Geochemical study of the geothermal field of Antsirabé (Madagascar)

Abstract

The geothermal CO₂-rich waters of the Antsirabé area result from mixing of hot deep water with superficial groundwaters. The temperature of the deep water was estimated by assuming equilibrium of the hot water with a mineral association characterized by chalcedony as solid silica mineral. The temperature and the CO₂ partial pressure at deep levels were estimated to be 150°C and 9-13 atm., respectively.