矿床地质2012，Vol.31Issue(5)：965-982,18.
新疆准噶尔北缘玉勒肯哈腊苏铜(钼)矿床流体包裹体和稳定同位素研究
Fluid inclusion and stable isotope study of Yulekenhalasu copper-(molybdenum) deposit in northern margin of Junggar, Xinjiang
摘要
Abstract
The Yulekenhalasu medium-size porphyry copper-(molybdenum) deposit occurs in the diorite porphyry, with some mineralization also observed in the porphyroid biotite quartz monzonite and volcanic rocks of the Beitashan Formation. Mineralization occurs as veinlets, veinlet-disseminations and stockworks. Wall-rock altera tion is well developed, and mainly comprises K-feldspathization, biotitization, quartzification, sericitization, magnetitization, gypsification, chloritization, and epidotization. According to cutting relationships of the ore veins, mineral assemblages, paragenetic sequence and ore fabrics, the ore-forming process can be divided into three metallogenic periods: porphyry, shear deformation and supergene periods. The sulfides-K-silicate stage and the molybdenite stage in the porphyry period constituted the main stages for copper mineralization and molybdenum mineralization, respectively. Two types of fluid inclusions, namely H2O-NaCl and H2O-CO2 ( + CH4/N2)-NaCl types, have been recognized in quartz and calcite. Homogenization temperatures of fluid inclusions in the sulfides-K-silicate stage vary from 141*0 to 500X3 , concentrated from 200℃ to 340℃ . Salinity ω(NaCleq)ranges from 2.96% to 14.97% . Ore fluid densities range from 0.60 to 0.98 g/cm3. Fluids of the carbonate stage are characterized by medium-low temperatures (140X3 to 320℃ ) and low salinities (2.74% to 10.61 % ). δ34S values of sulfides associated with mineralization range from - 4.5‰ to - 0.l%, with the peak being - 3.5‰, indicating that sulfur was derived from deep-seated magma. S18OSMOW values of quartz and calcite range from 9.l‰ to 13.2‰, with the correspondingΔ18OH O values between - 2.05‰ and 6.28‰, and δD values of fluid inclusions vary between - 120‰ and - 97‰. The combined isotopic data imply that the ore-forming fluids of the sulfides-K-silicate stage in the Yulekenhalasu Cu-(Mo) deposit were mainly derived from magmatic fluids, with a minor part from the meteoric water, and the fluids of the carbonate stage were mainly derived from the meteoric water, with a minor part from magmatic fluids. Cu-(Mo) mineralization in Yulekenhalasu took place in Middle Devonian ((373.9 ±2.2) Ma], related to the diorite porphyry. The decrease of temperature and pressure, the boiling of local ore-forming fluid, the water-rock exchange, and the compositional variation of ore fluids played important roles in ore-forming processes of the Cu-(Mo) ore bodies.关键词
地球化学/斑岩铜(钼)矿床/流体包裹体/硫、氢、氧同位素/成矿作用/玉勒肯哈腊苏/准噶尔北缘/新疆Key words
geochemistry/porphyry copper-(molybdenum) deposit/fluid inclusion/ sulfur-oxygen-hydrogen stable isotopes/metallogenesis/Yulekenhalasu/northern margin of Junggar/Xinjiang分类
天文与地球科学引用本文复制引用
杨富全,刘国仁,秦纪华,张志欣,刘振江,张立武,魏广智,刘锋,耿新霞..新疆准噶尔北缘玉勒肯哈腊苏铜(钼)矿床流体包裹体和稳定同位素研究[J].矿床地质,2012,31(5):965-982,18.基金项目
本文得到国家自然科学基金项目(编号:40972069)和国家重点基础研究发展计划项目(编号:2007CB411302)联合资助 （编号:40972069）
