The Xitieshan lead-zinc deposit is located at the northern margin of the Qaidam Basin, Qinghai Province, China, and had developed a complete marine sedimentary-exhalative system. Our preliminary study of ore-forming f...The Xitieshan lead-zinc deposit is located at the northern margin of the Qaidam Basin, Qinghai Province, China, and had developed a complete marine sedimentary-exhalative system. Our preliminary study of ore-forming fluids shows that fluid inclusions in quartz from altered stockwork rocks that represent the pipe facies have a wide range of temperature and salinity. The intense fluid activities are characteristics of the pipe facies of the exhalative system. Fluid inclusions in carbonates near the unstratified ore bodies hosted in the thick-bedded marble which represents vent-proximal facies are large in size and have moderate to high temperatures. They represent unerupted sub-seafloor fluid activity. Fluids in altered stockwork rocks and carbonates have similar H20-NaCI-CO2 system, both belonging to the sedimentary-exhalative system. The fluids migrate from the pipe facies to the unstratified ore bodies. Boiling of the fluids causes the separation of CO2 vapor and liquid H2O. When the fluids migrate into the unconsolidated thick-bedded marble, the escape of CO2, decreasing temperature and pressure as well as some involvement of seawater into the fluids result in the unmixing of fluids with high and low salinity and deposition of ore-forming materials. The two unmixed fluids were trapped in unconsolidated carbonates and the ore-forming materials were deposited in the unconsolidated carbonates to form the sedimentary-exhalative type unstratified ore bodies. The oreforming temperature of unstratified ore bodies is up to high temperature indicating that there is a huge ore-forming potential in its deep.展开更多
To enhance understanding of the flow characteristics around a sphere in both stratified and unstratified(UNS)fluids,large eddy simulations(LES)were conducted using a temperature-dependent density model at Re=3700.The ...To enhance understanding of the flow characteristics around a sphere in both stratified and unstratified(UNS)fluids,large eddy simulations(LES)were conducted using a temperature-dependent density model at Re=3700.The simulations were performed for flow around a sphere under UNS and stratified conditions(Fr=3).Horizontal and vertical vorticity,velocity,and streamline distributions were compared,and the evolution of vortex structures in the wake was analyzed.Furthermore,we quantified the velocity deficit,the root mean square(rms)of velocity components in all directions,and the turbulent kinetic energy(TKE)distribution.Additionally,the horizontal and vertical wake lengths were examined.The results demonstrate that the employed numerical simulation method accurately captures the behavior of stratified fluids,with outcomes in close agreement with experimental and numerical findings from previous studies.In the case of homogeneous fluid,a lower density value results in a faster decay of the velocity deficit.In stratified fluids,the vortex structures in the wake evolve through three distinct stages:3-D,non-equilibrium(NEQ),quasi-two-dimensional(Q2D).For x/D>2,the rms velocity in the vertical direction exceeds that in the other two directions.In UNS fluid,the TKE distribution forms a vertically elongated spindle shape,while in stratified fluid,it assumes an elliptical shape,being vertically compressed and horizontally expanded.The vertical extent of the density and density gradient distributions surpasses that of the wake.展开更多
基金This research is supported by the National Natural Science Foundation of China （No. 40672061） ； ＇National Science Support Plan Program＇ （2006BAB01A06） ； ＇National Basic Research Program of China＇ （No.2007CB411304 No. 2001 CB409806）.
文摘The Xitieshan lead-zinc deposit is located at the northern margin of the Qaidam Basin, Qinghai Province, China, and had developed a complete marine sedimentary-exhalative system. Our preliminary study of ore-forming fluids shows that fluid inclusions in quartz from altered stockwork rocks that represent the pipe facies have a wide range of temperature and salinity. The intense fluid activities are characteristics of the pipe facies of the exhalative system. Fluid inclusions in carbonates near the unstratified ore bodies hosted in the thick-bedded marble which represents vent-proximal facies are large in size and have moderate to high temperatures. They represent unerupted sub-seafloor fluid activity. Fluids in altered stockwork rocks and carbonates have similar H20-NaCI-CO2 system, both belonging to the sedimentary-exhalative system. The fluids migrate from the pipe facies to the unstratified ore bodies. Boiling of the fluids causes the separation of CO2 vapor and liquid H2O. When the fluids migrate into the unconsolidated thick-bedded marble, the escape of CO2, decreasing temperature and pressure as well as some involvement of seawater into the fluids result in the unmixing of fluids with high and low salinity and deposition of ore-forming materials. The two unmixed fluids were trapped in unconsolidated carbonates and the ore-forming materials were deposited in the unconsolidated carbonates to form the sedimentary-exhalative type unstratified ore bodies. The oreforming temperature of unstratified ore bodies is up to high temperature indicating that there is a huge ore-forming potential in its deep.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52001210,52131102).
文摘To enhance understanding of the flow characteristics around a sphere in both stratified and unstratified(UNS)fluids,large eddy simulations(LES)were conducted using a temperature-dependent density model at Re=3700.The simulations were performed for flow around a sphere under UNS and stratified conditions(Fr=3).Horizontal and vertical vorticity,velocity,and streamline distributions were compared,and the evolution of vortex structures in the wake was analyzed.Furthermore,we quantified the velocity deficit,the root mean square(rms)of velocity components in all directions,and the turbulent kinetic energy(TKE)distribution.Additionally,the horizontal and vertical wake lengths were examined.The results demonstrate that the employed numerical simulation method accurately captures the behavior of stratified fluids,with outcomes in close agreement with experimental and numerical findings from previous studies.In the case of homogeneous fluid,a lower density value results in a faster decay of the velocity deficit.In stratified fluids,the vortex structures in the wake evolve through three distinct stages:3-D,non-equilibrium(NEQ),quasi-two-dimensional(Q2D).For x/D>2,the rms velocity in the vertical direction exceeds that in the other two directions.In UNS fluid,the TKE distribution forms a vertically elongated spindle shape,while in stratified fluid,it assumes an elliptical shape,being vertically compressed and horizontally expanded.The vertical extent of the density and density gradient distributions surpasses that of the wake.
