贵州丹寨汞矿田甲烷包裹体研究及其地质意义

根据显微镜下观察和包裹体均一温度测定,在丹寨汞矿田中发现了大量高密度甲烷包裹体,其均一温度为-92.7～-118.2℃,密度为0.278～0.350g/cm3。与甲烷包裹体共生的盐水包裹体均一温度主要为170～230℃。以盐水包裹体的均一温度作为甲烷包裹体的捕获温度,用包裹体热力学方法计算出高密度甲烷包裹体在成矿过程中的捕获压力高达106.8～233.3MPa。高密度甲烷包裹体的发现,为丹寨古油藏中原油在深埋过程中受高温裂解作用产生超压环境提供了重要证据。甲烷包裹体的观测结果为研究油热裂解气藏的压力条件和探讨汞成矿与油气成藏之间的关系提供了重要信息。

A study of methane inclusions of the Danzhai mercury ore field in Guizhou Province and its geological significance

Based on the microscopic observation and inclusion homogenization temperature determination,a number of high-density methane inclusions are discovered in the Danzhai mercury field.Their homogenization temperatures vary between-92.7 and-118.2 ℃.The densities range from 0.278 to 0.350 g/cm3.The homogeneous temperatures of aqueous inclusion associated with methane inclusions are mainly 170~230 ℃.Using homogenization temperatures of aqueous inclusions as trap temperature of methane inclusions,it is calculated that trap pressure of methane inclusion varies from 106.8 to 233.3 MPa.The results indicate that methane inclusions were trapped in an overpressured environment.The methane inclusions provide important information for the study of pressure conditions of oil thermal cracking gas reservoir and for the discussion on the relationship between mercury mineralization and accumulation of oil and gas.