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Bradley ThomsonBradley Thomson

Assistant Professor
Planetary Geoscience

Department of Earth and Planetary Sciences
614 Strong Hall
1621 Cumberland Ave
Knoxville, TN 37996-1410

Phone: (865) 974-2699

Google Scholar

As a planetary geologist, I am interested in understanding the physical processes that have shaped the surfaces of the terrestrial planets, including impact, eolian, fluvial, lacustrine, and volcanic processes. I have endeavored to unravel the complex geologic histories of Mars, the Moon, and Venus using geologic mapping and geologic analysis with diverse types of remotely sensed data, including radar, optical, near-IR, thermal, and surface contact data. An overarching theme of my research is to constrain the nature and timing of physical processes in ancient planetary environments, particularly the drivers of planetary-scale climate change. I have also employed terrestrial analogs to provide greater insight into planetary processes. Furthermore, I have developed numerous pieces of custom-built software (particularly in MATLAB) to facilitate my research.

Peer-Reviewed Articles (* denotes student author)

  • Fassett, C. I., I. R. King, C. A. Nypaver, and B. J. Thomson, Temporal evolution of S-band circular polarization ratio of kilometer-scale craters on the lunar maria, Journal of Geophysical Research, doi:10.1029/2018JE005741, 2018.
  • *Nypaver, C., N. P. Lang, and B. J. Thomson, Geologic mapping, morphometric characterization, and statistical analyses of six venusian shield fields: Insights into the processes related to their formation, in Field Volcanology: A Tribute to the Distinguished Career of Don Swanson, edited by M. P. Poland, et al., GSA Special Publication 538, doi:10.1130/2018.2538(20), 2018.
  • Fassett, C. I., M. C. Crowley, C. Leight, M. D. Dyar, D. A. Minton, M. Hirabayashi, B. J. Thomson, and W. A. Watters, Evidence for rapid topographic evolution and crater degradation on Mercury from simple crater morphometry, Geophysical Research Letters, 44, 5326-5335, doi:10.1002/2017GL073769, 2017.
  • McCanta, M. C., M. D. Dyar, M. J. Rutherford, A. Lanzirotti, S. R. Sutton, and B. J. Thomson, In situ measurement of ferric iron in lunar glass beads using Fe-XAS, Icarus, 285, 95-102, doi: 10.1016/j.icarus.2016.12.029, 2017.
  • Patterson, G. W., A. M. Stickle, F. S. Turner, J. R. Jensen, D. B. J. Bussey, P. Spudis, R. C. Espiritu, R. C. Schulze, D. A. Yocky, D. E. Wahl, M. Zimmerman, J. T. S. Cahill, M. Nolan, L. Carter, C. D. Neish, R. K. Raney, B. J. Thomson, R. Kirk, T. W. Thompson, B. L. Tise, I. A. Erteza, C.V. Jakowatz, Bistatic radar observations of the Moon using Mini-RF on LRO and the Arecibo Observatory, Icarus, 283, 2-19, doi:10.1016/j.icarus.2016.05.017, 2017.
  • Denevi, B. W., A. W. Beck, E. I. Coman, B. J. Thomson, E. Ammannito, D. T. Blewett, J. M. Sunshine, M. C. De Sanctis, J.-Y. Li, S. Marchi, D. W. Mittlefehldt, N. E. Petro, C. A. Raymond, and C. T. Russell, Global variations in regolith properties on asteroid Vesta from Dawn’s low-altitude mapping orbit, Meteoritics and Planetary Science, 51(12), 2366–2386, doi:10.1111/maps.12729, 2016.
  • Thomson, B. J. and N. P. Lang, Volcanic edifice alignment detection software in MATLAB: Test data and preliminary results for shield fields on Venus, Computers & Geosciences, 93, 1–11, doi:10.1016/j.cageo.2016.04.012, 2016. [code download]
  • McCanta, M.C., R.G. Hatfield, B.J. Thomson, S. J. Hook, and E. Fisher, Identifying cryptotephra units using correlated rapid, non-destructive methods: VSWIR spectroscopy, X-ray fluorescence, and magnetic susceptibility, Geochemistry, Geophysics, Geosystems, 16(12), 4029-4056, doi:10.1002/2015GC005913, 2015.
