Distribution of isotopic ages of groundwater and its evolution and sustainable utilization in the Yuncheng Basin (In Chinese with English abstract)

By analysis of the Groundwater carbon isotope composition, combined with water chemistry characteristics, reveals the the basin deep confined groundwater recharge period of 22 ~ 3 ka BP (pmC of modern carbon percentage (a14C) 6 to 38). Shallow groundwater (71 ~ 89 pmC) is a mixture of modern water or water and old water isotopic composition of deep groundwater characteristics (δ18O ~ -10 ‰; δ2H ~ -70 ‰) show that by the recharge underground old water in a colder climate, while The isotopic composition of shallow groundwater (the δ18O -8 ‰; δ2H ~ -51 ‰) characteristics with modern Xi'an precipitation composition similar shallow groundwater NO3-; average content (31mg / L) than the deep groundwater (1.8 mg / L ) high δ15N-δ18ONO3 nitrate (0 ‰ ~ 5 ‰) revealed that the main source of nitrate integrated fertilizer. addition, the TDS of shallow groundwater evapotranspiration, mineral dissolution, up to 8.5 g / L (average 2.0 g / L), deep underground old water TDS of up to 1.8 g / L (mean 1.1 g / L), the water quality is relatively good. study area is mainly mined deep groundwater by the fault zone affect shallow groundwater has invaded deep groundwater and mixed with serious impact on the water quality of the deep groundwater. event of large-scale mixing of shallow groundwater and deep groundwater will cause deep underground old water NO3-, TDS content is getting higher and higher