Gully and defrosting activity have been visible here along the edge of a dune field, along with blocks of frost. Observations of the same area help us check for repeat activity, as well as measuring those meter-scale blocks that we’ve seen prior.

In this case, we want to compare any possible changes with a previous observation , which we acquired in 2011. We’ve also seen images where carbon dioxide frost was the driving process in creating new gullies , so we know their formation is occurring to this day. Tracking for changes, especially when we look at the 1-kilometer enhanced color swath, can help us find more.

This caption is based on the original science rationale.

Written by: HIRISE Science Team (audio: Tre Gibbs)   (17 June 2015)

More info and image formats at http://hirise.lpl.arizona.edu/ESP_039701_1095

Image: NASA/JPL/University of Arizona