皖北上前寒武系地球化学特征

皖北上前寒武系地层发育完整、露头连续、化石丰富,是研究我国上前寒武系重要地区之一。地层主要分布于安徽省凤阳县、淮南、淮北市和江苏徐州一带。下部青白口系以碎屑岩为主,上部震旦系以碳酸盐岩为主。本文利用剖面中大量化学、光谱分析资料,计算了不同岩类和各组平均化学成份,用“有序样品最优分割”法,对地层进行了化学分层,用点群分析、对应因子分析归纳了元素的组合规律,并用指相元素的含量和比值,分

GEOCHEMICAL CHARACTERISTICS OF UPPER PRECAMBRIAN STRATA IN NORTHERN ANHUI

In this paper,the average chemical compositions of various rocks and formations occurring in the upper Precambrian of northern Anhui are calculated by use of a vast amount of chemical and spectral data from the sections and compared with the crustal clarke values.According to the chemical compositions,the sections are chemically divided using the optimal partitioning method of ordered samples,and thus association laws of the elements in various rocks and formations are derived. The element contents are used to make Q-and R-mode cluster and factor analyses.The geochemical evolution trends of the elements in various formations are discussed in the light of the vertical distribution law of the elements and their contents in the strata,and sedimentary environments in different time are analysed using the contents and ratios of the facies-indicating elements.