Blockfall on the North Polar Layered Deposits
Blockfall on the North Polar Layered Deposits
ESP_036436_2645  Science Theme: Climate Change
The North Polar layered deposits (NPLD) are a stack of layers of ice and dust at the North Pole of Mars. The layers are thought to have been deposited over millions of years, as the atmosphere changed in response to the varying tilt of the planet’s axis. Learning to read this record could tell us much about recent conditions on Mars, but we first need to understand the processes that have shaped the NPLD.

Comparing this HiRISE image with an observation from the previous Martian year reveals an example of one of these processes: block falls. The slope is steep and fractured here, and a large chunk of dusty ice has tumbled down the slope and broken apart. Scientists on the HiRISE team are studying this process at many locations in order to measure how quickly the NPLD is changing.

Other changes are visible on the slope as well: sand patches have shifted, and in some places on the slope they have been eroded into grooves or troughs, most likely by the carbon dioxide frost (dry ice) that covers the North Pole in the winter.

Written by: Colin Dundas  (18 June 2014)

This is a stereo pair with ESP_036977_2645.
Acquisition date
05 May 2014

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
318.3 km (197.9 miles)

Original image scale range
32.2 cm/pixel (with 1 x 1 binning) so objects ~97 cm across are resolved

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

Solar incidence angle
65°, with the Sun about 25° above the horizon

Solar longitude
126.2°, Northern Summer

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North azimuth:  110°
Sub-solar azimuth:  323.9°
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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’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.