Domes on the Northern Plains
Domes on the Northern Plains
PSP_008561_2205  Science Theme: Volcanic Processes
This image shows a scene from the northern plains of Mars, near the edge of the lowland known as Acidalia Planitia.

Several features common to the area are visible. Most striking are the circular, pancake-shaped domes with pits or craters at the summit. These were once thought to be volcanic features, but recent research suggests that these are instead mud volcanoes. On Earth, mud volcanoes form when wet sediment is overpressured and squeezed out onto the surface. In many cases, these domes have finely fractured surfaces, which could be due to either desiccation (loss of water) or temperature changes in the ice.

The domes at this side are similar in color to the surrounding material, appearing as blue in HiRISE enhanced color. However, this may be due to a thin coating of dust, as an impact crater in the color swath appears to expose material of a different color.

The image includes some large troughs, up to hundreds of meters wide. These are also widespread in the area, forming crudely polygonal patterns on a multi-kilometer scale. These are distinct from the small polygons like those at the Phoenix landing site, which form by thermal cycling in ground ice; the origin of these giant polygons is still a subject of ongoing research.

Written by: Colin Dundas  (2 July 2008)
Acquisition date
24 May 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
300.9 km (187.0 miles)

Original image scale range
30.1 cm/pixel (with 1 x 1 binning) so objects ~90 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
76.1°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  357.5°
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Merged IRB
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IRB color
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Black and white
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non-map           (383MB)

IRB color
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Merged IRB
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Merged RGB
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RGB color
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B&W label
Color label
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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.