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204 Heroy Geology Laboratory Syracuse University Syracuse, NY 13244-1070 USA Office: 114 and 204 Heroy Geology Laboratory Phone: 315.443.7976 Department: 315.443.2672 Fax: 315.443.3363 Email: jakarson@syr.edu Current Research Interests
The focus of my research is structural and tectonic analysis of rift and transform plate boundaries. My approach involves the systematic collection of geological data in order to determine the geometry, chronology, and mode of formation of outcrop-scale deformation structures and their relation to crustal processes that operate on a regional scale. These studies are undertaken with the collaboration of geophysicists, petrologists, and geochemists in order to help understand the interplay of various geologic processes during deformation. Integrating the diverse perspectives available from different settings provides a cross-pollination of concepts that might not be possible from a single approach. TECTONIC WINDOWS INTO THE OCEANIC LITHOSPHERE -  Major tectonic escarpments provide “tectonic windows” into the internal structure of the oceanic crust. These exposures are mapped and sampled with submersibles such as ALVIN and various other seafloor mapping tools including deeply towed side-scan sonar systems and various remotely operated vehicles (ROV’s). The internal structure of the oceanic crust provides evidence of the interplay among magmatic, mechanical, and hydrothermal processes that occur beneath accreting plate boundaries and along transform faults. These studies have demonstrated that spreading processes at spreading centers with different plate separation rates (or magma budgets) function in very different ways and generate very different types of oceanic crust. INTERNAL STRUCTURE OF FAST-SPREAD OCEANIC CRUST –  At intermediate to fast spreading rates where the magma supply is robust, seafloor spreading generates a relatively uniform, layered crustal structure that is exposed in tectonic windows. These areas feature “inward-dipping” lava flows and “outward-dipping’ dikes and sheeted dikes over a complex assemblage of gabbroic rocks that crystallized in magma chambers. The overall structure implies that dramatic subaxial subsidence occurs beneath spreading centers and is responsible for the thickening of lava units as well as extensive faulting and rotation of upper crustal units. From this perspective, seafloor spreading resembles a continually collapsing caldera hidden beneath surficial lavas. Structures recording this type of spreading are exposed at the Pito Deep Rift, Hess Deep Rift, Blanco Transform, and ODP Holes 504B, 801C and 1256D.
EXTREME VARIATIONS IN SEAFLOOR SPREADING ON THE MID-ATLANTIC RIDGE -  At relatively low rates of plate separation and low magma supply faulting dominates over magmatic construction and major detachment faults and oceanic core complexes form in some settings like near the Kane and Atlantis Transform Faults. Crustal stretching promotes the exposure of upper mantle peridotites and serpentinization that may support low-temperature, off-axis hydrothermal vents like the Lost City Vent Field. In places where the magma supply is somewhat greater, magmatic construction is more important and only moderate crustal stretching occurs. Along the Mid-Atlantic Ridge, extreme variations in geologic structure and spreading processes occur over distances of a few tens of kilometers.
CRUSTAL SPREADING IN ICELAND –  The Mid-Atlantic Ridge spreading center rises to the surface in Iceland providing a remarkable ‘natural laboratory’ for the study of spreading-related processes. In Iceland narrow rift zones and transform faults define the active plate boundary. In the older parts of the island, glaciation has exposed crustal materials that formed at depths of 1-2 km beneath the actively spreading rift zones. Integrating observations from these 2 perspectives reveals the 3D structure of the crust from which spreading processes can be inferred. Icelandic spreading provides an excellent analog for other high-magma supply spreading environments like the East Pacific Rise.
OPHIOILTE COMPLEXES -  Studies of ophiolite complexes, ancient oceanic lithosphere exposed in mountain belts, reveal the deep structure of oceanic crust and upper mantle produced by seafloor spreading in various tectonic settings. Field structural investigations in ophiolite complexes such as the Bay of Islands Complex (Newfoundland), Bou Azzer (Morocco), and Macquarie Island (Southern Ocean) permit direct access to oceanic crustal and upper mantle rocks. Ophiolites of various ages link spreading processes from active mid-ocean ridges to the early Earth in Archean time.
EXTENSION & MAGMATISM IN RIFTS AND RIFTED MARGINS –  In the East African Rift System, detailed structural studies define the geometry and kinematics of active rifting and the birth of a rifted continental margin. Investigations of the ocean-continent transition and coastal dike swarms of the Tertiary East Greenland volcanic rifted margin in collaboration with the Danish Lithosphere Center reveal the earliest stages of seafloor spreading. Together these studies provide a view of the shallow- to deep-level processes that occur during the evolution of magmatic continental rifts.
