湘西、湘中新元古界—古生界微量元素地球化学特征

湘西湘中新元古界—古生界是金锑砷等金属矿床的重要产出层位。岩石地层微量元素地球化学研究对于认识矿源层以及矿床成因具有重要的意义。本文根据单一地球化学过程产生的地质体中元素含量趋向于正态分布的认识 ,对于湘西湘中的新元古界—古生界中的微量元素进行了系统研究 ,结果表明 :新元古界的板溪群和震旦系是Au、Sb、As的重要含矿建造 ;Pb在奥陶系、志留系中显著富集 ;Hg在寒武系和奥陶系中明显富集。古生代各地层中Sb、As、Hg、Au等成矿元素均不同程度地受到后期成矿作用的影响 ,泥盆系和石炭系中Sb、As的高平均含量是由成矿叠加作用所引起的。

TRACE ELEMENT GEOCHEMICAL CHARACTERISTICS OF NEOPROTEROZOIC-PALEOZOIC STRATA IN WESTERN AND CENTRAL HUNAN

Neoproterozoic-Paleozoic strata of western and central Hunan are the main ore-bearing beds of Au, Sb, As and other metal ore-forming elements. Many studies show that there is little relationship between igneous rocks and these metal deposits in the area. So studies on the geochemical characteristics of trace elements of the strata in western and central Hunan are very important for understanding the source of ore-forming elements and ore genesis. Based on the fact that the element content of a single geologic body formed by a unitary geochemical process tends to be normally distributed, the paper systematically studies the composition and distribution of minor and trace elements of the Neoproterozoic-Paleozoic strata in western and central Hunan. The results show the Banxi Group and Sinian system are the main ore-bearing formations of Au, Sb, and As. Pb is enriched in Ordovician and Silurian strata, and Hg in Cambrian and Ordovician strata. The contents of Sb, As, Hg, Au and other ore-forming elements in all Paleozoic strata are affected by mineralizing processes in the geological periods, and the high contents of Sb and As in the Devonian and Carboniferous strata are affected by the overlapping of ore deposition.;