Extreme alteration in an acid-sulphur geothermal field: Sulphur springs, Saint Lucia.

Abstract

Sulphur Springs is a vigorous geothermal field associated with the Soufrière Volcanic Centre in southern Saint Lucia. Intensely altered rocks occur over an area of at least 200 × 400 m, together with bubbling hot pools and fumaroles. The pools are sodium‑calcium-sulphate type, with pHs of 3–7 and temperatures of 41–97 °C. Fumaroles have temperatures up to, and at times above 100 °C. Gases collected from both fumaroles and bubbling pools have high contents of CO2 (601–993 mmol/mol) and commonly high H2S (3–190 mmol/mol).