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Volume 16 Issue 2
Jun.  2005
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Zhang Zhenliang, Huang Zhilong, Rao Bing, Guan Tao, Yan Zaifei. Concentration Mechanism of Ore-Forming Fluid in Huize Lead-Zinc Deposits, Yunnan Province. Journal of Earth Science, 2005, 16(2).
Citation: Zhang Zhenliang, Huang Zhilong, Rao Bing, Guan Tao, Yan Zaifei. Concentration Mechanism of Ore-Forming Fluid in Huize Lead-Zinc Deposits, Yunnan Province. Journal of Earth Science, 2005, 16(2).

Concentration Mechanism of Ore-Forming Fluid in Huize Lead-Zinc Deposits, Yunnan Province

  • Received Date: 2018-07-16
  • Rev Recd Date: 2018-07-16
  • Publish Date: 2018-07-16
  • The Huize Pb~Zn deposits of Yunnan Province, located in the south~central part of the Sichuan~Yunnan~Guizhou (SYG) Pb~Zn multimetal mineralization district (MMD), are strictly controlled by fault zones. The sources of ore~forming fluid in the deposits have been debated for a long time. Calcite, a gangue mineral, has uniform C and O isotopes. The δ13C PDB and δ18O SMOW values vary respectively from -2.1×10-3 to -3.5×10-3(mean -2.8×10-3) and 16.7×10-3~18.6×10-3(mean 17.7×10-3). No obvious difference can be found in C and O isotopes among occurrences and elevations and even ore~bodies. Types of inclusions include those of pure liquid (L),liquid~rich gas~liquid (L+V), and three~phase ones containing a daughter mineral (S+L+V) and immiscible CO2 with three phases (VCO2+LCO2+LH2O).Their homogenization temperatures vary from 110 to 400 ℃, and two peaks are shown. (87Sr/86Sr)0 ratios of calcite in the deposits are higher than those in the mantle and Emeishan basalts, and slightly higher than those in the Baizuo Formation, which the Huize lead-zinc deposits are found in. All of the(87Sr/86Sr)0 are low relative to those in the basement rocks. Fractionation of Sr isotope did not occur in the ore~forming fluid during the precipitation of minerals. The results indicate that the ore~forming fluid is homogeneous and derived from the mixing of different fluids. Gas liquid inclusions can be separated into two groups in 300~400 ℃ with a salinity of 5% ~ 6% and 12% ~ 16% NaCl respectively. However, the salinities of inclusions vary from 7 % to 23 % NaCl in 100~300 ℃, especially in 150~250 ℃. The formation pressures of faulted zones are (50-320)×10 5 Pa. The estimated pressures of the overlying rocks on the ore bodies are 574×105-640×105 Pa. The pressures of ore~forming processes would be 145×105 to 754×105 Pa. Therefore, pressure sharply reduced and boiling occurred when the ore~forming fluid flew into the fault zones. As a result, the ore~forming fluid was highly concentrated, and metallic minerals began to precipitate from the fluid on a great scale. The high~grade lead~zinc deposits were formed when the fluid was under saturation or over saturation conditions
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    沈阳化工大学材料科学与工程学院 沈阳 110142

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Concentration Mechanism of Ore-Forming Fluid in Huize Lead-Zinc Deposits, Yunnan Province

Abstract: The Huize Pb~Zn deposits of Yunnan Province, located in the south~central part of the Sichuan~Yunnan~Guizhou (SYG) Pb~Zn multimetal mineralization district (MMD), are strictly controlled by fault zones. The sources of ore~forming fluid in the deposits have been debated for a long time. Calcite, a gangue mineral, has uniform C and O isotopes. The δ13C PDB and δ18O SMOW values vary respectively from -2.1×10-3 to -3.5×10-3(mean -2.8×10-3) and 16.7×10-3~18.6×10-3(mean 17.7×10-3). No obvious difference can be found in C and O isotopes among occurrences and elevations and even ore~bodies. Types of inclusions include those of pure liquid (L),liquid~rich gas~liquid (L+V), and three~phase ones containing a daughter mineral (S+L+V) and immiscible CO2 with three phases (VCO2+LCO2+LH2O).Their homogenization temperatures vary from 110 to 400 ℃, and two peaks are shown. (87Sr/86Sr)0 ratios of calcite in the deposits are higher than those in the mantle and Emeishan basalts, and slightly higher than those in the Baizuo Formation, which the Huize lead-zinc deposits are found in. All of the(87Sr/86Sr)0 are low relative to those in the basement rocks. Fractionation of Sr isotope did not occur in the ore~forming fluid during the precipitation of minerals. The results indicate that the ore~forming fluid is homogeneous and derived from the mixing of different fluids. Gas liquid inclusions can be separated into two groups in 300~400 ℃ with a salinity of 5% ~ 6% and 12% ~ 16% NaCl respectively. However, the salinities of inclusions vary from 7 % to 23 % NaCl in 100~300 ℃, especially in 150~250 ℃. The formation pressures of faulted zones are (50-320)×10 5 Pa. The estimated pressures of the overlying rocks on the ore bodies are 574×105-640×105 Pa. The pressures of ore~forming processes would be 145×105 to 754×105 Pa. Therefore, pressure sharply reduced and boiling occurred when the ore~forming fluid flew into the fault zones. As a result, the ore~forming fluid was highly concentrated, and metallic minerals began to precipitate from the fluid on a great scale. The high~grade lead~zinc deposits were formed when the fluid was under saturation or over saturation conditions

Zhang Zhenliang, Huang Zhilong, Rao Bing, Guan Tao, Yan Zaifei. Concentration Mechanism of Ore-Forming Fluid in Huize Lead-Zinc Deposits, Yunnan Province. Journal of Earth Science, 2005, 16(2).
Citation: Zhang Zhenliang, Huang Zhilong, Rao Bing, Guan Tao, Yan Zaifei. Concentration Mechanism of Ore-Forming Fluid in Huize Lead-Zinc Deposits, Yunnan Province. Journal of Earth Science, 2005, 16(2).

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