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| Titel |
The solubility of gallium oxide in vapor and two-phase fluid filtration in hydrothermal systems |
| VerfasserIn |
Andrew Bychkov, Svetlana Matveeva, Stanislav Nekrasov |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250044249
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| Zusammenfassung |
| The solubility of gallium and aluminum oxides in gas phase in the system Ga2O3
(Al2O3)-HCl-H2O was studied at 150-350ºC and pressure up to saturated vapor. The
concentration of gallium increases with the increasing of HCl pressure. The formulae of
gallium gaseous specie was determined as GaOHCl2. The constant of gallium oxide
solubility reaction was calculated at 150, 200, 250, 300 and 350ºC. The concentration of
aluminum in gas phase is insignificant in the same conditions. The possibility of gallium
transportation in gas phase with small quantity of Al allow to divide this elements in
hydrothermal processes with gas phase. The Ga/Al ratio in muscovite can be used as the
indicator of gas phase separation and condensation. This indicator was not considered in the
geochemical literature earlier. The separation of gas and liquid phases was determined
in Akchatau (Kazahstan) and Spokoinoe (Russia) greisen W deposit by carbon
isotope fractionation of carbon dioxide in fluid inclusion. The important feature of
both ore mains is heterogenization and boiling of ore-forming fluids. Greisen ore
bodies are formed as a result of strongly focused solution flow in the T-P gradient
fields. It is possible to divide ore bodies of Akchatau in two types: muscovite and
quartz. Muscovite type veins are thin and have small metasyntactic zone. Quartz type
veins are localized in fault with large vertical extent (500 m) and content the large
quantity of wolframite. These veins formed in condition of significant pressure
decreasing from 2.5 to 0.5 kbar with fluid boiling. Gas and liquid phase separation
specifies the vertical zonality of quartz type veins. The gas phase with the high gallium
concentration is separated from a flow of liquid phase. Liquid phase react with the
granites forming greisen metasomatites. Condensation of the gas phase in upper parts
of massive produces the increasing of Ga/Al ratio in muscovite 3-5 times more,
then in granites and bottom part of vein (from 2-
10-4 to 8-
10-4 mass ratio). The
muscovite type veins has no separation between gas and liquid due to there thickness
and small pressure gradient. There is no difference in Ga/Al ratio in muscovite
from this veins. The Spokoinoe deposit is classified by mineralized dome type. The
heterogenization of fluid occurs in H2O-CO2 system for water phase and carbon dioxide with
temperature decreasing. Two-phase flow is separated in granite, forming greisen
metosomatites. The Ga/Al ratio in rock increase up to 3 times to the upper part of
metasomatitic zone. The Ga/Al ratio in muscovite can be applied for other hydrothermal
systems for geochemical indicator of gas phase separation and condensation zone
determination.
This work is supported by RFBR project 10-05-00670 and 10-05-00320. |
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