In this paper,the east ore section of the Pulang porphyry copper deposit is selected as the research object.The micro-thermometer and laser Raman spectroscopic technique are utilized to study the parameters of ore-for...In this paper,the east ore section of the Pulang porphyry copper deposit is selected as the research object.The micro-thermometer and laser Raman spectroscopic technique are utilized to study the parameters of ore-forming fluids such as pressure,temperature,and compositions.In the meantime,the fractal models,including the perimeter-area(P-A)model and number-size(N-S)model,are introduced to quantify the shape of fluid inclusions,and distinguish the stages of ore-forming fluids,respectively.The results show that the types of fluid inclusions are diversified,namely two-phase liquid-rich type,two-phase vapor-rich type,three-phase CO2-rich type,three-phase halite-bearing type and pure liquid type.The fluids of main mineralization stage are characterized by medium-high temperature(170.2–421.4°C),medium-high salinity(9.3 wt.%–33.3 wt.%),and low density(0.73–1.06 g/cm3).With the migration and evolution,the temperature,salinity,and pressure of ore-forming fluids gradually decrease,while the density of fluids increases.The liquid-phase compositions mainly include H2O,and the vapor-phase compositions consist of H2O,CH4,N2,and CO2,indicating the characteristics of reducing fluids and the mixing of atmospheric precipitation.In general,the characteristics of ore-forming fluids in the east ore section are similar to those of the first mining area,suggesting that the ore-forming fluids in the east ore section may not migrate from the first mining area.And the east ore section may be a relatively independent metallogenic system.Moreover,the fractal analysis results demonstrate that the shape of fluid inclusions formed in the same hydrothermal activity features self-similarity.The DAPvalues of fluid inclusions in B veins,ED veins,andD veins are 1.04,1.06 and 1.10,respectively,showing a gradually increasing trend from the main stage to the late stage of mineralization.Meanwhile,the shape of fluid inclusions ranging from B veins to D veins becomes increasingly irregular.It also reveals that the homogenization temperature satisfies fractal distribution with four scale-invariant intervals,suggesting that all B veins,ED veins,and D veins have experienced at least four hydrothermal activities.Compared with histogram,the N-S fractal model is able to describe the distribution characteristics of the ore-forming fluids’homogenization temperature more precisely.Therefore,it presents a potential tool for the stage division of ore-forming fluids.This research provides information about the characteristics of ore-forming fluids in the east ore section of the Pulang porphyry copper deposit,which is beneficial for further exploration in this region,and the extension of the application of fractal models in the study of fluid inclusions.However,further testing of fractal models on the fluid inclusion study is warranted to fully determine the universality.展开更多
The Pulang （普朗） porphyry copper deposit, located in the southern segment of the Yidun-Zhongdian （义敦-中甸） island arc ore-forming belt of the Tethys-Himalaya ore-forming domain, is a recently discovered large c...The Pulang （普朗） porphyry copper deposit, located in the southern segment of the Yidun-Zhongdian （义敦-中甸） island arc ore-forming belt of the Tethys-Himalaya ore-forming domain, is a recently discovered large copper deposit. Compared with the composition of granodiorite in China, the porphyry rocks in this area are enriched in W, Mo, Cu, Au, As, Sb, F, V, and Na2O （K1≥1.2）. Compared with the composition of fresh porphyry rocks in this district, the mineralized rocks are enriched in Cu, Au, Ag, Mo, Pb, Zn, W, As, Sb, and K2O （K2≥1.2）. Some elements show clear anomalies, such as Zn, Ag, Cu, Au, W, and Mo, and can be regarded as pathfinders for prospecting new ore bodies in depth. It has been inferred from factor analysis that the Pulang porphyry copper deposit may have undergone the multiple stages of alteration and mineralization： （a） Cu-Au mineralization; （b） W-Mo mineralization; and （c） silicification and potassic metasomatism in the whole ore-forming process. A detailed zonation sequence of indicator elements is obtained using the variability index of indicator elements as follows： Zn→Ag→Cu→Au→W→Mo. According to this zonation, an index such as （Ag＊Zn）D/（Mo×W）D can be constructed and regarded as a significant criterion for predicting the Cu potential at a particular depth.展开更多
The Pulang porphyry copper deposit,located in the Gezan tectonic-magmatic arc and south of the Yidun island arc,southwest of Sanjiang metallogenic belt in Yunnan province,is a super-large porphyry copper deposit.
