Professional Background

Dr. Spell earned a B.S. in Geology from the State University of West Georgia in 1985, a M.S. in Geology from New Mexico Tech in 1987, and his Ph.D. in Geology from the State University of New York at Albany in 1991. He held a postdoctoral fellowship at the Australian National University from 1991 to 1994 and was a Research Assistant Professor at the University of Houston from 1994 to 1996. He has been at UNLV since 1996.

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Teaching

Undergraduate:
• GEOL 101 - Introductory Geology: Exploring Planet Earth
• GEOL 220 - Mineralogy and Optical Mineralogy
• GEOL 221 - Optical Mineralogy and Petrography
• GEOL 330 - Introduction to Geochemistry
• GEOL 440 - Volcanology
• GEOL 449 - Geochronology
• GEOL 491 - Seminar in Geology

Graduate:
• GEOL 640 - Volcanology (cross listed Undergraduate)
• GEOL 649 - Geochronology (cross listed Undergraduate)
• GEOL 701 - Graduate Field Seminar
• GEOL 749 - Advanced Geochronology and Thermochronology
• GEOL 793 - Diffusion Theory and Heatflow
• GEOL 796 - Geochemistry

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Research

My interests include the development of continental volcanic centers and associated silicic eruptions and caldera collapse events, the Mesozoic and Cenozoic tectonic evolution of western North America and New Zealand, and intercalibration of isotopic dating techniques. All utilize 40Ar/39Ar dates generated in the Nevada Isotope Geochronology Laboratory here at UNLV. Click here for brief outlines of some research projects currently underway in these areas.

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Recent & Selected Publications

Total: 32 publications, 57 abstracts at professional meetings

Full Curriculum Vitae, 2007 (.pdf)

Kaymakci, N., Aldanmaz , E., Langereis, C., Spell, T. L., Gurer, O. F., and Zanetti, K. A., 2007, Late Miocene transcurrent tectonics in NW Turkey: Evidence from palaeomagnetism and 40Ar-39Ar dating of alkaline volcanic rocks, Geological Magazine, v. 144, p. 379-392.

Verdel, C., Wernicke, B.P., Ramezani, J., Hassanzedeh, J., Renne, P.R., and Spell, T.L., 2007, Geology and thermochronology of Tertiary Cordilleran-style metamorphic core complexes in the Saghand region of central Iran, Geological Society of America Bulletin, v. 119, no. 7/8, p. 961-977.

Kula, J.L., Tulloch, A.J., Spell, T.L. and Wells, M.L., 2007, Two-stage rifting of Zealandia-Australia-Antarctica: evidence from 40Ar/39Ar thermochronometry of the Sisters shear zone; Stewart Island, NZ, Geology. v. 35, no. 5, p. 411-414

Edgar, C.J., Wolff, J.A., Olin, P.H., Nichols, H.J., Pittari, A., Cas, R.A.F., Reiners, P.W., Spell, T.L. and Marti, J., 2007, The late Quaternary Diego Hernandez Formation, Tenerife: a complex cycle of voluminous explosive phonolotic eruptions and the factors responsible, Journal of Volcanology and Geothermal Research, v. 160, p. 59-85.

Wells, M.L., Beyene, M.A., Spell, T.L., Kula, J.L., Miller, D.A. and Zanetti, K.A., 2005, The Pinto Shear Zone; A Laramide Synconvergent Extensional Shear Zone in the Mojave Desert Region of the Southwestern Cordilleran Orogen, western United States, Journal of Structural Geology, Vol. 27/9, p. 1697-1720.

Leavitt, E.D., Spell, T.L., Wallace, A.R., Goldstrand, P.M., and Arehart, G.B., 2004, Geochronology of the Midas Low-sulfidation Epithermal Gold-Silver Deposit, Elko County, Nevada, Economic Geology, v. 99, p.1665-1686.

Reiners, P.W., Spell, T.L., Nicolescu, S., and Zanetti, K.A., 2004, Zircon (U-Th)/He thermochronometry: He diffusion and intercalibration with 40Ar/39Ar dating, Geochemica et Cosmochemica Acta, v. 68, p. 1857-1887.

Spell, T.L. and McDougall, I., 2003, Characterization and calibration of 40Ar/39Ar dating standards, Chem. Geol., v. 198, p. 189-211.

