[X] My Assistant

[Shaka]

Hope no one minds, but I felt we have to have a new topic, right from the start, as a compendium of all the Factual Observations on this incredible structure...this Mother Ship from another world...this...(who said Burgess Shale? I laughed at that at the time. ) Who will start us off with a detailed description of what we see before us TODAY February 5, 2006 - Super Sunday.
(I'll be running from game to Exploratorium all afternoon!

[imipak]

Now _that's_ what we like to see!

http://qt.exploratorium.edu/mars/spirit/fo...55P1206R0M1.JPG

My uneducated intuition makes me think the lower, thicker layers, which seem to have large grains (small pebbles?) embedded in them, are composed of volcanic ash rather than windblown (or water-washed) fine sediments. Of course intuition is reliably wrong...

Question to the geologists: does rock formed from volcanic ash appear any different (to the instruments on Spirit) if the ash fell onto standing water, or onto dry land? Hmm, and I suppose if we imagine that there are repeated episodes of ash fall and periods under water, it will make a difference if the sediments between the water and the ash are water permeable?

Clearly there's SOMETHING different between the lower, coarse layers and the higher fine layers. What else might it be? (this is a real question, not a rhetorical.)

[Shaka]

Now _that's_ what we like to see!

http://qt.exploratorium.edu/mars/spirit/fo...55P1206R0M1.JPG

My uneducated intuition makes me think the lower, thicker layers, which seem to have large grains (small pebbles?) embedded in them, are composed of volcanic ash rather than windblown (or water-washed) fine sediments. Of course intuition is reliably wrong...

Question to the geologists: does rock formed from volcanic ash appear any different (to the instruments on Spirit) if the ash fell onto standing water, or onto dry land? Hmm, and I suppose if we imagine that there are repeated episodes of ash fall and periods under water, it will make a difference if the sediments between the water and the ash are water permeable?

Clearly there's SOMETHING different between the lower, coarse layers and the higher fine layers. What else might it be? (this is a real question, not a rhetorical.)

Aha! But here it is!
http://qt.exploratorium.edu/mars/spirit/mi...55P2936M2M1.JPG
And what , pray tell, is it?
If it's sandstone, I don't see any grains .
If it's scoria, I don't see any gas spaces .
If threatened with torture, if I don't talk, I would quote a Past Maestro of Home Plate" It's deja vu all over again! It's the kind of fabric Oppy has been sinking her abrasive into all over Meridiani! Smooth-lumpy STUFF!
But a geologist would phrase it more ...esoterically.

[imipak]

Aha! But here it is!
http://qt.exploratorium.edu/mars/spirit/mi...55P2936M2M1.JPG
And what , pray tell, is it?
If it's sandstone, I don't see any grains .
If it's scoria, I don't see any gas spaces .

"Well... it's rock, isn't it?" /Arthur Dent

Actually the blueberry-esque concave dimples in the lower, whitish (in that image) material has brought the word 'slots' floating up from some dusty recess of the distant past, 18 months or more ago.

And really the darker, upper material *does* seem (to me) to be made up of sand-grains sized particles. As it happens there's an outside wall made of very soft grey-green sandstone about three feet <-- that way from my monitor that looks very like the farker material. it feels sandy if you rub your thumb over it, and there's a small heap of sand grains that have eroded out of it accumulating in tiny wind traps in the corners of wall and ground. It's a terrible building material - it weathers so fast that old older buildings in the area, there's a characteristic 'gumline' vertical profile - sort of a ' UUUUU ' shape, rotated through 90 degrees - where the mortar holding the wall together has withstood wind erosion more strongly than the building stone itself. Co-incidentally it looks a bit like the harder, then layers standing up proud of the adjacent layers, especially in the coarser-grained , thicker layers.


Anyway... I'm still boggling over the image of Homeplate being flipped over like a pancake by an impact event