  • Cahill, J. T. S., B. J. Thomson, G. W. Patterson, D. B. J. Bussey, C. D. Neish, N. R. Lopez, F. Scott Turner, T. Aldridge, M. McAdam, H.M. Meyer, R. K. Raney, L. M. Carter, P. D. Spudis, H. Hiesinger, J. H. Pasckert, The Miniature Radio Frequency instrument’s (Mini-RF) global observations of Earth’s Moon, Icarus, 243, 173-190, doi:10.1016/j.icarus.2014.07.018, 2014.
  • Fassett, C. I. and B. J. Thomson, Crater degradation on the lunar maria: Topographic diffusion and the rate of erosion on the Moon, Journal of Geophysical Research, 119(10), 2255-2271, doi:10.1002/2014JE004698, 2014.
  • Thomson, B. J., and F. El-Baz, Future Mars Rovers: The Next Places to Direct Our Curiosity, Eos Transactions, 95(35), 313-314, doi:10.1002/2014EO350001, 2014.
  • Thomson, B. J., J. A. Hurowitz, L. L. Baker, N. T. Bridges, A. Lennon, G. Paulsen, and K. Zacny, The effects of weathering on the strength and chemistry of Columbia River Basalts and their implications for Mars Exploration Rover Rock Abrasion Tool (RAT) results, Earth and Planetary Science Letters, 400, 130-144, doi:10.1016/j.epsl.2014.05.012, 2014.
  • Spudis, P. D., D. B. J. Bussey, S. M. Baloga, J. T. S. Cahill, L. S. Glaze, G. W. Patterson, R. K. Raney, T. W. Thompson, B. J. Thomson, and E. A. Ustinov, Evidence for water ice on the Moon: Results for anomalous polar craters from the LRO Mini-RF imaging radar, Journal of Geophysical Research, 118, 2016–2029, doi:10.1002/jgre.20156, 2013.
  • Thomson, B. J., N. T. Bridges, J. Cohen, J. A. Hurowitz, A. Lennon, G. Paulsen, K. Zacny, Estimating rock compressive strength from Rock Abrasion Tool (RAT) grinds, Journal of Geophysical Research, 118, 1233–1244, doi:10.1002/jgre.20061, 2013.
  • Thomson, B. J., D. B. J. Bussey, C. D. Neish, J. T. S. Cahill, E. Heggy, R. L. Kirk, G. W. Patterson, R. K. Raney, P. D. Spudis, T. W. Thompson, and E. A. Ustinov, An upper limit for ice in Shackleton crater as revealed by LRO Mini-RF orbital radar, Geophysical Research Letters, 39, L14201, doi:10.1029/2012GL052119, 2012.
  • *Bell, S. W., B. J. Thomson, M. D. Dyar, C. D. Neish, J. T. S. Cahill, and D. B. J. Bussey, Dating fresh lunar craters with Mini-RF, Journal of Geophysical Research, 117, E00H30, doi:10.1029/2011JE004007, 2012.
  • Bridges, N.T., M. C. Bourke, P. E. Geissler, M. E. Banks, C. Colon, S. Diniega, M. P. Golombek, C. J. Hansen, S. Mattson, A. S. McEwen, M. T. Mellon, N. Stantzos, and B. J. Thomson, Planet-wide sand motion on Mars, Geology, 40(1), 31–34, doi:10.1130/G32373.1, 2012.
  • Thomson, B. J., N. T. Bridges, R. Milliken, A. Baldridge, S. J. Hook, J. K. Crowley, G. M. Marion, C. R. de Souza Filho, A. J. Brown, and C. M. Weitz, Constraints on the origin and evolution of the layered mound in Gale crater, Mars using Mars Reconnaissance Orbiter data, Icarus, 214(2), 413-432, doi:10.1016/j.icarus.2011.05.002, 2011.
  • Neish, C. D., D. B. J. Bussey, P. Spudis, W. Marshall, B. J. Thomson, B. G. W. Patterson, L. M. Carter, The nature of lunar volatiles as revealed by Mini-RF observations of the LCROSS impact site, Journal of Geophysical Research, 116(E1), E01005, doi:10.1029/2010JE003647, 2011.
  • Neish, C. D., D. T. Blewett, D. B. J. Bussey, S. J. Lawrence, M. Mechtley, B. J. Thomson, and the Mini-RF Team, The surficial nature of lunar swirls as revealed by the Mini-RF instrument, Icarus, 215(1), 186-196, doi:10.1016/j.icarus.2011.06.037, 2011.
