SCIENTIA GEOGRAPHICA SINICA ›› 1984, Vol. 4 ›› Issue (2): 167-176.doi: 10.13249/j.cnki.sgs.1984.02.167

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FEATURES AND GENESES OF THE DIAMICTON IN THE LUSHAN REGION

Zhang Linyuan, Mu Yunzhi   

  1. Department of Geology and Geography, Lanzhou University
  • Online:1984-03-20 Published:1984-03-20

Abstract: The glacial problem of the Quaternary in the eastern part of China,especially in the mountains at low latitudes and low altitudes,has been debated among domestic and foreign researchers.The points in debate are those of glaciation and non-glaciation.This paper deals with the problem in the light of some features of the diamietons of the region. The allitic weathering of the diamicton is very obvious in the region. However,a key question for determining the sedimentary environment and its genesis is of period over which warm,humid weathering prevailed.Those who advocate glaciation of the Lushan have already pointed out that under the condi-tion of warm,humid weathering the deposition of diamictons often occurred. Based on analysis of data,however,the following is proposed:the composition of diamicton of Dagu period on the piedmont came from the weathered crust constructed by vermicular red soil,in the mountains.that is to say,lt had gone through strong warm and humid weathering before deposition.This proves that the warm,humid weathring prevailed in the region in the early period. Based on its generation and development process,the original diamictons of different ages and colours in the region can be divided into three types: modern slope sediments laid down by creep,slope sediments which came from earlier diamicton and crept slowly along the slopes cut by stream,and debris-mud flow sediments. Based on a series of charateristics of the diamictons,it is considerable that the diamicions in the Lushan are not of glacial origin,however,they can not be explained by any single non-glacial process.Diamictons of different ages and geomorphological expression have been produced by various mechanisms. The Dagu diamicton(corresponding to Mindel glaciation)which was said to be typical morainedebris is really a sediments of piedmont fan.Its main features can be explained by the mechanism of debris-mud flow accumulation.