PSP_002946_1765 shows a portion of interior layered deposits (ILD) in Juventae Chasma.

Juventae Chasma is a large depression near the equatorial canyon system Valles Marineris. The scene is along the top of a mound of layered deposits on the floor of Juventae Chasma. Dunes are seen in the low-lying, darker regions. Very fine layers are also seen (see subimage, approximately 1 km across). Understanding what kinds of materials formed the layers, how they were set in place, and how they have evolved will provide insight into Martian geologic history.

Many of the Martian chasmata (plural of chasma) contain ILD like these. The ILD were deposited a long time ago, but the actual method is unknown. It has been suggested that sedimentary layers in standing bodies of water or volcanic ash deposits comprise the ILD. The alternating layers could indicate regular, repeating cycles of deposition. It is possible that these layers once covered the entire chasma floor.

The IDL shown here have been modified by wind erosion. The yardangs seen near the top right of the image are evidence for wind sculpting of the deposits. It is interesting to note that there are very few craters in this scene, especially in the areas with visible layers. One crater can be found about half-way down the left side of the image amidst layers, and several craters are seen in the dark material on the right side of the image. This suggests that the ILD are eroding here fast enough to erase small craters before large numbers of them can accumulate.
Written by: Kelly Kolb

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For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. 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. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.