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Contact Information

Global Undersea Research Unit
P. O. Box 475
Moss Landing, CA 95039
Phone: (831) 633-7033
Fax: (831) 633-6872
wheat@mbari.org

Geoffery Wheat Research Professor

Geological Oceanography

Affiliations

Specialties

Education

Research Overview

I use chemical tracers to understand water-rock reactions in different physical, geochemical, and biological settings, examine effects of fluid flow on diagenetic processes and develop transport- reaction models for these geochemical processes, determine mechanisms of diagenetic reactions, evaluate geochemical cycles and crustal evolution, and conceive experimental approaches to solve geochemical problems.

During the past decade much of my research effort has centered on understanding problems associated with fluid circulation through the oceanic crust; circulation caused by the intrusion of basaltic magma on mid-ocean ridges, differential lithospheric cooling on mid-ocean ridge flanks, compression along zones of subduction, and differences in head gradient on continental shelves and margins. Although these geologic settings and mechanisms for fluid flow are vastly different, in each of these settings the fluid in basement reacts with and changes the crust as it is transported, resulting in chemical, mass, and thermal fluxes to and from the oceans. By examining this range of settings one can study the continued alteration and evolution of the crust as it passes along a continuum from the ridge axis to the flanks before it is ultimately recycled.

Current Research Projects

Links

Selected Publications

Parsons, P. K. F., C. G. Wheat, A. T. Fisher, E. A. Silver, M. Underwood, and M. Hutnak. 2004. Hydrothermal Seepage of Altered Crustal Fluids Seaward of the Middle America Trench, Offshore Costa Rica. J. Geophs. Res., submitted.                               

Wheat, C.G., and J. McManus. 2004. The potential role of ridge-flank hydrothermal systems on oceanic germanium and silicon balances. Geochim. Cosmochim. Acta, in press.

Wheat, C. G., M. J. Mottl, A. J. Fisher, D. Kadko, E. E. Davis, E. Baker. 2004. Heat Flow From a Basaltic Outcrop (Baby Bare) on a Ridge Flank:  Insights to the Role of Outcrops in Guiding Hydrothermal Discharge. J. Geophys. Res., in press.

Mottl, M. J., C. G Wheat, P. Fryer, J. Gharib, and J. B. Martin. 2004. Chemistry of springs across the Mariana forearc shows progressive devolatilization of the subducting slab. Geochim. Cosmochim. Acta, in press.

Buatier, M. D., D. Guillaume, C. G. Wheat, L. Hervé, and T. Adatte. 2004. Mineralogical characterization and genesis of hydrothermal Mn oxides from the flank of the Juan the Fuca Ridge. Am. Miner., in press.

Wheat, C. G. and M. J. Mottl. 2004. Geochemical Fluxes Through Mid-Ocean Ridge Flanks. In: Hydrolgeology of the Oceanic Lithosphere, Ed. E. E. Davis and H. Elderfield, Cambridge University Press, in press.

Wheat, C.G., H.W. Jannasch, M. Kastner, J.N. Plant, E.H. DeCarlo, and G. Lebon. 2004. Venting Formation Fluids from Deep Sea Boreholes in a Ridge Flank Setting: ODP Sites 1025 and 1026. Geochem. Geophys. Geosyst., 5 (8), Q08007, doi:10.1029/2004GC000710.

Jannasch H. W., C. G. Wheat, J. Plant, M. Kastner, and D. Stakes. 2004. Continuous chemical monitoring with osmotically pumped water samplers: OsmoSampler design and applications. Limnol. Oceanogr.: Methods, 2, 102-113.

Spinelli, G., L. Zuhlsdorff, A. T. Fisher, C. G. Wheat, M. Mottl, V. Spiez, and E. R. Giambalvo. 2004. Hydrothermal seepage patterns above a buried basement ridge, eastern flank of the Juan de Fuca Ridge. J. Geophys. Res., 109 (B1), B01102 , doi: 10.1029/2003JB002476.

Jannasch, H. W., E. E. Davis, M. Kastner, J. D. Morris, T. L. Pettigrew, J. N. Plant, E. A. Solomon, H. W. Villinger, C. G. Wheat. 2003. CORK II: Long-Term monitoring of fluid chemistry, fluxes, and hydrology in instrumented boreholes at the Costa Rica subduction zone. In Morris, J.D., H. W. Villinger, A. Klaus, et al., Proc. ODP, Init. Repts, 205, 1-36 [CD-ROM],  College Station, TX (Ocean Drilling Program).

