Summit Dunes and Their Sand Sources
NASA/JPL-Caltech/UArizona
Summit Dunes and Their Sand Sources
ESP_054082_1765  Science Theme: Aeolian Processes
The ultimate origin of the sediment that forms Martian dunes has long been debated. While sand dunes on Earth are primarily sourced by quartz-bearing components of granitic continental crust, it’s often suggested that sand on Mars derives from eroded volcanic flows or sedimentary deposits, but exact sources are often vague.

This image reveals a unique situation where this small dune field occurs along the summit of the large 1-mile-tall mound near the center of Juventae Chasma. The layered mound slopes are far too steep for dunes to climb, and bedform sand is unlikely to come from purely airborne material. Instead, the mound’s summit displays several dark-toned, mantled deposits that are adjacent to the dunes and appear to be eroding into fans of sandy material.

Along with local HiRISE images, spectral data from other instruments on MRO have confirmed such units are likely to be the sand source for these mound summit dunes and reveal how landscape evolution on Mars might occur.


Written by: Matthew Chojnacki (narration: Tre Gibbs)  (1 October 2018)
 
Acquisition date
08 February 2018

Local Mars time
15:12

Latitude (centered)
-3.533°

Longitude (East)
298.281°

Spacecraft altitude
265.9 km (165.2 miles)

Original image scale range
27.8 cm/pixel (with 1 x 1 binning) so objects ~83 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
16.9°

Phase angle
66.9°

Solar incidence angle
53°, with the Sun about 37° above the horizon

Solar longitude
126.7°, Northern Summer

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  35.4°
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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.