The grain construction of the yellow cinnamon soil and its significance in the upper reaches of Hanjiang valley

The grain-size construction of the "loess-like material" of the fist terrace,upper reaches of Hanjiang valley was analyzed.The results reveal that the grain parameters(σ=1.72,Kg=1.03,S=1.15) and the frequency curve of the loess are similar to paleosol(σ=1.73,Kg=1.03,S=1.15),but different with the flood SWD(σ=1.9,Kg=1.10,S=1.20).In the triangle,the loess and the paleosol concentrate in a small area,but the flood SWD is discrete distribution.Y values of the loess are smaller than —2.741 1,and the flood SWD are above —2.741 1.These certify that the paleosol inherit the basic feature of the loess,both are eolian.Contrasted with the loess of Weihe valley,quite similar,that indicate the homology.