Suretimeat Geothermal System: an Example of a Volcanic Geothermal System

Abstract

The Suritemeat geothermal system, Vanua Lava, Vanatu (New Hebrides), consists of a major hot sprin and fumarole field discharging hot acid water rich inCI, Feand AI. Water temperatures range up to a few metres beneath the surface and estimated reservoir tem eratures, based on silica concentration, are in excess of Minor acid hot springs are found on the N slopes of the volcano and neutral chloride springs flow at lower elevations. Examples of similar systems are found on volcanoes elsewhere and well-described examples are found in Japan and Taiwan.We propose a general model of avolcanic geothermal system in which perched acidic systems are heatedby gases rising through the volcano. Deeper, neutral to alkaline chloride hot water systems sit around a zone of conductively heated rock several kilometres below. Seepage from these systems is controlled by local permeability and structure and will usually appear near the base of the volcano. These deep systems are in some, and perhaps most instances, significantly larger than systems found in the summit region of volcanoes.