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Mineralogical and Geochemical Constraints on Arsenic Mobility in a Philippine Geothermal Field
Author(s) -
PASCUA Chelo,
SATO Tsutomu,
GOLLA Glenn
Publication year - 2006
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2006.tb00250.x
Subject(s) - arsenic , dissolution , geothermal gradient , oxidizing agent , kaolinite , arsenate , geology , redox , pyrite , chemistry , geochemistry , environmental chemistry , mineralogy , inorganic chemistry , organic chemistry , geophysics
Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe‐hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range of pH and redox conditions.