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.
<p>Channels formed by sublimation of a layer of seasonal dry ice are so dense in this area that they <a rel="nofollow" class="external text" href="http://static.uahirise.org/images/2016/details/cut/ESP_046414_0990.jpg">look like lace.</a> Gas flow erodes channels as it escapes to the surface of the overlying seasonal ice layer seeking the path of least resistance.
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The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace &amp; Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.
NASA/JPL-Caltech/Univ. of Arizona
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