  • Bridges, N. T., M. E. Banks, R. A. Beyer, F. C. Chuang, E. Z. Noe Dobrea, K. E. Herkenhoff, L. P. Keszthelyi, K. E. Fishbaugh, A. S. McEwen, T. I. Michaels, B. J. Thomson, and J. J. Wray, Aeolian bedforms, yardangs, and indurated surfaces in the Tharsis Montes as seen by the HiRISE Camera: Evidence for dust aggregates, Icarus, 205(1), 165-182, doi:10.1016/j.icarus.2009.05.017, 2010.
  • Brown, A. J., S. J. Hook, A. M. Baldridge, J. K. Crowley, N. T. Bridges, B. J. Thomson, G. M. Marion, C. R. de Souza Filho, J. L. Bishop, Hydrothermal formation of clay-carbonate alteration assemblages in the Nili Fossae region of Mars, Earth and Planetary Science Letters, 297(1-2), 174-182, doi:10.1016/j.epsl.2010.06.018, 2010.
  • McEwen, A. S, M. E. Banks, N. Baugh, K. Becker, A. Boyd, J. W. Bergstrom, R. A. Beyer, E. Bortolini, N. T. Bridges, S. Byrne, B. Castalia, F. C. Chuang, L. S. Crumpler, I. Daubar, A. K. Davatzes, D. G. Deardorff, A. DeJong, W. A. Delamere, E. Noe Dobrea, C. M. Dundas, E. M. Eliason, Y. Espinoza, A. Fennema, K. E. Fishbaugh, T. Forrester, P. E. Geissler, J. A. Grant, J. L. Griffes, J. P. Grotzinger, V. C. Gulick, C. J. Hansen, K. E. Herkenhoff, R. Heyd, W. L. Jaeger, D. Jones, B. Kanefsky, L. Keszthelyi, R. King, R. L. Kirk, K. J. Kolb, J. Lasco, A. Lefort, R. Leis, K. W. Lewis, S. Martinez-Alonso, S. Mattson, G. McArthur, M. T. Mellon, J. M. Metz, M. P. Milazzo, R. E. Milliken, T. Motazedian, C. H. Okubo, A. Ortiz, A. J. Philippoff, J. Plassmann, A. Polit, P. S. Russell, C. Schaller, M. L. Searls, T. Spriggs, S. W. Squyres, S. Tarr, N. Thomas, B. J. Thomson, L. L. Tornabene, C. van Houten, C. Verba, C. M. Weitz, and J. J. Wray, The High Resolution Imaging Science Experiment (HiRISE) during MRO’s Primary Science Phase (PSP), Icarus, 205(1), 2-37, doi:10.1016/j.icarus.2009.04.023, 2010.
  • Milliken, R. E., J. P. Grotzinger, and B. J. Thomson, Paleoclimate of Mars as captured by the stratigraphic record in Gale crater, Geophysical Research Letters, 37(4), doi: 10.1029/2009GL041870, 2010.
  • Spudis, P. D., D. B. J. Bussey, S. M. Baloga, B. J. Butler, D. Carl, L. M. Carter, M. Chakraborty, R. C. Elphic, J. J. Gillis-Davis, J. N. Goswami, E. Heggy, M. Hillyard, R. Jensen, R. L. Kirk, D. LaVallee, P. McKerracher, C.D. Neish, S. Nozette, S. Nylund, M. Palsetia, W. Patterson, M. S. Robinson, R. K. Raney, R. C. Schulze, H. Sequeira, J. Skura, T. W. Thompson, B. J. Thomson, E. A. Ustinov, and H. L. Winters, Initial results for the north pole of the Moon from Mini-SAR, Chandrayaan-1 mission, Geophysical Research Letters, 37(6), L06204, doi:10.1029/2009GL042259, 2010.
  • Weitz, C. M., R. E. Milliken, J. A. Grant, A. S. McEwen, R. M. E. Williams, J. L. Bishop, and B. J. Thomson, Mars Reconnaissance Orbiter observations of light-toned layered deposits and associated fluvial landforms on the plateaus adjacent to Valles Marineris, Icarus, 205(1), 73-102, doi:10.1016/j.icarus.2009.04.017, 2010.
  • Baldridge, A. M., S. J. Hook, J. K. Crowley, G. M. Marion, J. S. Kargel, J. L. Michalski, B. J. Thomson, C. R. de Souza Filho, N. T. Bridges, and A. J. Brown, Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars, Geophysical Research Letters, 36(19), doi:10.1029/2009GL040069, 2009
  • Marion, G. M., J. K. Crowley, B. J. Thomson, J. S. Kargel, N. T. Bridges, S. J. Hook, A. Baldridge, A. J. Brown, B. Ribeiro da Luz, C. R. de Souza Filho, Modeling aluminum–silicon chemistries and application to Australian acidic playa lakes as analogues for Mars, Geochimica et Cosmochimica Acta, 73(11), 3493-3511, doi:10.1016/j.gca.2009.03.013, 2009.
