HiRISE | Eroding Mesas Forming Seif and Barchan Dunes (PSP_007676

NASA/JPL/University of Arizona

Eroding Mesas Forming Seif and Barchan Dunes
PSP_007676_1385 Science Theme: Aeolian Processes

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This observation shows sand dunes within the Hellespontus region of Mars.

The sand appears to come from the layered mesas and knobs, features that have been eroded by powerful winds. The dunes here have a morphology indicating formative winds blowing from east to west (from right to left).

The primary indicator for this is the orientation of the barchan dunes, a dune type that on Earth has its horns in the downwind direction. Also, the steepest faces of the dunes are on the dunes’ eastern side, indicating easterly winds.

In addition to the barchans, some of the dunes are organized into a “seif,”, or longitudinal, form whereby their long axis is parallel to the wind. These are seen emanating from the sand sheets next to the mesas and knobs, as well as from some barchan horns.

Written by: Circe Verba, Nathan Bridges (18 April 2008)

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Acquisition date:	16 March 2008	Local Mars time:	3:09 PM
Latitude (centered):	-41.407 degrees	Longitude (East):	44.587 degrees
Range to target site:	256.9 km (160.6 miles)	Original image scale range:	51.4 cm/pixel (with 2 x 2 binning) so objects ~154 cm across are resolved
Map projected scale:	50 cm/pixel and North is up	Map projection:	EQUIRECTANGULAR
Emission angle:	6.7 degrees	Phase angle:	69.7 degrees
Solar incidence angle:	74 degrees, with the Sun about 16 degrees above the horizon	Solar longitude:	45.8 degrees, Northern Spring
For non-map projected products:
North azimuth:	97 degrees	Sub-solar azimuth:	49.8 degrees
For map-projected products
North azimuth:	270 degrees	Sub solar azimuth:	222.4 degrees

NEARBY OBSERVATIONS

Barchan Dunes in Crater
Dunes and Layered Mesas in Crater in Hellespontus Region
Dunes
Sand Dunes
Dunes
Dunes on Western Edge of Hellas Planitia

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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: Image: 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.