Or coexistence of radon and CO2 in caves of Ellenburger limestone could
indicate that the limestone is poorly permeable and simply doesn't allow for
good ventilation of gases produced below the surface. Radon is a product of
U-234 to thorium to radium to finally radon, with alpha particle decay (two
protons and two neutrons) and no release of chemical such as CO2 as byproduct.
Heating of limestone at high temperatures produces CO2 - but that would have to
be in excess of 800C (and even higher at higher pressures) - temperature that
is not attained until depth of 30+ km is reached. Therefore, this is not
likely to have an effect on local aquifers.
Rafal Kedzierski
