陕西省青山金矿床地质地球化学特征及成因初探

青山金矿床位于商丹缝合带及勉略缝合带之间的旬阳热水盆地边缘, 矿体呈脉状、囊状、透镜状、似层状等产出, 主要位于上泥盆统九里坪组黑色碳质板岩与下石炭统界河街组碳酸盐岩的接触带中。金矿石类型有原生的含金黄铁矿) 菱铁矿型及铁帽型, 矿石中主要金属矿物为菱铁矿、黄铁矿、褐铁矿、金, 成矿元素以Au-Ag-As-Sb-Ba组合为特征。成矿流体氢、氧同位素值具/氧漂移0现象, 成矿流体温度介于160～220 e, 流体包裹体成分显示成矿流体为重碳酸盐) 氯化钠型地下热卤水。由此推断, 该矿床为泥盆系矿源层中的金在中生代受雨水来源的地下热泉水长期循环改造、富集、沉淀, 在构造网络中、在浅成低温条件下形成的热泉型金矿床。

Preliminary Study on the Origin and Geochemical Characteristics in the Qingshan Gold Deposit, Shaanxi Province

Qingshan gold deposit occurred in the hydrothermal basinmarginwhich between the Shangdan suture zone andMianlue suture zone. The orebodys occur as vein, cystic, lenticular and stratoid bed in the carbonaceous slate and carbonatite, which located above the disconformity between JiulipingGroup and Jiehejie Group. The ores are divided into primary gold bearing pyrite-siderite type and gossan type. The main metallicmineral in the ore are siderite, pyrite, limonite and gold. The element association is Au-Ag-As-Sb-Ba. Hydrogen and oxygen isotope values of the ore-forming fluids have the phenomenon of / oxygen drift0. The metallogenic temperature ranges from 160～220 e, the ore-forming fluid is underground thermal brine which is bicarbonate-sodium chloride type. It is suggested that Qingshan golddeposit is hot spring type, which is formed by theMesozoic chronically repeated recycling in the Devonian System. The underground hot brine became progressively rich in gold and deposited in structure network.