| 甘肃-新疆北山成矿带典型矿床成矿流体研究进展及成矿作用探讨 |
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| 关键词:Beishan area ore-forming fluid ore-forming material mixing boiling |
| 基金项目:国家自然科学基金项目(编号: 40472056)；基本科研业务费(所长基金, 编号: J0811) |
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| Characteristics, Derivation and Evolution of Ore-Forming Fluids in Typical Gold Deposits of the Beishan Metallogenic Belt in Gansu-Xinjiang Border Area |
| Quartz and other sulfide minerals in typical gold deposits of Beishan area contain abundant aqueous, CO2-rich and CH4-rich inclusions, suggesting that the main volatiles in the ore-forming fluids are of the H2O-CO2-CH4 system. Microthermometic measurements of fluid inclusions demonstrate that all types of gold deposits have experienced multi-period and multi-stage hydrothermal activities, thus belonging to mineralization of middle-low salinity and meso-hypothermal as well as meso-epithermal fluids. δ13C values of CO2 and CH4 reveal that CO?2 and CH4 of the ore-forming fluids were respectively degassed from the magma and leached from the carbonaceous country rocks. Hydrogen and oxygen isotopic compositions indicate that the ore-forming fluids were initially magmatic fluids and subsequently mixed with large amounts of meteoric water derived from groundwater. S isotope compositions of ore sulfides reflect that besides the contribution of the country rocks, most sulfur were provided mainly by the country rocks via fluid infiltration and leaching. Lead isotope compositions of ore sulfides suggest multiple sources for the metals that range from the crust to the mantle, with certain amounts derived from the orogen or island arc.Data from microthermometric measurements of fluid inclusions, fluid components, carbon, hydrogen and oxygen isotopes of ore-forming fluids, and sulfur and lead isotopes of ore-forming materials in typical gold deposits together show that different types of gold deposits have varies geneses. In Mazhuangshan, Nanjinshan, Jinwozi and No. 210 gold deposits, mixing of different ore-forming fluids caused metal precipitation. In Xiaoxigong, Xinjinchang and Laojinchang gold deposits, however, hydrothermal fluids experienced convectional circulation around the magmatic intrusion at the early ore-forming stage and permeated into the country rocks at the late stage. |
| PAN Xiao-fei,LIU Wei.2010.Characteristics, Derivation and Evolution of Ore-Forming Fluids in Typical Gold Deposits of the Beishan Metallogenic Belt in Gansu-Xinjiang Border Area[J].Acta Geoscientica Sinica,31(4):507-518. |
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