spacefire,<br /><br />I know what you mean, there are many eye-fooling images coming from Mars however I am looking at many pieces of information as opposed to just one image.<br /><br />This is the info: (sorry for the repetition for those who have read this before but this just puts it all on one page):<br /><ol><br /> <li> The altitude in Chasma Boreale where the river lies is
5km (3.11 miles) below the mean Martian altitude which means that the atmospheric pressure is about 9 or 10 millibars. At this pressure water boils at about 7 degC (44.6 degF).<br /> <li>
Recent volcanic activity has been detected in the northern region. Although there may be no active volcanic activity above the surface today it is quite possible that the ground temperature in the Chasma Boreale basins is warm enough to melt water ice.<br /> <li>This
water vapor chart indicates a high concentration of water vapor at the same latitude at the Chasma Boreale basins.<br /> <li> In the ice pack above the basin there are
vents that appear to be created (MOC image E03-01758) by the release of steam indicating subsurface heating.<br /> <li> In
this image it is very apparent that the defrosting of the dunes is not uniform over the 8 day period when these images where captured (MOC images M21-01415 and M21-01920). The frost on the dunes closest to the river is vanishing faster than the frost on the dunes further away. This area is out in the open so there would be no difference in the amount of sunlight reaching both locations which are only a few hundred feet apart.<br /> <li> In the same two images (MOC images
M21-01415 and
M21-01920) steam can clearly be seen rising from the locati</li></li></li></li></li></li></ol>