YellowKnife Bay - Page 2

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Posts: xxx

Reply: 21

PostPosted: December 27, 2012 10:24 AM 

Take a look at this one...

That's some very bright material in the crevice under the big rock on the left, and looks different to all the calcite/gypsum veins elsewhere in the area. Surely worth having a poke around with MAHLI and ChemCam

Paul Scott Anderson

Posts: 53

Reply: 22

PostPosted: December 27, 2012 1:28 PM 

Look at all the "bubbles" in this Mastcam image from sol 137. They look like tiny vents... Most of them seem to be in one long "swath" across the bedrock, wonder if that is significant at all?


Posts: xxx

Reply: 23

PostPosted: December 27, 2012 2:31 PM 

I am starting the think that these rocks are peat.

The effect of weathering here seems to be pretty dramatic. Channels and little rock fragments everywhere. The large rocks look "droopy" with lots of overhangs.

Is it likely that water saturates the peat and then it breaks off and goes downhill . . . then voila, bright material is exposed in the newly visible layer?


Posts: xxx

Reply: 24

PostPosted: December 27, 2012 2:47 PM 

Great find JT!


Posts: 344

Reply: 25

PostPosted: December 27, 2012 3:17 PM 

Nice find, JT. Maybe that is frost or ice that stayed frozen because of the overhanging rock protecting it from the Sun's rays?


Posts: 125

Reply: 26

PostPosted: December 27, 2012 4:00 PM 

RE Reply 21 JT, I noticed that last night when I was looking at the latest images. Did you also notice the soil around the white stuff appears wet or stained. I agree, its worth having a poke.


Posts: xxx

Reply: 27

PostPosted: December 28, 2012 4:34 AM 

Thanks guys, the more I look at that white stuff under the rock the more it looks like efflorescence - the sort of thing you see on degrading concrete when minerals leach out and then dry. It can also happen when gypsum dehydrates to anhydrite. Both possibilities seem plausible in that sort of environment.

Paul - those bubble structures really are curious, tempting to call them 'barnacles'. I'm sure there's a more ordinary explanation, but I'll wager there's a lot of head-scratching going on at JPL to come up with one.

Overall, it seems to me there's much more going on in Yellowknife than in the previous terrain (the excitement about a white sand grain in rocknest seems a long time ago now), and I imagine there's some serious preparation going on for the next press conference. Looking forward to it.


Posts: xxx

Reply: 28

PostPosted: December 28, 2012 5:04 AM 

That looks more like a void under the rock JT. I think the bottoms of the rocks are spalling and now you can see under and behind the rock.


Posts: xxx

Reply: 29

PostPosted: December 28, 2012 5:34 AM 

John - Doh! I think you're probably right. Occam's razor wins again.


Posts: xxx

Reply: 30

PostPosted: December 28, 2012 8:50 AM 

This is turning out to be a very interesting place to stop I am going to call them barnacles until a rock guy tells me otherwise.


Posts: xxx

Reply: 31

PostPosted: December 28, 2012 10:29 AM 

Those Geo's out there would it stand to reason that if a area such as this one that has primarily clay rocks would be subject to animals getting stuck in the mud of the past, dying, being covered up then solidifying in to a rock? Then many years later due to something like techtonics or a surface impact that this rock would then be cracked open and reveal the fossil?

If all above is true, then look at the interesting rock, resembles the shell of a turtle or armadillo... etc.

Look to the bottom right of this image

Look to the bottom left of this image


Posts: xxx

Reply: 32

PostPosted: December 28, 2012 11:56 AM 

Here is another interesting photo. the middle area is remeniscent of some of our deserts that receive water maybe once a year. Saying so, I would postulate that this area was saturated not to long ago.. like 10 years ago or less. Any longer than that I would expect those thin peelings would be worn down by wind storms and such like.
Geologists let me know what you think


Posts: xxx

Reply: 33

PostPosted: December 28, 2012 12:35 PM 

Looks like the clay is still moist underneath these rocks. Maybe a good rock to drill in to for curiosity.


Posts: xxx

Reply: 34

PostPosted: December 28, 2012 1:42 PM 

Is the rock sliver have a reflective surface? It is on the left side towards the bottom of this picture.

right side bottom of this one

We all have seen reflective surfaces way off in the distance during this journey. Maybe this is one of them.


Posts: xxx

Reply: 35

PostPosted: December 30, 2012 5:53 PM 

Hey guys - Here's Yellowknife Bay in all of it's glory. Well. I had to fill in some thumbnails because we're still waiting on them.

But here:

When the Mastcam 100 images all come in (I have 3 days worth stitched all waiting for the rest), I will make a super Gigapan - It will be of both the MastCam 34 and the MastCam 100's view of Yellowknife Bay. The image will be HUGE. Twisted Evil

J.Chris Campbell

Posts: xxx

Reply: 36

PostPosted: December 31, 2012 10:23 AM 

Thanks impreprex the gigapan is looking great. Please let us kno when it is complete.

Hello, everyone, I figured I would put a actual name to JCC if I was bold enough to make some of the statements I have, I should be bold enough to own them.

Who knows maybe JPL will take a interest and offer me a Job.. Smile

Happy searching,
J. Chris Campbell


Posts: xxx

Reply: 37

PostPosted: January 2, 2013 12:46 AM 

Here is that "Super Mosaic" I promised:

Yellowknife bay at its finest. Smile


Posts: xxx

Reply: 38

PostPosted: January 2, 2013 12:48 AM 



Posts: 1

Reply: 39

PostPosted: January 2, 2013 5:35 AM 

Rock guy here.

I have not seen 'burst boils' like these before anywhere (reply 22), in the sense that they are small. Mud volcanoes have the same profile but can be much larger, even 1-2 metres across.

They look like gas bubbles that have blown upwards into the overlying sediments. It looks like they have formed in a finer grained sediment and pushed up into an overlying coarser sand layer, but the image is not good enough to be sure.

For those unfamiliar with looking at bedding planes, we have an oblique view here - imagine the layers gradually stepping up across the view, with the lowest layer in the foreground.

From a sedimentary origin point of view, sediments that have entrapped gas that escapes upwards in this manner occur in environments where deposition of the 'gassy' unit was rapid and where the sediments are fine grained sand or silt (think of the pretty sand pictures sold in wooden frames). Degassing structures are often seen in turbidite sequences but I don't think we had oceanic or even deep water sedimentation here! Flash floods is the obvious mechanism to invoke - I look forward to seeing what the experts make of them.

The ridges/trails that you can see behind some of them (from the camera position) are due to wind erosion, following their exposure to the present day environment.

J. Chris Campbell

Posts: xxx

Reply: 40

PostPosted: January 2, 2013 4:50 PM 

Thanks for the great gigapan

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