The thing I find interesting is that the white stuff is in the middle of a shadow. That makes me think it really is something white, and it does look like it's flowing down the hill in the right direction.
It wouldn't be the first time we have seen something leaking or creeping out of a rock. Nice find Noone.
Noone:We have come across this "white" looking substance before, if you check out Gigapan's Dingo Gap you will notice it quite a bit. More times than not, it is a scuff mark or crushed stone creating dust or powder which appears to look like a white liquid, like leaking paint. Usually right in the path of the rovers Aluminum wheels. But not so much in these images, I often wonder if just the tiniest bit of disturbance or abrasion shows the true color of the rock.. With that being said, I wouldnt find it hard to believe that if the rock rolled over some it would be just enough to scuff it. The leaking rock in your upper most picture is definitely intriguing and I am going to investigate that further. Good Find
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The whole universe is to the observable universe, as the observable universe is to an atom. - Alan Guth