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Gray Bebout, professor of earth and environmental sciences at Lehigh University

Gray Bebout

Professor

610.758.5831
geb0@lehigh.edu
216 STEPS
Education:

Postdoctoral Fellow (1989-1991) Geophysical Laboratory and Department of Terrestrial Magnetism, Carnegie Institution of Washington (now Carnegie Science, Earth and Planets Laboratory)

Ph.D., Geology, University of California, Los Angeles, 1989

M.A., Geology, University of Texas at Austin, 1984

B.S., Geology, University of Texas at Austin, 1981

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Research Areas

Additional Interests

  • Stable Isotope Geochemistry
  • Petrology
  • Astrobiology

Research Statement

In his research, Bebout considers the cycling of volatiles among the major Earth reservoirs (atmosphere, hydrosphere, biosphere, and lithosphere), with emphasis on understanding the metamorphic pathways affecting this flux. As one career-long research focus, he has explored the intriguing behavior of nitrogen and its utility in tracing modern and ancient biogeochemical cycling on Earth (and beyond). Bebout and his group currently investigate the (slow, non-anthropogenic) cycling of volatiles such as CO2 and N2 at Earth's subduction zones, with related research onging in the Italian/French Alps and on the North Island of New Zealand (the modern Hikurangi margin). The work on Hikurangi involves sampling of volcanic and cold-seep gases that are then analyzed at the GNS in Wellington, New Zealand, and at the University of Tokyo. Carbon, oxygen, and nitrogen isotope analyses of the rock samples collected in the Alps are conducted in Bebout’s laboratory at Lehigh University.

Another area of active research has been the study of “Mars analog” materials (available on Earth and known to be abundant on the modern Mars surface/near-surface), in particular analyzing altered volcanic glasses for their N concentrations and isotope compositions and the presence of key organic compounds. This astrobiology work is in part being conducted in collaboration with researchers at the Institute for Planetary Materials, Okayama University, located in Misasa, Japan. Bebout’s long-term affiliation with this institute began with a one-year sabbatical there in 2000.

Bebout's research laboratory is in the STEPS building, room 261 (across from the elevator in the C-wing), and at the center of this program is a gas-source isotope-ratio mass spectrometer capable of analyzing very small amounts of CO2, N2, and O2.

Biography

Bebout grew up in Texas and received B.S. and M.A. degrees in Geology from the University of Texas-Austin. His path toward Lehigh University included a five-year stop at UCLA (University of California, Los Angeles), where he received his Ph.D. degree, and the Carnegie Institution of Washington (now Carnegie Science), where he was a postdoctoral fellow for two years (1989-1991). He arrived at Lehigh in late 1991. Besides his research and teaching, he has served on and chaired faculty committees at the University, College, and Department levels — recently, he served as the EES Department Chair (2019-2024).

Honors and Awards

2018 Fellow, Mineralogical Society of America

Recent and Selected Publications (see the full listing at Google Scholar):

Bustos-Moreno, J. F., Bebout, G. E., and Savov, I. P., 2024, Nitrogen (N) and its isotopes in serpentinized forearc wedges and implications for N cycling across subduction zones. Geology, 53(2), 130–134, https://doi.org /10.1130/G52492.1

Bebout, G. E., Ota, T., Kunihiro, T., Carlson, W. D., and Nakamura, E., 2022, Lithium in garnet as a tracer of subduction zone metamorphic reactions: The record in UHP metapelites at Lago di Cignana, Italy, Geosphere, 18(3), 1020–1029, https://doi.org/10.1130/GES02473.1

Nikitczuk, M. P., Bebout, G. E., Ota, T., Kunihiro, T., Mustard, J. F., Flemming, R. L., Tanaka, R., Halldórsson, S. A., and Nakamura, E., 2022, Nitrogenous altered volcanic glasses as targets for Mars sample return: Examples from Antarctica and Iceland, Journal of Geophysical Research-Planets, 127, e2021JE007052. https://doi.org/10.1029/2021JE007052

Epstein, G. S., Bebout, G. E., Christenson, B. W., Sumino, H., Wada, I., Werner, C., and Hilton, D. R., 2021, Cycling of CO2 and N2 along the Hikurangi subduction margin, New Zealand: An integrated geological, theoretical, and isotopic approach, Geochemistry, Geophysics, and Geosystems, 22, e2021GC009650. https://doi.org/10.1029/2021GC009650

Bebout, G. E., 2020, 00140. Insights into subduction zone dynamics, Encyclopedia of Geology, 2nd Edition, Elsevier (Invited Article), https://doi.org/10.1016/B978-0-08-102908-4.00150-8

Jaeckel, K., Bebout, G. E., and Angiboust, S., 2018, Deformation-enhanced fluid and mass transfer along Western and Central Alps paleo-subduction interfaces: Significance for carbon cycling models, Geosphere, 14(6), 2355–2375, https://doi.org/10.1130 /GES01587.1

Bebout, G. E., Scholl, D. W., Stern, R. J., Wallace, L. M., and Agard, P., 2017, Twenty years of subduction zone science: Subduction Top to Bottom 2 (ST2B-2), GSA Today, 28, doi: 10.1130/GSATG354A.1

Bebout, G. E., and Penniston-Dorland, S. C., 2015, Fluid and mass transfer at subduction interfaces – The field metamorphic record, Invited Review Article, Lithos, 240-243, 228-258, http://dx.doi.org/10.1016/j.lithos.2015.10.007

Bebout, G. E., 2014, 4.20. Chemical and isotopic cycling in subduction zones, Invited Chapterin Rudnick, R. L., ed., 2nd Ed. Volume 4, Treatise on Geochemistry: The Crust, Elsevier, 703-747. http://dx.doi.org/10.1016/B978-0-08-095975-7.00322-3

Bebout, G. E., 2007, Metamorphic chemical geodynamics of subduction zones, Invited Frontiers Article, Earth and Planetary Science Letters, 260, 373-393, doi:10.1016/j.epsl.2007.05.050

Teaching

Bebout teaches in the areas of mineralogy, petrology, and geochemistry, at all levels of the undergraduate program and also at the graduate level. Following are the courses he currently offers.

EES 00x (Geology and Geopolitics of Critical Minerals)

EES 131 (Introduction to Rocks and Minerals)

EES 380 (The Practice of Science)

EES 471 (Stable Isotope Chemistry: Theory, Techniques, and Applications in the Earth and Environmental Sciences)

EES 293 Supervised Internship in Earth and Environmental Sciences 

EES 393 Supervised Research in Earth and Environmental Sciences