Teh Lung Ku




                                                      Professor of Earth Sciences
                                        Wilford and Daris Zinsmeyer Chair in Marine Studies

                                                    National Taiwan University, B.Sc., 1959
                                                      Columbia University, Ph.D., 1966

                              Postdoctoral, Lamont-Doherty Earth Observatory, 1966-67

                              Assistant Scientist, Chemistry Department, Woods Hole Oceanographic Institution,

                              Associate Professor of Geological Sciences, University of Southern California, 1969-75

                              Professor of Earth Sciences, University of Southern California, 1975-present

                              Visiting Scholar, Centre des Faibles Radioactivites, France, 1975-76, 1984

                              Visiting Professor, Harwell Laboratory, United Kingdom, 1983

                              Visiting Professor, Institute of Geology (1980), Institute of Geochemistry (1984), Institute of
                              Salt Lakes (1987), Chinese Academy of Sciences, People's Republic of China

                              Visiting Professor, Institute of Oceanography, National Taiwan University and Institute of
                                Earth Sciences, Academia Sinica, 1991

                              Visiting Professor, Kanazawa University, Japan, 1991

                               John Simon Guggenheim Fellow, 1983

                               Fulbright Senior Scholar to France, 1983-84

                               Fellow, Japan Society for the Promotion of Science, 1991

                               Fellow, American Geophysical Union, 1996-

                               Achievement Award, Chinese Engineers and Scientists Association of Southern
                                California (CESASC), 1997

                               Wilford and Daris Zinsmeyer Chair in Marine Studies, University of Southern
                                California, 1998-

                               Hsi-tze-wan Foundation Professor, National Sun Yet-Sen University, Taiwan, 1999-

                                Exploration and application ofnaturally-occurring isotopes, including actinide decay-series
                              nuclides,cosmogenic 10Be, 26Al and 36Cl, andstable isotopes of oxygen and carbon, as time and
                              property tracers in the ocean and onland.

                                Publications in marine and terrestrial geochronology, ocean mixing,water-column particle
                               dynamics, sediment diagenesis, kinetics of rock-waterinteraction, paleoceanography,
                              paleoclimate, closed-basin lake paleohydrology, Quaternary geology,archaeology, and
                              environmental studies.

                                                      Recent Research Activities

                                My research applies geochemistry to problems in oceanography, paleoclimatology, and
                              environmental concerns on a variety of timescales. To undertake these problems, I use naturally
                              occurring isotopic variations due to radioactive decay or mass fractionation as time and process
                              tracers and combine modeling techniques with radiochemical assay and mass spectrometry.

                                An important component of my research program has been to develop means of dating
                              natural deposits. I have explored theuse of decay-series isotopes and cosmogenic nuclides
                              (10Be and 26Al) to determine ages and sedimentation rates of such deposits as marine
                              sediments and ferromanganese nodules, fossil corals, and pedogeniccarbonates, and the use of
                              the fallout 137Cs/135Cs for recent sedimentationand erosion rates. In recent years, my
                              colleagues/students and I designed an extraction technique which enables us to measure 26Al in
                              marine sediments thus paving the way of effectively using this cosmic-ray produced isotope for
                              sediment chronology and other geophysical studies. Our exploratory research on the use of
                              226Ra/Ba ratios for dating biogenic carbonates has yielded promising results which not only
                              show the datability of coastal mollusc shells in Antarctica, but also should aid in tackling the
                              14C reservoir age problem in Southern Oceans. We have also developed the U-series isochron
                              method for dating a variety of sedimentary materials ranging from travertine to soil carbonate to
                              evaporitic salts. Successful applications of this technique have led us to the establishment of
                              late Quaternary chronologies of closed-basinlake salt deposits in the western U.S., western
                              China, and South America. Considerable efforts have also been spent to push the frontier in the
                              useof 226Ra and 226Ra as watermass time tracers.

                                Seeking new ways of extracting information about past environments in terms of climate and
                              ocean productivity changes constitutes another part of my research effort. On paleoclimate
                              studies, our isotopic (oxygen and carbon), chemical, and mineralogical studies on lake
                              sediments allow us to decipher the regional changes in climate and hydrology in great detail.
                              From a mass balance of 18O and water, and from an understanding of the factors controlling
                              the d13C-d18O covariance in lake sediments, we can deduce the volume change of a
                              closed-basin lake, hence changes in regional precipitation versus evaporation. Such
                              paleoclimatic reconstructions are being made in very high-resolution (subdecadal) for the
                              Mono and Owens Lakes of the Great Basin in the western U.S. We are pushing the
                              time-resolution limit (interannual to subdecadal) for deciphering the paleoclimatic signals
                              archived in the speleothem deposits of limestone caves. Results from our study of the Shihua
                              Cave near Beijing clearly revealed a climatic cyclicity that may tie to past variations of the
                              summer monsoon strength. We are studying a series of caves in eastern China from25o to 40o
                              N, in an attempt to unravel temporal shifts in the positions of the Intertropical Convergence
                              Zone (ITCZ) and the Northwest Pacific Subtropical High, hence possible linkage between the
                              Asian Summer Monsoons and El Ni*±o-Southern Oscillation (ENSO). We are confident that
                              this research will contribute to our understanding of not only the climate history of eastern
                              Asia, but also the factors influencing the monsoon fluctuations that are rooted in the global
                              climate variability. On paleoceanographic research, we have been critically evaluating the use of
                              particle-reactive isotope pairs of 230Th-231Pa and our newly proposed 26Al-10Be as proxies for
                              past oceanic productivity. These proxies have the advantage of being less affected by
                              post-depositional dissolution/mobility, in addition to having known production ratio for each of
                              the pairs.

