Currently forming gullies might still be from liquid water.

[exoscientist]

8 Years at Mars #1: New Dune Gullies <br />MGS MOC Release No. MOC2-1220, 20 September 2005 <br />http://www.msss.com/mars_images/moc/2005/09/20/dunegullies/index.html<br /><br />The gullies seen on sand dunes prior to this were believed also to be due to liquid water. It is only when they are seen to be produced currently that the suggestion is made by Malin et.al. that they are due to gas release. <br />However, there has been published research that the gullies can be produced under current conditions:<br /><br />Water Flowed Recently on Mars, NASA Scientists Say. <br />By Robert Roy Britt <br />posted: 24 August 2005 <br />"If liquid water pops out onto Mars' surface, it can create short gullies about 550-yards (500-meters) long," Heldmann said in a statement. "We find that the short length of the gully features implies they did form under conditions similar to those on present-day Mars, with simultaneous freezing and rapid evaporation of nearly pure liquid water." <br />http://www.space.com/scienceastronomy/050824_mars_gullies.html<br /><br />Formation of Martian Gullies by the Action of Liquid Water Flowing under Current Martian Environmental Conditions. <br />American Astronomical Society, DPS meeting #37, #32.10 <br />"We find that, contrary to popular belief, the fluvially-carved Martian gullies are consistent with formation conditions such as now occur on Mars, outside of the temperature-pressure stability regime of liquid water. <br />...our model indicates that these fluvially-carved gullies formed in the low temperature and low pressure conditions of present day Mars by the action of relatively pure liquid water." <br />http://adsabs.harvard.edu/cgi-bin/bib_query?2005DPS....37.3210H<br /><br />Fo <div class="Discussion_UserSignature"> </div>