Dr. Jean L. Dixon

Picture of Jean Dixon

Assistant Professor of Earth Science

Contact Information

Office:   Traphagen Hall #112
Phone:   (406) 994-3342
Email:  jean.dixon@montana.edu

Earth Surface Processes Lab

Office Hours:

By appointment during Summer-Fall 2016

Affiliations:

Montana Institute on Ecosystems (IOE)

Education:

Ph.D. Dartmouth College, Earth Science, 2009
B.A. Carleton College, Geology 2000

Research Interests:

I am a geomorphologist interested in the chemical, physical and biological processes at Earth’s Surface that form soil from rock, transport soil and sediment, and sculpt the landsurface. My research uses geochemical tools such as cosmogenic radionuclides to quantify the rates and patterns of Earth surface processes. I couple geochemical analysis with field observations, digital terrain analysis and simple numerical models to understand the primary controls on the evolution of diverse landscapes and the sensitivity of the Earth’s soils and surface to external forces such as tectonics and climate.

My research follows several broad themes:

  • Thresholds for soil formation and weathering
  • Topographic signatures and rates of geomorphic processes
  • The role of external forcings such as climate, tectonics and humans in landscape evolution
  • Geochemical tracing of sediment generation and transport

Courses Taught:

4 credits. Fall term. The study of the chemical and physical processes that sculpt Earth's surface and the resulting landforms. Prerequisite: ERTH 101IN.
4 credits. Spring term. Application of geologic principles to problems in environmetal and resource geology. Topics imclude analysis of environmental issues such as earthquake disaster preparedness, landslides, land use, floods and human occupation, ground water withdrawal and contamination issues, volcanic and coastal hazards, and the response of landscapes and people to resource development (minerals/air/water/energy). Laboratories will be used to analyze and debate data relevant to environmental problems from a geologic perspective.
3 credits. Spring term. This class builds on its prerequisite course, ERTH 307: Geomorphology, by providing in-depth examination into advanced topics and methods in the field of geomorphology. Specific course topics will alternate yearly, and may include (but are not limited to):
  • Tectonic Geomorphology
  • Earth’s ‘Critical Zone’: Where rocks, soil, water, air and life meet
  • Isotopic and quantitative tools in Geomorphology

 

Graduate Students

Sarah Benjaram

Rachel Jensen

Aaron Feldhaus

Grace Parker

Colin Quinn

Selected Peer-Reviewed Publications:

Jensen, R, and Dixon, JL (in review) A quantitative framework for understanding past environmental change using 10Be in lake sediments. Earth Surface Processes and Landforms

Uhlig, D, Schuessler, JA, Bouchez, J, Dixon, JL, von Blanckenburg, F (in review) Nutrient uptake as a driver of rock weathering in forest ecosystems. Nature Communications.

Dixon, JL, von Blanckenburg, F, Stüwe, K, and Christl, M (2016) Glaciation’s topographic control on Holocene erosion at the eastern edge of the Alps. Earth Surface Dynamics doi:10.5194/esurf-2016-29. Open Access.

Vitousek, P, Dixon, JL, Chadwick, OA (2016) Parent material and pedogenic thresholds: Observations and a simple model. Biogeochemistry: doi:10.1007/s10533-016-0249-x. Open Access.

Dixon, JL, Chadwick, OA, Vitousek, P (2016) Climate-driven thresholds for chemical weathering in postglacial soils of New Zealand. Journal of Geophysical Research - Earth Surface: 10.1002/2016JF003864. Open Access.

Legrain, N, J, Dixon, Stüwe, K, von Blanckenburg, F, Kubik, P  (2015) Post-Miocene landscape rejuvenation at the eastern end of the Alps. Lithosphere: L391.1.

Dixon, JL and Riebe, C (2014) Tracing and pacing soil across slopes. Elements: v. 10. P. 363-368.

Sugden, JC, Hartshorn, AS, J, Dixon, Montagne, C (2014) A slice through time: A Hyalite Canyon soil lithosequence. GSA Field Guides: v. 37, p. 101-114.

Hewawasam, T, von Blanckenburg, F, Bouchez, J, Dixon, JL, Schuessler, JA (2013) Slow advance of the weathering front during deep, supply-limited saprolite formation in the tropical highlands of Sri Lanka. Geochimica et Cosmochimica Acta: v. 118, p. 202-230.

Dixon, JL and von Blanckenburg, F (2012) Soils as pacemakers and limiters of global silicate weathering. Comptes Rendus Geoscience: v. 344. P. 597-609.

Dixon, JL, Hartshorn, AS, Heimsath, AM, Dibiase, R, and Whipple, KX (2012) Chemical weathering response to tectonic forcing: A soils perspective from the San Gabriel Mountains, California. Earth and Planetary Science Letters: 10.1016/j.epsl.2012.01.010

Dixon, JL (2011) Deceptively old Alpine gorges. Nature-Geoscience: News and Views. v. 4, p. 8-9.

Rasmussen, C, Brantley, Richter, D, Blum, A, Dixon, J and White, AF (2010) Strong climate and tectonic control on plagioclase weathering in granitic terrain, Earth and Planetary Science Letters: v. 301, p. 521-530.

Dixon, JL, Heimsath, AM, Burke, BC and Amundson, R (2009) The critical role of climate and saprolite weathering in landscape evolution. Earth Surface Processes and Landforms: v. 34, p. 1507-1521.

Dixon, JL, Heimsath, AM, Kaste, J and Amundson, R (2009) Climate driven processes of hillslope weathering. Geology: v. 37, p. 975-978.

