[X] My Assistant

[Harkeppler]

Another example of holes and possibly caverns can be seen in MGS photo R0701365

http://www.msss.com/moc_gallery/r03_r09/fu...07/R0701365.gif

There are a lot of sinks along some ridges along the northwest flank of Arsia Mons.

The most prominent feature is given as attachment, but there are several more.

Besides this, in the upper part of the original frame there are some black

streaks at another ridge which may indicate water or ice rich sediments

common to the Arsia Mons terrain.

So it could be said that the area is a collaps region loosing its icy layers and the caves may be sinkholes.

The center of the original image is at 238.11°E and 5.40°S.

Interestingly, dark downward running streaks and gullies are slso found in the higher layers of the Tharsis vulcanos and even across the caldera of Ceraunius Tholus.

Due to the lower pressure at high altitude the streaks should be shorter than those in valleys.

Harkeppler

Attached thumbnail(s)

 

[Harkeppler]

To explain the feature:

The dark gullies (indicated yet for clarity) give a hint that water (or brine) is draining from the walls of the ridges at the flanks several Mars vulcanos. This gives the idea, that the lava tunnels in that area may be collapse structures in ice rich regions when volcanic heat melted the ice and produced a lot of mud. Some of the lava tunnels are mud streams or collapsed and drained areas.

So, the Tharsis landscape seems to be water rich and a cave system in water rich sediments is of more biological interest than a dry magmatic one.
The gullies at the Arsia Mons flank are in the ultimate vicinty of the multiple-hole-cave-complex mentioned above.

In other words: If I have to look for life on Mars I would look in these caves at the Arsia Mons flanks.

Harkeppler

Attached thumbnail(s)

 

[djellison]

So, the Tharsis landscape seems to be water rich

From a few streaks, you're making an entire region 'water rich'.

That's a leap of faith.

Doug

[Harkeppler]

From a few streaks, you're making an entire region 'water rich'.

That's a leap of faith.

Doug

It may be.

I think it is interesting that at 5.5 km hight these gullies can be seen at the summit of Ceraunius Tholus. I am sure that there must be an ambient temperature and an sufficent pressure to allow the spilling of a fluid. So, I would not wonder that there are no such gullies at higher levels, so at the summits of the Tharsis main vulcanos.

Maybe it is possible to calculate the lenght of such gullies in dependence of the temperature, pressure and inclination of the walls.

Harkeppler

[mcaplinger]

I think it is interesting that at 5.5 km hight these gullies can be seen at the summit of Ceraunius Tholus.

These are not the features usually called gullies; the conventional view is that they are dry dust avalanches and do not involve a liquid. See, for example, Rob Sullivan's abstract http://www.lpi.usra.edu/meetings/lpsc2000/pdf/1911.pdf

[Harkeppler]

These are not the features usually called gullies; the conventional view is that they are dry dust avalanches and do not involve a liquid. See, for example, Rob Sullivan's abstract http://www.lpi.usra.edu/meetings/lpsc2000/pdf/1911.pdf

The best is the last sentence of that paper:

"Modeling is underway to determine if avalanche velocities and dynamics are sufficient to suspend dust during entrainment as the avalanche front moves downslope."

Maybe "if"... maybe not...

The dark streaks and fans looks very sharp and structured. There are at least four possibilities: 1. the dark material is the underground and the light toned one has been removed. 2. The dark material has been added. 3. The dark material is light toned material getting soaked. 4. The dark streak is a mix-up of the light toned maybe by turbulent gas.

Harkeppler

[mcaplinger]

The best is the last sentence of that paper:

"Modeling is underway to determine if avalanche velocities and dynamics are sufficient to suspend dust during entrainment as the avalanche front moves downslope."

That abstract is seven years old, so you may want to follow where the research went after that. It's not like you were the first to notice these features.