基金supported by the National Key R&D Program of China(No.2016YFC0600508)the Open Fund of the Research Center for Petrogenesis and Mineralization of Granitoid Rocks,China Geological Survey(No.PMGR202011)China Geological Survey(No.DD20190385)。
文摘In this paper,the east ore section of the Pulang porphyry copper deposit is selected as the research object.The micro-thermometer and laser Raman spectroscopic technique are utilized to study the parameters of ore-forming fluids such as pressure,temperature,and compositions.In the meantime,the fractal models,including the perimeter-area(P-A)model and number-size(N-S)model,are introduced to quantify the shape of fluid inclusions,and distinguish the stages of ore-forming fluids,respectively.The results show that the types of fluid inclusions are diversified,namely two-phase liquid-rich type,two-phase vapor-rich type,three-phase CO2-rich type,three-phase halite-bearing type and pure liquid type.The fluids of main mineralization stage are characterized by medium-high temperature(170.2–421.4°C),medium-high salinity(9.3 wt.%–33.3 wt.%),and low density(0.73–1.06 g/cm3).With the migration and evolution,the temperature,salinity,and pressure of ore-forming fluids gradually decrease,while the density of fluids increases.The liquid-phase compositions mainly include H2O,and the vapor-phase compositions consist of H2O,CH4,N2,and CO2,indicating the characteristics of reducing fluids and the mixing of atmospheric precipitation.In general,the characteristics of ore-forming fluids in the east ore section are similar to those of the first mining area,suggesting that the ore-forming fluids in the east ore section may not migrate from the first mining area.And the east ore section may be a relatively independent metallogenic system.Moreover,the fractal analysis results demonstrate that the shape of fluid inclusions formed in the same hydrothermal activity features self-similarity.The DAPvalues of fluid inclusions in B veins,ED veins,andD veins are 1.04,1.06 and 1.10,respectively,showing a gradually increasing trend from the main stage to the late stage of mineralization.Meanwhile,the shape of fluid inclusions ranging from B veins to D veins becomes increasingly irregular.It also reveals that the homogenization temperature satisfies fractal distribution with four scale-invariant intervals,suggesting that all B veins,ED veins,and D veins have experienced at least four hydrothermal activities.Compared with histogram,the N-S fractal model is able to describe the distribution characteristics of the ore-forming fluids’homogenization temperature more precisely.Therefore,it presents a potential tool for the stage division of ore-forming fluids.This research provides information about the characteristics of ore-forming fluids in the east ore section of the Pulang porphyry copper deposit,which is beneficial for further exploration in this region,and the extension of the application of fractal models in the study of fluid inclusions.However,further testing of fractal models on the fluid inclusion study is warranted to fully determine the universality.
基金supported by the National High Technology Research and Development Program of China (No 2006AA06Z113)the National Natural Science Foundation of China (No. 40772197)
文摘The Pulang （普朗） porphyry copper deposit, located in the southern segment of the Yidun-Zhongdian （义敦-中甸） island arc ore-forming belt of the Tethys-Himalaya ore-forming domain, is a recently discovered large copper deposit. Compared with the composition of granodiorite in China, the porphyry rocks in this area are enriched in W, Mo, Cu, Au, As, Sb, F, V, and Na2O （K1≥1.2）. Compared with the composition of fresh porphyry rocks in this district, the mineralized rocks are enriched in Cu, Au, Ag, Mo, Pb, Zn, W, As, Sb, and K2O （K2≥1.2）. Some elements show clear anomalies, such as Zn, Ag, Cu, Au, W, and Mo, and can be regarded as pathfinders for prospecting new ore bodies in depth. It has been inferred from factor analysis that the Pulang porphyry copper deposit may have undergone the multiple stages of alteration and mineralization： （a） Cu-Au mineralization; （b） W-Mo mineralization; and （c） silicification and potassic metasomatism in the whole ore-forming process. A detailed zonation sequence of indicator elements is obtained using the variability index of indicator elements as follows： Zn→Ag→Cu→Au→W→Mo. According to this zonation, an index such as （Ag＊Zn）D/（Mo×W）D can be constructed and regarded as a significant criterion for predicting the Cu potential at a particular depth.
基金granted by China State Mineral Resources Investigation Program (Grant No.12120114013701 and 1212011120608)
文摘The Pulang porphyry copper deposit,located in the Gezan tectonic-magmatic arc and south of the Yidun island arc,southwest of Sanjiang metallogenic belt in Yunnan province,is a super-large porphyry copper deposit.
