Stable isotope ratios of volcanic steam from White Island, New Zealand

Abstract

The D/H and18O/16O ratios of fumarole condensates from White Island, an andesite volcano in the Bay of Plenty, have been measured during the period 1965 to 1969 to determine the origin of the water and the changes which occur as the volcanic activity changes. The D/H and18O/16O ratios of all of the samples were correlated with a slope of −2. The δ18O values were proportional to the logarithm of the chloride concentration but with distinctly different relationships between the period from 1965 to 1967, and the period of tephra eruptions in 1968. In the latter period the chloride contents were close to that of sea water while in the former quieter period the contents were lower. The δD values follow a similar pattern but with a poorer correlation, indicating that a more variable process is controlling the deuterium results.