Abstract:

Defferent parts of high-curved meander point bar in Shatanzi area have different grain size.type-Ⅰ represents the grain size of reeled crest distributed in upper and lower point bars;type-Ⅱ shows the grain size distributed in upper point bars;type-Ⅲ shows that of bars with trenches. The main sedimentary structure of the study area is cross-bedding, and the scale of it decreased in ascending order and it transforms into sand ripple or horizental bedding.This Kind of sediments is characterized by coarts grains in upper parts but fine grains in lower parts,and have binary sedimentary stucture. Within 13 kinds of lithofaces,6 lithofacies assemblages could be classified suchas sand-mud mutated, reeled crest,upper point bar,reeled trough,bar with trenches and lower point bar lithofacies assemblages.The mound landform that is composed of multi-reeled crests and troughs,and the bars with deep-cut trenches is well developed.