Degassing flux

So far we discussed the case for 4He escape. 3He escape must at least be as effective as 4He the 4He lifetime against Jeans escape can be shown to be 70 times greater than the 3He lifetime. In the case of 4He, an inflow flux into the atmosphere is essentially the radiogenic 4He from the solid Earth. However, a flux from the interplanetary space may become important in the case of 3He inventory. From He implantation experiment on metal foil collectors in the Skylab, a spacecraft operated in a circular orbit at the altitude of 443 km from 1973 to 1974, Lind, Geiss, and Stettler (1979) concluded that the solar wind 3He precipitating from the magnetosphere to the upper atmosphere is comparable to 3He degassing flux from the solid Earth. 

Torgersen, T., O Donnel, J. (1991) The degassing flux from the solid Earth Release by fracturing. Geophys. Res. Lett., 18, 951 1. 

Torgersen T. (1989) Terrestrial helium degassing fluxes and the atmospheric helium budget implications with respect to the degassing processes of continental crust. Chem. Geol. 79, 1-14. 

Common in high temperature volcanic gases and a good indicator of magmatic degassing. Fluxes readily measured by remote sensing methods. 

Torgersen T. and Ivey G. N. (1985) Helium accumulation in groundwater II. A model for the accumulation of crustal He degassing flux. Geochim. Cosmochim. Acta 49, 2445-2452. 

Torgersen T., Kennedy B. M., Hiyagon H., Chiou K. Y., Reynolds J. H., and Clarke W. B. (1989) Argon accumulation and the crustal degassing flux of Ar in the Great Artesian Basin, Australia. Earth Planet. Sci. Lett. 92, 43-56. 

The degassing flux is proportional to the global rate of crustal production dAjdt, the degassing depth Ds, and the concentration of CO2 in the mantle ... 

Figures 12-15 describe the CO2 evolution of specific models indicated by the symbol in Figures 7 8. These models feature a current mantle reservoir / man of 1-44 x 10 moles and a current ridge degassing flux Fridge = 2 x 10 ...

There is no a-priori reason, nor significant evidence, that regions of the crust do or should exhibit a uniform steady-state degassing flux. 

Subduction flux to mantle has been different from degassing fluxes from subduction zone and mid-oceanic ridges. 

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