Professor of Geology, Department of Geology, University of Maryland
Ph.D., State University of New York at Stony Brook, 1984
M.S., State University of New York at Stony Brook, 1981
B.S., College of William and Mary, 1979

Research interests include the application of isotope and trace element geochemistry to fundamental problems in the origin and evolution of the early solar system, the chemical evolution of the Earth’s core, mantle and crust, and the interactions between various chemical reservoirs.

I am always on the lookout for qualified graduate students and normally support students as research assistants. If you are interested in the research we conduct and are considering the University of Maryland graduate program, please feel free to contact me at: rjwalker AT geol.umd.edu.

Isotope Geochemistry and Cosmochemistry

Professor Walker, colleagues and students at the University of Maryland Isotope Geochemistry Laboratory conduct research in several areas of Earth and planetary science. These study areas include: 1) the chemical evolution of the Earth's mantle, particularly with respect to the behavior of highly-siderophile elements (including: Re, Os, Ir, Pt, Pd, Ru), 2) the formation and crystallization histories of early solar system planetesimals, with current emphasis on early condensates and core formational processes, 3) the accretional and differentiation histories of Earth, Moon and Mars, 4) the origin of platinum-group element (PGE) and gold ores, 5) the use of Sr, Li, Mo and Os isotopes as tracers of Earth surface processes such as continental weathering, ocean chemistry evolution, and the movement of toxic metals through the environment.

The research program involves both students and research scientists, and has also included the participation of numerous visiting scientists from the US and abroad. The bulk of this research is accomplished using the facilities of the Isotope Geochemistry Laboratory, which at present consist of three solid source mass spectrometers, a multi-collector ICP-MS and ancillary equipment for isotope and trace element measurement. Current work in the lab includes the measurement of the ¹⁸⁷Re-¹⁸⁷Os, ¹⁹⁰Pt-¹⁸⁶Os, ¹⁴⁷Sm-¹⁴³Nd, ⁸⁷Rb-⁸⁷Sr, U-Pb, ¹⁸²W radiogenic isotope systems. We also conduct Mo and Li stable isotope measurements.

Overview of Selected Research Targets:

1. Study of the ¹⁸⁷Re-¹⁸⁷Os Isotope systematics of the Mantle through time
2. Development of Tools for the Detection of Core-Mantle Interaction
3. Isotopic Studies of Meteorites and Lunar Rocks
4. Creation and Death of Lithospheric Mantle: Study of the North China Craton

Vitae (with publications listing)
Past and Present Grants
Students and Their Projects

Last Revised July 2007