Friday, November 22, 2013

Hydrated Sulfate Landslides in Ophir Chasma

Giant landslides in Ophir Chasma host a variety of geologic surfaces and mineralogies. Some possess a variety of hydrated sulfate minerals that formed in the presence of partially acidic liquid water.

This image of an ancient, approximately 3 billion year-old landslide shows two distinct surface albedos, which are proportions of reflected light. These different toned surfaces also mark a transition from one sulfate mineralogy to another and variations in surface evolution.

The upper slopes to the north are light-toned due to an abundance of hydrated sulfate minerals and bright surface dust. The surfaces that make up the southern portions of the landslide are darker in tone due to the greater frequency of dark sediment that form strings of sand drifts. Additionally, the underlying units of bedrock consist of darker minerals with less hydration then those to the north, implying a change in the ancient aqueous environments that formed them.

Photo credit: NASA/JPL/University of Arizona

Note: For more information, see PIA17702: Hydrated Sulfate Landslides in Ophir Chasma.

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