Wheat, C.G., H.W. Jannasch, M. Kastner, J.N. Plant, and E.H. DeCarlo. 2003. Seawater Transport and reaction in upper oceanic basaltic basement: Chemical data from continuous monitoring of sealed boreholes in a mid-ocean ridge flank environment. Earth Planet. Sci. Lett., 216, 549-564, 2003.

Wheat, C.G., J. McManus, M.J. Mottl, and E. Giambalvo. 2003. Oceanic Phosphorus Imbalance: The Magnitude of the Ridge-Flank Hydrothermal Sink. Geophys. Res. Lett., 30(17), 1895, doi: 10.1029/2003GL017318, 2003.

Davis, A.S., D. A. Clague, R. A. Zierenberg, C. G. Wheat, and B.L. Cousens. 2003. Sulfide formation related to changes in the hydrothermal system on Loihi Seamount, Hawaii, following the seismic event in 1996. Canadian Mineralogist, 41: 457-472.

Fisher, A. T., E. E. Davis, M. Hutnak, V. Spiess, L. Zuhlsdorff, A. Cherkaoui, L. Christiansen, K. Edwards, B. Macdonald, H. Villinger, M. J. Mottl, C. G. Wheat, and K. Becker. 2003. Hydrothermal recharge and discharge across 50 km guided by seamounts on a young ridge flank. Nature, 421: 618-621.

McManus, J., T. F. Nägler, C. Siebert, C. G. Wheat, and D. Hammond. 2002. Oceanic molybdenum isotope fractionation: Diagenesis and hydrothermal ridge-flank alteration. Geochem. Geophys. Geosyst., 3(12), 1078, doi:10.1029/2002GC000356, 2002.

Spinelli, G., A. T. Fisher, C. G. Wheat, M. D. Tryon, K. M. Brown, and A. R. Flegal. 2002. Groundwater seepage into northern San Francisco Bay: Implications for dissolved metals budgets. Water Resources Res., 38(7), 10.1029/2001WR000827, 17 July 2002.

Wheat, C. G., M. J. Mottl, and M. Rudniki. 2002. Trace Element and REE Composition of a Low-Temperature Ridge Flank Hydrothermal Spring. Geochim. Cosmochim. Acta, 66: 3693 ]3705.

Fisher, A. T., H. Villinger, R. N. Harris, R. P., Von Herzen, M. Pfender, M. Müller, I., Grevemeyer,  N. Kaul, and C. G. Wheat. 2002. Comments on ADeep-penetration Heat Flow Probes Raise Questions about Interpretations from short Probes, by Géli et al, EOS Trans., Am. Geophys. Union, 82 (29), 317,320, 2001", EOS Trans., Am. Geophys. Union, 83: 196.

Giambalvo, E. C. I. Steefel, A. T. Fisher, N. D. Rosenberg, C. G. Wheat. 2002. Effects of fluid-sediment reaction on hydrothermal fluxes of major elements, eastern flank of the Juan de Fuca Ridge. Geochim. Cosmochim. Acta, 66: 1739-1757.

Butterfield, D. A., B. K. Nelson, C. G. Wheat, M. J. Mottl, and K. K. Roe. 2001. Evidence for basaltic Sr in midocean ridge-flank hydrothermal systems and implications for the global oceanic Sr isotope balance. Geochim. Cosmochim. Acta, 65: 4141-4153.

Monnin C., C. G. Wheat, B. Dupre, H. Elderfield,, and M. Mottl. 2001. Barite stability in marine sediments: Implication for the flux of hydrothermal barium from ridge flanks settings. Geochem. Geophys. Geosyst., 2, paper number 2000GC000073, 15 pages.

Wheat, C. G., H. W. Jannasch, J. N. Plant, C. L. Moyer, F. J. Sansone, and G. M. McMurtry. 2000. Continuous sampling of hydrothermal fluids from Loihi Seamount after the 1996 event. J. Geophys. Res., 105: 19353-19368.

Becker, N. C., C. G. Wheat, M. J. Mottl, J. L. Karsten, and E. E. Davis. 2000. A geological and geophysical investigation of Baby Bare, locus of a ridge-flank hydrothermal system in the Cascadia Basin. J. Geophys. Res., 105: 23557-23568.

