Friday, May 7, 2010

Light-Toned Rocks inside a Crater

This approximately 20 kilometer diameter impact crater is located just to the south of Coprates Chasma in Valles Marineris.

Near the center of the crater are some light-toned rocks. These rocks are very jumbled and broken up rather than flat-lying and layered. These observations suggest that the light-toned rocks once existed below the current terrain and were brought up by the process that created the crater.

Several other craters around Valles Marineris also reveal light-toned rocks in their central peaks suggesting that the light-toned rocks are a regional unit that is buried beneath the lava plains that now surround Valles Marineris.

Photo credit: NASA/JPL/University of Arizona

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