Robert C. Thunell

Senior Associate Dean for Natural Sciences
Carolina Distinguished Professor
Department of Earth and Ocean Sciences
Paleoceanography, Paleoclimatology, Deep Sea Sediments

A.B., 1973 Brown University;
M.S., 1975, Ph. D., 1978, University of Rhode Island;
Postdoctoral Fellow, 1978-1979, Woods Hole Oceanographic Institution
 

Research Areas: Reconstructing paleoceanographic and paleoclimatic conditions using deep sea sediments; measuring the production and flux of sediments in the ocean; calibration of paleoclimate proxies.  For laboratory facilities see Marine Sediments Research Lab

Paleoceanographic/ Paleoclimatic Reconstructions: The marine sedimentary record contains perhaps the best long-term archive of global climate change. Using a variety of analytical techniques, including micropaleontology, sediment geochemistry and stable isotope geochemistry, we are trying to reconstruct the paleoceanographic and paleoclimatic conditions that existed in various regions during the Neogene. Our current emphasis is on high resolution (decadal to century-scale) studies of late Pleistocene climate. This type of research is currently being carried out in the Gulf of California, offshore California, the southern Caribbean, the western North Atlantic, and the Indonesian region.

Sediment Production and Fluxes: Through the use of moored sediment traps, we are studying temporal variability in the production and flux of sediments in the ocean. In particular, we are studying seasonal to interannual changes in sediment flux in response to climate forcing and changing upper ocean conditions. Current sediment trapping studies in Santa Barbara Basin and the Gulf of California are designed to study the impact of ENSO on sedimentation in these regions. A third trapping program in Cariaco Basin is examining carbon fluxes in a coastal upwelling regime. Additionally, in all three of these regions sediment laminae are preserved on the sea floor due to anoxic bottom conditions and our sediment trap work is allowing us to model varve formation in these basins.

Climate Proxy Development and Calibration: Reconstructing the history of the oceans is dependent on our ability to reliably extract from the sediment record information on physical, chemical and biological processes. Our sediment trapping work is contributing to the development and calibration of various climate proxies. For example, we are studying the oxygen isotopic composition of multiple species of planktonic foraminifera in order to use this as a tool for reconstructing upper ocean thermal structure in the past.

Recent Publications:

Thunell, R., Benitez-Nelson, C., Muller-Karger, F., Lorenzoni, L.,, Fanning, K., Scranton, M., Varela, R. and Astor, Y., 2008. Si cycle in the Cariaco Basin, Venezuela: Seasonal variability in silicate availability and the Si:C:N composition of sinking particles, Global Biogeochemical Cycles, vol. 22, doi:10.1029/2007GB003096.

Goni, M., Aceves, H., Benitez-Nelson, B., Tappa, E., Thunell, R., Black, D., Muller-Karger, F. and Astor, Y., 2009. Oceanographic and climatologic controls on the compositions and fluxes of biogenic materials in the water column and sediments of the Cariaco Basin over the late Holocene, Deep-Sea Research 56, 614-640.

Romero, O., Thunell, R., Astor, Y. and Varela, R., 2009. Seasonal and interannual dynamics in diatom production in the Cariaco Basin, Venezuela, Deep-Sea Research 56, 571-581.
McConnell, M., Thunell, R., Lorenzoni, L., Astor, Y., Wright, J. and Fairbanks, R., 2009. Seasonal variability in the salinity and oxygen isotopic composition of seawater from the Cariaco Basin, Venezuela: Implications for paleosalinity reconstructions, Geochemistry, Geophysics, Geosystems 10, doi:10.1029/2008GC002035

Lorenzoni, L., Thunell, R., Benitez-Nelson, C., Hollander, D., and others. 2009. The importance of subsurface nepheloid layers in transport and delivery of sediments to the eastern Cariaco Basin, Venezuela, Deep-Sea Research 56, 2249-2262.

Saikku, R., Stott, L. and Thunell, R., 2009. A bipolar signal recorded in the western tropical Pacific: Northern and Southern Hemisphere climate records from the Pacific Warm Pool during the last ice age, Quaternary Science Reviews 28, 2374-2385.

Martinez, N., Murray, R., Thunell, R., Peterson, L., Muller-Karger, F., Lorenzoni, L., Astor, Y., and Varela, R., 2010. Local and regional chemical signatures of surface sediments of the Cariaco Basin and Orinoco Delta, Venezuela, Geology. 38, 159-162.

Wejnert, K., Pride, C., and Thunell, R., 2010. The oxygen isotope composition of planktonic foraminifera from Guaymas Basin, Gulf of California: Seasonal, annual and interspecies variability, Marine Microplaeontology 74, 29-37.

Poli, S., Meyers, P. and Thunell, R., 2010. The western North Atlantic record of MIS 13 to 10: Changes in primary productivity, organic carbon accumulation and benthic foraminiferal assemblages in sediments from the Blake Outer Ridge, Palaeogeography, Palaeoclimatology, Palaeoecology 295, 89-101.

Cronin, T., Hayo, K., Thunell, R., Dwyer, G., Saenger, C. and Willard, D., 2010. The Medieval climate anomaly and Little Ice Age in Chesapeake Bay and the North Atlantic Ocean, Palaeogeography, Palaeoclimatology, Palaeoecology 297, 299-310.

Newton, A., Thunell, R. and Stott, L., 2011. Changes in the Indonesian Throughflow during the past 2000 years, Geology 39, 63-66.

Bob Thunell
Dept. of Earth and Ocean Sciences
700 Sumter Street
Univ. of South Carolina
Columbia, SC 29208

Phone: 803 777-7593
FAX: 803 777-4525
Internet: thunell@geol.sc.edu