Scarp-Fed Dark Dunes
NASA/JPL/UArizona
Scarp-Fed Dark Dunes
PSP_010344_2655  Science Theme: Polar Geology
Multiple levels within the north polar layered deposits are visible in this HiRISE image.

The north polar layered deposits (NPLD) are a stack of dusty water-ice layers that are thought to record information about past Martian climates in the same way that ice-caps on the Earth record variations in our climate. These Martian layers are visible in the walls of troughs and scarps eroded into the stack. One such scarp-face is visible on the far left of the full image and decreases in height from left to right.

Scientists continue to debate the length of time required to accumulate this stack of layers with estimates ranging from a few million years to about a billion years. Although we donít yet know which layer corresponds to which time in Marsí history, we can still use these layers to try to understand how the climate has changed over this period.

The topmost layers, which are the most recent (far left of the image), are brighter and appear brownish in this false-color view. They are interpreted to be a mixture of water ice and dust. The lower layering is more complex and appears to be a mixture of bright whiteiish layers (that we think are ice) and dark blue-ish layers (which we think are mostly sand). A large pit in the center of the image penetrates deeply into this stack of layers and shows these alternating sandy and icy layers extending to depths of hundreds of meters (about 1000 feet).

Erosion of the dark sandy layers releases sandy material which collects into dunes such as the linear example that stretches across the middle of this image.


Written by: Shane Byrne  (19 August 2009)

This is a stereo pair with PSP_009885_2655.
 
Acquisition date
10 October 2008

Local Mars time
09:59

Latitude (centered)
85.689°

Longitude (East)
179.402°

Spacecraft altitude
314.9 km (195.7 miles)

Original image scale range
66.1 cm/pixel (with 2 x 2 binning) so objects ~198 cm across are resolved

Map projected scale
50 cm/pixel

Map projection
Polarstereographic

Emission angle
17.5°

Phase angle
84.7°

Solar incidence angle
70°, with the Sun about 20° above the horizon

Solar longitude
139.7°, Northern Summer

For non-map projected images
North azimuth:  175°
Sub-solar azimuth:  321.6°
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non-map           (86MB)

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RGB color
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ANAGLYPHS
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Full resolution JP2 download
Anaglyph details page

ADDITIONAL INFORMATION
B&W label
Color label
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Merged RGB label
EDR products
HiView

NB
IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

USAGE POLICY
All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
NASA/JPL/University of Arizona

POSTSCRIPT
NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.