It does not look deeper though ...
Gee, two sols of images missing (547, 548), and a RAT hole covered in sand.
Do you think we had a major "cleaning event" that was more fierce than the previous ones ?

And if you look closely you can see some of the RATted blueberries faintly through the blown dust, so I think this is the same hole.

Given the dustdevil activity at Gusev, I'd suspect similar aeolian activity at Meridiani. We may see fewer (or no) DDs here because Meridiani is less dusty, being paved in blueberries. Recall the rapid changes on the rover tracks at Purgatory-- within a few days, the underlying dust was streaking away from the disturbed areas.

--Bill


PS-- Oppy did take a series of solar panel MI's, so we may know if there was a cleaning event soon. And we can check the solar panel output as it has been decreasing.

It's the same hole for sure - but wow - lot of dust dumped in there

One would hope that if the nearby dust was blown INTO the hole - then dust would also be blown OFF the rover

Doug

It looks to me like they went back in with the brush. Many of the features looked pitted rather than covered with dust.

Yeah, in hindsight NASA has surely brushed at least one RAT hole.. So ignore what I wrote about whatever, blah blah

Back in with a brush and made it filthy? I dont think so. The clean rat hole is before the dusty rat hole chronologically. Dust deposition makes a lot more sense to me

Doug

Doug:

It looks less like dust deposition to me than the matrix breaking up, with the smooth surface disintegrating into clumps. At the risk of setting another wild goose chase off, I wonder whether static charges could have built up during the RATting which made the very fine particles dance about. I have yet to be convinced about macro-scale aoelian effects (microscopic dust layers, fine - it's just the big chaps that I have my doubts about!).

Bob Shaw

I'll have to stand over in the confused side of the aisle, too. Initially I saw this and thought "cuttings blown in", but I swear, the surface does look pitted and eroded. Thsi may be an optical illusion, and I'm waiting for more MI's.

--Bill

Strange crack in the terrain -

http://marsrovers.jpl.nasa.gov/gallery/all...B1P1700L0M1.JPG

Doug

A 360 degree panoramic view of Opportunity in the middle of the bedrock.

Taken with the L Navcam on Sol 550



jvandriel

Yes Doug, you can see it also in Sol550 jvandriel Panorama (Oppy traversed it) and in previous Sols I noticed other linear structures partially hidden, eventually related to this:

My idea is that there is a large "macro" crack system connecting many outcrops, and running below the dunes (we should think to a unique cracked pavement partially covered by dunes, in fact ...
They must be deep too and I strongly suspect they are the cause of "minicraters", as suggested by this image of aligned collapsed sand holes on the side of that dune!

(I never trusted to minicrater explaination...)

Dilo:

Very interesting - a sort of limestone pavement, Karst style topography below the dunes... ...hmmm.

And I never really bought the mini craters, either!

Bob Shaw

There sure are a crack there djellison, and agreeing with dilo, I was never comfortable with the idea of miniature impact craters.
Opportunity did pass a series of sinkholes on the way to Endurance suggesting there are a karst bedrock below. The minicraters might be paritialy filled sinkholes and the cracked lines like the one djellison pointed out could very well have come from underneath.

Starting from Jvandriel last Pano, I made a magnified vertical projection (5 cm/pixel) in order to better identify the macro-cracks:

Here I tried to identify them, with possible (not sure) connections:

It seems they form an (approximately) orthogonal grid, with one of the two directions going toward Erebus...

Seems reasonable if the cracking is connected to the Erebus impact. Intuitionally I would expect cracking around an impact to be either radial (if caused by the uplift of the crater rim) or concentric (if caused by the overpressure/underpressure couplet of the expanding shock-wave).

tty