Atmospheric noble gases 2 Excess Air

In contrast to surface waters, ground waters commonly contain significantly larger air-derived (noble) gas concentrations than the expected atmospheric equilibrium (Fig. 3). As the relative abundance of the noble gases in the excess is almost atmospheric, Heaton and Vogel (1979, 1981) called the gas surplus excess air . In the case of Ar the phenomenon was described at least 20 years earlier (Oana 1957). 

Until now, two models have been proposed to conceptual sze the fractionation of excess air in ground waters (Fig. 5). Although both models describe only the bulk behavior of atmospheric gas dissolution, the two concepts are able to describe the observed noble gas abundances, including the possible fractionation of the excess in favor of the heavy noble gases. 

In many cases the PR-model requires large amounts of initially dissolved excess air 

Although both concepts on the formation of excess air can produce the ground- 

Recently, laboratory experiments improving first experimental work of Groning 

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