Some seasonal ice on Mars is transparent so that the sunlight penetrates to the bottom of the ice. Heat from this sunlight can turn the ice directly into a gas in a process called sublimation and this gas can scour channels in the loose dirt under the ice.

Channels formed by sublimation of a layer of seasonal dry ice are so dense in this area that they look like lace . Gas flow erodes channels as it escapes to the surface of the overlying seasonal ice layer seeking the path of least resistance.

Written by: Candy Hansen (audio: Tre Gibbs)   (21 December 2016)

More info and image formats at http://hirise.lpl.arizona.edu/ESP_046414_0990

Image: NASA/JPL/University of Arizona