Wheat, C. G., H. Elderfield, M. J. Mottl, and C. Monnin. 2000. Chemical composition of basement fluids within an oceanic ridge flank: Implications for along-strike and across-strike hydrothermal circulation. J. Geophys. Res., 105: 13437-13447.

Wheat, C. G., and M. J. Mottl. 2000. Composition of pore and spring waters from Baby Bare: Global implications of geochemical fluxes from a ridge flank hydrothermal system. Geochim. Cosmochim. Acta, 64: 629-642.

Mottl, M. J., C. G. Wheat, C. Monnin, and H. Elderfield. 2000. Data report: Trace elements and isotopes in pore water from ODP Sites 1023 through 1032, eastern flank of the Juan de Fuca Ridge. Proc. ODP, Sci. Results, 168: 105-115.

Elderfield, H, C. G. Wheat, M. J. Mottl, C. Monnin, B. Spiro. 1999. Fluid and geochemical transport through oceanic crust: A transect across the eastern flank of the Juan de Fuca Ridge. Earth Planet. Sci. Lett., 172: 151-169.

Fryer, P., C. G. Wheat, and M. J. Mottl. 1999. Mariana Blueschist Mud Volcanism: Implications for conditions within the subduction zone. Geology, 27: 103 ]106.

Sansone, F. J., M. J. Mottl, E. J. Olson, C. G. Wheat, and M. D. Lilley. 1998. CO2-depleted fluids from mid-ocean ridge-flank hydrothermal springs. Geochim. Cosmochim. Acta, 62: 2247-2252.

Wheat, C. G., J. McManus, J. Dymond, R. Collier, and M. Whiticar. 1998. Hydrothermal fluid circulation through the sediment of Crater Lake, Oregon: Pore water and heat flow constraints. J. Geophys. Res., 103: 9931-9944.

Mottl, M. J., C. G. Wheat, E. Baker, N. Becker, E. Davis, R. Feely, A. Grehan, D. Kadko, M. Lilley, G. Massoth, C. Moyer, and F. Sansone. 1998. Warm springs discovered on 3.5 Ma-old oceanic crust, eastern flank of the Juan de Fuca Ridge. Geology, 26: 51-54.

Karsten, J. L., N. Becker, M. J. Mottl, and C. G. Wheat. 1998. Petrology of Baby Bare and Mama Bare lavas. Geophys. Res. Lett., 25: 117-120.

Wheat, C. G., M. J. Mottl, E. T. Baker, R. A. Feely, J. E. Lupton, F. J. Sansone, J. A. Resing, G. T. Lebon, and N.C. Becker. 1997. Chemical anomalies in the water column from low-temperature hydrothermal venting on the eastern flank of the Juan de Fuca Ridge. J. Geophys. Res., 102: 15433-15446.

The 1996 Loihi Science Team. 1997. Researchers rapidly respond to submarine activity at Loihi Volcano, Hawaii. EOS, 78: 229-233.

Davis, E.E., A. T. Fisher, J. V. Firth, and the ODP Leg 168 Scientific Party. 1997. Drilling program traces fluid circulation through Juan de Fuca Ridge crust. EOS, 78: 187-189.

Wheat, C. G., R. A. Feely, and M. J. Mottl. 1996. Phosphate removal by oceanic hydrothermal processes:  An update of the phosphate budget of the oceans. Geochim. Cosmochim. Acta, 60: 3593-3608.

McManus, J., R. Collier, J. Dymond, C. G. Wheat, and G. Larson. 1996. Using the deep lake oxygen budget in Crater Lake, Oregon to constrain mixing, carbon flux, and hydrothermal inputs.  Limnol. Oceanogr., 41: 722-731.


Mottl, M. J., F. J. Sansone, C. G. Wheat, J. A. Resing, E. T. Baker, and J. E. Lupton. 1995. Manganese and methane in hydrothermal plumes along the East Pacific Rise, 8E40' to 11E50'N. Geochim. Cosmochim. Acta, 59: 4147-4165.

Wheat, C. G. and R. E. McDuff. 1995. Mapping the fluid flow of the Mariana Mounds off-axis hydrothermal system: Pore water chemical tracers.  J. Geophys. Res., 100: 8115-8131.