                                Also going on are two environmental research projects which deal with problems of societal
                              concern of a more direct and immediate nature. Prior to the 1970s, coastal ocean off southern
                              California received significant amounts of man-made organic contaminants such as chlorinated
                              pesticides (DDTs), polychlorinated biphenyls (PCBs) and linear alkylbenzenes (LABs).
                              Although the contaminants are largely buried by sedimentation, an investigation of their
                              post-depositional movement and fate in the coastal marine environment is urgently needed. We
                              have launched studies to address this issue in the Palos Verdes Shelf area and in the San Diego
                              Bay. In collaboration with scientists from the Southern California Coastal Water Research
                              Project (SCCWRP), we measured the organic contaminants and some naturally-occurring
                              radioisotopes in seawater and sediment cores collected in the vicinity of the Whites Point
                              sewage outfall. As DDTs are largely bound to particles due to their large partition coefficients,
                              we can use the particle-reactive 234Th (half-life 24.1 d) in relation to its radioactive parent 238U
                              to trace the pollutants in sediments and seawater. The radioactivity distributions enabled us to
                              estimate the fluxes of the buried DDTs and PCBs across the seafloor and, upon reentry into the
                              sea, their water-column residence times in the region. A similar study is being carried out on the
                              resuspension, redistribution, and dispersal of PCBs and polycyclic aromatic hydrocarbons
                              (PAHs) in the San Diego Bay.

                                The second project related to environmental concerns is directed toward the characterization
                              and quantitative assessment of subsurface transport of radioactive waste contaminants at U.S.
                              DOE sites such as Hanford, Washington and the Idaho National Engineering and
                              Environmental Laboratory (INEEL). The long-term migration behavior of radionuclides in
                              underground aquifers can be understood through a study of the cumulative effects of transport
                              over geological times, and these effects can be assessed from the naturally occurring U and Th
                              decay-series disequilibria observed in the rock-water system. The decay series consist of
                              elements with diverse chemical properties and with isotopes having a range of decay mean lives.

                                Different geochemical behaviors of the nuclides lead to significant radioactive disequilibria
                              between parents and daughters in the interstitial fluids and associated solids. Both
                              thermodynamic and kinetic factors play a role in creating and maintaining the disequilibria. By
                              modeling the local mass balance of the various radioisotopes, with constraints placed by their
                              different decay rates and the parent-daughter relationships, one can derive information on
                              kinetics of rock-water interaction under a given geochemical and hydrologic environment, on
                              time scales of a few days to over a million years. Adopting this natural analog approach, we
                              have been studying the radionuclide and groundwater movements at INEEL. The study gives us
                              information on (1) sorption-desorption rate constants and retardation factors of various
                              radionuclides, (2) rates of precipitation and dissolution of rocks and their influence on
                              radionuclide transport, and (3) transit time and flow path of groundwaters at the site. Such
                              site-specific information is also of fundamental value for evaluating in-situ, long-term migration
                              of radionuclides in the far field of a nuclear waste disposal site.

                                The above-outlined research programs are the collaborative undertakings of many researchers
                              and institutions. The principal ones include:

                                USC Geochemistry Laboratory: T. L. Ku, S. Luo, H. C. Li, L. Stott, L. Wang, Y.
                                  Tang, H. Huang, J, Peng, D. Paulsen.
                                Lawrence Livermore National Laboratory: J. R. Southon.
                                Los Alamos National Laboratory: M. Murrell, R. Roback.
                                Binghamton University: T. K. Lowenstein.
                                Ohio State University: P. A. Berkman.
                                Southern California Coastal Water Research Project: E. Zeng.
                                Japan Marine Science and Technology Center: M. Kusakabe.
                                Institute of Earth Sciences, Academia Sinica: T. Lee, C.A. Huh.

                                            Geology 412, Oceans, Climate, and the Environment
                                            Geology 460, Geochemistry and Hydrogeology
                                            Geology 560, Marine Geochemistry
                                            Geology 564, Isotope Geochemistry
                                            Geology 555, Chemical Equilibria in Geology
                                            Geology 566, Geochemistry Seminar

                                           Click here to see a list of PUBLISHED PAPERS SINCE 1995

                                                            Richard Ku
                                                        Science Hall, Room 325E
                                                          USC Earth Sciences
                                                      Los Angeles, CA 90089-0740
                                                        email: rku@earth.usc.edu
                                                         phone: (213) 740-5826
                                                           fax: (213) 740-8801

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                                                        Last modified: January 18, 2000.
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