Structure of the North Polar Layered Deposits
Structure of the North Polar Layered Deposits
PSP_009293_2645  Science Theme: Polar Geology
The polar layered deposits on Mars are thought contain a record of global climate changes, similar to ice ages on Earth. This image shows that the geologic history of the north polar layered deposits (NPLD) has been complex enough to form angular unconformities.

An angular unconformity represents a gap in the geologic record, where erosion has removed material followed by deposition of more material on the eroded surface. In this image, the angular unconformities are recognized by the truncation, or cutting off of layers, for example right of center and at bottom center.

Also visible in this image are numerous streaks, perhaps caused by recent redistribution of frost by winds.

Written by: Ken Herkenhoff  (27 August 2008)
Acquisition date
20 July 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
320.4 km (199.1 miles)

Original image scale range
32.1 cm/pixel (with 1 x 1 binning) so objects ~96 cm across are resolved

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

Solar incidence angle
60°, with the Sun about 30° above the horizon

Solar longitude
101.3°, Northern Summer

For non-map projected images
North azimuth:  120°
Sub-solar azimuth:  321.6°
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Black & white is 5 km across; enhanced color about 1 km
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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

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.