Here is a Sol 645 L2-R2 Pancam x-eyed stereo pair based on a 3x1 panorama. At 760K it is a large file, but you can cut&paste stereo pairs of areas of interest from this image.

You can see the uneven bedrock surface noted earlier. And Payson is going to be an interesting spot...

--Bill

Definitively yes. Hope that the rovers' driver have enough courage to adventure among big ripples to reach Payson.

Rodolfo

And here is a Sol 649 Pancam of an "Arizona outcrop" showing a darkish, shadowed bluff area. Which may be the first example of the mysterious "dark unit".

Guesses whether it is Sedona, Show Low or Winslow?

--Bill

Around Erebus on Sol 649.

A panoramic view taken with the L0 navcam.

jvandriel

I've revised the Erebus overview map to exclude the overlap between the "Erebus area" and the "Mogollon" and "Erebus Highway" areas. This revision is partially based on the current Naming Of Names by Cornell/JPL.

--Bill

A little late but the images are just down.

A 360 degree pancam L1 panoramic view around Erebus on Sol 630.

Consisting of 27 images and 3.6MB.

jvandriel

You might notice that the eastern rim, the Vermillion Cliffs, is visible in the left frame of jvandriel's Sol 649 pan in Reply#354. It shows how deeply eroded Erebus is.

--Bill

It seems interesting to explain why there is an parallel lines about 4 meters long around the center of outcrops. It is a coincidence.

Rodolfo

Modified from jvandriel's Sol 649 pan in Reply#354, here is a 5x vertical exaggeration. It show the fracture patterns and sand distribution more clearly than the unexaggerated view. I'm looking forward to some of Phil's polar pans.

Interesting place, this.

--Bill

OK, Oppy looks to be getting ready for some IDD work on a layered peturbance.

http://qt.exploratorium.edu/mars/opportuni...KCP1214L0M1.JPG

Meanwhile, the pancams show pretty easy running to Mogolon, though she has to watch the dunes to the west.

http://qt.exploratorium.edu/mars/opportuni...EZP1700L0M1.JPG

http://qt.exploratorium.edu/mars/opportuni...EZP1700L0M1.JPG


I am thinking that when the time come to leave Erebus and head SE towards Victoria that the going will be rough, at least initially, due to having to cross a lot of dunes.

Actually, those last pics were apparently just a mid-drive pan. Oppy is even closer now. Do you think they will risk diving into the crater itself to get a proper approach to the low cliffs?

http://qt.exploratorium.edu/mars/opportuni...KCP0715L0M1.JPG

Those are navcam pics from sol 649 and Oppy is about to start driving by the dunes -- if that is the selected path -- to Mogollon.
Newer navcam pics looking S from sol 651 are those with "site/drive" id 64KC:

http://nasa.exploratorium.edu/mars/opportu...KCP0715L0M1.JPG



Yep.
It will be very important to select a route which tries to avoid the bigger dune fields.
And I think that this long drive by the northern Erebus rim gave the MER team the data needed to correlate the features seen on MOC imagery with those from the pancam; in other words, the capability to "see" the dunes/ripples on those orbital images.


Edited: I haven't seen you last entry until after mine was posted.

Looks like both Opportunity and Spirit will be doing some serious rock sniffing during the Thanksgiving holidays.

Opportunity
http://marsrovers.jpl.nasa.gov/gallery/all...KCP1214R0M1.JPG

Spirit:
http://marsrovers.jpl.nasa.gov/gallery/all...QRP1205L0M1.JPG

Only up to the next outcrop before reaching the dark outcrop since the view from these picture are still not so clear. So first, go to next small outcrop and study the place.

Just viewing from the above picture, it seems it is possible but by sure is to take another picture when Oppy is on the next outcrop.

Rodolfo

Yup, both rocks looks pretty interesting to hitch...

Rodolfo

The stuff in front of Opportunity looks amazing. No idea what the geological processes are but the horizontal pointed "jib" is way cool. Clearly there has been very little in the way of "violent" weather in this spot for a very long time - that thing must be incredibly fragile.

