On the Road Again - volume 8 - Page 20

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Posts: 344

Reply: 381

PostPosted: June 8, 2011 11:06 AM 

Sure looks like berries on the ripple to me.


Posts: 344

Reply: 382

PostPosted: June 8, 2011 11:25 PM 

Nice belated MI.


Posts: 3062

Reply: 383

PostPosted: June 9, 2011 12:24 PM 

Hi Barsoomer;

Grateful if you would explain why you call the reply #382 MI nice? even as compared with the other recently released MI's that show some interesting aspects of the pavement surface and of some berries emanating therefrom.

Kye Goodwin

Posts: 1166

Reply: 384

PostPosted: June 9, 2011 2:12 PM 

Serpens, re your 373, 374, Yes, I've been wondering how the bright rock and the dark soil are related for years, so I'm aware of the mainstream scenario. I've put a lot of thinking into how the soil might originate from the underlying rock, which is a simple theory and the typical case on Earth. It is strange that the rock, while pretty clearly eroding, doesn't contribute much to the soil, as if it goes from rock to dust and leaves the area without ever forming sand and getting mixed with the soil. You express some scepticism about the presence of nontronite in the rock. I've always wondered just how sure we should be about the mineral identifications, but I'll never understand the spectroscopy well enough to figure out where it might have gone wrong. The presence of a major mineral constituent that is unknown from Earth would likely confuse everything at the outset, and could never be discovered, as comparison with mixtures of known substances is always the process.

Re your 379, Those ripples in the image you linked are very rare at Meridiani. I've searched the entire library for examples. Almost all the ripples at Meridiani are "armoured" with granule-sized particles or larger. Those smooth structures occur in small clusters at most craters, sometimes in the interior, sometimes in the interior and on the rim, as at Skylab, and sometimes not at all. It is easy to speculate that the granule-free sand that makes up these ripples "originates" nearby, but then the aeolian processes that might have built the smooth ripples seem too inactive - too local. I've collected several examples of avalanches down the sides of structures like the largest "sand-tail" in that image, so I think they are quite active currently.


Posts: 344

Reply: 385

PostPosted: June 9, 2011 4:12 PM 

Hi Winston.

> why ... MI nice?

Maybe I'm becoming less discriminating due to lack of input! It seemed to me that this shot was from a slightly different angle, and showed the "holey" part on the bottom left in a different way than the previous images. Also, it shows well the odd patterns on the bottom right. The image does need to be brightened somewhat.


Posts: 344

Reply: 386

PostPosted: June 9, 2011 11:32 PM 

The ripple crests seem to be "highlighted" with dust here, giving them a kind of "spiny" appearance.

Bill Harris

Posts: 3

Reply: 387

PostPosted: June 10, 2011 9:56 AM 

@Hort: "As I have said many times the greatest Martian mystery is the thought processes of the MER team."

I have speculated that mission planning is recently being done by Senior Administrative Interns, and hte more I see, the more I think this is correct.

There was a press release the other day anunciating the mission goal of "Spirit Point", teh south end of the Cape York uplift, instead of the northern section, as originally proposed, which could have made an investigation of the unique ravine (channel? erosional feature?) on the NE flank of the hill.

At teh outset, mission planning was brilliant, but of late it has become the antithesis of that. It's Looney Tunes.



Posts: 344

Reply: 388

PostPosted: June 10, 2011 10:56 AM 

It's all about the orbital detection of clays, not about the geological morphology.

Spirit was targeted to Gusev based on morphology (lake-like features), which turned out to be a dud. The Opportunity site at Meridiani was based on the hematite signal, which was right on the money.

The lesson seems to be that geochemistry trumps geomorphology in choosing promising targets of exploration.


Posts: 344

Reply: 389

PostPosted: June 10, 2011 11:22 AM 

Apparent linear sequence of collapse features. Surface expression of cracks in the underlying bedrock?


Posts: 3465

Reply: 390

PostPosted: June 10, 2011 11:30 AM 

sol 2622 L0 3x1 in next drive direction:

with links to a pancam L2 3x1 detail and guestimated map position.

I am totally baffled by the last week's traverse: 115 meters closer to Spirit Point after driving around "Gemini5" crater northwards and taking 2 3 frame navcam panoramas and one L257 image of the NW corner ( largest ray ) - not yet down-linked.

Kye Goodwin

Posts: 1166

Reply: 391

PostPosted: June 10, 2011 1:16 PM 

Barsoomer, re your 389, These linear depressions in soil that cross-cut ripples are a very common feature of the Meridiani landscape, as I've been pointing out for years. They sure look like they are associated with fissures in the bright bedrock. The interesting question is how can the process of depression formation be proceeding in the present era. The big ripples are thought to have been active in the last 300,000 years. The fracturing that might account for the fissures in the rock is widely considered to be related to dehydration shrinkage that took place billions of years earlier. So why aren't the fissures simply filled with soil and mostly invisible? Why aren't they especially well hidden where ripples have "recently" covered them? I think that yes, the trench is the surface expression of cracks in the underlying bedrock, but HOW the trench can be active recently can't be explained by ancient fracturing.

