DETRITAL MODES OF SANDSTONE, CHEMICAL COMPOSITIONS OF MUDSTONE AND STRATIGRAPHIC DIVISION OF THE PRE-TERTIARY SYSTEM IN THE HUANGHUA DEPRESSION

Based on the analysis of detrital modes of sandstone and chemical compositions of mudstone in Pre-Tertiary system in Huanghua Depression,it is suggested that there are some important differences in the types of sandstone or in the trace elements and chemical compositions of mudstones because of different geological time.The cluster analysis indicates that the samples in same sequence are clustered into one group while the samples in different sequences show poor interrelation.In this paper,the characteristics of detrital modes and chemical compositions of sandstone and mudstones of the Upper Paleozoic and Mesozoic are presented.In the same time,the strata in this area can be divided into several sequences,especially for the overlain red beds occurred during the different geological time.This method can contribute the unique effect in stratigraphic division.