浙江湖州─长兴地区地层含矿性的地球化学评价

GEOCHEMICAL ASSESSMENT OF OREPOTENTIALITY OF THE STRATA IN HUZHOU CHANGXING AREA,ZHEJIANG PROVINCE

地层地球化学的研究范围正在日益拓宽．但其中心任务仍然是研究地层及其各类岩石中化学元素的分散与富集规律。实际上，元素的集散可回答成矿作用曾否发生，尤其是成矿作用发生的可能性问题．也就是地层含矿性的评价问题。本文以浙江省湖州─长兴地区地层岩石样品化学元素光谱分析数据为基本素材，对该区各地层组进行比较系统的地球化学研究．查明了各地层层位中Au、Ag、Cu、Pb、Zn和B共六个成矿元素的丰度及其它地球化学特征，着重从地层中成矿元素的相对富集与贫化、后期作用叠加强度、变化性以及元纱共生组合几个方面考察地层中成矿元素的分散与富集规律，在此基础上确定地层含矿性评价的准则与标志，进而对地层的含矿性进行评价．以揭示本区主要矿产的可能赋矿层位。

The focus of the geuchenlistry uf strata is still to examine the patterns of dispersion and concentration of chemical elements in strata and in d ifferent kinds of sedimentary rocks,although the scope of the geuchemistry of strata is becuming increasingly broad. In practice, the dispersion and concentratiun uf elements can be used to answer the question of whether or not the ore-forming processes unce vccurred,and sulve the problem of potentiality of ore formation or assessment of ore-potentiality of strata. Based on the spectral analysis results of the contents of trace elements of rock specimens in the strata in Huzhou-Changxing area, this paper carries out a systematical study of the geochemistry uf strata. By determining the abundances and other geochemical characteristics of the ore -forming elements Au, Ag, Cu Pb, Zn and B in each strata unit in the area, the patterns of dispersiun and concentration of ore-forming elements were exa-mined through the investigatiun of coneentrations or dilutions, intensities of overlapping post-sedimentation prvcesses, variatiuns, and element associatiuns of those elements. Furthermore, several criteria and indicators were provided for assessing the ore-potentinlity of each strata unit. At last, the strata units with good ore-potentiality in the area were brought to light by indicating their main ore-forming elements and the elementassoctations.