Check the following link:


[url="http://hirise-pds.lpl.arizona.edu/PDS/EXTRAS/RDR/PSP/ORB_003500_003599/PSP_003570_1915/PSP_003570_1915_RED.browse.jpg"]http://hirise-pds.lpl.arizona.edu/PDS/EXTR..._RED.browse.jpg
[url]

This new HIRISE shows slope streaks in Marte Valles, extending down a sloping ridge to an escarpment. The photo shows an attractive view, but what jumps out at me is when you scroll down to the southwest corner of the photo.

The prevailing lighting is from the southwest, casting shadows on the northeast side of the ridge. But on the southwest side of the escarpment is an area of deep shade, where there should be a sunlit escarpment. It appears that the escarpment has been undercut by a cave. And in this case, it is not a vertical cave, or sinkhole, but instead seems to be one that a rover (MSL?) could roll right into.

Ok, technically, no abyss. But I wanted to get USTRAX's attention!

David

It's amazing how even at HiRise resolutions, the slope-streaks just appear from nothing.

The outcrop is interesting... it looks like a similar one to the left has collapsed. What undermined them in the first place? Interesting texture in that plain...

Wow, that is interesting. The top curves so the wall below should vary in brightness in the uniform direction of lighting. Instead, the darkness appears uniform without. Would be very interesting to see this section in full res with contrast enhancement.

Got my attention! Let's see if ustrax takes the bait.....

Seriously that is a very cool image - being of limited bandwidth and disk space (and time) these days, I feel comfortable relying on the eagle eyes of the members of UMSF. I am not disappointed.

I so enjoy these features that bring Mars to life -with geology I can recognize on a human scale. I instantly thought of a family vacation to Canyonlands National Park, and the many overhangs our guide warned us to not stand upon. You have no idea how thin they are until you see them from the other side of the valley. When you are standing on top of them, they seem just as solid as the rest of the bedrock.

Look out future rovers!

By the way, here is the link to the original context image:


[url="http://hirise.lpl.arizona.edu/PSP_003570_1915"]http://hirise.lpl.arizona.edu/PSP_003570_1915
[/url}

There is nice discussion of the slope streaks, but no mention of the abyss cave.

David

That image displays an amazing collection of slope streaks of various ages. Interestingly, the new abyss very much resembles El Dorado (aka, the original Abyss). Here is a full res crop of that area from IAS Viewer.
Click to view attachment

Wow. Period.

Gonna go way out on a very thin limb here: Notice the numerous 'melt-streaks' on the main body of the massif; could this entire thing be mostly water ice? Given that, the aybss itself may be an outflow valve for the underside of this thing.

Would be interesting to look for for water vapor absorption spectra right here, esp. during different seasons & times of day.

Congrats, DF; this might be the first Martian "iceberg" found!

Notice the small dune field in the shadows, in Cosmic Rocker's high resolution view. (Thanks CR!). They appear to lie in a sinuous gully snaking from north to south along the face of the escarpment, and then turning back under the lip of the overhang in a more easterly direction. Whether it's a lava tube, or an ice cave, it sure looks like a great entry point for MSL to do some Martian caving!

David

I hate to be the party pooper here, but if you ask me that looks like one of the most dangerous places on the planet for a rover. What we are looking at is an overhang that is in the process of ongoing mass wasting. Note some of the fallen slabs that have no dunes or soil build up around them. I think they are very recent. The crevices above that they left in their wake still have the dark colored subsurface material and have not acquired the lighter dust that covers the entire planet. In short we have a vertical cliff and overhang that is presently shedding rocks and slabs down on to the floor below. It's not a place you'd want to send a billion dollar vehicle.

I can't picture it raining slabs, but just a fist sized rock would not be good if it happened to drop on top of a rover. But if it is dropping a rock per sol, chances are pretty good for making it thru there. The question is thru to what?

However, if rocks and slabs have been falling down over millenia, the ground there might be too rocky for a rover.

I think I agree with CosmicRocker here, that this is a replica of Eldorado.
I have taken his image and inverted the colours. It appears to me that there are dunes running allover the dark regions.

The overhang and streaks are neat, but of further interest is the fractured slab appearance of the terrain surrounding this massif (?), beyond the scarp. The northwest corner as well as the south is particularly interesting, looks like broken slabs of ice floating in a frozen sea. I've seen similar pics of Europa, not to mention here (Earth) in the polar regions. Does lava behave like this? Otherwise I would speculate that we may be looking at an island surrounded by a frozen sea covered by a layer of dust. Something different seems to underlie the eastern plain.

These Streaks are looking like a kind of fluid, is this possible?

Sounds familiar:
http://www.newscientist.com/article.ns?id=dn7039

Also mentioned here
http://www.unmannedspaceflight.com/index.php?showtopic=712

They've been seeing such "slope streaks" for decades... and they unfortunately think they're possibly just dust, but they are mysterious. If you google around you find papers like this:
http://www.lpi.usra.edu/meetings/7thmars2007/pdf/3203.pdf

The googling also found mention of this very "cave" at another forum, about 4 weeks ago.

I'm here...
Looking for teh abyss to come...
Maybe this is not it but the true abyss will come out somehow...

Very like the Eldorado abyss ive highly stretched the contrast and brightness and there is still only one area that remains dark. maybe the image wizards will fill that gap.
This dark soil looks more likely to have eroded from the mesa rather than been dumped there by a wind shadow like Eldorado although the ripples on top do look abyss like.
Roy