TY - CHAP
T1 - Coupled t (thermal) - h (hydrological) - c (chemical) process of geothermal alteration, based on experimentaland kinetic considerations
AU - Hara, Junko
AU - Tsuchiya, Noriyoshi
PY - 2004
Y1 - 2004
N2 - The style and intensity of hydrothermal alteration in active geothermal systems reflect the thermal regime and chemical composition of waters resulting from hydrothermal fluid-mineral interactions. This study uses an experimental approach to deduce dynamic mineral formation mechanisms in the active geothermal setting, to understand the interaction processes that produced Na-rich hydrothermal alteration zones in the East Hachimantai Geothermal Field (Japan). Hydrothermal experiments were conducted under saturated vapour pressure conditions, at 75 - 250 °C, using pyroclastic rock samples. The hydrothermal (laboratory) alteration of Tamagawa Welded Tuff did not proceed according to expected stoichiometric constraints, with respect to observed mineral formation and whole rock chemical compositions, and there is a great disparity in mineral dissolution rates and incorporation of elements into new-formed minerals. Mass transport coefficients and enrichment of certain major element in the reacted solutions resulting from hydrothermal fluid/rock interaction also varied, which lead us to interpret a new diffusion - advection -reaction rate equation that enables kinetic and mass transport parameters to be quantitatively estimated.
AB - The style and intensity of hydrothermal alteration in active geothermal systems reflect the thermal regime and chemical composition of waters resulting from hydrothermal fluid-mineral interactions. This study uses an experimental approach to deduce dynamic mineral formation mechanisms in the active geothermal setting, to understand the interaction processes that produced Na-rich hydrothermal alteration zones in the East Hachimantai Geothermal Field (Japan). Hydrothermal experiments were conducted under saturated vapour pressure conditions, at 75 - 250 °C, using pyroclastic rock samples. The hydrothermal (laboratory) alteration of Tamagawa Welded Tuff did not proceed according to expected stoichiometric constraints, with respect to observed mineral formation and whole rock chemical compositions, and there is a great disparity in mineral dissolution rates and incorporation of elements into new-formed minerals. Mass transport coefficients and enrichment of certain major element in the reacted solutions resulting from hydrothermal fluid/rock interaction also varied, which lead us to interpret a new diffusion - advection -reaction rate equation that enables kinetic and mass transport parameters to be quantitatively estimated.
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U2 - 10.1016/S1571-9960(04)80114-9
DO - 10.1016/S1571-9960(04)80114-9
M3 - Chapter
AN - SCOPUS:77957098146
T3 - Elsevier Geo-Engineering Book Series
SP - 655
EP - 660
BT - Elsevier Geo-Engineering Book Series
PB - Elsevier Ltd
ER -