Horton, Yes, it seems that the normal flow of information from Oppy to the public has changed somehow in recent weeks. I've noticed that the JPL website is much further behind than usual, which I find frustrating because I usually wait for them to sort the images chronologically and display them as thumbnails. For example, many of the pancam images of Skylab are still not posted and its been weeks since they appeared on the Exploratorium? Normally the delay has been just a few days.


Posts: 344

Reply: 392

PostPosted: June 10, 2011 3:37 PM 

Kye, that's very interesting. It seems the underlying fracture may have some influence on the surface movement of the ripples.

Consider the analogy of a stream passing over a completely submerged rock. Would there be some surface expression of the passage over the rock? Maybe turbulence could extend upward for some distance?

Another possibility, which I think you have suggested, is that there is some emission or emanation from the fracture that is rising to the surface and disturbing either the ripple movement or the stationary ripples. The analogy would be something like the "hot-spot" that has produced the Hawaiian Island chain.


Posts: 344

Reply: 393

PostPosted: June 10, 2011 4:55 PM 

If the cracks are close to the surface, and if one side of the crack is lower than the other, forming a "step" in the subsurface, then as the ripples pass over the crack, they may fall to the lower surface, resulting in a persistent discontinuity?

Or if there is some tectonic-like movement of the underlying plates, perhaps caused by varying thermal proparties, then there may be continuing collapses?


Posts: 5

Reply: 394

PostPosted: June 10, 2011 6:51 PM 

I thought that Hort's idea that the subsurface void space may be perpetuated due to sublimation of ice at depth in the old fractures.


Posts: xxx

Reply: 395

PostPosted: June 10, 2011 9:14 PM 

Combination of CRISM-mapped mineralogy and HiRISE multi-band colour images indicate that the phyllosilicates are concentrated in the annulus of the crater in the centre of Cape York. There are some scattered deposits in the plain near CY which would be attributed to aeolian erosion deposits from that concentration. Spirit point does not have any phyllosilicates in any published work I have seen? So like Bill I am perplexed by their intent. Mayhap they think that climbing mid CY to get to that annulus is impracticable, or maybe they have more detailed analysis which they are hiding away (like the ESA) until Opportunity gets there. Perhaps the crater at spirit point actually excavated phyllosilicates?

The level of effort on Curiosity planning will be escalating and I guess that means delegation of Opportunity planning to the junior echelons – not that those junior echelons are not very bright people. The JPL site updates have begun to evidence poor spelling and grammar from time to time which is unfortunate, although with the web it is simple to make retrospective corrections, but such errors should not occur in the first place in official releases. Going back over the JPL site the geochemical indications they provided for Eagle and Endurance were extremely good. Not so much over the latter years. Perhaps the problem is lack of information on why decisions have been made, rather than any problem with the decision itself.


Posts: 344

Reply: 396

PostPosted: June 11, 2011 12:23 AM 

Serpens, suppose the location of the phyllosilicates is as you say. What would you think is the easiest route to get to that location given the known climbing abilities of the rover?


Posts: 3465

Reply: 397

PostPosted: June 11, 2011 7:54 AM 

The sun has just set on sol 2623 and Oppy drove an incredible 5 hours today. The drive index passed 1295 about an hour before Oppy finally stopped so I'm guessing another record breaking backwards drive - close to 200 meters.

The official sol 2622 traverse map is now available and my guestimate missed by about 5 meters.


Posts: xxx

Reply: 398

PostPosted: June 11, 2011 8:44 PM 

Barsoomer - from DEM that crater looks approachable from the west but that would depend on a heap of things not visible from our armchairs. For instance, is the westerly onlap a purgatory style trap. How wide and deep are the 'truncation' channels that surround CY and could the rover handle them?

The East side of CY and that notch to the North are probable targets and possibly a trip along the East side is on the cards. If we can't climb CY there is no way we can climb the hills to the south and there would be no value going there.

At around Spirit Point there seems to be a possible contact that they may be targeting. Or maybe they don’t intend to firm up on a plan until they get a close up look at CY. I'm not sure that even the Shadow knows what goes on in the minds of the rover planners. It would be nice ‘outreach’ if they gave an indication of their intent but I guess the extremely small group of enthusiasts that still follow this mission do not attract much attention.

For my side I just hope that they retained some of the engineers that designed the MER to develop Curiosity.


Posts: 344

Reply: 399

PostPosted: June 12, 2011 2:24 AM 



The course charted will take Opportunity up to Endeavour's Cape York by way of Botany Bay, Arvidson confirmed. "Botany Bay through CRISM data shows hydrated sulfates and it's an easier approach to the southern side of Cape York where the phyllosilicates are exposed."


Posts: 250

Reply: 400

PostPosted: June 12, 2011 3:46 AM 

At least we will get a nice pan of the perculiar landslide feature on the south eastern tip of CY quite soon. I hope that the MER team tries to climb CY though after inspection of the southern tip of CY is finished. Smile

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