Where Does the Sand Come From?
Where Does the Sand Come From?
ESP_051780_1725  Science Theme: Mass Wasting Processes
The grains of sand that make up sand dunes on Earth and Mars have a hazardous existence because of the way that they travel. Wind-blown sand is lifted above the surface of each planet before crashing onto the ground and bouncing in a sequence of repeated hops, a process called saltation.

Sand grains can also roll along the ground as they are blown by the wind, and they are also jostled by other sand gains that are similarly flying across the surface. All of these repeated impacts tend to wear down the sand grains, smoothing them into a more spherical shape and breaking off small fragments that supply the vast dust deposits of Mars. This process (known as comminution) ultimately destroys sand grains and limits the length of time that the particles exist. The fact that we see active sand dunes on Mars today requires that sand particles must be resupplied to replace the grains that are lost over time. Where are the modern day sources of sand on Mars?

This image shows one possible place where sand grains are being produced on Mars today. Discovered in images from the Context Camera, this region exhibits dark material that is being eroded from dark layers in the bedrock of a semicircular depression near the boundary of the Southern highlands and the Northern lowlands. Downslope lineations support the notion that these dark sediments are derived locally, and did not accumulate here by coincidence because of the winds.

This image and the processes described therein was suggested and studied by Ariana Boyd (University of Tennessee).

Written by: Paul Geissler (audio: Tre Gibbs)  (9 October 2017)
Acquisition date
13 August 2017

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
266.9 km (165.9 miles)

Original image scale range
26.7 cm/pixel (with 1 x 1 binning) so objects ~80 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
48°, with the Sun about 42° above the horizon

Solar longitude
46.6°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  38.0°
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

Black and white
map-projected   (429MB)

IRB color
map-projected   (246MB)

Black and white
map-projected  (198MB)
non-map           (234MB)

IRB color
map projected  (67MB)
non-map           (206MB)

Merged IRB
map projected  (95MB)

Merged RGB
map-projected  (91MB)

RGB color
non map           (198MB)
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

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

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

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.