Introduction
My research interests span many orders of magnitude from crustal-scale tectonic processes to micron-scale textural and petrologic problems. Much of my work focuses on understanding the relationships and feedbacks among deformation, metamorphic, and magmatic processes, and the consequent implications for crustal structure and tectonic evolution of continents. This requires collaboration with other workers and a general research approach that is integrated across multiple disciplines. Therefore, much of my research involves the integration of tools from structural geology, petrology of sedimentary, igneous and metamorphic rocks, and geochronology.
My current and past research includes general contributions to 1) understanding deep crustal processes through the study of exposed high-pressure granulite terranes and lower crustal xenoliths, 2) metamorphic & structural fabric controls on rheology & crustal seismic anisotropy, and 3) accessory phase petrogenesis & in situ geochronological techniques. This work reflects studies from a variety of crustal levels and tectonic settings including the 1) deep levels (1.0-1.5 GPa) of a reactivated Archean craton in the western Canadian Shield with comparative implications for modern Himalayan tectonics, 2) the middle crust (~0.3-0.7 GPa) of a Proterozoic accretionary orogenic belt in southern Wyoming and in the Upper and Lower Granite Gorges of the Grand Canyon (Arizona), and 3) upper crustal exposures in the Sierra Nevada arc and Basin & Range provinces of California and Nevada as well as the Adelaide Rift Complex in South Australia.
Current Research Projects
Lower crustal properties & processes; xenoliths from
western and central U.S.
High-pressure granulites & deep crustal processes, Canadian Shield& Wyoming craton
Metamorphism and crustal juxtaposition in the Lower Granite Gorge, Grand Canyon, AZ
Paragenesis and in situ dating of authigenic monazite and xenotime
Dept. of Geological Sciences
University of Colorado-Boulder
Campus Box 399
2200 Colorado Ave.
Email: mahank@colorado.edu
Phone: 303-492-2755
Recently funded research grants
SGER: Integrated petrophysical and seismological investigation of crustal fabric and seismic anisotropy of a major crustal suture zone, the Cheyenne Belt, Wyoming (See CBprojectsummary.pdf), ~9/07-9/09, NSF-Geophysics, EAR 0750035, Co-PI’s: A. Sheehan & V. Schulte-Pelkum.
Collaborative Research: Thermal Evolution of North American Lower Crust: U-Pb Thermochronological Constraints on the Physical Properties of the Continental Lithosphere, 1/08-1/10, NSF-Earthscope, Co-PI with Sam Bowring.
Recent Publications (highlight title for link)
Mahan, K.H., Goncalves, P., Flowers, R.M., Williams, M.L., and Hoffman-Setka, D., In Review, The role of heterogeneous strain in development and preservation of a polymetamorphic record in high-pressure granulites, Journal of Metamorphic Geology.
Flowers, R.M., Bowring, S.A., Mahan, K.H., Williams, M.L., In Press, Craton stabilization and disruption from the lower crustal record in the western Canadian shield, Contributions to Mineralogy and Petrology.
Williams, M.L., Karlstrom, K.E., Dumond, G., Mahan, K.H., In Press, Perspectives on the architecture of continental crust from integrated field studies of exposed isobaric sections, GSA special publication on Crustal Sections.
Dumond, G., Mahan, K.H., Williams, M.L., and Karlstrom, K., 2007, Metamorphism in middle continental crust, Upper Granite Gorge, Grand Canyon, Arizona: implications for segmented crustal architecture, processes
at 25-km-deep levels, and unroofing of orogens, Geological Society of America Bulletin, v. 119; no. 1-2; p. 202-220; DOI: 10.1130/B25903.1.
Mahan, K.H., 2006, Retrograde mica in deep crustal granulites: implications for crustal seismic anisotropy, Geophysical Research Letters, v. 33, L24301, doi:10.1029/2006GL028130.
Mahan, K.H., Goncalves, P., Williams, M.L., and Jercinovic, M.J., 2006, Dating metamorphic reactions and fluid flow: application to exhumation of high-P granulites in a crustal-scale shear zone, western Canadian Shield, Journal of Metamorphic Geology, v. 24, p. 193-217, doi:10.1111/j.1525-1314.2006.00633.x.
Mahan, K.H., Williams, M.L., Flowers, R.M., Jercinovic, M.J., Baldwin, J.A., Bowring, S.A., 2006, Geochronological constraints on the Legs Lake shear zone with implications for regional exhumation of lower crust, Western Churchill Province, Canadian Shield, Contributions to Mineralogy and Petrology. v. 152, p. 223-242, doi:10.1007/s00410-006-0106-3
Flowers, R.M., Mahan, K.H., Bowring, S.A., Williams, M.L., Pringle, M.S., Hodges, K.V., 2006, Multistage exhumation and juxtaposition of lower continental crust in the western Canadian Shield: Linking high-resolution U-Pb and 40Ar/39Ar thermochronology with P-T-D paths, Tectonics, v. 25, TC4003, doi:10.1029/2005TC001912.
