Dark Dunes in Bright Craters on Mars

The terrain and craters are very bright and the dunes are very dark. Could it be this is frozen terrain and whatever is creating the dunes is leaking up from cracks in the ice? Could this terrain be a frozen lake/sea? This Mars Express image is h2249_0000 and I could not find any info on it.


files.abovetopsecret.com...


files.abovetopsecret.com...


files.abovetopsecret.com...

Anyone know/want to guess what we are seeing here?

a reply to: LookingAtMars

Dark matter appears that it was once liquid at some point. Or possible it looks that way due to wind erosion. Appears to be very solid though.

yep, I'm curious, too

good subject here

The second photo appears to have some height to it by the shadow to the left..

Strange..

a reply to: LookingAtMars
It's darker dust. Termed "basalt dunes", they are composed of volcanic ash.

On Mars, by contrast, dunes are made up mostly of dark, dense minerals like olivine, from volcanic basalt. The dunes get darker with time as finer dust, which contains lighter-colored feldspar minerals, blows away.

www.sciencemag.org...

a reply to: LookingAtMars


Could be the " Bagnold Dunes "

nineplanets.org...

a reply to: LookingAtMars

Nice find
It appears the darker solid material or slurry beneath the lighter surface material is maybe warmer or less cooler then the top surface material. In turn causing the top surface material to melt or erode, revealing what is beneath.

a reply to: Phage

But where is it coming from and why is it not covered with frost? Like most of the other terrain in the image is?
No sure it is frost but that is all I can figure.

a reply to: Ophiuchus 13

Could be, maybe because it is dark it is absorbing more heat and melting the frost.

a reply to: alldaylong

No, I do not think this image is anywhere near Curiosity.

That bottom image is of Rabe Crater?

Zooming in on the western (top in the main colour image) portion of the crater reveals distinct layers of dark material exposed in the crater walls. One possible interpretation is that the impact crater punched through the top surface to reveal these otherwise hidden layers. Over time, this material has been eroded and swept up by wind to form the dunes seen towards the centre of the crater.

www.esa.int...


a reply to: LookingAtMars

Look at all those grooves and lines around the crater. It's like something freezes, turns into dust, blows away, lands outside the crater, melts and flows back into the crater, or gets blown back onto the ridges, then melts back into the base of the crater. A complete micro-climate.

a reply to: Phage

You can also see dark streaks through-out the image, kinda like dust devil streaks (more evident in the much larger original image these images were taken from and then reduced to be able to upload to ATS). Maybe most of the material under the frost is dark?

a reply to: LookingAtMars
Some is, apparently.



Here's a nice high resolution image from HIRISE, of the dunes.

a reply to: stormcell

The shape of some of the smaller craters and the level bottoms of the larger craters give me the impression that much of the terrain is a frozen lake/sea.

a reply to: Phage
Nice find

It looks organic. Probably not under near lunar conditions but?...

a reply to: Nickn3

Please expand on what you are saying. Not sure I know what you mean, but I would like to understand.

Winds and air pressure are different on Mars too. A 60 mile an hour wind feels like a gentle breeze.

Low atmospheric pressure combined with lo gravity creates different sand scape than here on Earth.

Researchers conclude that the meter-scale ripples are built by Martian wind dragging sand particles the way flowing water drags sand particles on Earth -- a different mechanism than how either dunes or impact ripples form. Lapotre and co-authors call them "wind-drag ripples."

"The size of these ripples is related to the density of the fluid moving the grains, and that fluid is the Martian atmosphere," he said.

I'd love to see that working up close.

Nasa.gov

Very interesting and nice catch.
It is definitely an extrusion of molten material. The flow lines go out and then there is a barrier that folds back where it could not get larger, creating the pool. It also probably happened quickly.

What is below those craters is not typical geology, so it could be a number of minerals.
If there once was life on mars, there must be coal beds... an interesting but very speculative possibility.
Viscosity between oil and coal.