Ice grain size and the rheology of the martian polar deposits |
| |
| Authors: | Amy C Barr Sarah M Milkovich |
| |
| Institution: | a Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, USA
b Jet Propulsion Laboratory, California Institute of Technology, M/S 183-501, 4800 Oak Grove Drive, Pasadena, CA 91109, USA |
| |
| Abstract: | The history and dynamics of the martian polar deposits (MPD), the largest known water reservoirs on Mars, are of great interest, but estimates of ice grain size are required before detailed modeling can be performed. We clarify the microphysical processes that may control grain size in the MPD. If the MPD are ∼2% dust by mass, the maximum ice grain size is ∼1 mm due to grain boundary pinning by silicate microparticles. Relatively dusty layers in the MPD will have smaller grain sizes. If MPD ice has a very low impurity content and has experienced a significant amount of strain, grains may reach a steady state size of ∼1.5 to 3 mm due to dynamic recrystallization, wherein a steady state grain size is maintained due to the balance of grain growth and destruction during flow. If the near-bed ice in the MPD is warmed close to its melting point and has been extensively sheared, grain sizes at its base may be between 10 and 40 mm, by analogy with warm, dirty, near-bed ice in terrestrial ice sheets. |
| |
| Keywords: | Mars Ices |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
