摘要
小秦岭金矿西段矿脉、花岗岩、变质岩的氧、氢同位素及流体包裹体测试结果表明:小秦岭金矿属燕山期形成的热液石英脉型金矿床,主要成矿温度为280—300℃,其成矿物质来自变质地层及燕山期重熔花岗岩浆,成矿流体水为变质地层水、花岗岩浆水及地表水的混合产物。
The Xiaoqinling gold ore district is located in the southern part of the North China platform. The strata in the district are volcano-sedimentary sequence of Archean Taihua facies. There are a few Yanshanian granitic intrusions, named Huashan, wenyu and Niangniangshan from west to east. Gold deposits are found around the Wenyu intrusion and controlled by Dayueping-Jinloban anticline and its derivative structures. Most of the deposits are of quartz vein type, containing pyrite, chalcopyrite, gelena, sphalerite etc. Wall rocks show alterations such as sericitization, silicification, chloritization, pyritization and carbonatization, δ^(18)O_(H_2O) and δD_(H_2O) of inclusions in quartz are 9.18‰ and - 63.2‰ for metamorphic rocks, 9.89‰ and -85.7‰ for granite, 9.89‰ and -77.7‰ for felsic vein rocks, and 11.04‰ and -78.5‰ for quartz veins,respectively. In mine water, δ^(18)O=- 9.57‰ and δD=-74‰ Calculations show that δ^(18)O values of metamorphic rocks, granites, vein rocks and ore-forming solutions are 7.26‰ 7.00‰ 5.69‰ and 1.99‰ respectively. Nine inclusion samples have been studied. They are dominantly liquid inclusions, with a few gaseous inclusions and three-phase inclusions containing daughter crystals of NaCl and liquid CO_2. The inclusions are usually 2—5μm in size, and have rounded, roundish or irregular forms. Inclusionss are usually aligned in certain direction. Homogenization temperatures of the inclusion are mostly in the range of 280℃—300℃ The pH and Eh values of inclusions are 6.02 and 98.28 for quartz in metamorphic rocks, 3.66 and 238.47 for quartz in granite, respectively. The pH and Eh values of quartz, sphalerite and calcite in the veins are 4.79, 5.95 and 6.22, and 171.55, 103.00 and 87.02, respectively. Gaseous phase of the inclusions is dominated by water vapor, with a little CO_2, CH_4, and CO. Ore fluids are acid to weak acid, poor in K^+, Na^+, and rich in Ca^(2+) and Mg^(2+); granitic solution is acid, poor in Ca^(2+) and Mg^(2+), and rich in K^+ and
出处
《矿床地质》
CAS
CSCD
北大核心
1991年第3期283-288,共6页
Mineral Deposits
