Down in the Paleochannels
Down in the Paleochannels
ESP_042625_1655  Science Theme: Aeolian Processes
Transverse aeolian ridges—or TAR—are mysterious, wind-blown features that are intermediate in size between ripples and much larger sand dunes.

Ripples form from hopping sand grains, and dunes form from sand grains being blown over longer distances. One hypothesis for TAR formation is that larger grains like pebbles are rolled on top of smaller ripples; then, finer dust settles into the cracks, “inflating” the pebbles, making the TAR larger than typical ripples.

Looking between the TAR, one sees a network of ancient, beaten-up channels that were carved by water, lava, or both.

This whole area is located in Solis Planum, an interesting, tectonic terrain south of Noctis Labryinthus which generally slopes toward the south.

Written by: Kirby Runyon (narration: Tre Gibbs)  (25 November 2015)
Acquisition date
30 August 2015

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
252.1 km (156.7 miles)

Original image scale range
from 25.2 cm/pixel (with 1 x 1 binning) to 50.4 cm/pixel (with 2 x 2 binning)

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
50°, with the Sun about 40° above the horizon

Solar longitude
34.8°, 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   (1180MB)

IRB color
map-projected   (814MB)

Black and white
map-projected  (600MB)
non-map           (536MB)

IRB color
map projected  (338MB)
non-map           (739MB)

Merged IRB
map projected  (378MB)

Merged RGB
map-projected  (365MB)

RGB color
non map           (708MB)

HiClip mini HD

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.