Geology and Ore-forming Fluid of Silver-Lead-Zinc Lode Deposit of Shagou, Western Henan Province
|School||Chinese Geology University (Beijing)|
|Course||Mineralogy,petrology, Mineral Deposit Geology|
|Keywords||Geological Silver lead and zinc Fluid inclusions Ore-forming fluids Shagou Xiong'ershan|
The the western Henan Shagou thin veined Ag-Pb-Zn sulphide deposit is located in the North China the southern edge Xiong'ershan region, composed of sulfide quartz veins and quartz - carbonate - mica altered rocks of both types of mineralization. The main lode mineral paragenetic sequence can be divided into the early quartz - pyrite stage (I), sphalerite - coarse-galena - quartz - a small amount of silver the owner mineralization stage (II1) and galena - quartz - sphalerite - silver the owner mineralization stage (II 2 ) and late calcite - quartz stage (III). Stage (I) quartz Q 1 , the two-phase (LV) and three-phase (LVH) fluid inclusions, both inclusions can capture the results of a salt through the saturated fluid. The two-phase (LV) uniform temperature of 147 ~ 198 ℃, homogeneous liquid phase; salinity of 6.45 to 11.10 percent. Three-phase (LVH) the fluid inclusions temperature (LVH → LH) for 108 ~ 246 ℃; salinity of 30.06 to 37.40%. High salinity probably by magma differentiation fluid sudden decompression, decompression boiling may be an important mechanism for precipitation EW-trending quartz - pyrite veins. Stage (I) milky white quartz Q2 natively, two-phase (LV) inclusions uniform temperature of 285 ~ 360 ℃, an average of 325 ° C. To calculate the balance of the kinds of quartz the δ 18 sup> O H 2 O 325 ℃ 7.8 ~ 9.5 ‰, falling into the range of magmatic fluids; δD -96 ~ -84 ‰, close to magmatic fluid. Pyrite δ 34 sup> the S 4.4 ~~ 6.3 ‰, slightly higher than the magma sulfur. On behalf of the fluid inclusions in quartz Q2 natively in magmatic fluids led. Stage (II1) homogenization temperature of fluid inclusions in quartz and sphalerite natively two-phase (LV) 185 ~ 357 ℃, an average of 240 ° C, uniform for the liquid phase; salinity from 4.65 to 10.11%, 7.77% on average. Stage quartz (II2) natively two-phase (LV) inclusions homogenization temperature of 145 ~ 288 ℃, an average of 194 ° C, uniform for the liquid phase; salinity 1.91 to 10.86%, with an average of 6.38%. Stage (II1) compared to the temperature and salinity. Component analysis combined with inclusions and early melting temperature, the main mineralization stage (II1 and II2) for the low-temperature low salinity containing CO 2 of H 2 O-NaCl- KCl salt solution system. The fluid δ 18O H 2 O -0.3 ~ 4.2 ‰. δD -88.8 ~ -59.8 ‰; chart δ18OH2O-δD roughly located in the middle of magmatic water and stormwater lines, suggesting that atmospheric water mixed with magmatic hydrothermal. The mixing of meteoric water and magmatic water and lower temperature may be the main mechanism of the Shagou Ag, Pb, Zn precipitation. Stage (III) calcite and quartz natively two-phase (LV) inclusions homogenization temperature of 129 ~ 208 ℃, homogeneous liquid phase; salinity from 1.40 to 4.03%. For low-temperature low-salinity aqueous fluid, temperature and salinity continues to decrease. The fluid δ of the stage 18 sup> the O H 2 O -2.7 ~ -0.1 ‰, δD -73 ~ -60 ‰, δ 18 sup> O H 2 O -δD closer to the water line, suggesting that the increase in the proportion of atmospheric water. That the deposit is related to magmatic fluids in low-temperature low-salinity hydrothermal vein filling - account type Ag-Pb-Zn deposits of ore-forming fluids.