Jointed Rocks Near Nilosyrtis Mensae
NASA/JPL/UArizona
Jointed Rocks Near Nilosyrtis Mensae
PSP_007701_2095  Science Theme: Sedimentary/Layering Processes
This image shows a part of the floor of a large, heavily modified crater in the Nilosyrtis Mensae region. The cliffs in the northern and southern parts of this image are walls of an irregular erosional pit and expose some of the infilling material. The crater itself was mostly filled in and then eroded.

An interesting aspect of the rocks at the edge of the pit is the widespread fracturing. The rocks of the upper layer are broken up along cracks called joints. On Earth, these commonly form when rocks are subjected to stresses, due to factors like cooling or the removal of weight due to erosion.

The upper layer forms the cliffs because it is relatively hard to erode, and protects the underlying material. This commonly happens when a lava flow covers weaker sedimentary rocks, but the joints at this site suggest that this resistant layer might be sedimentary. The rock appears to be breaking into broad, thin slabs; lava flows often fracture into columns or relatively uniform blocks as they cool.

Written by: Colin Dundas  (7 May 2008)
 
Acquisition date
18 March 2008

Local Mars time
14:52

Latitude (centered)
29.126°

Longitude (East)
72.180°

Spacecraft altitude
288.9 km (179.6 miles)

Original image scale range
28.9 cm/pixel (with 1 x 1 binning) so objects ~87 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
1.6°

Phase angle
39.2°

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

Solar longitude
46.7°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  359.3°
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   (985MB)

IRB color
map-projected   (433MB)

JP2 EXTRAS
Black and white
map-projected  (469MB)
non-map           (486MB)

IRB color
map projected  (155MB)
non-map           (352MB)

Merged IRB
map projected  (264MB)

Merged RGB
map-projected  (256MB)

RGB color
non map           (346MB)
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/University of Arizona

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.