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Exposed subsurface ice sheets in the Martian mid-latitudes
Colin M Dundas1, Ali M Bramson2, Lujendra Ojha3
1Astrogeology Science Center, U.S. Geological Survey, 2255 N. Gemini Drive, Flagstaff, AZ 86001, USA.
Science (New York, N.Y.)
|January 13, 2018
Summary
Martian mid-latitudes contain thick, shallow deposits of subsurface water ice. Erosion exposes these ice-rich layers, causing scarps to retreat due to sublimation, revealing Mars
Area of Science:
- Planetary Science
- Geology
- Climate Science
Background:
- Broad regions of Martian mid-latitudes are covered by thick, smooth mantles.
- Erosion of these mantles forms scarps, exposing the internal deposit structure.
- Subsurface ice is a key resource and indicator of past climate on Mars.
Purpose of the Study:
- To investigate the composition and structure of Martian mid-latitude ice deposits.
- To understand the processes affecting exposed ice deposits, such as sublimation.
- To assess the potential of these deposits as archives of past climate.
Main Methods:
- Field investigation of eight scarp locations in the Martian mid-latitudes.
- Analysis of exposed deposit thickness, depth, and structural features.
- Observation of active scarp retreat and associated sublimation processes.
Main Results:
- Exposed deposits contain water ice exceeding 100 meters in thickness.
- Ice is found from depths as shallow as 1-2 meters below the surface.
- Actively retreating scarps are driven by the sublimation of exposed ice.
Conclusions:
- Martian ice deposits likely formed from compacted snowfall during high-obliquity periods.
- These massive, fractured, and layered ice deposits represent significant climate archives.
- The vertical structure of these deposits can preserve a record of ice deposition and past Martian climate.
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