Tritium Released from Mantle Source: Implications for Natural Nuclear Fusion in the Earth’s Interior

This paper summarizes the observation results of mantle tritium ( 3 H) in two volcanic lakes, Lakes Nemrut (Turkey) and Laacher (Germany). The presence of excess 3 H in the lakes can be explained as material released from mantle source because of the correlation of excess 3 H with mantle 3 He and 4 He. We conclude that excess 3 H in these two lakes, after the origin of the excess 3 H from atmosphere and conventional nuclear reactions are excluded and the correlation of the excess 3 H and mantle 3 He is considered, might be from a mantle source and produced by nuclear fusion (d–d reaction) in the deep Earth. We have also investigated helium isotopes in the hydrothermal vent fluids at Mid-Ocean Ridge (MOR). The results show nearly constant 3 He/ 4 He ratio ( 3 He/ 4 He = 1.12 ± 0.13 × 10 −5 ) and approximately constant 3 He/heat ratios ((5–10) × 10 −18 mol/J). The correlation of 3 He with 4 He and heat suggests that it is reasonable to suppose 3 He is produced by nuclear fusion (d–d reaction) and 4 He from α-decay of U and Th in the deep Earth. Based on that, 3 He/ 4 He ratios for 10 hydrothermal vent fluids are calculated. The results agree with the measurement at hydrothermal vent fluids and Mid-Ocean Ridge Basalts (MORB) on the average. We concludes that the narrow distribution of 3 He/ 4 He ratio peaked at ∼8 R A in MORB can be explained by the hypothesis that 3 He is produced in nuclear fusion.