Characteristics Of H-O Isotopes In Lake-water And Groundwater In Badain Jaran Desert

Badain Jaran desert is the second biggest desert in China, and the third in theworld. Compared with other deserts, Badain Jaran desert is famous for the highestsand dune in the world and large number of lakes in the desert. It has become DesertWorld Geo-Park. In recent year, scientists from all the world have made lots of studieswhich focused on the characteristic and source of the water in Badain Jaran desert.However, formation and evolution of lakes and source of groundwater in the deserthave the different conclusions. In this paper, the characteristic of lake water andgroundwater in the desert was studied through the analysis of hydrogen and oxygenisotope.Typical water sampling and evaporation experiments were conducted in BadainJaran desert in the study. First of all, a lake was chosen as a representative of the lakesin the desert. The lake water was sampled in different depth of the lake, which showedthat the lake water was mixed so great that the lake water near the shore had theenough representative, and the groundwater was sampled near the lake. Then theevaporation experiments and Leaching tests were conducted with the lake water andgroundwater in the desert in summer which confirmed the change laws of hydrogenand oxygen isotope; the linear equation of evaporation was obtained; and thehomology was explained.Basing the conclusions which mentioned above and combining the data whichwas from previous studies, we made a statistical analysis of hydrogen and oxygenisotope in lake water and groundwater. Both D and18O in every water samplefit the normal distribution, and the variability of D was very more severe than18O.The negative deuterium excess in lake water and groundwater suggested that thewater had gotten through the evaporation in dry climate condition. The deuteriumexcess of the water in the desert was very different from the lake water andgroundwater in HeiHe River basin, but similar to the isotope characteristic of groundwater in Yabulai Mountain. It suggested that Yabulai Mountain was one of thesupply areas of the groundwater in Badain Jaran desert. The deuterium excess ingroundwater in the desert was great negative, very different from other deserts, whichmight be the special result of continental climate conditions.