| NASA Center: |
Jet Propulsion Laboratory |
|---|
| Image # : |
PIA01034 |
|---|
| Date : |
06/22/2000
|
|---|
|
Title
Evidence for Recent Liquid Water on Mars: Gullies
Full Description
Gully landforms proposed to have been caused by geologically-recent
seepage and runoff of liquid water on Mars are found in the most
unlikely places. They typically occur in areas that are quite cold,
well below freezing all year round. Like the old adage about moss on
trees, nearly all of them form on slopes that face away from sunlight.
Most of the gullies occur at latitudes between 30 and 70.
The highest latitude at which martian gullies have been found is around
70-75 S on the walls of pits developed in the south polar pitted
plains. If you were at this same latitude on Earth, you would be in
Antarctica. This region spends much of the winter--which lasts
approximately 6 months on Mars--in darkness and at temperatures cold
enough to freeze carbon dioxide (around -130C or -200F).
Nevertheless, gullies with very sharp, deep, v-shaped channels are seen
on the pit walls.
Based upon the locations of the tops of the channels on the slope shown
here, the inferred site of liquid seepage is located at a layer in the
pit wall about 1/3 of the way down from the top of the MOC image.
The channels start wide and taper downslope. The area above the
channels is layered and has been eroded by mass movement dry
avalanching of debris--to form a pattern of chutes and ridges on the
upper slope of the pit wall. The top layer appears to have many
boulders in it (each about the size of a small house), these boulders
are left behind on the upper slopes of the pit wall as debris is
removed.
Keywords
Liquid Water Gullies Mars MOC Mars Orbiter Camera Mars Global Surveyor
Subject Category
Planet-Mars, Mars Global Surveyor,
Reference Numbers
- Center:
JPL
- Center Number:
PIA01034
- GRIN DataBase Number:
GPN-2000-001984
Source Information
- Creator/Photographer: NASA
- Original Source: digital
| Resolution | Format | Width
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Medium |
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Large |
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Updated October 31, 2002
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