A CHANNEL BAR IN THE UPPER REACHES OF THE CHANGJIANG RIVER-RESEARCH ON RECENT SEDIMENT OF SHANHUBA IN CHONGQING, SICHUAN PROVINCE

Shanhuba in Chongqing is a channel bar in the upper reaches of the Changjiang River. In the different parts of the bar, there are a lot of different forms of stratification and bedding plane structure. The various ripple marks on the surface of the bar are comparable to those in the near-shore intertidal area. The typical"inverted V"sturcture on the cross-strati- fication of the channel bar is especially better than that on beach barrier and beach cusp. The sedimentary model established by studying the relationship between the bedding structure and grain-size cyclothems of the channel bar and its sedimentary history, can be used to look for fluvial sedimentary deposits. The Shanhuba channel bar in Chongqing will possibly be one of the best localities for making geological tours and researches on present channel bar.