Blocks and Valleys in Southwestern Melas Chasma
Blocks and Valleys in Southwestern Melas Chasma
PSP_004384_1705  Science Theme: Landscape Evolution
This HiRISE image covers a portion of the wallrock and canyon floor in southwestern Melas Chasma.

Along the floor of Melas Chasma is an unusual blocky deposit composed of light-toned blocks in a darker matrix. The high resolution of the HiRISE image reveals layers only a few meters thick in some of the light-toned blocks. The blocks vary in size but most fall between 100 to 500 meters in diameter.

Although most blocks appear rounded, others have angular edges and can be very elongated. The morphologies of the blocks suggest ductile deformation, such as from a flow or by tectonic disruption after emplacement. Windblown (aeolian) ripples are interspersed between the blocks in the darker matrix.

Small valleys can be seen along the wallrock to the south. The wallrock is a mixture of two geologic units that differ mainly in their reflectance. The light-toned unit appears to be thinner and only exposed in localized spots. Several of the light-toned deposits are seen only in the valleys, suggesting they were either deposited or are exposed by erosion.

Written by: Cathy Weitz  (8 August 2007)

This is a stereo pair with ESP_012216_1705.
Acquisition date
04 July 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
257.7 km (160.2 miles)

Original image scale range
28.3 cm/pixel (with 1 x 1 binning) so objects ~85 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
45°, with the Sun about 45° above the horizon

Solar longitude
269.7°, Northern Autumn

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  337.8°
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   (1988MB)

IRB color
map-projected   (774MB)

Black and white
map-projected  (750MB)
non-map           (1004MB)

IRB color
map projected  (293MB)
non-map           (765MB)

Merged IRB
map projected  (477MB)

Merged RGB
map-projected  (454MB)

RGB color
non map           (741MB)
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.