西藏丁青县扎格拉金矿床地质特征、流体包裹体特征及成因

扎格拉金矿位于班公湖—怒江结合带东段及冈底斯—念青唐古拉板片北缘的腾冲—班戈岩浆弧带上；受被动陆缘深海复理石建造、 脆—韧性剪切带和深成岩浆活动控制。流体包裹体类型以单相和A型两相盐水溶液包裹体为主；次为B型两相盐水溶液包裹体、 富CO2两相包裹体和含CO2三相包裹体；成矿流体属中低温和中低盐度H2O-NaCl-CO2体系。氢、 氧同位素和相对富含K+、 Na+、Ca2+、 Mg2+、Cl-、SO2-4 的包裹体液相成分；显示成矿流体主要来自长期封存于沉积岩的深循环热（卤）水中；矿床成因类型为浅成中低温地下热（卤）水溶滤型金矿床。其成矿特征和流体性质与穆龙套型金矿床具有诸多相似性；研究该区域对西藏“沙丁板岩系”分布区金铜多金属找矿具有重要意义。

Geological characteristics and petrogenesis of the Zhagela gold deposit in Dingqing,Tibet

The Zhalage gold deposit is located in the Tengchong-Bange magmatic arc at the northern margin of the Gangdese-Nianqingtanggula terrane, in the eastern part of the Bangong-Nujiang suture. Its occurrence is controlled by a suite of abyssal flysch, brittle-ductile shear zone, and plutonic magma activity. The fluid inclusions are mainly of single-phase or A-type double-phase salt-water systems, and subordinately B-type double-phase or CO₂-enriched double-and three-phase salt-water systems. The ore-forming fluid belongs to an epithermal to mesothermal(120 ℃～340 ℃)H₂O-NaCl-CO₂ system with low to moderate salinity(6.4%～14%). The hydrogen and oxygen isotopes and the liquid phase composition of the fluid inclusions which are enriched in K⁺, Na⁺, Ca²⁺, Mg²⁺, Cl^-, SO^2-₄ indicate that the ore-forming fluids were dominantly deep-circulating hot brine water that is chronically stored within the sedimentary rocks. The gold deposit was formed through leaching by hot brine water under hypabyssal epithermal-mesothermal conditions. The Zhalage gold deposit resembles the Muruntau gold deposit in terms of ore-forming geological background, and the characteristics of ore geology and ore-forming fluid. It is likely that a breakthrough can be achieved if more invests can be put for the exploration of the "sandin slate" gold-copper polymetallic ore in the region.