Analysis on Formation of Underwater Delta Shoal and Tidal Groove of Lianzhou Gulf Nanliujiang River

In light of relervant data along with drilling and hydrological data obtained by the author when undertaking the program: The Influence of Modern Evolution of Nanliujiang River Delta on Whirlpool Silt in Beihai Harbour,the article analyzes underwater delta shoal and tidal groove of Nanliujiang River in terms of material composition,sand sources,geomorphological combination,the features of sediments along with the formation of underwater delta of Nanliujiang river.The result shows that the formation of great shoal of underwater delta is attributed to long-term sediments of sands from Nanliujian river to sea.Furthermore,the formation of tidal current groove has close relationship with the conditions of water dynamics,landshape and geomorphology.These two main styles of geomorphology are very stable after longterm geographic evolution.