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Collection:
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NASA Great Images in Nasa Collection
Collection
NASA Great Images in Nasa Collection
Collection
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Title:
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Evidence for Recent Liquid Water on Mars: Gullies
Title
Evidence for Recent Liquid Water on Mars: Gullies
Title
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Full Description:
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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.
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.
Full Description
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Date:
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06/22/2000
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NASA Center:
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Jet Propulsion Laboratory
NASA_Center
Jet Propulsion Laboratory
NASA Center
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Subject Category:
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Planet-Mars
Subject_Category
Planet-Mars
Subject Category
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Subject Category:
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Mars Global Surveyor
Subject_Category
Mars Global Surveyor
Subject Category
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Keywords:
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Camera
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Keywords:
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Liquid
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Keywords:
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Surveyor
Keywords
Surveyor
Keywords
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Keywords:
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Orbiter
Keywords
Orbiter
Keywords
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Keywords:
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Mars
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Keywords:
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Global
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Keywords:
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Water
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Keywords:
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MOC
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Keywords:
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Gullies
Keywords
Gullies
Keywords
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Audience:
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General Public
Audience
General Public
Audience
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facet_what:
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Earth
facet_what
Earth
facet_what
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facet_what:
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Surveyor
facet_what
Surveyor
facet_what
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facet_what:
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Polar
facet_what
Polar
facet_what
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facet_what:
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Mars
facet_what
Mars
facet_what
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facet_what:
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Mars Global Surveyor Orbiter (MGS)
facet_what
Mars Global Surveyor Orbiter (MGS)
facet_what
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facet_where:
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Jet Propulsion Laboratory
facet_where
Jet Propulsion Laboratory
facet_where
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facet_where:
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Mars
facet_where
Mars
facet_where
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facet_where:
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Jet Propulsion Laboratory (JPL)
facet_where
Jet Propulsion Laboratory (JPL)
facet_where
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facet_when:
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06-22-2000
facet_when
06-22-2000
facet_when
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facet_when_year:
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2000
facet_when_year
2000
facet_when_year
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Image #:
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PIA01034
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original_url:
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original_url
original_url
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UID:
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SPD-GRIN-GPN-2000-00 1984
UID
SPD-GRIN-GPN-2000-00 1984
UID
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Center:
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JPL
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Center Number:
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PIA01034
Center_Number
PIA01034
Center Number
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GRIN DataBase Number:
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GPN-2000-001984
GRIN_DataBase_Number
GPN-2000-001984
GRIN DataBase Number
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Creator-Photographer:
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NASA
Creator-Photographer
NASA
Creator-Photographer
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Original Source:
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digital
Original_Source
digital
Original Source
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