广西乐业林旺金矿床地质特征及控矿因素分析

Geological Characteristics and Ore-Controlling Factors of Linwang Gold Deposit

广西乐业林旺金矿是滇黔桂＂金三角＂近年新发现的中型矿床之一,具有层控和断控的双重特点。矿床位于同生断裂附近褶皱和断裂构造最为发育的地方,含矿地层为槽盆相中三叠统百逢组,赋矿围岩为含钙质砂岩。原生矿石具典型的浸染状构造,主要载金矿物为含砷黄铁矿,次为毒砂。蚀变类型为硅化、黄铁矿化、毒砂化、辉锑矿化、碳酸盐化、粘土化等。金主要以＂不可见＂的纳米级超显微包裹金形式存在于含砷黄铁矿环带中。成矿流体具有中低温（178-230℃）、低盐度（w（NaCl）5%-7%）、中低密度（0.79-0.94 g/cm^3）的特点。这些特征表明林旺金矿属于卡林型金矿。地层、褶皱和断裂是矿区最主要的控矿因素,三者的有机组合控制了矿体形态和产出部位。

Linwang gold deposit,located in Leye of Guangxi,is a newly-discovered middle-scale Carlin-type gold deposit in Yunnan-Guizhou-Guangxi triangle area in southwestern China,with dual characteristics of stratabound and fault-controlled orebodies.The deposit developed in the intensive folding and faulting positions near the contemporaneous growth fault.The main ore-bearing unit is Baifeng Formation of middle Triassic.Ore-hosting wallrocks are calcareous arenites and siltstones.Disseminated structure is typical in primary ores.Main gold-bearing minerals are arsenian pyrites and arsenopyrites.Major mineralization and alteration types are silicification,pyritization,arsenopyritization,stibnit ization,carbonatization and argillation.Submicroscopic-microscopic gold is within the outer rim of arsenian pyrites and arsenopyrites.The ore-forming fluid is moderate temperature（178-230 ℃）,low salinity（w（NaCl）5%-7%）and low density（0.79-0.94 g/cm^3）.All these characteristics show that Linwang deposit can be classified to Carlin-type gold deposit.Stratum,fold and fault are the principal ore-controlling factors,and control the shape and location of orebodies..