Monday, April 16, 2012

A Volcanic Pit Chain and Dust Avalanches

This observation shows a volcanic pit chain in Amazonis Planitia.

Associated with two of the pits are meandering channels that splay into distributary patterns to the north. This suggests that the pits are eruptive centers, with the channels carved by lava.

A close-up image shows the eastern wall of the westernmost pit. The fluid-like streaks are the products of dust avalanches, with the dark color resulting from a thin coating of dust that has been removed from the surface.

The upper wall of the pit shows at least four distinct layers, each representing a sequence of one or more lava flows. A hazy, blueish haze bounds the outer circumference of the pit, perhaps resulting from suspended dust. The plains near the pit appear heavily muted, indicating a thick dust cover.

Photo credit: NASA/JPL/University of Arizona

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