Burke, BC, Heimsath, AM, Dixon, JL, Chappell, J, Yoo, K (2009) Weathering the escarpment: chemical and physical rates and processes, south-eastern Australia. Earth Surface Processes and Landforms: 10.1002/esp.1764.

Selected Conference Proceedings:

Feldhaus, A* and Dixon, JL, (2016) Short-term effects of variable snowpack on soil chemical and biophysical weathering. Paper 328-5. GSA Annual meeting in Denver, 2016.

Dixon, JL (2015) Unravelling heterogeneity in erosion-weathering feedbacks and critical zone architecture. 2015 American Geophysical Union, Fall Meeting, San Francisco CA. Abstracts with Programs.

Jensen, R* and Dixon, JL (2015) Meteoric 10Be in Lake Cores as a Measure of Climatic and Erosional Change. 2015 American Geophysical Union, Fall Meeting, San Francisco CA. Abstracts with Programs.

Benjaram, S* and Dixon, JL (2015) Soil chemical weathering under morphologic and climatic controls in the Northern Rockies, Montana. 2015 American Geophysical Union, Fall Meeting, San Francisco CA. Abstracts with Programs.

Ulizio, T*, Bilbrey, C*, Stoyanoff, N* and Dixon, JL (2015) Using confidence intervals and recurrence intervals to determine precipitation delivery mechanisms responsible for mass wasting events. 2015 American Geophysical Union, Fall Meeting, San Francisco CA. Abstracts with Programs.

Dixon, JL, Chadwick, OA, Vitousek, PM (2014) Climate control on soil age and weathering thresholds in young, post-glacial soils of New Zealand.  2014 American Geophysical Union, Fall Meeting, San Francisco, CA. (Invited Talk)

Vitousek, PM, Dixon, JL, Chadwick, OA (2014) Climate variability, soil fertility, and pedogenic thresholds. 2014 Ecological Society of America Meeting, Sacramento, CA.

Dixon, JL, Legrain, N, von Blanckenburg, F, Stuwe, K (2014) Post-Glacial Topographic vs. Tectonic Forcings on Erosion in the Eastern Austrian Alps. Goldschmidt 2014, Sacramento, CA. (Invited Talk)

Uhlig, D, Schuessler, JA, Bouchez, J, von Blanckenburg, F, Dixon, JL (2014) Mg isotopes as weathering tracer in the Critical Zone at Sierra Nevada, CA. Goldschmidt 2014, Sacramento, CA.

Dixon, JL (2013) Climate driven thresholds for post-glacial soil development. EP52A-03. Presented at 2013 American Geophysical Union, Fall Meeting, San Francisco CA. (Invited Talk)

von Blanckenburg, F and Dixon, JL (2012) Do mountains withdraw CO2?  Goldschmidt 2012, Montreal Canada. (Invited Talk)

von Blanckenburg, F and Dixon, JL (2012) Using cosmogenic nuclides to explore the limits to soil formation and weathering. 2nd International Conference on Hydropedology. Leipzig Germany.

Dixon, JL (2012) Can weathering shape landscapes? – Insight from rocky slopes and deep regolith. EP44B-01. Presented at 2012 Fall Meeting, American Geophysical Union, Fall Meeting, San Francisco CA. (Invited Talk)

Dixon, JL and von Blanckenburg, F (2012) Limits to weathering and Earth Surface climate feedbacks. EP52A-05. 2012 American Geophysical Union, Fall Meeting, San Francisco CA.

Dixon, JL and von Blanckenburg, F (2011) Speed limits to soil weathering and CO2 withdrawal. Presented at 2011 Goldschmidt Meeting. Mineralogical Magazine: v. 75, p. 767.

Legrain, N, Stuwe, K, Dixon, JL, von Blanckenburg F, Kubik, P (2011) Large scale, small amplitude, post-Miocene surface uplift in the non-glaciated Eastern Alps: river profile analysis and cosmogenic-derived 10Be denudation rates. Geophysical Research Abstracts, European Geosciences Union, v. 13, EGU2011-10708.

Dixon, JL, Hartshorn, AS, Heimsath, AM, DiBiase, RA, Whipple, KX (2010) Chemical weathering in the San Gabriel Mountains of California: The influence of erosion rates, soil depth, and transport processes on soil chemical losses. EOS Transactions, American Geophysical Union, Fall Meeting Supplement, EP42A-08. (Invited Talk)

Dixon, JL, Hartshorn, AS, Heimsath, AM (2010) Weathering, soil depth and erosion in the San Gabriel Mountains: The tectonic signature on chemical weathering. Geophysical Research Abstracts, European Geosciences Union, v. 12, EGU2010-9209. (Invited Talk)

Dixon, JL  (2010) Erosion-weathering feedbacks: From deep saprolites to rocky slopes. Meeting of the European Surface Processes Group. (Invited Talk)

Hartshorn, AS, Dixon, JL, Heimsath, AM, Khomo LM, Rogers, KH, Chadwick, OA (2009) The tempo of soil differentiation along granitic catenas: How poor soils get poorer and rich soils get richer. Ecological Society of America. SYMP18-6.

Rasmussen, C, Brantley, SL, Richter, D, Blum, A, Chadwick, O, Dixon, JL, Hartshorn, AS, White, AF, Williams, JZ (2009) Climate and regolith constraints of chemical weathering and mass flux in granitic terrain. EOS Transactions, American Geophysical Union, Fall Meeting Supplement, EP52B-02.