by eggyolk_6

An interesting crescent shape feature at the bottom right hand corner. any idea how it forms, why the shape is so different even though the wind is blowing in the same direction?

Posted July 15, 2013 3:18 PM

by Kitharode moderator

Hi. I'm guessing that there's no special reason why this shape appears, just the ice thickness, strength of venting, wind at the time, etc. Perhaps there's a crescent shape in the rock below that has had an effect. I could easily be wrong. 😉

Posted July 15, 2013 3:35 PM

by mschwamb scientist, translator

We think that the wind has a big impact on shape, so that you get a fan shape if the wind is blowing when the dirt particles get uplifted and brought to the surface by the carbon dioxide gas geyser, and an ellipse shape is produced if there is no wind. That one looks more like a blotch than a fan so it could have been forming with some wind and no wind .

Cheers,
~Meg

Posted July 16, 2013 8:13 AM

by p.titchin in response to Kitharode's comment.

Hi all, This just looks like a random pattern of several venting events to me. A very quick look at the HiRISE for this shows many similar. I've noticed when marking areas with many fan deposits, they often seem to have similar blotchy patches. I can't actually see much of a crescent, but have (probably wrongly) assumed before that wind conditions at the time, and the pressure of venting plus perhaps some topography, have led to a 'blotch' rather than a 'fan'. Directly above this area of blotches are a couple of blotchy patches which also have struggled and failed to be fans.

Posted July 16, 2013 7:37 PM