Liquid on Mars??
This picture may be of a liquid on Mars - because the reflections of the creeks are almost perfectly mirror imaged in the water below, which takes coincidence a little far.
Note that darker parts of the hill above are refelcted darker in the lake below. This would not occur as a shadow effect - only from a reflection. This may be an illusion, but it is very doubtful. I think it is the real thing. You will need a very convincing argument otherwise to convince me - and I am a skeptic.
You need to get a blow up of the left hand side to 125% or more to see what I mean. I have some idea of what the fluid could be.
Regards
Peter Ness