Abstract: The paper reported the repeatedly measured result of ³He/⁴ ratio for the gas samples collected from 5 springs and artesian wells in Nanjing—Zhenjiang region.The values of the ratios are variable, ranging from (6.18±0.17)×10^-6to (3.12±0.08)×10^-7。The highest value appears in bubbling gases of the hot spring (42UC±) at Tangquan, and the lowest in the artesian well at Jurong.
³He/⁴ ratios (Rs) for gas samples collected from 5 sites can be grouped into two types.In one type, the He/4He ratios of bubbling gases of two hot springs are obviously higher than the atmospheric ratio (Ratm), being 4.4 Ratm and 4.1 Ratm respectively.The high ³He/⁴ ratios were first observed in this study.In another type, they are lower than Ratm.
The above difference of two type gases Rs reflects the difference in source and origin of gas samples and the difference in geological setting property of the sites where samples were collected.The high ³He/⁴ value of hot spring gases in this area may be related to magmatic activity since Cenozoic.It is an evidence that the primordial ³He of He—rich is still emanating from the deep interior of the earth.