Bob Varga, Senior Scholar, Director of the Keck Geology Consortium
B.S. in Geology, University of Arizona
M.S. in Geology, University of Arizona
Ph.D. in Geology, University of California, Davis
Structural Geology, Tectonics,
Paleomagnetism, Geology of the Oceanic Crust
Office: Edmunds Building 252
Lab: (909) 607-XXXX
My current research interests are primarily directed toward understanding the architecture of extended terranes, both in the oceans and within continental rifts. Since 1984, I have been working on the structure and dynamics of magma emplacement within the Troodos ophiolite on the island of Cyprus. This work has led to the recognition of the importance of amagmatic, structural extension at mid-ocean ridges and of lateral melt migration along ridge crest axes. In the Basin & Range, I have been working on the details of extension of continental crust. My work is directed specifically at detailing the segmentation of continental rifts along their lengths. Our work in the Black Mountains has shown that the symmetry of rifts change dramatically within accommodation zones characterized by intermeshing normal faults of opposite dip direction. In both ophiolites and within the Basin & Range, I augment structural observations and geologic mapping with paleomagnetics which helps us document and quantify both the type and magnitude of structural rotations. I have also participated in cruises to “tectonic windows” into crust produced at the East Pacific Rise. At Hess Deep (1999) and at Pito Deep (2005) we were able to collect fully oriented samples of middle-upper crustal rocks. These samples are providing important constraints on not only the structural and tectonic setting at ridges and in microplates, but also on how magma moves at fast to super-fast spreading ridges. I am also working on the origin of Icelandic “flexure zones” as analogs for fast-spreading ridges. See my Paleomagnetics Web Pages for details.
Courses Taught at Pomona
- GEO123: Neotectonics
- *Horst, A.J., Varga, R.J., Gee, J.S., Karson, J.A., in press, Paleomagnetic constraints on deformation at superfast-spread oceanic crust exposed t Pito Deep Rift: Journal of Geophysical Research.
- Hickman, R.G., Varga, R.J., and Altany, R., 2009, Structural style of the Marathon thrust belt, west Texas: Journal of Structural Geology, v. 31, p. 900-909 (download PDF)
- Varga R. J., A. J. *Horst, J. S. Gee, J. A. Karson (2008), Direct evidence from anisotropy of magnetic susceptibility for lateral melt migration at superfast spreading centers, Geochemistry. Geophysics. Geosystems., 9, Q08008, doi:10.1029/2008GC002075 (download PDF)
- Varga, R.J. and Bettison-Varga, L., 2005, Reflections on writing a successful NSF-RUI proposal in the geosciences: CUR Quarterly, v. 25, n. 2, p. 67-71.
- Varga, R.J., Karson, J.A., and Gee, J.S., 2004, Paleomagnetic constraints on deformation models for uppermost oceanic crust exposed at the Hess Deep rift: Implications for axial processes at the East Pacific Rise: Journal of Geophysical Research, B020104, p.1-22. (download PDF)
- Varga, R.J., Faulds, J.E.,Snee, L.W., Harlan, S.S., and Bettison-Varga, 2004, Miocene extension and folding in an anticlinal segment of the Black Mountains accommodation zone, Colorado River extensional corridor, southwestern United States: Tectonics, v. 23, TC1019, p. 1-19. (download PDF)
- Varga, R.J., 2003, The sheeted dike complex of the Troodos ophiolite and its role in understanding mid-ocean ridge processes: in Dilek, Y., ed., Ophiolite Concept and the Evolution of Geologic Thought: Geological Society of America Special Paper 373.
- Varga, R.J., 2001, Geologic Map of the Grasshopper Junction SE Quadrangle, Mohave County, Arizona: Arizona Geological Survey Digital Geologic Map 7.
*denotes student authorship