Layers in Spallanzani Crater
NASA/JPL/University of Arizona
Layers in Spallanzani Crater
PSP_003442_1215  Science Theme: Sedimentary/Layering Processes
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This image shows light-toned layered deposits along the floor of Spallanzani crater, a 72 kilometer (45 mile) diameter crater located just southeast of Hellas Planitia.

These layered deposits may be remnant sediments once deposited within the crater. Mechanisms for sediment deposition include windblown debris, airfall volcanic ash, or sediments that accumulated in a lake on the crater floor.

The layers within Spallanzani Crater are eroding in a stair-stepped pattern. Each layer appears as a sequence of a broad flat area or plateau, which drops off abruptly down to the next flat surface (see subimage; 1045 x 585, 597 KB). This stair-stepped pattern suggests that the layers have discreet boundaries that may be the result of differing compositions, time of deposition, or both. Near, but not at the edge of each plateau, the material is fracturing into polygonal plates or blocks that tilt downward away from the plateau center (see subimage).

The slopes are covered in debris, and not fallen plates or blocks from the plateau edge. This suggests that the layers are composed of weak materials that are protected by a stronger, more coherent surface.

The crater is named after the 18th century Italian biologist, Lazzaro Spallanzani (1729-1799).

Written by: Maria Banks  (5 July 2007)

This is a stereo pair with PSP_003574_1215.
 
Acquisition date
21 April 2007

Local Mars time:
15:50

Latitude (centered)
-58.069°

Longitude (East)
86.392°

Spacecraft altitude
251.6 km (157.3 miles)

Original image scale range
25.2 cm/pixel (with 1 x 1 binning) so objects ~76 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle:
1.0°

Phase angle:
58.1°

Solar incidence angle
59°, with the Sun about 31° above the horizon

Solar longitude
223.4°, Northern Autumn

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  25.5°
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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.