The hydrogen and oxygen stable isotope analysis of the karst spring in Heilongtan

Heilongtan areais located at foothill of Wulao Mountains in the northern suburb of Kunming City, emerges along east branch of Heilongtan Fault.There are three karst springs distributed in this area,i.e. Qingshuitan,Hunshuitan and Xiaoshuitan.In this paper,hydrogen and oxygen stable isotope method is used to analyze the samples of precipitation water and spring water periodically to investigate the origin of the springs and the characteristics of the aquifer in the area.The following conclusions have been made:1)the i-sotope analysis of precipitation water and spring water shows that the spring is originated from precipitation, especially in summer;2)Gaussian mixture model shows that the recharge of Qingshuitan is not only from the Yemao mountain,but also from runoff infiltration which is not minor in quantity.Recharge types are differ-ent in wet season and dry season for the Hunshuitan karst system.The Xiaoshuitan karst system receives re-charge mainly from the northern Permian limestone aquifer,and sparingly from the fissure water from the northeastern basalt mountain.