Courses
Graduate Students
Facilities Available for Investigations of Spreading Center Tectonics
• Olympus and Zeiss Research Microscopes equipped for photomicroscopy• Geocompass- a device for use in measuring the orientation of structural features on the seafloor from Human Occupied Vehicles (e.g., Alvin) and Remotely Operated Vehicles (e.g., Jason II) • 42-inch video monitor and other displays • Macintosh computers and peripherals for image processing • Tape decks for viewing digital video tape of seafloor geology • JOEL JXA 733 Scanning Electron Microscope for imaging and ESBD analyses • 4WD Vehicle for fieldwork in Iceland • Rock saws and facilities for making petrographic thin sections • Rock drills and accessories for paleomagnetic sampling Selected Publications2002Karson, J.A., Geologic structure of the uppermost oceanic crust created at fast- to intermediate-rate spreading centers, Ann. Rev. Earth Planet. Sci., 30, 347-384, 2002. Karson, J.A., E.M. Klein, S.D. Hurst, C.E. Lee, P.A. Rivizzigno, D. Curewitz, A.R. Morris, and Hess Deep ‘99 Scientific Party, Structure of uppermost fast-spread oceanic crust exposed at the Hess Deep Rift: Implications for subaxial processes at the East Pacific Rise, Geochemistry, Geophysics, Geosystems (G-Cubed), 3, doi:10.1029/2001GC000155], 2002. Karson, J.A., M.A. Tivey, and J.R. Delaney, Internal structure of uppermost oceanic crust along the western Blanco Transform Scarp: Implications for subaxial accretion and deformation at the Juan de Fuca Ridge, J. Geophys. Res., 107(B9), 2181, doi:10.1029/2000JB000051, 2002. Lawrence, R.M., J.S. Gee, and J.A. Karson, Magnetic anisotropy of serpentinized peridotites from the MARK Area: Implications for the orientation of mesoscopic structures and major fault zones, J. Geophys. Res., 107(B4), 2073, doi:10.1029/2000JB000007, 2002 Stewart, M.A., E.M. Klein and J.A. Karson, The geochemistry of dikes and lavas from the north wall of the Hess Deep Rift: Insights into the four-dimensional character of crustal construction at fast-spreading mid-ocean ridges, J. Geophys. Res., 107, doi 10, 1029/2001JB000545, 2002. 2003 Alt, J.C., G. Davidson, D.A.H. Teagle and J.A. Karson, The isotopic composition of gypsum in the Macquarie Island Ophiolite: Implications for sulfur cycle and the subsurface biosphere in oceanic crust, Geology, 31, 549-552, 2003. Früh-Green, G.L., D.S. Kelley, S.M. Bernasconi, J.A. Karson, C. Boschi, K.A. Ludwig, D.A. Butterfield, 30,000 Years of Hydrothermal Activity at the Lost City Hydrothermal Field, Science 301, 495-498, 2003. 2004 Hurst, S.D. and J.A. Karson, Side-scan processing and interpretation along the northern wall of the Hess Deep Rift: Texture analysis and geologic ground-truth, J. Geophys. Res. 109 (B02107, doi:10.1029/2002JB002116, 2004. Rivizzigno, P.A. and J.A. Karson, Mid-ocean ridge fault zones preserved on Macquarie Island: Faulting, hydrothermal processes and magmatism in an oblique-spreading environment, Geology 32, 125-128, 2004. Varga, R.G., J.A. Karson and J.S. Gee, Paleomagnetic constraints on deformation models for oceanic crust exposed at the Hess Deep Rift: Implications for axial processes at the East Pacific Rise, J. Geophys. Res. 109 (B2102), doi:10.1029/2003JB002486, 2004. 2005 Karson, J.A., J. Francheteau, J.S. Gee, K.M. Gillis, N.W. Hayman, R. Hékinian, R.N. Hey, S.D. Hurst, E.M. Klein, D.F. Naar, R.G. Varga and Pito Deep 2005 Scientific Party, Nested-scale investigation of tectonic windows into super-fast spread crust exposed at the Pito Deep Rift, Easter Microplate, SE Pacific, InterRidge Newsletter, 14, 5-8, 2005. Kelley, D.S., J.A. Karson, G.L. Früh-Green, D.R. Yoerger, T.M. Shank, D.A. Butterfield, J.M. Hayes, M.O. Schrenk, E. Olson, G. Proskurowski, M. Jakuba, A. Bradley, B. Larson, K. Ludwig, D. Glickson, K. Buckman, A.S. Bradley, B. Brazelton, K. Roe, M.J. Eland, A. Delacour, S.M. Bernasconi, M.D. Lilley, J.A. Baross, R.E. Summons, and S.P. Sylva, Geological, biological, and hydrothermal processes at the Lost City Vent Field: A serpentinites-hosted ecosystem: The Lost City Hydrothermal Field, Science 307, 1428-1434, 2005. Pollock, M.A., E.M. Klein, J.A. Karson, and M. A. Tivey, Temporal and spatial variability in the composition of lavas exposed along the Western Blanco Transform Fault, G-cubed 6 (11), doi:10.1029/2005GC001026, 2005. Stewart, M.A., J.A. Karson and E.M. Klein, Four-dimensional upper crustal construction at fast-spreading mid-ocean ridges: A perspective from an upper crustal cross-section at the Hess Deep Rift, J. Volcanology Geothermal Res. 144, 287-309, 2005. 