广西大厂矿区大福楼锡矿床流体包裹体及成矿作用

通过对大厂矿田大福楼矿床的岩石学、矿物学、构造地质学以及流体包裹体等方面的系统分析，解析矿床地质以及成矿流体特征。结果表明，大福楼矿区主要发育硅化、碳酸盐化、绢云母化、黄铁矿化以及磁黄铁矿化等5种围岩蚀变类型，产出有层状、穿层状以及网脉状等矿化类型。矿石结构主要为交代结构、自形?半自形粒状结构、固溶体结构等，矿石构造表现为块状、浸染状、细脉状、网脉状和角砾状等，主要发育有浸染状、致密块状、细脉状和角砾状等多种矿石类型。研究显示，大福楼矿床主要存在6种流体包裹体类型，包括单相气相包裹体、单相盐水溶液包裹体、两相富蒸汽包裹体、两相富液体包裹体、三相含CO2包裹体以及富NaCl子矿物包裹体，流体形成的主体温度范围为120~150°C、230~270°C以及350~460°C。然而，成矿流体则主要形成于高温环境下，即350~460°C。成矿过程中，构造作用至关重要，通常控制着锡矿体的规模、产状以及形态。鉴别出4种热液流体类型，包括 H2O?NaCl?CaCl2体系、H2O?CaCl2体系、H2O?NaCl?MgCl2体系以及 H2O?MgCl2体系。与大厂矿田的其他矿床具有相似之处，大福楼矿床也同样具有多种成矿流体来源的特征，总体上属于壳幔联合作用的产物。

Fluid inclusion and mineralization of Dafulou tin deposit in Dachang metal district, Guangxi, south China

Based on the study of the petrology, mineralogy, structural geology and fluid inclusion of the Dafulou ore deposit in the Dachang ore field, the ore deposit geology and ore-forming fluids were analyzed. It shows that there are five main hydrothermal alteration types in the Dafulou ore district, namely the silicification, carbonate, sericite, pyrite and pyrrhotite. The mineralization types are composed of the stratiform type, interlayer type and stockwork type. The ore textures present as metasomatic texture, euhedral-subhedral granular texture and solid solution texture. The ore structure consists of massive structure, dissemination structure, fine veined structure, stockwork structure and brecciated structure. Four ore types are recognized, namely the disseminated ore, dense massive ore, veinlet ore and brecciated ore. Six types of fluid inclusions are determined, i.e. the single-phase gaseous fluid inclusions, single-phase salt solution fluid inclusions, two-phase vapour-rich fluid inclusions, two-phase liquid-rich fluid inclusions, three-phase CO2-rich fluid inclusions and solid（s）-bearing fluid inclusions, all of which form in three dominant temperature scopes, 120-150, 230-270, 350-460 °C. But, the majority of them form in the high temperature environment （350-460 °C）. The tectonism plays an important role in the mineralization, which usually controls the scale, occurrence and shape of the Sn orebody. There are four types of hydrothermal fluid systems, H2O-NaCl-CaCl2, H2O-CaCl2, H2O-NaCl-MgCl2 and H2O-MgCl2. Similar to the other ore deposits in the Dachang ore field, there also exists the multiple source of ore-forming fluids. Overall, the Dafulou ore deposit should be the result of the crust-mantle interaction.