Temporal-Spatial Variation of Isotopic Compositions as Indicators of Hydrodynamic Conditions of a Large Karst Water System

摘要

Studies of the Niangztguan karst water system, a representative large karst water system in northern China, show that the temporal-spatial evolution in isotopes of hydrogen and oxygen could reveal the resource composition of groundwater and flow system. The large karst water system consists of local shallow groundwater flow system and deep regional or medium groundwater flow system, and the attenuation of spring discharge is the result of over-use of groundwaters or drainage in mining activitities. The temporal-spatial variation of 34S indicates the origin of sulfate in groundwater and the higher sulfate is caused either by dissoved gypsum in aquifer or by pyrite oxidation in coal-bearing formations, or both. All isotopic studies show that the original flow system has been changed tremendously by anthropogenic processes.