C 14 radiocarbon dating
This apparent age of oceanic water is caused both by the delay in exchange rates between atmospheric CO2 and ocean bicarbonate, and the dilution effect caused by the mixing of surface waters with upwelled deep waters which are very old (Mangerud 1972).A reservoir correction must therefore be made to any conventional shell dates to account for this difference.
One modern plant growing near the emanations had an apparent age of 1390 yr.
The volcanic effect has a limited distance however. (1980) found that at 200 m away from the source, plants yielded an age in agreement with that expected.
They suggested that the influence of depleted CO2 declined rapidly with increasing distance from the source.
In such a case, it is very difficult to ascertain the precise reservoir difference and hence apply a correction to the measured radiocarbon age.
Spurious radiocarbon dates caused by volcanic emanations of radiocarbon-depleted CO2 probably also come under the category of reservoir corrections.