This image shows the end of a small channel near Athabasca Valles on Mars. Athabasca is an example of a Martian “outflow channel,” likely carved by a massive flood of groundwater. However, it is now coated with a thin veneer of lava, following a massive volcanic eruption that flowed down the channel.
This smaller channel is also covered by the same lava flow. It might have originally been carved by water and later draped by lava that partially drained away, but it is also possible that hot, swift lava cut down into the ground. In either case, the reason a channel formed here is the ridge running across the image. Once fluid reached the top of this ridge, flow was concentrated there and carved a deeper channel.
The upstream half of the channel is visible in PSP_008265_1860 .
Written by: Colin Dundas (17 July 2013)
This is a stereo pair with ESP_040453_1860 .
More info and image formats at http://hirise.lpl.arizona.edu/ESP_032066_1860
Image: NASA/JPL/University of Arizona