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摘要
The Jiapigou gold belt (> 150 t Au), one of the most important gold-producing districts in China, is located at the northeastern margin of the North China Craton. It is composed of 17 gold deposits with an average grade around 10 g/t Au. The deposits are hosted in Archean gneiss and TTG rocks, and are all in shear zones or fractures of varying orientations and magnitudes. The delta S-34 values of sulfide from ores are mainly between 2.7 aEuro degrees and 10 aEuro degrees. The Pb isotope characteristics of ore sulfides are different from those of the Archean metamorphic rocks and Mesozoic granites and dikes, and indicate that they have different lead sources. The sulfur and lead isotope compositions imply that the ore-forming materials might originate from multiple, mainly deep sources. Fluid inclusions in pyrite have He-3/He-4 ratios of 0.6 to 2.5 Ra, whereas their Ar-40/Ar-36 ratios range from 1,444 to 9,805, indicating a dominantly mantle fluid with a negligible crustal component. delta O-18 values calculated from hydrothermal quartz are between -0.2 aEuro degrees and +5.9 aEuro degrees, and delta D values of the fluids in the fluid inclusions in quartz are from -70 aEuro degrees to -96 aEuro degrees. These ranges suggest dominantly magmatic water with a minor meteoric component. The noble gas isotopic data, along with the stable isotopic data, suggest that the ore-forming fluids have a dominantly mantle source with minor crustal addition.
- 出版日期2014-1
- 单位中国科学院地质与地球物理研究所; 中国科学院地质与地球物理研究所兰州油气资源研究中心
