Ancient Rivers
NASA/JPL/University of Arizona
Ancient Rivers
ESP_042924_2195  Science Theme: Fluvial Processes


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Early in Martian history, liquid water energetically carved the surface, forming channel systems that look remarkably similar to river valleys and drainage networks on Earth. Exactly how these channels formed—by rainfall, snowmelt, or seepage from underground springs—is often debated.

The answer has important ramifications about the early Martian climate. Clues about the source of the water may indicate the shape, layout, and scale of the various tributaries in a channel system.

Our image shows an example of just such a water-carved channel. The channel pattern, called “dendritic” because of its tree–like branching, begins at the top of the image and runs down over the rim of an ancient impact basin across the basin floor.

The soil surface overlying these channels, and indeed the entire landscape, has been changed and reworked over the intervening millions of years, by the combined actions of wind and ice. Over time, the original channels become muted or even erased. Nevertheless, some characteristics of the smallest tributary channels are still visible at scales seen by HiRISE.

Written by: Mike Mellon (audio: Tre Gibbs)   (13 January 2016)

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Acquisition date
23 September 2015

Local Mars time:

Latitude (centered)

Longitude (East)

Range to target site
301.8 km (188.6 miles)

Original image scale range
30.2 cm/pixel (with 1 x 1 binning) so objects ~91 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
45.3°, Northern Spring

North azimuth:

Sub-solar azimuth:
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   (735MB)

IRB color
map-projected   (383MB)

Black and white
map-projected  (314MB)
non-map           (344MB)

IRB color
map projected  (109MB)
non-map           (279MB)

Merged IRB
map projected  (207MB)

Merged RGB
map-projected  (201MB)

RGB color
non map           (270MB)
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

For information about NASA and agency programs on the Web, visit: 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.