Martian Dichotomy Boundary
Martian Dichotomy Boundary
PSP_001414_2165  Science Theme: Geologic Contacts/Stratigraphy
This observation crosses over a part of the hemispheric dichotomy boundary on Mars which separates low-lying northern plains from older southern highlands.

In the northern part of the scene, much of the surface is covered with small boulders, most only 1 to 2 meters wide (1 meter is approximately 1 yard). In other areas, it appears that sand or dust has accumulated in depressions, forming light patches. These areas also show short sinuous or linear features, likely ripples formed from wind-blown material. The southern part contains an old valley, now mantled by later deposits, and has a pitted texture due to erosion.

It has been proposed that the lowland was once filled by an ocean. In this case several arcuate or linear features along the boundary slope could be old shorelines, but this interpretation is still debated. The features have been modified by erosion, and in some cases appear to slope towards the highlands.

Written by: Colin Dundas  (6 December 2006)

This is a stereo pair with PSP_001968_2165.
Acquisition date
14 November 2006

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
293.5 km (182.4 miles)

Original image scale range
58.7 cm/pixel (with 2 x 2 binning) so objects ~176 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
49°, with the Sun about 41° above the horizon

Solar longitude
135.3°, Northern Summer

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  357.2°
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   (280MB)

IRB color
map-projected   (143MB)

Black and white
map-projected  (117MB)
non-map           (147MB)

IRB color
map projected  (43MB)
non-map           (110MB)

Merged IRB
map projected  (273MB)

Merged RGB
map-projected  (261MB)

RGB color
non map           (106MB)
Map-projected, reduced-resolution
Full resolution JP2 download
Anaglyph details page

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.