Layered Deposits in Ritchey Crater
Layered Deposits in Ritchey Crater
PSP_003249_1510  Science Theme: Geologic Contacts/Stratigraphy
This image shows eroding layered deposits in Ritchey Crater, a large impact crater in the Southern highlands.

Three general units are visible: a relatively dark upper layer, a light middle unit, and the floor material, which may be mostly obscured by dust. The dark cap layer appears to be relatively hard and resistant, while the light material is weak. Once the upper layer is removed, the light layer does not last long.

This subimage from the top center part of the image shows this stack. The dark unit is thin and breaking into boulders. The light material is actually divided into smaller layers, and is pervasively fractured. However, the boulders falling from the edge are mostly small and rarely remain intact if they move more than a few meters. The cracking of the layer could be due to water loss from the layer, or to regional tectonic effects such as stresses from burial and erosion. The base unit is partially covered by wind-blown ripples.

It is unclear how each of these layers formed. Volcanic ash layers, lake or stream deposits, or sandstone deposited by dunes can all produce horizontal layers. Unraveling the origin would provide important clues to Mars' past.

Written by: Colin Dundas  (10 October 2007)

This is a stereo pair with PSP_003526_1510.
Acquisition date
06 April 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
254.7 km (158.3 miles)

Original image scale range
25.9 cm/pixel (with 1 x 1 binning) so objects ~78 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
53°, with the Sun about 37° above the horizon

Solar longitude
214.1°, Northern Autumn

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  9.8°
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   (717MB)

IRB color
map-projected   (376MB)

Black and white
map-projected  (329MB)
non-map           (407MB)

IRB color
map projected  (116MB)
non-map           (315MB)

Merged IRB
map projected  (178MB)

Merged RGB
map-projected  (170MB)

RGB color
non map           (314MB)
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.