Rovers on Mars

I can not get the image from Spirit to paste so I'll have to post a link. If I were to pick up this rock in Connecticut I would interpret it as spalling on basalt due to water freezing.

link to Spirit photo

I agree. Though the presence of the round nodules is disconscerting to the view.

I get the feeling that if I applied a pick to the cracks I would find far more resistance than expected in common sedimentary rock. The little holes in the rocks are particularly uncharacteristic; almost as though the rocks have been melted (with associated gas release), and then cooled, and then wind worn for eons. I can imagine molten volcanic origin, or impact related shock melt.

The advantage of the shock melt view is that shock melt could include sedimentary deposits as well as melting and "boiling", and we know that impacts are common on Mars, including the area Opportunity is in.

It's all very entertaining.

A further indulgence... I get the feeling of extreme age in the images of the rocks. I think there is sedimentation here along with melting, all buffered with the sand blasting of alien centuries.

One thing is for sure, even these simple rocks bear the unmistakable mark of an "alienness" which is extraordinary in Earth terms.

Not every layer is completely homegeneous. There can be a convex or concave portion in a layer.

Thes are exciting puzzles to cherish.

BTW, I can recommed the Maestro application.

http://mars.telascience.org/home

Im not sure I understand what we mean by a "once melted sedimentary layer". You mean that sedimentary rock has formed and then melted? or are you using the term "melting" to signify anything of volcanic origin.?

I think the genesis is the sediments that form the rock are volcanic ash and glass nods (tephra) and this mixed
sized particles either settled by dropping out of the air or fell into water and formed as aqueous settling.
I lean toward the air "classification" mode cause some layers seem convoluted and if they fell into water the laminae would usually be horizontal and pretty much parallel with the bottom.(just like varved lake seds).

Not that melting of the entire layers but my conjecture is that layers's surfaces must have a short period of melting in the past.
We have yet to know the true color of those tiny balls. Their color may totally different from that of the outcrop or that of the ground soil.

An orbiter has found the Opportunity Landing Site from above.


And here is
How It Found the Outcrop.

Wow, that's amazing. It landed right inside a perfectly sized crater; not too deep for it to get out of, but big enough to have an exposed crater wall. One of the scientists called it a "hole in one".

If the color in the photo is true, the pebbles are bluish.

well we can see here that the little spheres are very neat,. We can also see that the spheres are contemporaneous with the "ash fall' they are actually embedded within the matrix rock and some are plucked out , leaving these little pock marks. They are probably some silicate like ol;ivine, could be that the bluish color is an artifact of reflection due to the wind abrasion or their emplacement imprints.
The spheres are much more wind resistant than the matrix, which looks only partly cemented.(indurated)
This is looking more and more like a welded tuff deposited in a water body. I bet that theJPL geoscience team is scouring the lit for analogous structures

"a welded tuff deposited in a water body"

.. Maybe true.

Wow, this is amazing. I've been trying to keep up with you all. What fun!

We probably don't have much in the way of analogy when it comes to those little spheres (so many of them, and embedded in the rock... amazing), but the following formation keeps popping into my head:
The Deccan Traps in India

This false-color image taken by the panoramic camera onboard the Mars Exploration Rover Opportunity highlights the spherules that speckle the rock dubbed Stone Mountain. The colors in this picture were exaggerated or stretched to enhance the real difference in color between Stone Mountain and its collection of granular dots.

It's amazing to me, but the spherules are actually *embedded* in the rock. I never expected this.

The simplest explanation would seem to be that the spherules were just laying on the surfact (just as they are today), and they were buried by layers of material (I'm guessing volcanic ash, or possibly impact ash). Given the embedded spherules, is there any doubt now that these rocks are sedimentary? I don't see how they could be anything else with those spherules embedded like that.

The question would be whether the "ash" landed in water or on dry land to form the rock.

Then there's the "smooth" edges of the rockface... could that be wind worn, or is that heat melted from the impact which formed this crater?

Is there a way to determine if it's a heat melt form, or a weathering form (Farmerman)?

This is amazing stuff. In comparison, the land forms in Gusev crater (where Spirit is) seem boring.

Best regards everyone,

The beads may have been stuck to the rock while they were still hot, immediately after an impact of meteor somewhere nearby.

Hi Satt, the Spheroids are actually embedded in the rock, not just stuck to its surface. This was stated by one of the mission scientists (I included the quote below). In addition, in the pictures posted previously, I can see a couple of them still embedded.

[From the rover site: The first outcrop rock Opportunity examined up close is finely-layered, buff-colored and in the process of being eroded by windblown sand. "Embedded in it like blueberries in a muffin are these little spherical grains," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers' scientific instruments. Microscopic images show the gray spheres in various stages of being released from the rock.]

Well, I won't stick to my view about the beads, or spherules, this time.

However I will, for the moment, modify my sentence as follows, and see the research by Opportunity:

The beads may have been stuck to the rock while they were still hot, immediately after impacts of meteors or volcanic activities somewhere nearby.

So, you're suggesting that the spheroids may have actually become embedded in the rock due to the force of whatever stuck them there?

It's an interesting idea... still it looks like the pebbles are embedded in the matrix, but not fused to it. I would think that if they were projected into a molten surface they would be fused more completely.

I guess we need to determine how the structure was formed before we can deduce that it's sedimentary.

Need more data.

if you read my earlier posts maybe I didnt do a good job with all the geobabble. I was speculating on this when you had shown some of the first closeups.My hypothesis is as follows

The volcano or "hot spot" that ejected all the ash and sphereules happened at the same time. On earth , we see this very thing with tephra, which is an ash, that contains glass, and all kind of other melted crap. It gets thrown out from the source and cools.

the atuff lands according to an atmospheric separation scheme that obeys settling velocity rules (heavies settle first then dust fills in later)

This goes on over and over so we have layers of this welded tuffaceous material. It contains the glass beads and ash layers. Sometimes a swarm of volcanoes (like the Deccan floods, except the ejected material is full of silica and water)

The layers set up and lay there and become wind eroded over millions and maybe a billion years.

The martian tectonic is felt to have been a mess of migrating "hot spots' like the area under the Hawaiian Islands or the snake River Plains in Idaho.
The hot spots remain fairly stable but the plates migrate atop.
Mars was felt to be like an early earth
then sometime in our past, the tectonic engine of Mars just stopped , no differentiated mantle and molten core to generate subduction and, some people say, this is what cause the Martian atmosphere to get hostile so that terraforming may not work because there is no way that CO2 is generated to keep a "greenhouse"

My main question now is one of mechanics and density . How does it happen that those little spheres are all about the same size. On earth, when we have ejecta shooting out from an acidic vent, they are all kinds of sizes.
Even the spherules in the rock seem to be the same sizes.

The rounding of the rock matrix is nothing more than wind scouring, you can see the patterns in which the glass spheres were actually plucked out of the rock.

If the tephra got shot into the air and landed in some water that would explain the rather thin laminae of the rock layers better than would just settlement through the air.
If there was a lake , or a shallow sea and these volcanic showers would spurt out of the water like the volcanoes in Iceland, then as the smoke and ash dropped back from the volcanic pulses, it would settle more finely.

Id still like some conjecture as to why those little spheres are all about the same size. I mean they look like they dont vary geometrically or logarithmically, but arithmetically. That is unearthlike