Davis, G.A., Yadong, Z., Darby, B.J. and Spell, T.L., 2002, Geometric and temporal evolution of an extensional detachment fault, Hohhot metamorphic core complex, Inner Mongolia, China, Geology, v. 30, p. 1003-1006.

Spell, T.L., Smith, E.I., Sanford, A. and Zanetti, K.A., 2001, Systematics of xenocrystic contamination: Preservation of discrete feldspar populations at McCullough Pass Caldera revealed by 40Ar/39Ar dating, Earth and Planetary Science Letters. v. 190/3-4, p. 153-165.

Justet, L. and Spell, T.L., 2001, Effusive eruptions from a large shallow magma chamber: The Bearhead Rhyolite, Jemez Volcanic Field, New Mexico, Jour. Volc. Geotherm. Res., v. 107, p. 241-264.

Spell, T.L., McDougall, I., and Tulloch, A.J., 2000, Thermochronologic constraints on the breakup of the Pacific Gondwana margin: The Paparoa Metamorphic Core Complex, South Island, New Zealand, Tectonics, v. 19, p. 433-451.

Spell, T.L., McDougall, I., and Doulgeris, A., 1996, Cerro Toledo Rhyolite, Jemez Volcanic Field, New Mexico: 40Ar/39Ar geochronology of the transition between two caldera forming eruptions, Geol. Soc. Am. Bull., v. 108, p. 1549-1566.

Spell, T.L. and Harrison, T.M., 1993, 40Ar/39Ar geochronology of post-Valles Caldera rhyolites, Jemez Mountains volcanic field, New Mexico, J. Geophys. Res., v. 98, p. 8031-8051.

Spell, T.L., DeLong, S.E., and Creasy, W.R., 1993, Characterization of Fourier transform ion cyclotron resonance mass spectrometry for quantitative isotope ratio measurements, Int. Jour. Mass Spectrom. Ion Phys., v. 124, p. 223-239.

Spell, T.L., Kyle, P.R., Thirlwall, M.F., and Campbell, A., 1993, Isotopic and geochemical constraints on the origin and evolution of postcollapse rhyolites in the Valles Caldera, New Mexico: J. Geophys. Res., v. 98, p. 19,723-19,739.

Spell, T.L. and McDougall, I., 1992, Revisions to the age of the Brunhes - Matuyama boundary and the Pleistocene geomagnetic polarity timescale, Geophys. Res. Lett., v. 19, p. 1181-1184.

Spell, T.L., Harrison, T.M., and Wolff, J.A., 1990, 40Ar/39Ar dating of the Bandelier Tuff and San Diego Canyon ignimbrites, Jemez Mountains, New Mexico: Temporal constraints on magmatic evolution, J. Volcanol. Geotherm. Res., v. 43, p. 175-193.

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Students

• Joseph Kula, Mesozoic Tectonic History of the Southwestern U.S. and New Zealand (preliminary title), Ph.D. dissertation, in progress.

• Katie Wooton, Petrogenesis of Recent Extracaldera Rhyolites, Yellowstone Volcanic Field, Wyoming: Implications for Future Eruptions, M.S. Thesis, in progress.

• Penny Padmore, The Canovars Canyon Rhyolite, Jemez Volcanic Field, New Mexico: Multiple Discrete Source Magmas or a Potentially Caldera-forming Magma System?, M.S. Thesis, in progress.

• Nicole Nastanski, Evolution of the Yellowstone Plateau Volcanic Field during the past 500 ka, Completed M.S. thesis, August 2005.

• Leigh Justet, Multi-phase evolution of the Jemez Volcanic Field, New Mexico: Implications for the genesis and evolution of continental silicic volcanic centers, Completed Ph.D. dissertation, December 2003.

• Joseph Kula, Thermochronology and geobarometry of the Granite Mountains, southeast California: Exhumation of a plutonic complex during collapse of the Sevier Orogeny, Completed M.S. thesis, October 2002.

• Leigh Justet, The geochronology and geochemistry of the Bearhead Rhyolite, Jemez volcanic field, New Mexico, Completed M.S. Thesis, May 1999.

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Professional Memberships

• Mineralogical Society of America
• American Geophysical Union
• Geological Society of America
• International Association of Volcanology and Chemistry of the Earth’s Interior

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