【作者】 夏勇；

【导师】 涂光炽； 高振敏；

【作者基本信息】 中国科学院研究生院（地球化学研究所） ， 矿床地球化学， 2005， 博士

【摘要】 黔西南地区是我国最重要的卡林型金矿床集中区,在该区卡林型金矿床具有断裂型和层控型两大类。断裂型金矿床产于高角度压扭性断裂中,赋矿层位一般为中、下三叠统地层,容矿岩石主要是泥质粉砂岩和粉砂质泥岩。层控型金矿床主要产于上二叠统地层中,容矿岩石主要是不纯的生物碎屑灰岩,背斜控矿明显。由于目前断裂型金矿研究程度高,而层控型金矿研究程度低.近年来在层控型金矿床中一些大型和特大型矿床以及富矿体和高品位矿石的新发现,使层控型金矿床成为黔西南卡林型金矿床的重要和具有特征的类型。因此,作者选择了水银洞金矿床这个大型较富的卡林型金矿床进行系统研究,对其成矿特征和金的超常富集机制获得以下认识: 1.金矿床受构造与有利岩性组合的双重控制。金矿床位于灰家堡背斜核部,矿体产在粘土岩→灰岩→粘土岩组合之灰岩中,以层状、似层状为主。一些低角度的断层控制了少量的断裂型金矿体。 2.金矿床具有低温成矿特征,主成矿期流体包裹体的均一温度220℃±。出现硅化、白云石化、黄铁矿化和粘土化等围岩蚀变,特征的Au-As-Hg-Tl元素组合。矿石中Au主要不均匀分布在富砷环带中。纳米金可能是水银洞金矿床金的主要存在形式,并且快速沉淀在几个微米宽的细小黄铁矿中的砷黄铁矿环带和几十微米小的热液毒砂中。成矿条件的骤变和黄铁矿的吸附是重要因素。 3.成矿流体具有低温低盐度和较高压力和富挥发份的特点,均一温度在220℃±,盐度在6±Wt%NaCl,压力为1.6±0.4Kbars,在V_CH4+N2+CO2包裹体中CH₄含量高达63mole%、N₂为18mole%、CO₂为19mole%。高压和富挥发份促使成矿流体从深部迁移至控矿背斜核部,并由于断层的作用挥发份的快速逃逸,压力骤降,促使流体快速卸载,形成金的快速沉淀,形成微细浸染壮的原生金矿石。 4.成矿物质主要来自深部。系统的岩矿地球化学研究和同位素示踪显示出,成矿物质可能是燕山期构造岩浆活动形成的成矿流体（幔源铅）上升溶解地壳铅和混入地壳淋滤铅,而形成的壳幔物质的混合;容矿地层均为正常沉积作用形成,更多还原

【Abstract】 The southwestern Guizhou Province is the most important metallogenic province of Carlin-type gold deposits in China. There are two kinds of Carlin-type gold deposits: fault-controlled and stratabound. The fault-controlled Carlin-type gold deposits are localized at the compressive shear faults and hosted in siltstones and silty mudstones of Middle or Lower Triassic. The stratabound Carlin-type gold deposits are controlled by anticlines and hosted in silty bioclastic limstones of Upper Permian. There are lots of studies on fault-controlled gold deposits, but a few on stratabound deposits. Recently, the new findings of some large scale stratabound gold deposits with high grade orebodies and ores make stratabound gold deposits as an important and characteristic kind of Carlin-type gold deposits in the area. The Shuiyindong gold deposit, the most important stratabound Carlin-type gold deposit, has been studied systematically, and the major understandings on its characteristics and model for it are as follows:1. The gold deposit is controlled by both the structure and favorable lithology. It was located nearby the core of the Huijiabao anticline and orebodies are hosted in thelimestone within the sedimentary series of clayrock--limestone--clayrock. Most oforebodies are stratiform ones. However, some orebodies with less importance are controlled by low angle faults and called as fault-controlled orebodies.2. The gold mineralization occurred under low-temperature with Th of 220℃±.Common hydrothermal alteration types such as silicification, dolomitization, and pyritization have been observed. The gold deposit has characteristic elemental assemblages of Au-As-Hg-T1. Gold mainly presents as native gold, as liny inclusions in As-rich pyrite rims on earlier stage pyrites and arsenopyrites. The As-rich pyritesand arsenopyrites are also very small (about several tens of μ m), which indicates更多还原