Some land formations on Mars suggest the presence of water ice. These features could have been created by viscous creep of ice below the surface in Martian permafrost. To determine how much ice would be needed to form the observed topography on Mars, Durham et al. conducted laboratory experiments to simulate the frozen Martian sand.
They tested frozen sand mixtures with different types of sand and with various amounts of ice. Surprisingly, the authors found that the most important factor affecting whether the mixture was mobile or jammed was not the amount of ice, or the temperature or stress on the mixture, but the dry packing density of the sand. They found that the minimum amount of ice needed to mobilize the sand is the amount that fills the pore space at the dry packing density of the sand.
The results help explain some of the land formations seen on Mars and provide a new way to estimate Martian water content.
The research is published in Geophysical Research Letters. Authors include William B. Durham and Hendrik J Lenferink: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; Asmin V. Pathare: Planetary Science Institute, Pasadena, California, USA; Laura A. Stern: U.S. Geological Survey, Menlo Park, California, USA.
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