Advective versus diffusive transfer of noble gases in basins

Advective versus diffusive transfer of noble gases in basins 

These studies illustrate the complex problem of the nature of noble gas transfer in basins. There is no doubt that both advection and diffusion play major roles, but the respective strengths of each process are very different depending on the scale of observa- 

The problem is much more difficult in the case of semi-permeable or even impermeable layers such as shales or marls where the connectivity between pockets of interstitial water is uncertain and difficult to evaluate from laboratory measurements. 

Labor-atory experiments indicated either relatively high He mobility in analogs of deep-sea sediments at rates comparable to, although slightly lower than, diffusion in water (1.3-3.0x10 mol/m. s, Ohsumi and 

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