Office: 5723 Science & Engineering Bldg
Phone: (615) 322-2986
Ph.D. University of Washington, 2009
B.S. Pomona College, 2002
I am a geomorphologist who specializes in using cosmogenic nuclides to study landscape evolution (how landscapes change through time) and how environmental changes are reflected across a landscape. To do this, I utilize a variety of dating techniques, including exposure dating with cosmogenic isotopes (such as Be-10 and Al-26) and lichenometry, which allow me to study questions about the timing of geologic events and the rate at which geomorphic processes occur. Most of my field areas are glacial terrains, and many of my projects look at determining the timing of glacial events and how quickly glacial deposits have changed since they were deposited.
Additionally, I have broad interests in environmental management and the role of science in decision making. I study the sustainable use of natural resources, quantifying environmental impacts using life cycle assessments, and the role of science in environmental decision making.
I am working on research projects in Antarctica, Peru, and the Sierra Nevada, CA. Each of these projects involves glacial geology and utilizing dating techniques to determine the timing of glaciations and the rates of geomorphic processes.
In Antarctica, I study the glacial history of the continent and Cenozoic climate change, and to study this I visit the ice-free areas of Antarctica that contain glacial deposits, which record previous episodes of glaciation. These ice-free areas are extremely cold and dry deserts that are very similar to the environmental conditions found on the surface of Mars and the Moon. One application of my work is to understand the rates of geomorphic processes that are operating in this extreme climate so that we can correctly interpret the environmental and glacial history of Antarctica. In December of 2010, I will be going to the Transantarctic Mountains with Jaakko Putkonen and a group from the University of North Dakota. Click here to see their project page.
In Peru, I am working with Steve Wernke, an archeologist here at Vanderbilt University. Dr. Wernke is beginning an excavation at Mawchu Llacta, which is in the Colca Valley in southern Peru. I am assisting this project by looking at the environmental history of the site when it was occupied, which overlaps with the time period commonly known as the little ice age. By finding and dating glacial moraines associated with this glacial expansion, I can directly provide temperature and precipitation information about the site. To date young moraines like this, I have been developing a growth rate curve for the lichen rhizocarpon geographicum, which grows in a radial pattern, so the diameter of these lichens can be used to date surfaces. You can see some photos from our 2010 field season here.
Morgan, D., J. Putkonen, G. Balco, and J. Stone (2010). Quantifying regolith erosion rates with cosmogenic nuclides 10Be and 26Al in the McMurdo Dry Valleys, Antarctica, J. Geophys. Res., 115, F03037, doi:10.1029/2009JF001443.
Morgan, D.J., Putkonen, J., Balco, G., and Stone, J.O.H. (In press), Degradation of glacial deposits quantified with cosmogenic nuclides, Quartermain Mountains, Antarctica. Earth Surface Processes and Landforms.
Putkonen, J., G. Balco, and D. Morgan (2008), Slow regolith degradation without creep determined by cosmogenic nuclide measurements in Arena Valley, Antarctica, Quaternary Research, 69(2), 242-249, doi:10.1016/j.yqres.2007.12.004.
Putkonen, J., M. Rosales, N. Turpen, D. Morgan, G. Balco, and M. Donaldson (2007), Regolith transport in the Dry Valleys of Antarctica, in Antarctica: A Keystone in a Changing World—Online Proceedings of the 10th ISAES X, edited by AK Cooper and CR Raymond et al., USGS Open-File Report, vol. U.S. Geological Survey Open-File Report 2007-1047.
Morgan, D.J., Born, B., Cook, R., Radenovic, H., and S. Renzi, (2007), Seattle Food System Enhancement Project: Greenhouse Gas Emissions Study. University of Washington, Program on the Environment Certificate in Environmental Management Keystone Project, 2006-2007. City of Seattle, Department of Neighborhoods.
Cook, R., Morgan, D.J., Radenovic, H., Renzi, S., and B. Born, (2007), Seattle Food System Enhancement Project. University of Washington, Program on the Environment Certificate in Environmental Management Keystone Project, 2006-2007. City of Seattle, Department of Neighborhoods.
Morgan, D.J., Putkonen, J., Balco, G., and J. Stone (2009). Sublimation of ground ice and erosion of glacial deposits quantified with cosmogenic nuclides, McMurdo Dry Valleys, Antarctica. American Geophysical Union Annual Meeting, San Francisco, CA.
Putkonen, J., Jahraus, T., Morgan, D., and G. Balco (2009). Direct quantification of current sediment transport on surfaces in varying climates, WA and ND, USA and Dry Valleys, Antarctica. Geological Society of America, Abstracts with Programs, Vol. 41, No. 7, p. 336.
Morgan, D.J., Putkonen, J., Balco, G., and J. Stone (2008). Colluvium erosion rates in the McMurdo Dry Valleys, Antarctica. American Geophysical Union Annual Meeting, San Francisco, CA.
Balco, G., Shuster, D.L., Morgan, D., and J. Putkonen (2008). Combined measurements of cosmogenic Be-10, Al-26, and Ne-21 in quartz used to discern temporal changes in rates of Antarctic landscape evolution. American Geophysical Union Annual Meeting, San Francisco, CA.
Born, B., and Morgan, D.J. (2007). Urban Sustainability, Climate Change, And The Food System: Measuring Urban Food System Impacts on Greenhouse Gases Association of Collegiate Schools of Planning, ACSP 2007 Annual Conference, October 18-21 in Milwaukee, Wisconsin.
Morgan, D.J. and Putkonen, J. (2006). Geomorphic indicators of sediment transport in the McMurdo Dry Valleys, Antarctica. Scientific Committee on Antarctic Research (SCAR) Second Open Science Conference, July 2006.
Morgan, D.J. and Putkonen, J (2005). Sediment transport in the McMurdo Dry Valleys, Antarctica. Geological Society of America Abstracts with Programs, Vol. 37, No. 7, p. 304.
Field Trips and Photos
Here are some photos from recent field trips in the EES department:
GeoconclaveEach year, a team of undergraduate students from the EES department competes in the Tennessee Geoconclave. This is a friendly geology competition between geology departments from Tennessee Universities, and it includes academic events (rock id, mineral id, etc.), non-technical challenges (rock hammer throwing, geode rolling, etc.), and the Rock Bowl (a geology focused quiz-bowl).
In 2009, the Vanderbilt Rock Stars won the Rock Bowl competition, bringing home the coveted Rock Bowl plaque!