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地幔流体中稀有气体同位素组成与其所处的大地构造背景和深部地幔岩浆活动性质有关。大洋中脊玄武岩的3He/4He值为8～10Ra;热点型地幔源区的3He/4He值最高在30Ra以上;弧后盆地玄武岩和地幔包体的He同位素组成为5～22Ra,变化范围较宽;大陆地幔包体的He同位素比值为3～10Ra;金刚石的氦组分既有原始捕获的,也有外界注入的。我国东部裂谷盆地中存在3He/4He比值为2.7～6.4Ra的幔源气藏,幔源气的运移和聚集成藏与区域深大断裂有关。地幔源区40Ar/36Ar值为350左右,并随陆壳物质的加入而增高。地幔中有太阳型Ne存在,多数样品中Ne、Xe同位素比值与大气值一致,同时也发现了Ne、Xe同位素组成相对于大气的过剩现象,认为是由核成因造成的。
The isotopic composition of rare gas in the mantle fluid is related to the tectonic setting and the magma activity in the deep mantle. The 3He / 4He value of mid-oceanic basalts is 8 ~ 10Ra, the highest 3He / 4He value of hot-mantle source is above 30Ra, and the He isotope composition of basalts and mantle inclusions is 5-22Ra in the back-arc basins. ; The He isotope ratio of the mantle enclave in the mainland is 3 ~ 10Ra; the helium component of diamond is both originally captured and externally injected. There is a mantle source gas reservoir with 3He / 4He ratio 2.7 ~ 6.4Ra in the eastern rift basin. The migration and accumulation of mantle source gas are related to the deep deep faults in the region. The value of 40 Ar / 36 Ar in the mantle source area is about 350 and increases with the addition of continental crust material. In the mantle, there are solar neutrons. Ne and Xe isotope ratios of most samples are in agreement with the atmospheric values. At the same time, Ne and Xe isotopic compositions are also found to be excess relative to the atmosphere, which is believed to be caused by nuclear genesis.