Ph.D Opportunty: Cryo-aeolian deposits on Mars and Earth

PhD Project title: Cryo-aeolian deposits on Mars and Earth

dune ice

Guidlines for application to the EPSP Group at TCD are outlined here

 Internal Deadline April 4th 2016.
This student will be based at Trinity College Dublin.

S/he will be jointly supervised by Professors at Trinity College Dublin and the University of Arizona.

Supervisors:

Dr. Mary Bourke, Department of Geography, Trinity College Dublin.

Dr Shane Byrne, Lunar and Planetary Laboratory, University of Arizona

Carbon dioxide ice-covered dunes in the North Pole of Mars. the dark areas are locations where the ice has sublimated.

A significant finding of the High Resolution Imaging Science Experiment (HiRISE) on board the Mars Reconnaissance Orbiter is the confirmation of active surface processes under the current Mars climate. Many of these processes in the polar regions are linked to seasonal volatile and wind cycles, such as the migration of aeolian bedforms, avalanches of CO2 ice from polar cliffs and formation of new gullies.

Aeolian dunes in our solar system are modified by a myriad of processes that operate at the surface-atmosphere boundary. Many are climate dependent and bring with them a suite of sediment transport processes. On Earth sediment transport by wind dominates active dune deposits, however, non-aeolian transport such as grain flows, slumping, fluvial and debris flows, also occur (Ahlbrandt and Andrews, 1978; Hugenholtz et al., 2007; Hunter, 1977; Talbot and Williams, 1979). Grainflows, slumps and gullies have also been shown to modify Martian dunes (Bourke, 2012; Diniega et al., 2010; Dundas et al., 2012; Fenton, 2006; Horgan and Bell, 2012).

Relatively little is known of these aeolian deposits on Mars or indeed on Earth. Martian dunes at high latitudes may contain significant amounts of water ice deposited directly from the atmosphere within pore spaces which affects their morphology and migration. Similarly, surface CO2 frosts have also been shown to modify martian dunes through processes that have no terrestrial analogue. A better understanding of these systems is important for understanding volatiles both as geomorphic agents but also as easily accessible resources which may be required for future human missions to Mars.

This Ph.D research will study volatile emplacement, storage and preservation in aeolian dunes on Earth and Mars. The research will quantify the geomorphic work of active surface aeolian process on annual timescales. The analysis of HiRISE image data will enable the production of baseline quantitative data on aeolian process rates and sediment transport volumes. Specific approaches involve 1. Quantifying seasonal ice-related dune change on Mars. 2. Conducting a field analogue study at a cold-climate dunefield on Earth. 3. Modelling (1 and 2-D) of ice emplacement mechanisms on Mars.

Essential skills:

Excellent written and oral English communication skills. Field experience in geomorphology or geology. Clean Driver License. Strong background in Physical Geography, Geology or Earth Science. The ability to work alone and in a team. Good numerical skills for modelling component of the work and some previous computer programming experience.

Desirable:

Experience working with Mars data sets. Good working knowledge of GIS. Highly motivated and independent student. Completion of a Masters degree.

References

 Ahlbrandt, T.S., Andrews, S., 1978. Distinctive sedimentary features of cold-climare eolian deposits, North Park, Colorado. Palaeogeography, Palaeoclimatology, Palaeoecology, 25, 327-351.

Bourke, M.C., 2012. Seasonal change in North Polar dune morphology suggest the importance of Cryo-aeolian activity, 43rd LPSC Conference, abs. # 2885.

Diniega, S., Byrne, S., Bridges, N.T., Dundas, C.M., McEwen, A.S., 2010. Seasonality of present-day Martian dune-gully activity. Geology, 38(11), 1047-1050.

Dundas, C.M., Diniega, S., Hansen, C.J., Byrne, S., McEwen, A.S., 2012. Seasonal activity and morphological changes in martian gullies. Icarus, 220(1), 124-143.

Fenton, L.K., 2006. Dune migration and slip face advancement in the Rabe Crater dune field, Mars. Geophysical Research Letters, 33(L20201), doi:10.1029/2006GL027133.

Horgan, B.H.N., Bell, J.F., III, 2012. Seasonally active slipface avalanches in the north polar sand sea of Mars: Evidence for a wind-related origin. Geophysical Research Letters, 39(9), L09201.

Hugenholtz, C.H., Wolfe, S.A., Moorman, B.J., 2007. Sand-water flows on cold climate eolian dunes: environmental analogs for the eolian rock record and Martian sand dunes. Journal of Sedimentary Research, 77(8), 607-614.

Hunter, R.E., 1977. Basic types of stratification in small eolian dunes. Sedimentology, 361-387.

Talbot, M.R., Williams, M.A.J., 1979. Cyclic Alluvial Fan Sedimentation On The Flanks Of Fixed Dunes, Janjari, Central Niger. Catena, 6, 43-62.

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