Geochemistry of Low Temperature Geothermal Systems in New Caledonia

Abstract

Thermal springs in New Caledonia are overall typical of low temperature, deep circulation geothermal systems, with 1ow flow rates and a 1 ow d i ssol ved solids content. They appear to be associated with faulting and occur in two localities, one near the central east coast and one in the south-east of the island. Stable isotope data show the waters to be essentially of meteoric experienced low temperature rock-water reactions. Chemical analyses also suggest some deep mixing of saline groundwater in the northern group of springs and an appreciable seawater content in the south-eastern group in Prony Bay. Chemical thermometers suggest that a maximum subsurface equi 1ib r i temperature of may e x i Computer calculation of AG values shows the northern spring waters to be saturated with silica, probably chalcedony, which may be the white encrustation being deposited. chemically different and deposition from them is greater, consisting of subaerial terraces largely and submarine formations composed