Texas A&M Department of Geology & Geophysics
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Photo of Andrew Hajash

M.T. Halbouty Building,
Room 224
Geology & Geophysics, TAMU
College Station, TX 77843-3115

hajash@geo.tamu.edu

Phone: 979-845-0642
Fax: 979-845-6162
Andrew Hajash, Jr.
Professor
Ph.D., Texas A&M University, 1975


Current Research
Courses Taught
Publications
Affiliations
Professional Experience

Current Research
bullet Experimental investigations of water/rock interactions in the subsurface, including: Determining the chemical and mechanical aspects of intergranular pressure solution of quartz sand; Investigating the kinetics of pore-volume loss and quartz-water reactions at effective stress; Studying the effects of organic acids on porosity modification in sandstone reservoirs; and Using a coupled experimental and theoretical approach to investigate the role of carboxylic acids on mineral solubility, dissolution kinetics, pH-buffering, metal-ligand complexes, aluminum mobility, and generation of porosity.
bullet Fluid-assisted compaction and deformation of reservoir lithologies, U. S. Department of Energy, Basic Energy Sciences, Geosciences, A.K. Kronenberg, A. Hajash, J.S. Chester, F.M. Chester, 8/1/98 to 7/31/01, $537,853.
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bullet Geology 101/103/104: Principles of Geology
bullet Geology 209: Field Methods*
bullet Geology 204/302: Introduction to Petrology
bullet Geology 245: Quantitative Geology
bullet Geology 300; Field Geology *
bullet Geology 330: Geologic Field Trips
bullet Geology 451: Introduction to Geochemistry
bullet Geology 454: Evolution of the Earth's Crust
bullet Geology 485A: Exploration Geophysics for Geologists
bullet Geology 659: Volcanic Geology
bullet Geology 660: Theoretical Petrology
* Team taught

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Publications
He, W., Hajash, A., Chester, F., Chester, J., and Kronenberg, 2003, Evolution of fluid chemistry and the rate-controlling processes during creep compaction of quartz sand: 1. Experimental Investigations, Submitted to Geochim. et Cosmochim. Acta., June 2003.

He, W., Hajash, A., Sparks, 2003, Evolution of fluid chemistry and the rate-controlling processes during creep compaction of quartz sand: 2. Numerical Modeling, Submitted to Geochim. et Cosmochim. Acta., June 2003.

He, W, Hajash, A., and Sparks, D., 2003, Creep compaction of quartz aggregates: Effect of pore-fluid flow rates - A combined experimental and theoretical study. Am. Journal Science, v. 203, 73-93.

He, W. Hajash, A., and Sparks, D., 2002, A model for porosity evolution during compaction of sediments, Earth and Planetary Science Letters, v. 197, 237-244.

Muhuri, A., Dewers, T.A. and Hajash, A., "Comparison of experimental pressure solution creep in water-saturated porous halite, calcite, gypsum, and quartz aggregates," Geology, accepted, revised version sent 11/99.

Hajash, A., He, W., 1999, "Creep compaction of quartz sand: effects of pore-fluid flow rates," Am. Geoph. Union, EOS Trans. Amer. Geophys. Union, v. 80, p. 171.

He, W., Lang, R., Chester, F., Chester, J., Hajash, A., and Kronenberg, A., 1999, "Creep compaction of quartz aggregates under dry and fluid-saturated conditions, Am. Geoph. Union, EOS Trans. Amer. Geophys. Union, v. 80, p. 239.

Hajash, A., Carpenter, T.D., and Dewers, T.A., 1998, "Dissolution and time-dependent compaction of albite sand: Experiments at 100 degrees C and 160 degrees C in pH-buffered organic acids and distilled water," Tectonophysics, v. 295, 93-115.

Hajash, A., 1998, "Experimental investigations of water/rock interactions in flow-through hydrothermal systems: solution-transfer creep in quartz sands," Chinese University of Geosciences, Wuhan, PRC, Invited presentation, 6/98.

Hajash, A., 1998, "Experimental investigations of water/rock interactions in flow-through hydrothermal systems: Dissolution of feldspar in inorganic acids," Chinese University of Geosciences, Wuhan, PRC, Invited presentation, 6/98.

Hajash, A., R. Yilmaz, A. K. Kronenberg, F. M. Chester, and J. S. Chester, 1998, “Fluid-assisted compaction of quartz aggregates at low temperature and subcritical effective pressure,” Eos Trans. AGU, 79, F820.

Dewers, T. A. and Hajash, A. 1995, Rate laws for water-assisted compaction and stress-induced water-rock interaction in sandstones, J. Geophys. Res., Vol. 100, pp. 13,093-13,112.

Dewers, T. A. and Hajash, A. 1994, Rate laws for water-assisted densification and stress-enhanced water-rock interaction in sandstones: Prodeeding of Workshop LXIII on the , USGS Red Book Conference on the Mechanical Involvement of Fluids in Faulting, National Earthquake Hazards Reduction Program; Uniter States Department of Interior, U.S. Geological Survey Open File Report 94-228, pp. 576-611.

Franklin, S.P., Hajash, A., Dewers, T.A., and Tieh, T.T., 1994, The role of carboxylic acids in albite and quartz dissolution: an experimental study under diagenetic conditions,Geochim. et Cosmochim. Acta.,vol. 58, 4259-4279.

Hajash, A., 1994, Comparison and Evaluation of Experimental Studies on Dissolution of Minerals by Organic Acids: In The Role of Organic Acids in Geological Processes, eds. Lewan, M. and Pittman, E., Springer-Verlag. 201-225.

Hajash, A., Franklin, S, and Reed, C., 1992, Experimental feldspar dissolution in acetic and oxalic acids at 100ƒC, 345 bars., In Proceedings of the 7th International Water/Rock Symposium, ed. Kharaka, Y., A.A. Balkema, Rotterdam, Netherlands., vol. 1, p. 325-328.

Reed, C.L. and Hajash, A., 1992, Dissolution of granitic sand by pH-buffered carboxylic acids: A flow-through experimental study at 100ƒC, 345 bars, Am. Assoc Petrol. Geol.Bulletin . v. 76, p. 1402-1416.

Elias, B.P. and Hajash, A., 1992, Changes in quartz solubility and porosity due to effective stress: An experimental investigation of pressure solution,Geology , v. 20, p. 451-454.

Extended List of Publications

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Affiliations
bullet Center for Tectonophysics.
bullet Environmental & Engineering Geosciences and Hydrogeology.
bullet Geochemistry, Mineralogy, and Petrology.
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Professional Experience
Department Head, Department of Geology and Geophysics, Texas A&M University, College Station, Texas, January, 1999 - present.

Assistant Head, Department of Geology and Geophysics, Texas A&M University, College Station, Texas, June, 1996 - December, 1998.

Professor, Department of Geology and Geophysics, Texas A&M University, College Station, Texas, January, 1994 - present.

Associate Professor, Department of Geology, Texas A&M University, College Station, Texas, December 1981 - December 1993.

Consultant, Amoco Production Company, Tulsa, Oklahoma, June 1985 - August 1985.

Research Scientist, Senior Grade, Amoco Production Company, Tulsa Research Center, Tulsa, Oklahoma, June 1983 - August 1983.

Research Scientist, Senior Grade, Amoco Production Company, Tulsa Research Center, Tulsa, Oklahoma, June 1982 - August 1982.

Assistant Professor, Department of Geology, Texas A&M University, College Station, Texas, May 1975 - December 1981.

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