贵州务川汞矿带木油厂矿田地质特征及成矿模式

摘 要]截至2007 年1 月,经核实贵州务川木油厂汞矿实际保有汞金属资源储量为1郾2912 万吨,居全国之冠。文章在介绍矿田地质特征的基础上,应用多种测试成果及现代矿床学的成矿理论综合研究,认为汞源来自上地幔,辰砂中的硫来源于地层中的石膏。矿床的形成与地下低温热卤水的活动关系密切,当含矿热液流经含石膏岩层之后,遇硫源在Eh 值下降、pH 值中偏碱性、温度下降、压力减小的条件下,发生一系列的蚀变反应,从而形成了以“大而贫冶为其特征的木油厂矿田。其成矿方式以交代为主,充填次之;成矿时代归属燕山期。拟建的成矿模式(图)对今后在务川汞矿带外围寻找隐伏矿床具有指导意义。

Geological Characteristics and Metallogenic Model of the Muyouchang Orefield in the Wuchuan Mercury Mineralization Belt,Guizhou Province

Abstract:Until January 2007,the resources and extractable Hg reserves in the Muyouchang mercury orefield in Wuchuan,Guizhou province is 12,912 thousand tons after verifying,ranking the first in China. This paper presents the geological characteristics of the orefield and makes a comprehensive metallogenic study based on various test results and modern deposit theory. We suggest that the mercury in this region is originated from the upper mantle, and sulphur of the cinnabar comes from the gypsum of the stratum. The formation of ore deposit is closely related to the activity of low-temperature hot brine water in the subsurface. When ore-bearing hydrothermal fluid passed through gypsum beds,its Eh value decreased,and pH value was of intermediate-alkaline nature. And when the temperature and pressure decreased,a series of alteration reactions occurred,thus forming a big but poor Muyouchang orefield. Its main metallogenic process is through replacement,and the subsidiary filling process. The metallogenic epoch is the Yanshanian period. The suggested metallogenic model has guidance significance for prospecting concealed deposits outside the Wuchuan mercury mineralization belt in the future.