Signs of Aeolian and Periglacial Activity at Vastitas Borealis
NASA/JPL/University of Arizona
Signs of Aeolian and Periglacial Activity at Vastitas Borealis
PSP_001481_2410  Science Theme: Rocks and Regolith
Spanish 

WALLPAPER

800  1024
1152  1280
1440  1600
1920  2048
2560

HIFLYER

PDF, 11 x 17 in
This observation shows a region of approximately 7 x 7 kilometer (4.4 x 4.4 miles) located in Vastitas Borealis, part of the Northern Plains.

The surface imaged is relatively young, as indicated by the lack of recent impact craters. Aeolian and periglacial activity seem to be the dominant geological processes at work, as shown by numerous crisscrossing dust devil tracks and ubiquitous polygonal features, respectively.

Dust devils form when the sun warms up the air near a flat, dry surface. Warm air then rises quickly through the cooler air above and starts spinning, causing a forward motion. The spinning, forward-moving cell may pick up dust and sand as it advances, thus leaving behind a "clean" track. We infer from this image that a thin veneer of light-colored particles of dust and/or fine-grained sand cover relatively darker materials, apparent in the dust devil tracks.

The tracks pictured in this image are in many cases more than 30 meters (27 yards) wide and over 4 kilometers (2.5 miles) long, surpassing the dimensions of average terrestrial dust devil tracks.

The polygons visible in the subimage, which covers approximately 400 x 250 meters (350 x 225 yards), are in the order of 10 meters (0.9 yards) across; in some cases they are delimited by aligned rocks. Similar features in both shape and scale are found in terrestrial periglacial regions such as Antarctica, where ice is present at or near the surface.

Antarctica's polygons and rock alignments are produced by repeated expansion and contraction of the soil-ice mixture due to seasonal temperature oscillations; dry soil falling into the cracks form sand wedges and amplify this effect. This results in polygonal networks of stress fractures and in the resurfacing and sorting of rocks along these fractures.

(Thin diagonal lines are artifacts in the image).

Written by: Sara Martinez-Alonso   (24 March 2010)

Click to share this post on Twitter Click to share this post on Facebook Click to share this post on Google+ Click to share this post on Tumblr
 
Acquisition date
19 November 2006

Local Mars time:
15:13

Latitude (centered)
60.711°

Longitude (East)
318.541°

Range to target site
310.2 km (193.9 miles)

Original image scale range
31.0 cm/pixel (with 1 x 1 binning) so objects ~93 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle:
0.3°

Phase angle:
56.0°

Solar incidence angle
56°, with the Sun about 34° above the horizon

Solar longitude
137.9°, Northern Summer

North azimuth:
97°

Sub-solar azimuth:
336.1°
JPEG
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

JP2
Black and white
map-projected   (571MB)

IRB color
map-projected   (228MB)

JP2 EXTRAS
Black and white
map-projected  (200MB)
non-map           (251MB)

IRB color
map projected  (54MB)
non-map           (214MB)

Merged IRB
map projected  (160MB)

Merged RGB
map-projected  (151MB)

RGB color
non map           (191MB)
ADDITIONAL INFORMATION
B&W label
Color label
Merged IRB label
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
For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. 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. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.