NEW STUDIES REVEAL THAT ONCE SNOW FELL IN MARS' DEEP VALLEYS

 

New studies of Mars' deep valleys have revealed that once snow might very well have fallen on the red planet. 

The valleys above, in fact, seem to have been created by the kind of erosion particular to snowfall. The scientific term for this is 'runoff by orographic precipitation', or moisture carried to the top of the mountain and deposited onto the slopes.  

The valley configuration and their grooves are unequivocal signs that once water flowed on Mars.  What the scientists don't yet know is where the water came from.  Did it bubble up from underground lakes, as are present on Enceladus, or did it fall upon the mountains as snow or rain?

But this new evidence of the valley formation gives renewed clues that the water might very well have precipitated from the sky, versus having come from below the surface. 

A study of Hawai'i's own microclimate gives clues to the orographic deposit of water on mountains.  In the great island of Hawai'i, the tropical winds do not have enough force to reach the summit, thereby dumping the water on the side of the island, making that side a tropical jungle. The opposite side of the island, the western side, is almost desertified, since it is under a rain shadow cast by the mountain peak. 

Valley networks that were found below mountain peaks in four distinct regions are the subject of this study.  The direction of the prevailing winds must be ascertained to validate the theory, for each location. 

The scientists proceeded to do simulation studies and found that the precipitation would have been strongest at the head of the densest valley network.  "their drainage density varies in the way you would expect from the complex response of precipitation to topography," Prof. Scanlon, of Brown University asserted. 

The next phase of the study is the snowmelt model for the General Circulation Model of the Mars studies.   The cause and speed of the snowmelt are important in determining the formation of the valley patterns and the confirmation of the snow as the principal or sole agent in the geological formation of the valleys.  The snowmelt study will also give particular insight to the climate on Mars going back to billions of years ago. 

Source : Science Daily / 7.24.13