Geosciences Research Division

Research Interests

  • Quantification of abrupt temperature changes using measurements of nitrogen and argon isotopes in ice cores
  • Mechanisms of millennial-scale climate oscillations and climate bifurcations
  • Pleistocene global carbon cycle variations deduced from oxygen and noble gas measurements in ice cores
  • Reconstructing changes in atmospheric noble gas composition over the past million years from air trapped in glacial ice
  • Radiocarbon of methane in late glacial-age ice as a test of the sedimentary methane clathrate degassing hypothesis.
  • Isotopic fractionation of air in polar firn (snow) due to gravitational settling and thermal diffusion, with implications for gas age-ice age differences and leads and lags of climate versus greenhouse gases in ice core records


  • B.A., Oberlin College, Ohio
  • M.A., University of California, Santa Barbara
  • Ph.D., Columbia University, Lamont-Doherty Earth Observatory


Research Lab Website