蓟县等地震旦地层沉积地球化学（Ⅰ）

Sinian strata (isotopic ages ranging from 1900-850 m.y.) in Oihsien, county and its vicinity have been studied in more detail from the standpoint of sedimentary geochemistry. Average chemical composition of various sedimentary rocks in the Sinian sequence (sandstone, siltstone, shale, dolomite and limestone) have been calculated.The periodicity and general trend as exhibited in the course of evolution of element association have been demonstrated by mathematical statistics based on numerious chemical analyses and semiquantitative spectroscopic data with the aid of electronic computer. In accordance with the above results the classification of elements are proposed on a more reasonable ground. Considerable attention has been paid to the periodicity and evolutionary eharacterictics of rocks, minerals and elements. The mode of occurrence of elements is examined in the light of trace-element concentrations and the relative coefficients between them in different components (clastic debris, clay, and ete.) from a variety of rocks and carbonates. Finally, the relationship between background abundances of elements and mineralization, and the effect of submarine eruption on sedimentation and the enrichment of some elements, for example, K, St, Mn, B, P, Pb and Zn, have also been dealt with.