Hydrothermal He and CO2 at Wudalianchi intra-plate volcano, NE China

3 He abstract Chemical and isotopic compositions have been measured for CO2-rich bubbling gases discharging from cold springs in Wudalianchi intra-plate volcanic area, NE China. Observed 3 He/ 4 He ratios (2-3 RA) and d 13 C values of CO2 (� 5‰ to � 3‰) indicate the occurrence of a mantle component released and trans- ferred to the surface by the Cenozoic extension-related magmatic activities. The CO2/ 3 He ratios are in wide range of (0.4-97 � 10 9 ). Based on the apparent mixing trend in a