# Blue Dunes on Mars



## Alexa (Jun 24, 2018)

This is really cool ! NASA released a photo from Lyot Crater showing blue dunes. I wonder what lies beneath and what they are made of.







Once in a Blue Dune


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## BAYLOR (Jun 24, 2018)

Looks like a concentration of some type of mineral.


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## Ray Pullar (Jun 24, 2018)

Cobalt Blue (CoAl2O4)?  Or Prussian Blue (iron hexacyanoferrous)?


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## Brian G Turner (Jun 25, 2018)

Mars is covered with iron compounds, and iron compounds can be very different colours depending on how the electrons between atoms are shared. 

Mars normally gets its red colour from Iron (III) Oxide - aka rust - but I'd guess the above picture shows something like an accumulation of Iron (II) Sulphate, which is blue.


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## Cat's Cradle (Jun 25, 2018)

Surely there must be giant sandworms in the vicinity?  (I think spice is said to have a blue luminescence in one of those books.)


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## Alexa (Jun 25, 2018)

Cat's Cradle said:


> Surely there must be giant sandworms in the vicinity?  (I think spice is said to have a blue luminescence in one of those books.)



My first impression was that could be some kind of blue fish.


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## Alexa (Jun 25, 2018)

Brian G Turner said:


> Mars is covered with iron compounds, and iron compounds can be very different colours depending on how the electrons between atoms are shared.
> 
> Mars normally gets its red colour from Iron (III) Oxide - aka rust - but I'd guess the above picture shows something like an accumulation of Iron (II) Sulphate, which is blue.



One of the rovers should confirm the composition one of these days. This could support a human mission and excavation machines for future mines. Maybe Mars is the new Eldorado. A very expensive one, at least for the moment.


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## tinkerdan (Jun 25, 2018)

Now I can't get out of my head the sound of The Marcels singing:  Blue Dune.


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## -K2- (Jun 25, 2018)

Maybe they're just sad...

K2


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## Vertigo (Jun 25, 2018)

One thing I find interesting (which no doubt will be due to differences in density, grain size etc.) is the totally different form of the dunes, much larger ones built of much smaller ones, whereas the surrounding dunes are consistently relatively medium in size.

Also the fact that there is so little mixing, there are some traces of the blue on the surrounding dune, but assuming the 'blue deposit' is ancient (which seems likely for it be ground down small enough to form dunes) it seems surprising to me that it is so distinct from the surrounding material.


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## -K2- (Jun 25, 2018)

I found the dunes in the field near it even more interesting.  They must be of a dense/heavy material to be so defined.






K2


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## Vertigo (Jun 25, 2018)

-K2- said:


> I found the dunes in the field near it even more interesting.  They must be of a dense/heavy material to be so defined.
> 
> 
> 
> ...


Or is it actually the opposite for them to have stayed (floated) above the surrounding material. Or maybe they just have to be larger particles; if you stir up a container of different sized gravel all of the same rock (and therefore density) don't the larger particles always end up on the surface?


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