I agree, that very thin 'finger' might have been created by slow and relatively gentle sandblasting. Theres some amazing shapes that have been created in deserts on Earth by that process, this is another on a miniature scale.

Mexican Hat rock in Utah comes to mind.

This is going to be a wonderful area to explore. I put a couple of Hazcam stereo pairs in the "Mogollon MI" thread; if need be, they can be linked to.

These features are so delicate. Not surprising, they are the result of high velocity impacts of micron-sized abrasive particles over very long periods of time.

Reminds me of the "house with crystal pillars on the planet Mars by the edge of an empty sea…" in The Martian Chronicles...

--Bill

The below picture, at the bottom, before the last light color outcrop there is a zone with dark stones. From here, I am not sure if these dark stones are elevated as a rim or these dark stones are of cobbles lying on top of outcrop. I seems that these dark stones are the protuberence or a rim of Erebus.

http://qt.exploratorium.edu/mars/opportuni...I6P2421L2M1.JPG

Rodolfo

Looking at the Navcam images in this area of Mogollon, I've found a fault that appears to be post-polygonal fracturing. FWIW, another puzzle-piece in this Wonderland...

--Bill

Good vision. I see the facture. The puzzing thing is that the facture is so lineal and long.

Rodolfo

So what about this possibility:
We have the large impact that caused Erebus. This caused the polygonal shattering in this area immediately surrounding the crater. Once all that had settled and compacted the heat pulse travelled down through the subsurface and melted a subsurface ice\CO2 pocket which led to a slight lateral slide of a large surface blocks. This stuff appears to be extremely brittle but even so the linear nature of these cracks doesn't really gel with this idea all that well unless the inter polygonal material had cemented into quite strong material between the original impact and the slide.

Here is part of sol 652 "drive-direction" pancam mosaic, focused on the dark outcrop at Mogollon rim.

Click to view attachment (380k)

Wrt the path to that outcrop here are two proposals, the left one going directly to the outcrop, and the right one going by the top of the oucrop.

Click to view attachment (126k)

But as already noticed here, it seems to be too early to take a decision. For instance, this last mosaic is an 8x1 pano; 4 to 6 pics are common sizes while bigger ones are only taken when the path is not clear.

It also means that there cannot have been even a single minor earth tremor in Meridiani for a long, long time....

tty

The general way to the Mogollon bluff/outcrop is clear and seems to be a safe route; I see lag deposits of dark cobbles which usually implies a firm surface to drive upon. From your Sol 652 pans we can begin to see the nature of this dark unit that we've been drooling on for the past few hundred Sols and past few thousand meters.

Attached below is below is an image of a published section of this area from J.P. Grotzinger in _Earth and Planetary Science Letters_ (I'll look up the cite later). Sorry to step on someone's © toes, but this is a scholarly discussion adn this does seem to be _the_ definitive section.

We'll know more once we get to plinking about on the dark unit.

Helvick, that is a reasonable possibility. Seeing this relative motion along that fracture is another checkbox in the geomorphological checklist of this region. Now that we are _at_ the crater rim (as opposed to _near_) there will be more examples of this.

--Bill

Burns Cliff ;


Nico

Looks like one part of this 'mini cliff' collapsed some time ago:

Here is a reference to and discussion of that paper on the stratigraphy of the Burns Formation I noted above:

http://www.unmannedspaceflight.com/index.p...topic=1684&st=0

The weathering of the mini-bluff is consistent with what we saw at Burns Cliff and what we can spot at the Mogollon Rim. This tells a lot about the nature of the rock: in the eastern US Appalachian Valley and Ridge province, ridges are resistant sandstone and avlleys re less-resistant shales and non-resistant limestones. Conversely, in the arid US southwest, limestones are ridge-formers.

--Bill

The first 360 degree panoramic view around Erebus on Sol 649.

Taken with the L0 navcam.

jvandriel

and the 2nd one from Sol 649.

Also taken with the L0 navcam.

jvandriel

and a panoramic view from the driving direction on Sol 650.

Navcam L0.

jvandriel

And the 360 degree panoramic view on Sol 651.

