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View Full Version : Wow, look at these layers



Crazieman
2004-Jun-15, 02:54 PM
From Opportunity's latest pictures in Endurance

http://marsrovers.jpl.nasa.gov/gallery/all/1/n/137/1N140345551EFF3182F0006R0M1.JPG

jumpjack
2004-Jun-15, 03:40 PM
From Opportunity's latest pictures in Endurance


I suppose it is not a layering, but a "pavement"; a 3d view would clarify this. I think we are looking at an horizontal pavement which, on the 2d screen, looks like a vertical layering.

ToSeek
2004-Jun-15, 04:32 PM
From Opportunity's latest pictures in Endurance


I suppose it is not a layering, but a "pavement"; a 3d view would clarify this. I think we are looking at an horizontal pavement which, on the 2d screen, looks like a vertical layering.

It could be layering, depending on how the crater sliced into the bedrock.

beskeptical
2004-Jun-15, 07:26 PM
Looks like a layered duck, walks like a layered duck....

Even if it is horizontal, it could be moved from its original position.

I want to know what all the tiny dark spots are. Is it artifact or ????

aurora
2004-Jun-15, 07:56 PM
Looks like a layered duck, walks like a layered duck....

Even if it is horizontal, it could be moved from its original position.

I want to know what all the tiny dark spots are. Is it artifact or ????

Looks like more blueberries to me.

and it does look like sedimentary (or volcanic) strata.

RBG
2004-Jun-15, 08:08 PM
The layering question is one I've been thinking about too.

Until seeing that photo above, I thought it to be broken up "pavement" but wondered why its surface might be exactly lining the top of the crater. (Maybe the meteor concussion cleanly cleaved off the overlying layers? A surface layer that has collapsed into the hole that was created? Or layer-upon-layers that have been uplifted to point 90 degrees up from which they were formed?)

I wouldn't have believed the latter, but a close examination of that above shot clearly shows what appears be dense layering perpedicular to the surface.

I don't know what the tiny dark spots are but why couldn't they be (or be related to) all the blueberries that have been seen in the area?

RBG

Squink
2004-Jun-15, 10:11 PM
The layering question is one I've been thinking about too.

Until seeing that photo above, I thought it to be broken up "pavement" but wondered why its surface might be exactly lining the top of the crater. (Maybe the meteor concussion cleanly cleaved off the overlying layers? A surface layer that has collapsed into the hole that was created? Or layer-upon-layers that have been uplifted to point 90 degrees up from which they were formed?)

I wouldn't have believed the latter, but a close examination of that above shot clearly shows what appears be dense layering perpedicular to the surface. You're not alone in wondering about that. Pavement like areas have been showing up ever since eagle crater, and there doesn't seem to be a good explanation for them yet. Could prolonged wind erosion produce such an large assortment of rocks flattened flush to the surface? I suppose that in the absence of rain, there's not much else going on.

On the other hand, the interior of endurance resembles what the dish at Arecibo might look like after a few millenia of weathering :wink:

jumpjack
2004-Jun-16, 12:31 PM
Pavement like areas have been showing up ever since eagle crater, and there doesn't seem to be a good explanation for them yet. Could prolonged wind erosion produce such an large assortment of rocks flattened flush to the surface? I suppose that in the absence of rain, there's not much else going on.

On the other hand, the interior of endurance resembles what the dish at Arecibo might look like after a few millenia of weathering :wink:
Maybe a thin layer of the martian soil melts when hit by meteors (just like our sand wuold do, I suppose), then it becomes cold very quickly, and it breaks, just like cement when drying... Then, erosion enlarge cracks, and we obtain that sort of "pavement"... :-s

Jumpjack

Squink
2004-Jun-16, 05:53 PM
Maybe a thin layer of the martian soil melts when hit by meteors (just like our sand wuold do, I suppose), then it becomes cold very quickly, and it breaks, just like cement when drying... Then, erosion enlarge cracks, and we obtain that sort of "pavement"... A fusion crust wouldn't show layering, nor would you expect to find embedded blueberries.

atomoid
2004-Jun-17, 08:52 PM
Could prolonged wind erosion produce such an large assortment of rocks flattened flush to the surface? I suppose that in the absence of rain, there's not much else going on.

Thats all it is, heres my "loosely-amalgamated" theory anyway:
- The "bedrock" is merely loosely cemented silty materials and volcanic ash that hasnt been compacted or metamorphosized by very much overlying weight or heat over the eons (this area has been exhumed on the order of only several meters) and as a result doesnt hold together very well against the gentle erosional forces on Mars (which include windblown sand, dust, gravity, meteor impacts, solar radiation and some water vapor frost deposition and its related weathering and perhaps some other stuff going on). All the blueberries fall out of the loose matrix as it dissolves away, the bedrock areas will tend to erode faster than any areas that are covered by blueberries or harder mineralized rocks, so as a result youll see most of the soft bedorck is plane flat to the level of the ground where it is protected by wind. you should see areas where the bedrock is lower than the surrounding soils and in fact there area many areas where this is the case on the plains such as the dimples and divets many of which have flat rock surfaces visible at the bottom.

aldo12xu
2004-Jun-18, 11:01 PM
What we're seeing there is a contact between two rock types. The whiter rock in the lower 3rd is the white evaporite sequence we saw at Eagle Crater. The layered, more darker rocks on the upper third of the picture were deposited before the Eagle rocks. NASA has determined the Layered Unit to be sandstones formed from the erosion of basaltic lava flows. They think sulpher from the volcanoes could've mixed with surface or ground water to create a sulphuric acid solution which altered the Layered Units to create the Eagle Units. This happened about 3 billion years ago. When the meteorite collided to form Endurance Crater, the bedrock was broken up and thrown out as jumbled ejecta blocks. After millions and millions of years of wind erosion, plus the other processes described by atomoid, everything was worn down to what we see today.

Here's a couple of articles that go into this:

http://www.spacedaily.com/news/mars-mers-04zzzzx-printready.html
http://www.spacedaily.com/news/mars-life-04d1.html