On the Road Again - volume 3 - Page 5

Hort; It appears to me that ,except for the deeper"red-dust" filled depressions, everything that is rust colored turns blue in the animation including the dust covered soil surface.
I have noticed these knobby protrusions in an earlier image(can't remember which one)and attributed them to some kind of mineral accumulation in the meteorite.
I think it is very unlikely that they are
later berries.

sol 2022 ( Oct 1, 2009 ) L257 pan of Falcon crater:

The most interesting observation to me is that the wall of this fresh crater is higher on the southwest side -- and this is true of quite a few "fresh" craters over several square km in this area.

Oppy is about 120 meters north of a similar lopdided but larger 18 meter crater.

My guess is that a large iron-nickel skipped into this area from the northeast, exploded and peppered the surrounding area with fragments continuing southwest.

Notice how the ejecta around Falcon is lying on top of the dunes - implying the crater is younger than the dunes ( less than a million years old??? ) implying the meteorites falls were very recent - if in fact some of the craters are associated with the irons.

IF the 18 meter crater is visited I fully expect to see an iron-nickel in or near the southwest wall.

Hort; Interesting image of Falcon showing the atypical knobby beds that have been thrown up on the SW side.
These are obviously older and are similar to some we saw back at VC.
I agree with you about how these lopsided craters formed but don't think they are related to the meteorites we just visited which I think are much older.
I doubt we will find any fragments of ni/fe around these as they would be very small and probably still buried in the bottom of the craters.

Your image of the Meridiani surface showing second order dessication cracks is interesting, especially the bigger chunk of berry material with a few berries protruding.
Berries accreted together as they fell

Hort; It just occured to me that the knobby beds I mentioned in 83 may contain aggregations of the berry material you show.

sol 2038 L256R2 of Mackinac:

with a link to shadow details.

Notice the small piece of the meteorite on the center bottom.

Again, the dark soil has collected under the meteorite.

sol 2038 L256R2 second view of Mackinac:

Hort; Much thanks for the meteorite images which keeps oppys trip from being boring..
Mackinac appears to have a bunch of little nobs protruding from it which may be resistant inclusions..

What amazes me is the inticate sculpturing of these objects including the small fragment.
Billions of years of wind scour couldn't have done this without some early,differential chemical leaching of the various components.

Speaking of "boring" ( if that can be said of any picture from another planet)...

sol 2040 ( Oct 20, 2009 ) L0 3x1:

Looks like another 70+ meter backwards drive to the southwest. I was sort'a hoping for a move to the south towards the 18 meter crater...

OK, back to sleep in the back of the bus for a few kilometers...

True we should not take it for granted that

A) We get to see a Hort picture everyday always top stuff

And

B) We get to see a new pic of the surface of a neighbouring Planet and all the bibs and bobs that lie on it every week.

sol 2041 ( Oct 21, 2009 ) L6 4x1 in next drive direction after another 70+ meter SW move:

Zzzzzzzz...

Yo....Hort, I remember reading awhile back, you told us about "Autostitch". I downloaded it set it up and lo and behold. A little box came up and said trial version has expired. ????????

John, did you download autostitch from the page [link] ??

The FAQ says that you should dowload the latest version from this web page if you get the expired message.

The redownload has always worked for me when I get the expired message.

Thanx Hort.

sol 2042 ( Oct 22, 2009 ) L0 3x1:

Yet another 70+ m backward drive towards the SW.

Another pile of cobbles:

That makes somewhere around 8 large cobble mounds altogether that have been imaged by Oppy. I'm puzzled by how little interest they seem to have drawn from the rover science team. They are very clear evidence that some as yet unimagined process has acted on the Meridiani plain. Impact is the only option that I have ever seen mentioned in the official science discussion, and that mention has been brief and vague. If we imagine that the cobble piles arrived by the explosive ballistic flight of ejecta from a distant crater then how did the cobbles stay together in the air and manage to land in a pile? If the cobble concentration arrived as a single large piece that subsequently eroded into many small fragments, why then did that one big object fail to create a secondary crater?

Of course larger Mars impacts (creating craters over 5 km across) tend to form a continuous ejecta blanket though a process of fluidized ejecta transport, not by a ballistic scattering of independent pieces. The fit with cobbles size-sorted and distributed in clusters over the plain might be quite good if a fluid surge is contemplated. It occurs to me that most of the larger regolith particles (granule-sized and bigger) might have been originally distributed over the plain by impact surge.

sol 2042 L6 2x1 of cobble field:

and a HIRise view of the sol 2042 area:

The cobble field appears to be on the dunes - thus younger than the dunes. The field appears to be quite localized on the HIRise map.

Horton, re your reply 95, Yes I'm going out on a limb to call this or the others a "pile" of cobbles because we haven't wheel-trenched any of them. I think that it is a reasonable possibility that the cobbles are piled and dust has infilled all the spaces between them leaving only the surface cobbles visible. I also accept as reasonable that the cobbles could be resting on mostly finer material as the spherules demonstrably are in places. Either way this is a dense concentration of cobbles compared with their average presence along the route.

Thanks much for posting the panorama in reply 93. I have just noticed that this cobble field seems to have a couple of short ridges in it. They run about at right angles to the viewing direction. They are fairly prominent dark coarse-grained features just above the center of the panorama. The odd thing is that they do not have the same orientation as either the big north-south ripples or the smaller diagonal ripples.

Please help me to see if those are really ridges in the cobble-field or some sort of illusion, by posting a binocular pair.

We've seen apparently ripple-shaped cobble concentrations at least once before. I wonder which way they were oriented? I'll have to find them and compare.

Reply 95 now has links to 3D pairs.

> If we imagine that the cobble piles arrived by the explosive ballistic flight of ejecta from a distant crater then how did the cobbles stay together in the air and manage to land in a pile?

Why distant? The area looks like it got sprayed with debris from a nearby glancing impact. The context image from Hort does show nearby areas that look possibly excavated.

Barsoomer, re your 98, We have seen many examples of ejecta thrown from small craters. There is usually a lot on the rim and less at greater distance. Generally the entire debris field has been visible from one rover station. By a "distant" impact then I mean one not immediately apparent like the craters that accompany most of the concentrations of ejecta that we have seen. If the cobble concentration was created by a small local impact then it should have made a crater immediately adjacent to the cobbles based on the evidence of other small impacts.

This is one of a few "cobble mounds" that Oppy has imaged and none to my memory were adjacent to small craters.

I remember seeing a PILE of cobbles that looked like a heap of road apples left by a mule. There were several comments left on this forum wondering why it was just "driven by". Wonder if it was a different type of meteorite, say carboniferous chondrite that had been weathered for a billion years.