Experimental and theoretical investigation of quartz and corundum solubilities and their application to phase equilibria and mass transfer in the geothermal system, Svartsengi, Iceland

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5269533

Ragnarsdottir, K V

Experimentally reversed quartz solubilities at 250{degree}C and at 250, 500 and 1000 bars yield values of the logarithm of the molality of aqueous silica of {minus}2.126, {minus}2.087 and {minus}2.038, respectively. These solubility determinations and analyses of fluid pressures in geothermal systems indicate that pressure is significant when calculating quartz equilibrium temperatures from silica concentrations in waters of deep thermal reservoirs. The results of this investigation, combined with other reported quartz solubility measurements, yielded a pressure-sensitize silica geothermometer for fluids that have undergone adiabatic steam loss. The bulk composition and mineralogy of hydrothermally altered tholeiite, along with the composition and speciation of fluid, have been determined for a well-defined alteration zone at 240{degree}C and 110 bars at Svartsengi, Iceland. Thermodynamic analyses of authigenic minerals and downhole fluid indicate that the fluid maintains a state close to equilibrium with the secondary mineral phases chlorite, epidote, albite, quartz, calcite, prehnite, anhydrite, pyrite and magnetite, whereas remnant primary labradorite and augite are out of equilibrium with the fluid. Experimentally reversed corundum solubilities in pure water at 400{degree} to 700{degree}C and 0.7 to 3 kbar yield values of dissolved aluminum that range from 1-4 ppm Al. Corundum solubility increases with increasing pressure at constant temperature. The dissolved aluminum appears to form a charged species under these conditions and the aluminum complex is probably of the form of Al(OH).

• Research Organization: Northwestern Univ., Evanston, IL (USA)
• OSTI ID: 5269533
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
152002 -- Geothermal Data & Theory-- Properties of Minerals & Rocks
152003* -- Geothermal Data & Theory-- Rock-Water-Gas Interactions
152004 -- Geothermal Data & Theory-- Isotope & Trace Element Studies
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHLORITE MINERALS
CORUNDUM
DEVELOPING COUNTRIES
DISSOLUTION
EQUILIBRIUM
EUROPE
FLUIDS
GEOTHERMAL FIELDS
GEOTHERMAL FLUIDS
GEOTHERMAL SYSTEMS
GEOTHERMOMETERS
GEOTHERMOMETRY
HYDROTHERMAL ALTERATION
ICELAND
IRON COMPOUNDS
IRON SULFIDES
ISLANDS
MASS TRANSFER
MEASURING INSTRUMENTS
MINERALOGY
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PARTIAL PRESSURE
PHASE STUDIES
PRESSURE EFFECTS
PYRITE
QUARTZ
ROCK-FLUID INTERACTIONS
SATURATION
SILICA
SILICATE MINERALS
SILICON COMPOUNDS
SILICON OXIDES
SOLUBILITY
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
THERMOMETERS
TRANSITION ELEMENT COMPOUNDS
WESTERN EUROPE