Thomas Martin Johnson

1987 …2020
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Personal profile

Professional Information

Prof. Johnson's group focuses on environmental geochemistry, isotope geochemistry, and hydrogeology.  The group is working to better understand several redox-sensitive contaminant elements, including chromium, selenium, uranium, and mercury.  They develop and use methods for measurement of the stable isotopes of these and other elements as indicators of key geochemical reactions, contamination sources, and past environments on Earth.

The group uses the department's multicollector ICP-MS laboratory constantly to make these measurements and often develops or improves measurement methods. 


  • GEOL 117: The Oceans
  • GEOL 118: Natural Disasters
  • GEOL 370/GEOG 370/ESE 320: Water Planet/Water Crisis
  • GEOL 470: Hydrogeology
  • GEOL 562: Isotope Geochemistry
  • GEOL 579: Isotope Hydrogeology


Ph.D., University of California at Berkeley

Office Address

3030A Natural History Building

Fingerprint Fingerprint is based on mining the text of the expert's scholarly documents to create an index of weighted terms, which defines the key subjects of each individual researcher.

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Research Output 1987 2020

reactive transport

A Mesoarchean shift in uranium isotope systematics

Wang, X., Planavsky, N. J., Hofmann, A., Saupe, E. E., De Corte, B. P., Philippot, P., LaLonde, S. V., Jemison, N. E., Zou, H., Ossa, F. O., Rybacki, K., Alfimova, N., Larson, M. J., Tsikos, H., Fralick, P. W., Johnson, T. M., Knudsen, A. C., Reinhard, C. T. & Konhauser, K. O., Oct 1 2018, In : Geochimica et Cosmochimica Acta. 238, p. 438-452 15 p.

Research output: Contribution to journalArticle

uranium isotope

Field Application of 238U/235U Measurements to Detect Reoxidation and Mobilization of U(IV)

Jemison, N. E., Shiel, A. E., Johnson, T. M., Lundstrom, C. C., Long, P. E. & Williams, K. H., Mar 20 2018, In : Environmental Science and Technology. 52, 6, p. 3422-3430 9 p.

Research output: Contribution to journalArticle


A cenozoic seawater redox record derived from 238U/235U in ferromanganese crusts

Wang, X., Planavsky, N. J., Reinhard, C. T., Hein, J. R. & Johnson, T. M., Jan 2016, In : American Journal of Science. 315, 11, p. 64-83 20 p.

Research output: Contribution to journalArticle

uranium isotope

Geological evolution of the marine selenium cycle: Insights from the bulk shale δ82/76Se record and isotope mass balance modeling

Mitchell, K., Mansoor, S. Z., Mason, P. R. D., Johnson, T. M. & Van Cappellen, P., May 1 2016, In : Earth and Planetary Science Letters. 441, p. 178-187 10 p.

Research output: Contribution to journalArticle

mass balance