Astronomy:Green (Martian crater)
Gullies in Green Crater, as seen by HiRISE.
Debris flows have been observed on some of the dunes in this crater. Some researchers believe that they may be caused by liquid water. Liquid water could be stable for short periods of time in the summer in the southern hemisphere of Mars. These gully-like debris flows may be due to small amounts of ice melting.
East side of Green Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter).
Dunes in Green Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Note: this is an enlargement of the previous image. Thin dark lines are dust devil tracks. The crater on the right is a smaller crater that sits on the floor of Green Crater. Some old glaciers are visible as arc-shaped ridges. An arrow points to one of the glaciers.
Barchan dunes are present in Green Crater and visible in pictures below. When there are perfect conditions for producing sand dunes, steady wind in one direction and just enough sand, a barchan sand dune forms. Barchans have a gentle slope on the wind side and a much steeper slope on the lee side where horns or a notch often forms.
- "Gazetteer of Planetary Nomenclature | Green". International Astronomical Union. http://planetarynames.wr.usgs.gov/Feature/2244.
- Reiss, D, R. Jaumann. 2003. Recent debris flows on Mars: Seasonal observations of the Russell Crater dune field. Geophysical Research Letters: 30, 1321.
- Pye, Kenneth; Haim Tsoar (2008). Aeolian Sand and Sand Dunes. Springer. pp. 138. ISBN 9783540859109. https://archive.org/details/aeoliansandsandd00pyek.
Original source: https://en.wikipedia.org/wiki/ Green (Martian crater). Read more