INDICATION OF ENVIRONMENTAL ISOTOPES IN IDENTIFYING THE GROUNDWATER RECHARGE SOURCES IN ILI RIVER VALLEY

This study analyzes the distribution characteristics of δD and δ¹⁸O in phreatic water, shallow confined water, spring water and surface water, as well as the δ¹³C of five groups of groundwater samples from hydrologic drilling wells. The results show that both groundwater and surface water originate from the local meteoric water. The phreatic water and shallow confined water, belonging to the same aquifer system, have a strong hydraulic connection. The age of deep confined water is about 20 ka, older than the shallow confined water, belonging to sedimentary buried water, with weak hydraulic relation between the two. The δ¹³C values of phreatic water and shallow confined water are close to each other, approximating that of atmospheric CO₂(-7‰) which serves as the main source of carbon in groundwater of the study area.