Overflow channels and climbing dunes on Mars

Two interesting features are seen in the images from the Mars Reconnaissance Orbiter's HiRISE camera.



The first feature is the overflow channels that were created either by water or lava. There are signs of the presence of both, so there was definitely some flowing water there. Water interacted with lava to create rootless cones. www.uahirise.org...

The other feature is sand dunes that are climbing up the slopes of a mountain range, due to very strong wind. There are ripples and land slides in places, and the wind keeps the things flowing, as it were. www.uahirise.org...

I love seeing images like these, they show Mars to be a living environment with dynamic processes, past or present.

By the way, while searching info about dunes, I came across this photo from Earth: link
Those sand avalanches are very similar in appearance to the much-discussed "trees" on Mars: link which are of course also sand avalanches, albeit much darker in colour.