Professor Udo Fehn

Udo Fehn
Ph.D.
Technical University of Munich 1973
Professor of Geology
fehn@earth.rochester.edu

Links:

Post-Doctoral Researcher

U of R Earth and Environmental Sciences

Interests:

Primary research focus is the movement of fluids in the earth's crust, with an emphasis on dating and tracing studies utilizing two cosmogenic isotope systems, ¹²⁹I and ³⁶Cl. Currently, these isotopic systems are used in the following areas: A study of volcanic fluids associated with the subduction process in order to detect the origin and history of volatiles in arc volcanoes. The inital focus of this study was Central America (e.g. Snyder and Fehn, 2002), followed by current investigations in New Zealand and Japan. The second focus is the determination of the history of ¹²⁹I deposition in marine sediments over the last 80 Ma and the relation to the presence of different types of organic material. An important application of this approach is the determination of origin and migration of gas hydrates in marine sediments (e.g. Fehn et al., 2000).

Finally, we are involved in the application of the two isotopic systems for the understanding of the hydrology associated with coal produced methane in a large natural gas deposit in the Western United States (snyder et al., 2003). While the first two studies are supported by grants from the National Science Foundation, the third project is sponsored by industry. In addition, we have measured (Rao et al., 2002) and are continuing to monitor the distribution and movement of anthropogenic ¹²⁹I through the environment (Snyder and Fehn, 2004). The release of this isotope was initially due to atmospheric weapons tests, but is now related to the reprocessing of nuclear fuel.

Because of the extremely low abundance of ¹²⁹I and ³⁶Cl in nature, detection of these isotopes is possible only by accelerator mass spectrometry (AMS), a highly sensitive method originally developed at the University of Rochester. Currently, the sample preparation is carried out here in the Cosmogenic Isotope Lab, but the AMS determinations take place as a collaborative effort with PrimeLab at Purdue University.