摘要
The present work provides an online Bench II-IRMS technique for the measurement of stable chlorine isotope ratio,which is used to measure the δ^(37)Cl of 38 groundwater samples from the Karst and Quaternary aquifers in Anyang area.The regional distribution and signature of δ^(37)Cl value are characterized on the base of isotopic data.The results suggest that the δ^(37)Cl value of Quaternary groundwater decreases with increasing Cl^(−) concentration,and has no correlation with δ^(18)O andδD values,but closely correlates with the depth to water table.The fractionation mechanism of the chlorine isotope is expounded according to the type of groundwater.The δ^(37)Cl value of karst water is generally positive,which is relevant to the dissolution of evaporite(gypsum mine),and may be caused by the mixing of groundwater and precipitation.The groundwater of Quaternary unconfined aquifer is mainly recharged by precipitation,and the δ^(37)Cl value of groundwater is generally negative.The δ^(37)Cl value of groundwater in Quaternary confined aquifer is more negative with increasing the depth to water level and elevated Cl^(−) concentration,which is possible to result from the isotope fractionation of ion filtration.The groundwater with inorganic pollutants in Quaternary unconfined aquifer has generally a positive δ^(37)Cl value.
