Link Outcrop

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unfrozen caveman rover fan







PostPosted: October 11, 2012 11:34 PM 

As my moniker suggests, I have a primitive understanding of the complexities of geology, but would anyone here agree that, while Link Outcrop itself is quite interesting, the gravel found at it is an amazing and unique find? It's the most earth like collection of rock yet, isn't it? And I don't mean because of the "enhanced" color but because of their shapes and placement.To me it looks just the peebles along a river's edge. What else but water could form and place them this way?

And, in the linked pic, what process would cause the gravel on the left side to be so clean, and to be scattered on top of other gravel that is well buried? It looks amazingly recent, not like something sitting there a billion years after water flowed over it.

Of course it's such a small field of view that we can't see this patch in context, and it may not look as dramatic in un-"enhanced" color, but I still find it fascinating. BTW I couldn't find any un-enhanced shot it at the official site, wonder if there's any out there somewhere else.

Sorry for so many questions, but hopefully it's an interesting topic for someone on this blog, just don't forget to dumb it down a bit 8-)

Thanks for reading

[link]


-ucrf

MPJ


Posts: 250

Reply: 1



PostPosted: October 12, 2012 2:38 PM 

Hello ucrf, this has been briefly discussed in the initial Curiosity topic already. The "raw" data is available at the NASA MSL site (it doesn't look less interesting there).

I and other here have assembled a few brightness/contrast altered close-ups from the raws as well:

_mod_13x.jpg

Its a pity they rushed by that great site so fast but maybe they return for further studies as indicated by Grotzinger.

Kye Goodwin


Posts: 1166

Reply: 2



PostPosted: October 13, 2012 2:59 PM 

ucrf, Yes, I've been a long time sceptic about an ancient Mars climate that allowed persistent Earth-like runoff of surface water. I'm still sceptical, but I think that those rounded pebbles are the best evidence yet found. The loose pebbles are much easier to see than the ones still held by the rock, which leaves open the possibility that the rounding may have happened through weathering after their release, but I haven't been able to find an example in the MER library of similarly rounded stones. The rounding is impressive, but the sorting is not. A catastophic one-time flood or many other processes could account for the mixture of particles in the rock. If there was a alluvial fan created by persistent or repeated flows then we might yet see more compelling examples of sorting.

The highland valley networks (as distinct from the huge outflow channels which are generally accepted as catastrophic features) look like fluvial channels at first sight but have never looked quite right to most scientists as the result of persistent Earth-like surface runoff. The examples in Gale Crater are similar to others in many locations. Many at Gale are wide for the area they might have drained and all the smaller scale tributaries are missing. The channels on the crater walls are easier to accept as familiar fluvial features than the canyons on the mound, some of which seem way too wide and short, and some seem to grade into other mound features attributed to wind erosion.

Here's an image that shows some of the channels on the walls and the mound:

Here's more on the "streambed" that I came across:

http://www.messagetoeagle.com/curiosityevidencestream.php#.UHmtXI5hoqa




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