Taken with the L0 navcam.

jvandriel

I disagree. Until we know the rate of aeolian erosion on these deposits it's really difficult to say. I agree that it's really old, but I don't agree that the structure has been in such a fragile condition for its entire history. Perhaps there was an earthquake in the recent past and the precursor to this little spear was all that was left of a larger structure that broke off. The rate of erosion allowed the wind and sand enough time to erode it to it's present condition (while also turning to dust the crumbled remains of the parent rock below in which it was embedded.)

Erosion is a constant and ongoing process and any time during that process one may observe unlikely fragile remnants. They come and go. Like the rock in Utah pictured above. At this time in the history of the American Southwest it is a rare and unlikely formation, but over the eons there have doubtless been others that have since fallen and broken. In the future there will surely be more that have yet to erode. We are looking at a snapshot in time, but in the case of the Martian setting there is an entire dataset missing, preventing us from arriving at absolute dating conclusions.

I have changed the brightness.

Now it's clear to see.

jvandriel

Would it be vandalism if Oppy drove forward a bit, and knocked that overhanging piece of rock off with her right front wheel? Would be interesting to see how this freshly exposed surface differs from the rest.

Actually "The Mexican Hat" is not a rarity at all. There are any number of similar weird rock formation in the Four Corners area (The Navajo Twins, Zion, Arches, Bryce Canyon, Monument Valley etc etc). There are two reasons for this, the Triassic Navajo sandstone, which is both strong and easily eroded, and the fact that the whole Colorado Plateau has risen about a mile in the last few million years so erosion has been very intense (that's the explanation for Grand Canyon by the way, the Colorado River has stayed at the original level). Incidentally it is also one of the more seismically stable parts of North America.

tty

Talking about the southwest...some more landscapes with familiar looking themes, but on a much larger scale...

Airbag

As promised (although somewhat later than planned), the full resolution version is now online.



Click image.

James

Actually it is rare. Compared to all the sandstone spires in the Southwest it is rare. Look at the square miles involved and the shear number of spires and outcrops. It seems like there are lots of them because travelers over the last two centuries have identified them and turned them into landmarks and tourist stops so we know where they all are. But in the greater scheme of things such "balancing rocks" are not common.

FWIW It's not just sandstone that the Colorado River carved. Below the Great Disconformity at the bottom of the Grand Canyon is a massive layer of one of the hardest rocks known - the 2 billion year old Vischnu Schist. It scratches glass real well, but that's a heartbreaking story for another day.

A panoramic view around Erebus on Sol 652.

Taken with the L2 pancam.

jvandriel

http://www.little.id.au/travel/kangaroo_is...ble_rocks_2.htm
This sites show the 'weird' rocks is Australia, the rocks are massive granite and are mostly wind fomed (some water) and a few are large (many tons) with hardly any point of contact with the surface they are on.
Attached is a picture of one of the rocks from the site.
Reckless

Here's a rough falsecolor (L 257) mosaic of the outcrop currently in front of Opportunity.

I think we will be here for a while; fascinating differences in the layering. And still almost no obvious blueberries within the rock itself, yet many in the "sand". Did they come from a more recent, already eroded away layer, or can we just not see the blueberries in the rock layers at this scale?

Airbag

I've been looking at this set of images. Isn't it fascinating the way that the laminations are separating from the rocks? I'd guess that the rocks are finely laminated and the laminations are separating from the rock by thermal processes and are then moved about by the wind.

---Bill

WOW! I like the picture, where is the high resolution picture ¿?

Thanks!!

PS: Sorry, its my first post, where is the delete button ¿?

Nope, anyway. But ...
Tu puedes borrarlo con solo editar tu correo y ponga una para que el administrador lo elimina.

Rodolfo

Here is the link ot 1275x521 image (higher resolution). Nico only posted a "thumbnail" image.

http://www.awalkonmars.com/A2287-294PFCM12L257preview.jpg


There is no "message delete" as such; you can edit the message to remove the erroneous sentences and request that the moderator remove the message.

--Bill

Closer to Mogollon; here is a 5x exagerration of the Sol 652 Pancam pan. Mogollon is centered, with Payson to the left.

I'd love to have an L257 or L456 sequence from here...


--Bill

Thanks for the info and the pic