Layers at Margin of Hellas Impact Basin
Layers at Margin of Hellas Impact Basin
PSP_008387_1510  Science Theme: Geologic Contacts/Stratigraphy
This image shows an area within a depression at the northern inner rim of the Hellas impact basin. Prominent layers of rock are visible, expressed here as topographic benches and cliffs.

The layers exhibit various brightnesses (in the black and white image, from the HiRISE red filter) and colors (in the color RGB product). The geology of the Hellas basin is complex, with the original impact that formed the structure occurring more then four billion years ago. Since then, the basin has been modified by many processes, including volcanism, wind, water, and maybe glacial activity.

This makes it challenging, without further study, to know the origin of the layers seen here. However, some insight is gained simply by looking at the texture of the layers, which HiRISE can see with its high resolution. For example, many of the bright layers appear jointed; that is, they contain cracks in a regular, commonly polygonal, arrangement. Volcanic rocks can form such textures upon cooling, as can water-rich sediments upon drying.

Regular patterns of ripples are visible throughout the image, indicating pervasive wind activity. The color sub-image shows two boulders that have rolled from the cliffs to the east. Bounce marks are also apparent between the boulders and cliffs. Because the bounce marks have not been filled in with dust or sand, the boulders must have rolled down the slope fairly recently.

Written by: Nathan Bridges  (25 June 2008)
Acquisition date
10 May 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
261.2 km (162.3 miles)

Original image scale range
52.2 cm/pixel (with 2 x 2 binning) so objects ~157 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
71°, with the Sun about 19° above the horizon

Solar longitude
70.2°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  48.5°
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   (235MB)

IRB color
map-projected   (129MB)

Black and white
map-projected  (118MB)
non-map           (128MB)

IRB color
map projected  (47MB)
non-map           (127MB)

Merged IRB
map projected  (216MB)

Merged RGB
map-projected  (212MB)

RGB color
non map           (115MB)
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.