Fretted Terrain and Fresh Crater
NASA/JPL-Caltech/UArizona
Fretted Terrain and Fresh Crater
PSP_006661_2185  Science Theme: Impact Processes
This image shows fretted terrain in a Northern Hemisphere trough. Fretted terrain is the jumbled, lineated material filling the trough. The lineations (lines) mark movement of material, usually away from trough walls.

Much of the material filling the trough has a pitted texture. This likely formed from sublimation, when ice goes directly to a gas. When subsurface ice sublimates, it leaves a hole beneath the surface. The overlying material collapses and fills this hole, causing a pit to form.

The terrain outside the trough is covered in craters and muted circles. The muted circles are craters that have relaxed over time. As time goes on, the crater’s topography becomes more subdued. Relaxation in this region is thought to occur because of the presence of ground ice.

In the center of the trough is a fresh crater; we call it “fresh” because of its very steep walls. The big rocks in and around the crater are ejecta, material that was thrown out when the impact occurred, some of which has rolled back inside. The color image shows that one of the walls is much bluer than its surroundings. This might be from smaller particles blown into the crater by the wind.

Written by: Kelly Kolb  (3 March 2008)
 
Acquisition date
28 December 2007

Local Mars time
14:23

Latitude (centered)
38.114°

Longitude (East)
28.853°

Spacecraft altitude
297.1 km (184.7 miles)

Original image scale range
30.0 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
Equirectangular

Emission angle
7.7°

Phase angle
41.1°

Solar incidence angle
47°, with the Sun about 43° above the horizon

Solar longitude
9.3°, Northern Spring

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  327.4°
JPEG
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

JP2
Black and white
map-projected   (1762MB)

IRB color
map-projected   (780MB)

JP2 EXTRAS
Black and white
map-projected  (943MB)
non-map           (767MB)

IRB color
map projected  (253MB)
non-map           (553MB)

Merged IRB
map projected  (452MB)

Merged RGB
map-projected  (461MB)

RGB color
non map           (536MB)
ADDITIONAL INFORMATION
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products
HiView

NB
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

USAGE POLICY
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/JPL-Caltech/UArizona

POSTSCRIPT
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.