Thermal karst groundwaters with temperatures ranging from 32.8 to 62.5 ℃ were found at Taiyuan（太原） City,the capital of Shanxi（山西） Province.To identify the origin of the thermal groundwater,the following tracers were used in this study：δD,δ18O,4He,3He/4He,and major chemical constituents in water.Hydrochemical and isotopic data indicate that the thermal groundwaters in the basin area are a mixture of thermal waters from the West Mountain and those from the East Mountain.Furthermore,the 4He and 4Heexc concentrations of the thermal groundwater samples are usually lower than those of the cold groundwater samples,and there is an evidently negative correlation between the temperature and the 4He concentration in thermal groundwaters from the West Mountain and the ba-sin,which means that with the increase in temperature,the He concentration increases in the vapor phase and decreases in the aqueous phase.In the plot of 3He/4He vs.4He/20Ne of all water samples：air,crust,and mantle,all thermal groundwater samples are distributed near the line between the point of air and that of crust,suggesting that atmospheric and crustal helium is the main source for that in thermal groundwaters.In other words,there are no mantle-derived fluids mixed in the thermal groundwaters.
Loess has unique compositions and structural characteristics and can be used for environmental protection.Differences between the surface characteristics of the Malan loess from the suburbs of Taiyuan,Shanxi Province before and after reaction with Cr(Ⅲ) solution were studied by SEM/EDS,IR and XRD.The results showed that the Malan loess has a strong ability to remove Cr(Ⅲ) from the solution.The surface characteristics of loess include an effect on Cr(Ⅲ) in solution,as supported by the strong test evidence including the disappearance of Cr peak in the EDS spectrum,the disappearance of carbonate characteristic peaks in the infrared spectrogram,and the positive correlation between Fe and Cr peaks.
MA TengWANG YanxinLUO WeiHUANG ZhengHE XinHE JunTIAN Chunyan
