Warm springs, South Island, New Zealand, and their potentials to yield laumontite

Warm springs (40 degrees to 65 degrees C) of the South Island, New Zealand are all super saturated with laumontite and with few exceptions are either in equilibrium with or are unsaturated with calcite and albite. Two gels with cation-oxygen-silicon were found as deposits forming from the waters. The isotopic measurements show the waters to be meteoric in origin. From isotopic compositions, dissolved CO ~2~ species are in part from organic carbon and in part from the solution of calcite, although there may be a magmatic CO ~2~ contribution. The CO ~2~ partial pressures range from an exceptionally low value of 5.3X10 (super -6) atm to an exceptionally high value of 1A atom. The CO ~2~ partial pressures are dependent variables and do not control the chemical reactions. Analcime should not be regarded necessarily as a lower grade metamorphic facies indicator nor should prehnite necessarily be regarded as a higher grade metamorphic product. Rather, they may be products of different chemical rather physical conditions.