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Nanjing, China

Wang X.-D.,Chinese Academy of Geological Sciences | Wang X.-D.,Institute of Geo Fluids | Nl P.,Institute of Geo Fluids | Yuan S.-D.,Chinese Academy of Geological Sciences | Wu S.-H.,Chinese Academy of Geological Sciences
Geology in China | Year: 2012

The Muziyuan tungsten deposit is a medium-size quartz-vein type tungsten deposit in southern Jiangxi Province. The model using surface mica line and quartz line can be used in search for concealed quartz vein type ore deposit. Based on detailed petrographic observations, the authors carried out microthermometric and Raman microspectroscopic studies of fluid inclusions in wolframite -quartz veins of the Muziyuan tungsten deposit. Experimental results show that fluid inclusions in quartz have recorded at least two periods of fluid activities. These two kinds of fluid are of the high temperature, low salinity and low density NaCl-H2O fluid system and the low temperature, low salinity and medium density NaCl-H2O fluid system respectively. In the evolution process of ore-forming fluids in the Muziyuan tungsten deposit, high temperature stage experienced some boiling, resulting in the decomposition of the metal complex in ore forming fluids and ore deposition, whereas the lowtemperature phase was mainly subjected to the natural cooling process, and the fluid mineral precipitation resulted mainly from the temperature decrease. Source


Chen H.,Institute of Geo Fluids | Ni P.,Institute of Geo Fluids | Liu J.,Institute of Geo Fluids | Yan J.,First Geo Exploration Institute | And 2 more authors.
Acta Petrologica Sinica | Year: 2011

The Pingshui copper deposit found in the 70's is the biggest copper deposit in Zhejiang Province, and is a typical massive sulfide deposit in the northeast part of Qinzhou-Hangzhou collision belt between Yangtze and Cathaysia blocks. However, up to now the researches about ore-forming fluid, especially fluid inclusions on it are still lacked. This study made a systematic research works on fluid inclusions in Pingshui copper deposit. The type of fluid inclusions is very sample, mainly the liquid (H20)-rich inclusions. The fluid inclusion studies show that there are two types: Ha, the primary liquid-rich fluid inclusions, the homogenization temperatures and primary salinities of fluid inclusion are 192∼245°C and 2.75% ∼5. 7% NaCleqv, respectively: IIb, the secondary Liquid-rich fluid inclusions, the homogenization temperatures and primary salinities of fluid inclusion are 158 ∼ 189°C and 2. 75% ∼4. 76% NaCleqv, respectively. And that the main component of fluid is H2O, without other vapors, determined by Raman microspectroscopy. The identification of fluid verified the causation of Pingshui copper deposit, that it belongs to a typical volcanic-hosted massive sulfide deposit. These results are of great significance for further researches on the genesis, formation and evolution of the Pingshui copper deposit. Source


Meng F.,Institute of Geo Fluids | Meng F.,CAS Nanjing Institute of Geology and Palaeontology | Ni P.,Institute of Geo Fluids | Ge C.,Nanjing University | And 4 more authors.
Acta Petrologica Sinica | Year: 2011

Halite is a major evaporate mineral in the surface environment, and it contains abundant fluid inclusions formed during crystal formation, which can record the brine temperatures of crystal growth in ancient oceanic salt ponds and salt lakes in geological history. Using the "cooling nucleation method", homogenization temperature of fluid inclusions in halite can be measured. However, the interpretation and application of the homogenization temperature in palaeotemperature reconstruction is not straightforward. Fluid inclusions in halite can be captured in cumulate halite crystals formed at the air-water interface or in chevron halite crystals formed at the water-sediment interface. Lowenstein et al. (1998) carried out a microthermometric analysis on halite crystals grown in the laboratory through evaporation of halite-saturated brines in flasks submerged in water baths; however how to translate brine temperature into air temperature is the key question of paleoclimate. In this study, we measured a series of homogenization temperature of fluid inclusions in both cumulate and chevron halite crystals grown in the laboratory at a temperature of 40°C (air temperature) in a thermostatic air drying oven in 20cm deep brine in order to reconstruct the paleotemperature using homogenization temperatures directly. The homogenization temperatures range from 10.61 to 39.9°C. The results show that only the maximum homogenization temperature of fluid inclusions (Th,max) matches brine temperatures. Both cumulate halite and chevron halite have a similar Th,max, both types of halite can be used in paleotemperature reconstruction in shallow water. Source


Cai Y.,Institute of Geo Fluids | Ni P.,Institute of Geo Fluids | Shen K.,Shandong Institute and Laboratory of Geological science | Zhu X.,Institute of Geo Fluids | And 4 more authors.
Acta Petrologica Sinica | Year: 2011

According to the study on the metallogenic fluid characteristic from Dongxiang copper deposit, we examine the metallogenic mechanism, the nature and origin of ore-forming fluid. Based on petrographie observations of ore-bearing quartz collected from the deposit, we have found that there are three different generations of quartz. Fluid inclusion studies show that the homogenization temperature and primary salinities are 144 ∼ 195°C and 0. 35% ∼4. 95% NaCleqv in the first generation, respectively. The second generation formed in relatively higher temperature range 193 ∼ 298°C, and salinities are 1.40% ∼ 6.59% NaCleqv. The thrid generation of quartz mainly consists of pyrite, chalcopyrite and quartz, the primary inclusions are generally three types: vapor (type II), brine (type I), and daughter-mineral bearing multiphase inclusions (type V) in the third generation. The statistics on the measured filling temperatures of type II and type V reveal peaks at 300 ∼ 340°C and 280 ∼ 320°C respectively, while those on the salinities of fluid inclusions peak at 0. 35% ∼5. 86% NaCleqv and 29. 4% ∼41. 9% NaCleqv respectively. Raman analysis of the fluid inclusions indicates that, in the gaseous phase, water vapor is dominant with small amount of CO2 and CH4. Hydrogen and Oxygen isotopic compositions are within the range of magmatic water. Fluid boiling resulted in the discharge of a large amount of copper from Cu-bearing fluid. Source


Wang G.,Institute of Geo Fluids | Ni P.,Institute of Geo Fluids | Zhao K.,Institute of Geo Fluids | Liu J.,Institute of Geo Fluids | And 3 more authors.
Acta Petrologica Sinica | Year: 2011

Dexing district of Northeast Jiangxi Province is one of the large ore concentrating areas in the eastern metallogenic belt of China. Yinshan lead-zinc-copper (gold) polymetallic deposit is one of large subvolcanic hydrothermal ore deposit, China. Mineralization consists of quartz, sphalrite, galena, and various amounts of base metal sulfides in veins. Texture evidence shows that the ore minerals (e. g. sphalerite and galena) are spatially associated with quartz veins and veinlets. Previous studies of fluid inclusions mainly focus on quartz vein associated with sphalerite. In this study, we use petrography, microthermometry and Raman analysis to study on the fluid inclusions in sphalerite and quartz in early quartz veins, and in late quartz veinlets. The results show that there are different from the types of fluid inclusions, homogenization temperatures (Th) and salinity between sphalerite and coexisting quartz veins. The early quartz veins contain two-phase, aqueous-carbonic inclusions, and have average homogenization temperature of 249.8°C and salinity of 8. 3% NaCleqv. The two-phase, aqueous inclusions occur in sphalerite and late quartz veinlets, with Th of 224.0°C, 168.2°C, and salinity of 8. 1% NaCleqv, 4. 3% NaCleqv, respectively. Therefore, we conclude that the fluid inclusions in gangue minerals in Yinshan deposit can not provide reasonable estimates of the depositional conditions of the ore minerals, even though they are intimately intergrown. Source

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