Noachis quadrangle

The Noachis quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Noachis quadrangle is also referred to as MC-27 (Mars Chart-27).^[1]

The Noachis quadrangle covers the area from 300° to 360° west longitude and 30° to 65° south latitude on Mars. It lies between the two giant impact basins on Mars: Argyre and Hellas. Noachis is so densely covered with impact craters that it is deemed among the oldest landforms on Mars. When a location on Mars is as old, it is said to be Noachian in age.

In many places on Mars, buried craters are being exposed.^[2] That is a crater formed long ago, then was buried, and is now being exposed. This takes place in Noachis, as Noachis is plenty old enough for this process to take place.

The first piece of human technology to land on Mars landed (crashed) in the Noachis quadrangle. The Soviet's Mars 2 crashed at 44.2° S and 313.2° W. It weighed about one ton. The automated craft attempted to land in a giant dust storm. To make conditions even worse, this area also has many dust devils.^[3]

Scalloped topography

Certain regions of Mars display scalloped-shaped depressions. The depressions are believed to be the remains of an ice-rich mantle deposit. Scallops are created when ice sublimates from frozen soil. This mantle material probably fell from the air as ice formed on dust when the climate was different due to changes in the tilt of the Mars pole.^[4] The scallops are typically tens of meters deep and from a few hundred to a few thousand meters across. They can be almost circular or elongated. Some appear to have coalesced, thereby causing a large heavily pitted terrain to form. The process of producing the terrain may begin with sublimation from a crack because there are often polygon cracks where scallops form.^[5][6]

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  Scalloped Terrain at Peneus Patera, as seen by HiRISE. Scalloped terrain is quite common in some areas of Mars.

Dust Devil Tracks

Many areas on Mars experience the passage of giant dust devils. A thin coating of fine bright dust covers most of the Martian surface. When a dust devil goes by it blows away the coating and exposes the underlying dark surface creating tracks. Dust devils have been seen from the ground and from orbit. They have even blown the dust off of the solar panels of the two Rovers on Mars, thereby greatly extending their lives.^[7] The twin Rovers were designed to last for 3 months, instead they have lasted more than six years and are still going after over 8 years. The pattern of the tracks have been shown to change every few months.^[8] The image below of Russel Crater shows changes in dust devil tracks over a period of only three months, as documented by HiRISE. Other Dust Devil Tracks are visible in the picture of Frento Vallis.

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  Russell Crater Dust Devil Changes, as seen by HiRISE. Click on image to see changes in dust devil tracks in just 3 months.

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  Frento Vallis, as seen by HiRISE. Click on image to see better view of Dust Devil Tracks.

Craters

Impact craters generally have a rim with ejecta around them, in contrast volcanic craters usually do not have a rim or ejecta deposits. As craters get larger (greater than 10 Km in diameter) they usually have a central peak.^[9] The peak is caused by a rebound of the crater floor following the impact.^[10] Sometimes craters will display layers. Craters can show us what lies deep under the surface.

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  Maunder Crater, as seen by HiRISE. The overhang is part of the degraded south (toward bottom) wall of crater. The scale bar is 500 meters long.

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  Asimov Crater, as seen by HiRISE. Bottom of picture shows southeastern wall of crater. Top of picture is edge of mound that fills most of the crater.

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  Gullies on mound in Asimov Crater, as seen by HiRISE.

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  Layers in west slope of Asimov Crater, as seen by HiRISE.

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  Close-up of layers in west slope of Asimov Crater. Shadows show the overhang. Some of the layers are much more resistant to erosion, so they stick out. Image from HiRISE.

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  East Slope of Central Pit in Asimov Crater, as seen by HiRISE. Click on image to see more details of the many gullies.

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  Kaiser Crater (large crater in upper part of image)context for THEMIS image.

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  Detail of south wall of Kaiser Crater, as seen by THEMIS. Top of image shows part of a dune field.

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  Rabe Crater Floor, as seen by HiRISE. Click on image to see layers. Dark sand that made the dunes was probably blown in from elsewhere.

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  Crater that was buried in another age and is now being exposed by erosion, as seen by the Mars Global Surveyor, under the MOC Public Targeting Program.

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  Floor of crater in Noachis quadrangle, as seen by HiRISE under HiWish program.

Sand Dunes

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  Dark dunes (probably basalt), in an intracrater dune field, Noachis. Picture from Mars Global Surveyor, under the MOC Public Targeting Program.

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  Wide view of dunes in Noachis, as seen by HiRISE.

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  Close-up View of dunes in previous image, as seen by HiRISE. Note how sand barely covers some boulders.

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  Barchan sand dunes in the Hellespontus region, as seen by HiRISE. The horns point in the downwind direction.

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  Proctor Crater ripples and dunes, as seen by HiRISE.

Gallery

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  Quadrangle map of Noachis labeled with major features.

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  Dissected Mantle with layers, as seen by HiRISE.

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  Twisted Terrain in Hellas Planitia, but actually located in Noachis quadrangle. Imagine trying to walk across this. Image taken with HiRISE.

References

See also

• Climate of Mars
• Water on Mars
• Geology of Mars