  • Han, G., M. B. Dusseault, E. Detournay, B. J. Thomson, and K. Zacny, Principles of Drilling and Excavation, in Drilling in Extreme Environments, edited by Y. Bar-Cohen and K. Zacny, Wiley-VCH, pp. 31-140, doi:10.1002/9783527626625, 2009.
  • Thomson, B. J., E. B. Grosfils, D. B. J. Bussey, and P. Spudis, Thickness of basalts in Mare Imbrium, Geophysical Research Letters, 36(12), L12201, doi: 10.1029/2009GL037600, 2009.
  • Zacny, K., Y. Bar-Cohen, K. Davis, P. Coste, G. Paulsen, S. Sherrit, J. George, B. Derkowski, S. Gorevan, D. Boucher, J. Guerrero, T. Kubota, B. J. Thomson, S. Stanley, P. Thomas, N. Lan, C. McKay, T. C. Onstot, C. Stoker, B. Glass, S. Wakabayashi, L. Whyte, G. Visentin, E. Re, L. Richter, M. Badescu, X. Bao, R. Fincher, T. Hoshino, P. Magnani, and C. Menon, Extraterrestrial Drilling and Excavation, in Drilling in Extreme Environments, edited by Y. Bar-Cohen and K. Zacny, Wiley-VCH, pp. 347-557, doi:10.1002/9783527626625, 2009.
  • Bridges, N. T., S. J. Hook, J. K. Crowley, C. Roberto de Souza Filho, J. B. Macambira, G. de Lima Pereira Silva, and B. J. Thomson, Brazilian analog for ancient marine environments on Mars, Eos Transactions, 89(36), doi:10.1029/2008EO360001, 2008.
  • Grant, J. A., R. P. Irwin, III, J. P. Grotzinger, R. E. Milliken, L. L. Tornabene, A. S. McEwen, C. M. Weitz, S. W. Squyres, T. D. Glotch, and B. J. Thomson, HiRISE imaging of impact megabreccia and sub-meter aqueous strata in Holden Crater, Mars, Geology, 36(3), 195-198, doi:10.1130/G24340A.1, 2008.
  • Thomson, B. J., N. T. Bridges, and R. Greeley, Rock abrasion features in the Columbia Hills, Mars, Journal of Geophysical Research, 113, E08010, doi: 10.1029/2007JE003018, 2008.
  • Thomson, B. J., P. H. Schultz, and N. T. Bridges, Extracting scientific results from robotic arm support operations:  A technique for estimating the density and composition of rocks on Mars, The Mars Journal, 4, 27-32, doi:10.1555/mars.2008.0003, 2008.
  • Bridges, N. T., P. E. Geissler, A. S. McEwen, B. J. Thomson, F. C. Chuang, K. E. Herkenhoff, L. P. Keszthelyi, S. E. Martínez-Alonso, Windy Mars: A dynamic planet as seen by the HiRISE camera, Geophysical Research Letters, 34, L23205, doi:10.1029/2007GL031445, 2007.
  • Chuang, F. C., R. A. Beyer, A. S. McEwen, and B. J. Thomson, HiRISE observation of slope streaks on Mars, Geophysical Research Letters, 34, L20204, doi:10.1029/2007GL031111, 2007.
  • McEwen, A. S., C. J. Hansen, W. A. Delamere, E. M. Eliason, K. E. Herkenhoff, L. Keszthelyi, V. C. Gulick, R. L. Kirk, M. T. Mellon, J. A. Grant, N. Thomas, C. M. Weitz, S. W. Squyres, N. T. Bridges, S. L. Murchie, F. Seelos, K. Seelos, C. H. Okubo, M. P. Milazzo, L. L. Tornabene, W. L. Jaeger, S. Byrne, P. S. Russell, J. L. Griffes, S. Martínez-Alonso, A. Davatzes, F. C. Chuang, B. J. Thomson, K. E. Fishbaugh, C. M. Dundas, K. J. Kolb, M. E. Banks, and J. J. Wray, A closer look at water-related geologic activity on Mars, Science, 317, 1706-1709, doi:10.1126/science.1143987, 2007.
  • Thomson, B. J. and P. H. Schultz, The geology of the Viking Lander 2 site revisited, Icarus, 191, 505-523, doi:10.1016/j.icarus.2007.05.011, 2007.
  • Thomson, B. J. and J. W. Head, Utopia Basin, Mars: Characterization of topography and morphology and assessment of the origin and evolution of basin internal structure, Journal of Geophysical Research, 106, 23,209-23,230, doi:10.1029/2000JE001355, 2001.
  • Head, J. W., H. Hiesinger, M. A. Ivanov, M. A. Kreslavsky, S. Pratt, and B. J. Thomson, Possible ancient oceans on Mars: Evidence from Mars Orbiter Laser Altimeter data, Science, 286, 2134-2137, doi:10.1126/science.286.5447.2134, 1999.

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