John V. Walther
Ph.D., Berkeley
Matthews Professor
Director of Undergraduate and Graduate Studies
Phone 214-768-3174
Email walther@smu.edu
- Experimental and Theoretical Aqueous Geochemistry
- Kinetics of Dissolution and Fluid-Mineral Surface Interactions
- Mineral Solubilities as a Function of Temperature, Pressure and Solution Composition
Courses Taught
GEOL 1305 - Oceanography
GEOL 3366 - Environmental Geology and Geochemical Cycles
GEOL 5384 - Hydrogeology
GEOL 5386 - Geochemistry
GEOL 6370 - Aquatic and Mineral-Water Interface Geochemistry
Research Statement
John Walther's research efforts are geared to increase our understanding of mineral-solution interaction at the Earth's surface and in its crust, from both a theoretical and experimental standpoint. Under this umbrella a variety of projects concerning the composition and transport of fluids in groundwater, hydrothermal systems, and during metamorphism are proceeding.
He uses a unique large volume apparatus in the hydrothermal lab to measure mineral solubilities in H2O at the supercritical temperatures and pressures found in the crust. Walther also supervises research in the wet chemical lab to look at rates of reactions between minerals and solutions at near earth surface conditions and to characterize the adsorptive properties of mineral surfaces.
Research Details
Selected Publications
1994, Mazor, J.J. and Walther, J.V., Dissolution kinetics of silica glass as a function of pH between 40 and 85 degrees C: J. Non-Crystalline Solids , v. 170, p. 32-45.
1994, Xie, Z. and Walther, J.V., Dissolution stoichiometry and adsorption of alkali and alkaline earth elements to the acid-reacted wollastonite surface at 25 degrees C: Geochim. Cosmochim. Acta , v. 58, p. 2587-2598.
1994, Walther, J.V., Fluid-rock reactions during metamorphism at mid-crustal conditions: J. Geology , v. 102, p. 559-570.
1995, Walther, J.V. and Holdaway, M.J., Comment: Mass transfer during Barrovian metamorphism: Amer. J. Sci. , v. 295, p. 1020-1025.
1996a, Walther, J.V., Fluid production and isograd reactions at contacts of carbonate-rich and carbonate-poor layers during progressive metamorphism: J. Metamorphic Geol. , v. 14, p. 351-360.
1996b, Walther, J.V., Relation between rates of aluminum silicate mineral dissolution, pH, temperature, and surface charge: Amer. J. Sci. , v. 296, p. 693-728.
1997a, Walther, J.V., Determination of activity coefficients of neutral species in supercritical H2O solutions: Geochim. Cosmochim. Acta , v. 61, p. 3311-3318.
1997b, Walther, J.V., Comment: Feldspar dissolution at 25 degrees C. and low pH: Amer. J. Sci. , v. 297, p. 1012-1021.
1997c, Walther, J.V., Experimental determination and interpretation of the solubility of corundum in H2O between 350 and 600 degrees C from 0.5 to 2.2 kbar: Geochim. Cosmochim. Acta , v. 61, p. 4955-4964.
2001, Mukhopadhyay, B. and Walther, J.V., Acid-base chemistry of albite surfaces in aqueous solutions at surficial conditions, Chemical Geology, Chem Geology, v.174, p. 415-443.
2001, Walther, J.V., Experimental determination and analysis of the solubility of corundum in 0.1 and 0.5 m NaCl solutions between 400 and 600°C from 0.5 to 2.0 kbar, Geochim. Cosmochim. Acta, v. 65, p. 2843-2851.
2002, Walther, J.V., Experimental determination and analysis of the solubility of corundum in 0.1 molal CaCl2 solutions between 400 and 600°C at 0.6 to 2.0 kbar, Geochim. Cosmochim. Acta, v. 66, p. 1621-1625.
2004, Walther, J.V., Comment on: “Negative pressure of stretched liquid water. Geochemistry of soil capillaries,” by L. Mercury and Y. Tardy (2001) Geochim. Cosmochim. Acta, 65, 3391-3408 and “Thermodynamic properties of solutions in metastable systems under negative or positive pressures, by Mercury L., Azaroual M., Zeyen H., and Tardy Y. (2003): Geochim. Cosmochim. Acta, 67, 1769-1785. Geochim. Cosmochim. Acta, v. 68, 2771-2773.
2005, Walther, J.V., Essentials of Geochemistry, Jones and Bartlett, Boston, 704 pp.