On the Road Again - volume 4 - Page 7

sol 2123 ( Jan 13, 2010 ) map position:

Looks like there was no interest in atypical outcrop.

The new position is about 32 meters from the last position.

It's great to see Oppy on the move again. I kind of hope that we don't see any more interesting exotic rocks for a while. They may help to fill in the big picture in the long run but they don't seem to have contributed much to understanding Oppy's neighborhood in particular. On to Endeavour.

Hort

Going back to your reply #107. I wonder if we should be so quick to toss out the earlier inferences of perhaps an E/M effect being the cause of your RATted SODs mysterious movement. Since you infer in 107 the possibility of a small "cleaning" event, could it be that we are fortuitously witnessing at the micro scale the actual effects of the even more mysterious "cleaning" event? Could it be that the cleaning event might be associated with an E/M event which shows up in the anomalous movement of the SODS?

The SODs are probably magnetic as suggested in the phoenix microscope capture images. Could microenvironmental changes in E/M fields, generated by whatever force, be responsible for cleaning them off the arrays?

Could the inferred stickiness of the SODs be due to magnetism and even miniscule amounts of moisture? Could the dust devils also have an electrical component that might be associated with the cleaning events at Gusev while some other E/M phenomenon would be associated with these events at Meridiani?

Winston

The sol 2124 move was about 46 meters south from the sol 2123 position.

I will tackle the panoramas later this evening.

Jeepers Kye. There are chunks of the solar system strewn about. I wish we'd not passed up some of the stuff we did. I mean, what you imply is "Don't look out the side windows, there is nothing to see there, look out the windshield, ahead we go." Mother in law is kind of like that. She has driven to Las Vegas, hoping to hit the jackpot three or four times a year. Never sees ANYTHING but the mile markers. Never wins either.

sol 2124 ( Jan 14, 2010 ) final look back at Marquette Island:

with a link to the 180 navcam pan looking north

and looking forward:

with a link to the 180 navcam pan looking south.

John, re your 124, and my 121, because the current mainstream explanation of Meridiani includes playa lakes and concretions growing in a water-saturated formation I am still hoping that some more evidence that bears on these extraordinary theories might turn up before Oppy stops roving. We have seen holes blasted into the layered sediments (impact craters) but we have not yet seen a situation where the sediments have been placed at a pre-existing margin of any kind. At Endeavour Crater it appears that the layered sediments embay hills formed by the rim ejecta and the sediments may slope down into the crater partially filling it. These places may give us key new information about the most extraordinary discoveries so far. A meteorite or a piece of igneous rock impact-ejected from an unknown Martian location just doesn't have much chance of helping to explain the layered rock or the spherules. There are already many similar iron meteorites in laboratories and the 30-plus known Mars meteorites are, like Marquette Island, igneous and from unknown locations on Mars. I'm not saying that this new evidence is worthless, but only that it isn't likely to be "key" in understanding the most interesting aspects of Meridiani.

Is it possible the apparent broad swale we are crossing may be due to fluvial erosion of the Meridiani beds ?

I think the sol 2124 area is rough because of the two very old 9 and 12 meter craters about 24 meters ahead.

It does appear that this is a low area relative to the 12 meter fresh crater about 250 meters distant.

Here are the sol 2124 3D if you wish to examine the craters in detail.

The sol 2125 drive was over about 4 hours ago, so the images should be posted to Exploratorium by 3:45 PM EDT.

Thanks Hort; It just looks like there are more scarps than can be attributed to the old craters.

#128:
Good image processing quality despite Oppys blurred eyes, Horton. As usual. Interesting targets under way.

I think that the two craters in Horton's panorama (reply 125) are strangely lacking in ejecta. There is no more debris around their rims than on this nearby piece of ground without craters:

In many cases piled crater ejecta appears to have been "planed" smooth by erosion in-place but here it is altogether gone. The crater walls are still pretty distinct though. I suspect that the ejecta has been transported rather than eroded along with a lot of the loose coarse material we've been seeing.

I think these two craters are very old and being exhumed, which may account for the lack of ejecta.

This is a strange area. There is a smattering of dark gravel at the ripple-bedrock contact with local concentrations of gravel lenses (see the dark area in Kye's image). And the ripples are looking more active-- look at the longitudinal streamers coming of of the ripple crests. Active sand= loose entrapping sand, so she needs to watch her step especially since we're running off clean, safe bedrock.

Also, did you notice the dust accumulation on the side of the top of the antenna in this image?

--Bill

Kye; Can I interpret your comment in 131 to mean you also think fluvial activity may have effected this area ?

Bill

The pattern of the dust accumulation you referred to in your #133 looks somewhat like the water splats on the Phoenix wheel strut.

Thanks for your informative posts.

Winston

sol 2125 looking towards the fresh crater "Concepcion":

with links to navcam pans forward and backward.

To me the most interesting features in this pan are the several reddish ejecta streaks pointing back towards Concepcion. Definitely a "recent" event.

And here is the peculiar eroded bedrock on sol 2123:

with links to 3D pairs.

There was definitely "somthin' goin' on" here.

The atypical outcrop looks almost like some conglomeratic material imbedded in the Meridiani beds.
A possible indication of past fluvial activity.

Makes me suspicious that some don't want preconceived ideas disturbed by a little added effort.

Ben, re your 133, I'm still going on about impact-surge which I tend to think of as basically a catastrophic fluvial event in which the fluid is a mixture of liquid water and solid particles of varying sizes. The regolith includes a lot of material that is not derived from the bedrock but is also too coarse to have been plausibly moved long distances by wind. Most of the larger loose pieces seem to be impact related, impactites, ejecta and meteorites. I suspect that most of the exotic regolith particles larger than dust have arrived here originally in an impact-surge from a distant huge event. The other obvious possibility is that more familiar (non-surge) impact processes have produced and placed all the coarse particles.

I have trouble seeing how the cobble mounds could be placed as ballistic ejecta, but on the other hand they would make great gravel bars formed in a surge. Fluid movements of any kind are going to sort the solid particles they mobilize and drop them in concentrations.
The largest exotic particles like Block Island and Marquette Island should have caused craters in the bright rock where they are if they were simply primary or secondary ballistic impactors. Every big exotic rock we have seen seems to be simply lying on the surface of the bright rock with no crater, pedestal, moat or yardang, like there has been no interaction with the bright rock at all. This is all consistent with the large pieces being moved by surge and just left wherever the surge dropped them. Since that event there has been no significant erosion of the bright rock except by ongoing small impacts.

Horton, Ben, the atypical outcrop (reply 36) shows us great exposures but doesn't show even a hint of layering. That's enough in itself to make it unusual. It seems to fracture much like the other outcrops though? I tend to see an eroded remnant of something different added above the typical bright rock.

Ben, I was sitting here staring at the atypical outcrop. and I just understood your reference to conglomerate in reply 136. Yes, it is tempting to see those cobble-sized pieces eroding from the front of the outcrop as having once been separate before being cemented together. If that's what we're looking at it gets really interesting. We may have seen something similar at Madrid:

KYE; back when we were looking at Madrid, I remember thinking this could be conglomeratic material filling a channel eroded into the bright layers and later covered by the angular ejecta from VC.

I have difficulty accepting a surge with the power to cut channels and form the rounded cobbles to the degree we see in the removed (atypical) material.

We must have had some earthly impacts that were large enough to form surge deposits but I don't recall anyone suggesting widespread erosion and channel filling caused by a surge in our geologic record.