figure of feature of sand ridges; Second, it analysed geomorphic type of the sand ridges and tide valley, and divided the sand riges into recent and ancient ares. The recent sand ridges have models of "O", "V"."E"and "S" by figure and derived from the underwater ridges, tide range ridges and storm ridges by hydrodynamic function. The ancient sand ridges are derived from erosion and coverage. The geomorphic types of tide valley are tide stream, small tide channel, tide channel, chief channel and tide trough.Finally, it discussed some developing laws of the geomorphic sand ridge. It explains this type of sand ridge consists of sediments such as the delta of ancient Yangtze river, Huaihe river (Yellow river) and Huaghe river. The Yangtze river's sediment is the base of sand ridge and the southern shore line in sea regession. After the Huaihe river (Yellow river) brought about a great number of sediment to this ridge along the southern jiangsu coast, the ridge remains to be developed after the Huanghe river took its course to the north. The tidal current is the chief factor controlling the development and figure of these sand ridges. It shed light on the figure and develoment process of "O", "E", "V"and "S" models.1. The length and direction of the sand ridge are decided by tide change and the direction of current.2, The height of sand ridge results from the amount of silt, the elevation and subsidence of place and the sedimentary environment.