THE FUNDAMENTALPRINCIPLE AND METHOD FOR DEFININGTHE PROLUVIAL FANS IN ASMALL RED BASIN ACCORDING TO THE STATISTICS OF GRAVELS

The author made a systematical investigation of the composition, size,content and mode ofoccurrence of gravels in proluvium as well as the contact relationships and facies indicator ofsedimentary sequences in the small Ma’ ao red basin, Xiushui County. Then he found the con-tent, average volume and mixing coefficient using the method of mathematical statistics andconstructed the related contour diagram and paleocurrent diagram. Through an integrated analysis and treatment he finally constructed a geological sketch map showing the distribution ofthe proluvial fans and essentially ascertained the distribution range and superimposition relationof the prouvial fans and the laws of their development and evolution. This study is still in an ex-ploratory stage and some problems await further improvement and perfection.