Isotope Geochemistry

Isotope geochemists develop and use isotopic ratio methods to study fundamental Earth Processes, as well as environmental and energy problems of national interest.

Several Earth and Environmental Sciences Area research programs are supported through the Center for Isotope Geochemistry (CIG), which includes stable isotope and noble gas isotope laboratories; an analytical chemistry laboratory; the Inductively Coupled Plasma Multi-Collector Magnetic Sector mass spectrometry laboratory; and a thermal-ionization mass spectrometry laboratory located on the UC Berkeley campus. There is also an affiliation with the cosmogenic isotope laboratory in UC Berkeley’s Space Sciences Laboratory. The CIG facilities enable state-of-the-art characterization of all types of earth materials. The instrumentation and laboratories are an integral part of the Center’s focus on new ways to use isotopic ratio methods to study fundamental earth processes, and environmental and energy problems of national interest.

Examples of current research programs are:

  1. Development of models that use isotopic composition data from element pairs in fluids to constrain fluid flow rates, water-mineral reaction rates, and the geometry and spacing of fractures in rock matrices
  2. Development and application of noble gas isotopes as natural tracers for fluid source and movement in hydrocarbon and geothermal systems, and as induced phase-partitioning tracers for monitoring geologic sequestration of CO2
  3. Development of techniques for dating Quaternary geological events using U-Th-He
  4. Use of the isotopic signatures of contaminants (e.g., N, O, U isotope ratios) to determine their sources
  5. Tracking subsurface biological activity with shifts in stable isotope ratios of H, C, N, O, S for monitoring in situ bioremediation
  6. The fractionation of the isotopes of Ca, Cr, and Fe by biogeochemical processes
  7. The use of carbon isotopes to quantify rates of organic carbon cycling and storage efficiency in soils, the impact of climate change on carbon cycling, and linkages between carbon, water, and nitrogen cycles
  8. Tracking and apportioning sources of atmospheric aerosols using Pb, Sr, and Nd isotopes
  9. Applications of hydrogen and oxygen isotopes to issues concerning the water cycle