Williams, M.L., Jercinovic, M.J., Goncalves, P., and Mahan, K.H., 2006, Format and Philosophy for Collecting, Compiling, and Reporting Microprobe Monazite Ages, Chemical Geology, v. 225, p. 1-15.
Baldwin, J.A., Bowring, S.A., Williams, M.L., and Mahan, K.H., 2006, Geochronological constraints on the crustal evolution of felsic high-pressure granulites, Snowbird tectonic zone, Canada, Lithos, v. 88, p. 173-200, doi: 10.1016/j.lithos.2005.08.009.
Mahan, K.H. and Williams, M.L., 2005, Reconstruction of a large deep-crustal exposure: Implications for the nature of the Snowbird Tectonic Zone and early growth of Laurentia, Geology, v. 33, p. 385-388, DOI:10.1130/G21273.1.
Mahan, K.H., Williams, M.L., and Baldwin, J.A., 2003, Contractional uplift of deep crustal rocks along the Legs Lake shear zone, western Churchill Province, Canadian Shield. Canadian Journal of Earth Sciences, v. 40, p. 1085-1110, doi: 10.1139/E03-039.
Mahan, K.H., Bartley, J.M., Coleman, D.S., Glazner, A.F., Carl, B.S., 2003, Sheeted intrusion of the synkinematic McDoogle pluton, Sierra Nevada, California, Geological Society of America Bulletin, v. 115, p. 1570-1582, DOI: 10.1130/B22083.1.
Mahan, K.H., Williams, M.L., Baldwin, J.A., and Bowring, S.A., 2001, Juxtaposition of deep crustal and middle crustal rocks across the Legs Lake shear zone in northern Saskatchewan. In Summary of Investigations, Vol. 2. Saskatchewan Geological Survey, Saskatchewan Energy Mines, 2001-4.2.
Recent Abstracts
Hetherington, C.J., Williams, M.L., Jercinovic, M.J., Mahan, K.H., 2007, The mineralogy and petrology of xenotime: A bridge between monazite and zircon. Workshop: “Accessory minerals in-situ: microanalytical methods and petrological applications”, Kraków, Poland, 15-16th September.
Davis, J.L., Hill, E., Wernicke, B.P., Mahan, K.H. and Bisnath, S., 2007, Postseismic deformation near Yucca Mt., Nevada, 2007 AGU Joint Assembly, Acapulco, Mexico, May 22-25.
Mahan, K.H., Guest, B., Wernicke, B., Niemi, N., 2006, New structural and low-temperature AHe thermochronological data from the southeastern Stateline Fault Zone, California and Nevada, Fall AGU meeting, San Francisco, CA.
Mahan, K.H., 2006, Retrograde mica in deep crustal granulites: implications for crustal seismic anisotropy, Gordon Research Conference on Rock Deformation, Big Sky, Montana.
Mahan, K.H., Goncalves, P., Flowers, R.M., Williams, M.L., 2006. Polymetamorphic High-Pressure Mafic Granulites and Lower Crustal Processes in the Snowbird Tectonic Zone, Western Canadian Shield. Granulites and Granulites conference, Brasilia, Brazil.
Flowers, R.M., Bowring, S.A., Williams, M.L., Mahan, K.H., 2006, Temporal constraints on the evolution of HP granulites: Metamorphism and multistage exhumation of lower continental crust in the western Canadian Shield. Granulites and Granulites conference, Brasilia, Brazil.
Dumond, G., Goncalves, P. Mahan, K.H., Williams, M.L., Jercinovic, M.J., Bowring, S.A., 2006, “White Gneiss” of the Snowbird Tectonic Zone, Western Canadian Shield: Neoarchean UHT-HP Melting in Lowermost Continental Crust, Granulites and Granulites conference, Brasilia, Brazil.
Bartley, J., Glazner, A., Mahan, K.H., 2006, Pluton emplacement processes inferred from geologic mapping of the Split Mountain roof pendant, Sierra Nevada Batholith. Geological Society of America (GSA) Annual meeting, Philadelphia, PA.
Williams, M.L., Jercinovic, M.J., Dumond, G., Mahan, K.H., Hetherington, C.J., 2006, Microprobe monazite analysis: Integrating composition, texture, and chronology to characterize host-rock tectonics. Geological Society of America (GSA) Annual meeting, Philadelphia, PA.
Williams, M.L., Dumond, G., Goncalves, P., Mahan, K.H., Flowers, R.M., Bowring, S.A., 2006, Melting and flow of lowermost continental crust, East Lake Athabasca area, Saskatchewan. Geological Society of America (GSA) Annual meeting, Philadelphia, PA.
Dumond, G., Goncalves, P., Mahan, K.H., McLean, N., Williams, M.L., Bowring, S.A., 2006, Minerals,
mountains, and eleven orders of magnitude of intra-continental deformation: monazite in the context of metamorphic and igneous tectonites. Geological Society of America (GSA) Annual meeting, Philadelphia, PA.
Kevin H. Mahan
Research Faculty, CU-Boulder
PhD Geosciences 2005
University of Massachusetts-Amherst
General research Interests:
structural geology, metamorphic petrology, tectonics
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