Sinuous Ridges in Elysium Planitia
Sinuous Ridges in Elysium Planitia
ESP_068041_1845  Science Theme: Fluvial Processes
A sinuous ridge is a thin and meandering formation that gives the appearance of a stream channel, but stays raised above the surface rather than incised into it. It is believed that these ridges were once stream channels that cut down into the surface.

Flowing water can have a number of effects on a channel bed, such as sorting grains and depositing rocks, all while removing loose material. The water can also carry a number of dissolved minerals that become deposited and cement the remaining grains together. The result is a stream bed that has become “armored.”

Once the stream stops flowing and dries up, this armored layer can resist future erosion. Over the millions of years that follow, forces such as wind can gradually remove the original material of the surrounding terrain, but the stream bed can remain. Examining the characteristics of the ridge can reveal clues about the amount of water and the flow speed that existed long ago.

Written by: Mike Mellon (narration: Tre Gibbs)  (18 March 2021)
Acquisition date
31 January 2021

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
271.9 km (169.0 miles)

Original image scale range
27.2 cm/pixel (with 1 x 1 binning) so objects ~82 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

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

Solar longitude
356.3°, Northern Winter

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  358.3°
Black and white
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IRB color
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Merged IRB
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Merged RGB
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RGB color
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Black and white
map-projected   (744MB)

IRB color
map-projected   (385MB)

Black and white
map-projected  (327MB)
non-map           (430MB)

IRB color
map projected  (129MB)
non-map           (351MB)

Merged IRB
map projected  (205MB)

Merged RGB
map-projected  (197MB)

RGB color
non map           (345MB)
10K (TIFF)

B&W label
Color label
Merged IRB label
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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

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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.