Abstract:

Hutuo River has dried up and cut off perennially because of climate drought since the mid-1970s. The river ecosystem has suffered severe damage. It is the basis of river ecosystem recovery and wetland ecological environment reconstruction to study the shallowly buried paleochannel of Hutuo River. In this paper, the sedimentary facies of Hutuo River paleochannel are studied using the methods of grain size analysis. And the sedimentary environmental change process of the study area since 30 ka.B.P.is discussed on the basis of high density sampling and detailed data. The results show that the paleochannel section is composed of two sedimentary segments with the boundary of 1,060 cm. The lower segment is deposited from 29.4 to 26.9 ka.B.P.. Limnetic facies sediments are developed in the study area. The upper segment is deposited from 26.9 ka.B.P. to the present. Fluvial facies sediments are developed in this stage, including two kinds of fluvial subfacies. The grain size characters are changed between the two segments correspondingly.

Key words: paleochannel, grain size, sedimentary environment, Hutuo River