Tectonics and Geodynamics at UNM

Overview

The Tectonics and Geodynamics group merges a variety of disciplines to address questions about the structure and evolution of continental lithosphere, and the processes that operate to form and deform it. Principal faculty include John Geissman (paleomagnetism and regional tectonics), Karl Karlstrom (structural geology), Jane Selverstone (metamorphic petrology), and Mousumi Roy (geodynamics and geophysics). The program involves a strong field emphasis that makes use of the spectacular field laboratories such as the Rocky Mountain/Colorado Plateau region, the Basin and Range province, the San Andreas fault, the Alps, and the Tibetan Plateau (see field photos!). We emphasize the interaction of deformational and metamorphic processes at all scales, structural studies of lithospheric evolution, and geodynamic modeling of brittle faulting and ductile deformation and their interactions.

The Tectonics and Geodynamics group is involved in several inter-disciplinary collaborative projects that involve our faculty and those within other groups at UNM and other institutions. In addition, faculty and students in the tectonics group interact closely with other programs and labs at UNM such as:

• surface processes for neotectonic studies (McFadden, Meyer)
  
• the UNM Geochemistry group (Asmerom, Crossey, Sharp)
  
• the UNM Sedimentology and Stratigraphy Group (Elrick, Smith)
  
• the SEM and TEM laboratories for deformation mechanism studies
  
• the radiogenic isotope laboratory for geochronology
  
• the stable isotope lab and fluid inclusion lab for studies of fluids
  
• XRF and XRD laboratories for geochemical studies
  
• the UNM Microprobe Lab for P-T path studies
  
• and the New Mexico Tech geochronology lab for Ar/Ar and fission-track thermochronology.

Our facilities also include a microscopy lab, a GIS spatial analysis facility, a total station, and a tectonic modeling lab with digital image analysis and UNIX computing capabilities (our UNIX facility is undergoing major expansion and upgrades – watch for details!).

Courses are offered in advanced structural geology, advanced metamorphic geology, paleomagnetism, geodynamics, and geophysics,as well as a variety of topical tectonics seminars (see Current Course Offerings and Schedule for recent courses).

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Faculty Research Interests

John Geissman      (Go to Research Web Page)

Applications of paleomagnetism to geologic problems, particularly in orogenic belts (e.g.,Western Cordillera of North America, eastern Himalayan syntaxis); geomagnetic field behavior; relations between rock magnetic properties and igneous and sedimentary processes; the great “battle” – science vs. creationism.

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Karl Karlstrom (Go to Research Web Page)

My main interests are in structural geology and tectonics. My students and I use the excellent field laboratories in the southwestern U.S. for a variety of field and analytical studies of deformed rocks. Recent research projects include:

• assembly and growth of Proterozoic lithosphere in the Southwest;
• interaction of deformation, metamorphism, and plutonism during middle crustal flow;
• Meso- and Neoproterozoic intracontinental deformation and sedimentation in the Grand Canyon;
• reactivation of Proterozoic structures during Ancestral Rockies and Laramide tectonism; and
• a model for the juxtaposition of the Southwestern U.S with Australia in the Proterozoic.

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Mousumi Roy (Go to Research Web Page)

I am interested in geodynamic modeling of tectonic processes in the lithosphere, for example the growth and evolution of the Colorado Plateau; rheology and deformation of continental crust; evolution and mechanics of brittle fault systems, e.g. the San Andreas fault system; fault friction and earthquakes; joint-modeling of gravity and seismic tomography data; geodesy; interactions between tectonic deformation and erosional processes in high mountains, e.g. the Alps. Recent research projects include:

• the geomorphic and geodynamic expression of orogen-parallel extension in the Alps,
• crust and mantle structure at the Transverse Ranges, CA and in the Los Angeles Basin,
• topographic evolution of the Colorado Plateau and the Rio Grande Rift.

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Jane Selverstone (Go to Research Web Page)

Metamorphic petrology, with emphasis on interactions between tectonic and petrologic processes. Reconstruction of pressure – temperature – time – deformation histories of young and old orogenic belts. Fluid inclusions as indicators of conditions of faulting. Current projects focus on shear zone evolution in the Alps, kinematic and P-T history of Proterozoic tectonism in Colorado, and interrelationships between deep-seated crustal processes and landscape development in the Alps. 

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Graduate Students (and main Advisor)

Jaime Barnes (MS, Selverstone) – Starting Fall 2000, probably will work on Alpine shear zones

Aaron Cavosie (MS, Selverstone) – Proterozoic shear zones and ophiolites in Colorado Front Range

Micah Jessup (Karlstrom) – Black Canyon of Gunnison, Co. – middle crustal processes

Annie McCoy (MS, Karlstrom) – Colorado Mineral Belt, shear zone reactivation, gravity models (with Roy)

Mark Quigley (MS, Karlstrom) – Virgin anticline of Nv/Az – Proterozoic ancestry at W. edge of the Col. Plateau

Colin Shaw (PhD., Karlstrom) – Proterozoic lithosphere evolution, Colorado

Kurt Steffen (MS, Selverstone) – Interactions of deformation and metamorphism in Alpine shear zones

Mike Timmons (Ph.D, Karlstrom) – Late Precambrian extension in the S.W. US, 1.1 Ga and 0.8 Ga

Amanda Tyson (Karlstrom) – Park Range, Co: ultramafics, mélanges, Paleoproterozoic accretion, reactivation

Undergraduate Students (and main Advisor)

Eb Crawford (Karlstrom)

Eileen Embid (Selverstone) – petrology of ophiolitic mélange, Colorado Front Range

Nancy Natek (Roy) – gravity models of the Los Angeles Basin and Transverse Ranges

Diana Strickland (Karlstrom and Selverstone) – Proterozoic evolution of the Zuni Mountains, New Mexico

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Collaborative Research Projects 

• Continental Dynamics of the Rocky Mountains (CDROM) - Karlstrom, Roy, and 15 investigators at other universities
  
• Geomorphic and Geodynamic Response to Extension in Convergent Orogens - Selverstone, Roy, and Frank Pazzaglia (Lehigh)
  
• Late Proterozoic Evolution of the Grand Canyon - Karlstrom, Crossey, Elrick, Geissman, with Sam Bowring (MIT) and Andrew Knoll (Harvard)
  
• Topographic evolution of the Rio Grande Rift and the eastern Colorado Plateau – Roy, Karlstrom, with Martha House (Caltech), Shari Kelley (New Mexico Tech), Frank Pazzaglia (Lehigh)
  
• Interactions between deformation and metamorphism: controls on shear zone rheology and metamorphic memory – Selverstone and Adrian Brearley (UNM)

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Other Links

• Colorado Mineral Belt Shear Zone
  

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Field Photos

(L to R) Mousumi, Kurt, Frank, and Jane in the Alps! 

Irreverent grad students Steve and Aaron

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