AVERAGE CHEMICAL COMPOSITION OF LOESS IN CHINA: AS A GOOD REPRESENTATIVE OF THE UPPER CONTINENTAL CRUST

The average chemical composition of loess in China has been measured and calculated by the method of mass-welghted average calculation on the basis of extensive sampling and labora-tory chemical analysis. Great differences are noticed in chemical composition between loess of China and the lower or the bulk crust,the former being characterized by the relative enrichment of LIL elements and the latter two by the enrichment mainly of siderophile elements. Much si-milarity is indicated in chemical composition between loess of China and the upper crust. In addi-tion to the enrichment of Ca and B and the depletion of Na and Nb,the majority of the other ele-ments in the loess of China show little or, even no difference in contents from those in the upper crust. The above charaeterisitics indicate tha loess of China typically belongs to upper crustal material. Loess of China not only provides a kind of ideal natural average samples of the exposed upper continental crust,but also can be used,if its average chemical composition is taken into consideration,to represent the chemical composition of the upper continental crust.