南秦岭造山型金矿地质特征及成矿模式——以陕西山阳夏家店金(钒)矿床为例

Geological Characteristics and Metallogenic Model of the Orogenic-type Gold Deposit in South Qinling:A Case of Xiajiadian Gold(Vanadium)Deposit,Shanyang County,Shaanxi Province

在总结山阳夏家店金（钒）矿床产出地质背景、矿床地质特征的基础上，分析和研究了矿区控矿因素、成矿元素基本分布统计规律、成矿流体特征、同位素特征，建立了矿床成矿模式。该矿床金矿体主要受含矿岩系和镇安-板岩镇断裂的次级断裂控制，从地表到深部金的品位、厚度呈波状变化，走向上呈尖灭再现趋势，流体包裹体主要为气液两相，以富CO2（10%）、低盐度（3%-5%）为特征，主成矿期均一温度集中于240-280℃，成矿深度为3 km。同位素分析显示成矿流体主要来源于大气水与建造水的混合，部分来源于深部。由此建立了夏家店金矿成矿模式，认为夏家店金矿床以构造-流体成矿作用为主，是由构造的多期作用形成薄弱带，地下热卤水经地热或岩浆驱动在构造薄弱带附近循环萃取矿源层中的矿质在构造带中沉淀而形成的造山型金矿。

On the basis of summing up geological setting and feature of Xiajiadian gold deposit, Shanyang County, Shaanxi province, this paper researched ore-controlled factors, statistic distribution law of ore-forming elements, metallogenic fluid characteristics, isotope features, and created a metallogenic model of this gold deposit. The gold ore body is mainly controlled by ore-bearing rock series and secondary fault in Zhen＇an-Banyanzhen fracture. From surface to deep, the grade and thickness of gold ore show wave transformation, and display thinning out and recurrence in trend. Its fluid inclusion mostly consists of gas-liquid two-phase, which is featured by rich CO2 （10%） and low salinity （3%—5%）. The homogeneous temperature of main mineralization period concentrates between 240-280 ℃, and the metallogenic depth is 3 km. Isotope analysis indicates that metallogenic fluid mainly derives from mix of meteoric water and formation water, with a small part from the deep. In view of the findings, we founded a metallogenic model of Xiajiadian gold deposit, and concluded that the gold mine was predominantly a tectonic-fluid deposit of orogenic-type, which formed by the sedimentation of mineral substances cyclically leached from ore source bed by underground hot brine driven by geothermal or magma.