Baker, E. T., R. A. Feely, M. J. Mottl, F. J. Sansone, C. G. Wheat, J. A. Resing, and J. E. Lupton. 1994. Hydrothermal plumes along the East Pacific Rise, 8E40' to 11E50'N:  Plume distribution and relationship to the apparent magmatic budget.  Earth Planet. Sci. Lett., 128: 1-17.

Wheat, C. G. and J. Tribble. 1994. Diagenesis of amorphous silica in Middle Valley, Juan de Fuca Ridge.  In: Mottl, M. J., Dais, E. E., Fisher, A. T., and Slack, J. F. (Eds.), Proc. ODP, Sci. Results, 139: College Station, TX (Ocean Drilling Program), 341-349.

Wheat, C. G., J. Boulegue, and M. J. Mottl. 1994. A technique for obtaining pore water chemical composition from indurated and hydrothermally altered sediment and basalt: The Ground Rock Interstitial Normative Determination (GRIND).  In: Mottl, M. J., Dais, E. E., Fisher, A. T., and Slack, J. F. (Eds.), Proc. ODP, Sci. Results, 139: College Station, TX (Ocean Drilling Program), 429-437.

Butterfield, D.A., R. E. McDuff, J. M. Franklin, and C. G. Wheat. 1994. Geochemistry of hydrothermal vent fluids from Middle Valley, Juan de Fuca Ridge.  In: Mottl, M. J., Dais, E. E., Fisher, A. T., and Slack, J. F. (Eds.), Proc. ODP, Sci. Results, 139: College Station, TX (Ocean Drilling Program), 395-410.

Mottl, M. J., C. G. Wheat, and J. Boulegue. 1994. Timing of ore deposition and sill intrusion at Site 856:  Evidence from stratigraphy, alteration, and sediment pore-water composition.  In: Mottl, M. J., Dais, E. E., Fisher, A. T., and Slack, J. F. (Eds.), Proc. ODP, Sci. Results, 139: College Station, TX (Ocean Drilling Program), 679-693.

Wheat, C. G. and M. J. Mottl. 1994. Data Report:  Trace metal composition of pore water from Sites 855 through 858, Middle Valley, Juan de Fuca Ridge.  In: Mottl, M. J., Dais, E. E., Fisher, A. T., and Slack, J. F. (Eds.), Proc. ODP, Sci. Results, 139: College Station, TX (Ocean Drilling Program), 749-755.

Wheat, C. G. and R. E. McDuff. 1994. Hydrothermal flow through the Mariana Mounds:  Dissolution of amorphous silica and degradation of organic matter on a mid-ocean ridge flank. Geochim. Cosmochim. Acta, 58: 2461-2475.

Mottl, M. J. and C. G. Wheat. 1994. Hydrothermal circulation through mid-ocean ridge flanks:  Fluxes of heat and magnesium. Geochim. Cosmochim. Acta, 58: 2225-2237.

Wheat, C. G. and M. J. Mottl. 1994. Hydrothermal circulation, Juan de Fuca Ridge eastern flank: Factors controlling basement water composition. J. Geophys. Res., 99: 3067-3080.

Lupton, J. E., E. T. Baker, M. J. Mottl, F. J. Sansone, C. G. Wheat, J. A. Resing, G.  J. Massoth, C. I. Measures, and R. A. Feely. 1993. Chemical and physical diversity of hydrothermal plumes along the East Pacific Rise, 8E45'N to 11E50'N. Geophys. Res. Lett., 20: 2913-2916.

Davis, E. E., D. S. Chapman, M. J. Mottl, W. J. Bentkowski, K. Dadey, C. Forster, R. Harris, S. Nagihara, K. Rohr, C. G. Wheat, and M. Whiticar. 1992. FlankFlux:  An experiment to study the nature of hydrothermal circulation in young sea floor. Can. J. Earth Sci., 29: 925-952.

Wheat, C. G. 1990. Fluid circulation and diagenesis in an off-axis hydrothermal system:  The Mariana Mounds.  Ph. D. Dissertation, University of Washington, Seattle, WA. pp. 204.

Wheat, C. G. and R. Carpenter. 1988. MnCl- and MnSO40 association constants to 170EC. J. Solution Chem., 17: 467-480.

Loder, T.C., J. A. Love, J. Kim, and C. G. Wheat. 1983. Nutrient and hydrographic data for the Great Bay Estuarine System, New Hampshire-Maine, Part II, January, 1976-June 1978. University of New Hampshire Marine Program Report UNH-MP-D/TR-SG-83-4. 149 pp.