2006 Boschi, C., G.L Früh-Green, A.G. Delacour, D.S. Kelley, and J.A. Karson, Mass transfer and fluid flow during detachment faulting and development of an oceanic core complex, Atlantis Massif (MAR 30°N), G-cubed 7(1), doi:10.1029/2005GC001074, 2006. Karson, J.A., G.L. Früh-Green, D.S. Kelley, E.A. Williams, D.R. Yoerger, and M. Jakuba, Detachment shear zone on the Atlantis Massif Core Complex, Mid-Atlantic Ridge 30°N, G-Cubed 7 (6), doi:10.1029/2005GC001109, 2006. Sæmundsson, K. and J. A. Karson, Stratigraphy and tectonics of the Húsavík-Western Tjörnes area, Unpublished Report, prepared for Alcoa and HRV Engineering, ÍSOR-2006/-32, 35 pp and 1:20,000 Geological Map. 2007 Christeson, G.L., K.D. McIntosh and J.A. Karson, Inconsistent correlation of seismic layer 2a and lava layer thickness in oceanic crust, Nature 445, doi:10.1038/nature05517, 2007. Hayman, N.W. and J.A. Karson, Faults and damage zones in fast-spread crust exposed on the north wall of the Hess Deep Rift: Conduits and seals in seafloor hydrothermal systems, G-Cubed, 8, 10, Q10002, doi:10.1029/2007GC001623, 2007. Kelley, D.S., G.L. Früh-Green, J.A. Karson, and K.A. Ludwig, Lost City hydrothermal field revisited, Oceanography 20, 4, 90-99, 2007. Perk, N.W., L.A. Coogan, J.A. Karson, J.A., E.M. Klein, and H.D. Hanna, The primitive lower oceanic crust from Pito Deep: Implications for the accretion of the lower crust at the southern east Pacific Rise, Contributions to Mineralogy and Petrology, doi:10.1007/ s00410-007-0210-z, 2007. 2008 Heft, K., K.M. Gillis, M.A. Pollock, J.A. Karson, E.M. Klein, Constraints on the nature of axial hydrothermal systems from the sheeted dike complex exposed at Pito Deep, G- Cubed 9 (5), Q05O07, doi:10.1029/2007GC001926, 2008. Varga, R.G., A. Horst, J.S. Gee and J.A. Karson, Direct evidence from anisotropy of magnetic susceptibility for lateral melt migration a superfast spreading centers, G-Cubed 9 (8), Q08008, doi:10.1029/2008GC002075, 2008. 2009 Hayman, N.W. and J.A. Karson, Faulting and hydrothermal alteration in superfast spread crust of the East Pacific Rise exposed at Pito Deep, G-cubed 10, in press, 2009. Pollock, M.A., E.M. Klein, J.A. Karson and D.S. Coleman, Compositions of dikes and lavas from the Pito Deep Rift: Implications for accretion at superfast spreading centers, Journal of Geophysical Research, in press, 2009.
Education
B.S. (Geology) Case Institute of Technology (CWRU), 1972 M.S. (Geology) State University of New York at Albany (SUNYA), 1975 Ph.D. (Geology) State University of New York at Albany, 1977 Professional Experience Teaching Assistant, Department of Geological Sciences, SUNYA, 1972-1976 Research Assistant, Department of Geological Sciences, SUNYA, 1976-1977 Postdoctoral Fellow, University of Toronto, 1977-1979 Postdoctoral Scholar, Woods Hole Oceanographic Institution (WHOI), 1979-1980 Assistant Scientist, Department of Geology and Geophysics, WHOI, 1980-1984 Summer Faculty Fellow, Department of Geology and Planetology, Jet Propulsion Lab, California Institute of Technology, 1984 and 1985 Associate Scientist, Department of Geology and Geophysics, WHOI, 1984-1986 Associate Professor, Department of Geology, Duke University, 1986-1992 Professor, Department of Geology, Duke University, 1992-1996 Adjunct Research Scientist, Lamont-Doherty Earth Observatory, 1992-2002 Research Fellow, Danish Lithosphere Center, 1994-2000 Professor, Division of Earth & Ocean Sciences, NSEES, Duke University, 1996-2006 Chairman, Division of Earth & Ocean Sciences, NSEES, Duke University, 1996-2000 Professor, Department of Earth Sciences, Syracuse University, August 2006-present Jessie Page Heroy Professor and Chair, Department of Earth Sciences, July 2007-preseent Research Interests Structural and tectonic analysis of extensional and transform fault environments from ophiolites, contemporary oceanic crust, Iceland, continental rifts, and continental margins; fault geometry and kinematics; deformation and metamorphism in high-strain zones. Professional Affiliations Fellow of the Geological Society of America; American Geophysical Union; International Association of Structural and Tectonic Geologists; Working Group on Mediterranean Ophiolites Web Sites Department of Earth Sciences, Syracuse University: http://earthsciences.syr.edu Hess Deep Expedition: http://www.nicholas.duke.edu/hessdeep/hessdeep.html Lost City Cruise 2003: http://www.lostcity.washington.edu Lost City NOAA Exploration: http://oceanexplorer.noaa.gov/explorations/05lostcity Macquarie Island: http://www.aad.gov.au/stations/macca Pito Deep Cruise 2005: http://www.nicholas.duke.edu/pitodeep/index.html |
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