Knobs and Mounds on the Northern Plains
Knobs and Mounds on the Northern Plains
PSP_001916_2220  Science Theme: Composition and Photometry
This observation shows surface features on the Northern plains of Mars.

Light-toned mounds occur across the image. The northern (top) part is dominated by small knobs or patches, while there are features hundreds of meters across to the south. The larger features frequently have one or more craters and an irregular shape; it has been proposed that these features are mud volcanoes, which erupt mud instead of lava. On Earth, mud volcanoes usually form in conditions of tectonic pressurization or rapid burial of sediments.

At high resolution, the knobs show some fine lineations which may be wind-blown material, but are otherwise very smooth. In between the mounds the surface is rough and rich in boulders. The few boulders on the mounds were likely ejected from nearby impact craters. Information like this from HiRISE images provides useful constraints on the formation and material of these knobs and cones.

Written by: Colin Dundas  (17 January 2007)
Acquisition date
23 December 2006

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
300.5 km (186.8 miles)

Original image scale range
from 30.3 cm/pixel (with 1 x 1 binning) to 60.5 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
55°, with the Sun about 35° above the horizon

Solar longitude
155.1°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  346.5°
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   (710MB)

IRB color
map-projected   (464MB)

Black and white
map-projected  (345MB)
non-map           (237MB)

IRB color
map projected  (138MB)
non-map           (306MB)

Merged IRB
map projected  (211MB)

Merged RGB
map-projected  (216MB)

RGB color
non map           (291MB)
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’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.