Based on the chronological data and relevant geological evidence, the chronological framework of the major geological events of the granulite terrain in northwestern Hebei Province and its adjacent areas has been esta...Based on the chronological data and relevant geological evidence, the chronological framework of the major geological events of the granulite terrain in northwestern Hebei Province and its adjacent areas has been established. Basic lava eruption occurred in the span of 2868-2932 Ma, resulting in the formation of the early crust. The TTG magma emplacement took place c.2761 Ma ago. Subsequently basic magma intruded into the supracrustal rocks at 2650 Ma, resulting in crustal thickening. The thickening was enhanced at 2561-2503 Ma by the widespread intrusions of granodioritic magma. In the period of 2477-2461 Ma charnockite intruded, accompanied by regional granulite facies metamorphism. The second stage of granulite facies metamorphism occurred c. 2300 Ma ago, and finally pink granite intrusions at 2144-2087 Ma resulted in the formation of a granite zone.展开更多
The Dongping gold deposit is contained within an inner contacting zone of the Hercynian Shuiquangou alkali syenite. The ores occur as veins or as replacement bodies. Fluid inclusion observation shows that in early and...The Dongping gold deposit is contained within an inner contacting zone of the Hercynian Shuiquangou alkali syenite. The ores occur as veins or as replacement bodies. Fluid inclusion observation shows that in early and main mineralizing stages inclusion types are gas and gas-liquid inclusions, respectively. Gas inclusions occur in isolation in vein quartz, their homog-enization temperature is 372-306°C, and salinity 3.7-1.0 wt% NaCl. Gas-liquid inclusions occur in clusters or healed fractures but do not cut quartz boundary with homogenization temperature 342-267°C and salinity 1.9-0.8 wt% NaCl. Stable isotope measurements show that at main gold mineralization, hydrogen and oxygen isotopic ratios of the mineralizing fluids are -70.8‰-108.4‰ and 2.44‰-4.05‰, respectively. Primary ore fluids in Dongping are higher temperature and lower salinity NaCl-CO2-H2O fluids, and come from Yanshanian granitic magmatism. Fluid im-miscibility, fluid-rock interactions and meteoric water adding were main reasons for gold deposition.展开更多
文摘Based on the chronological data and relevant geological evidence, the chronological framework of the major geological events of the granulite terrain in northwestern Hebei Province and its adjacent areas has been established. Basic lava eruption occurred in the span of 2868-2932 Ma, resulting in the formation of the early crust. The TTG magma emplacement took place c.2761 Ma ago. Subsequently basic magma intruded into the supracrustal rocks at 2650 Ma, resulting in crustal thickening. The thickening was enhanced at 2561-2503 Ma by the widespread intrusions of granodioritic magma. In the period of 2477-2461 Ma charnockite intruded, accompanied by regional granulite facies metamorphism. The second stage of granulite facies metamorphism occurred c. 2300 Ma ago, and finally pink granite intrusions at 2144-2087 Ma resulted in the formation of a granite zone.
基金the Key Programs of Chinese Academy of Sciences (Grant No. KZCX1-07) and the Projects from Ministry of Science and Technology of China (Grant No. G1999043207).
文摘The Dongping gold deposit is contained within an inner contacting zone of the Hercynian Shuiquangou alkali syenite. The ores occur as veins or as replacement bodies. Fluid inclusion observation shows that in early and main mineralizing stages inclusion types are gas and gas-liquid inclusions, respectively. Gas inclusions occur in isolation in vein quartz, their homog-enization temperature is 372-306°C, and salinity 3.7-1.0 wt% NaCl. Gas-liquid inclusions occur in clusters or healed fractures but do not cut quartz boundary with homogenization temperature 342-267°C and salinity 1.9-0.8 wt% NaCl. Stable isotope measurements show that at main gold mineralization, hydrogen and oxygen isotopic ratios of the mineralizing fluids are -70.8‰-108.4‰ and 2.44‰-4.05‰, respectively. Primary ore fluids in Dongping are higher temperature and lower salinity NaCl-CO2-H2O fluids, and come from Yanshanian granitic magmatism. Fluid im-miscibility, fluid-rock interactions and meteoric water adding were main reasons for gold deposition.
