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What is the pressure at the center of the earth?

I don't know what it is at the precise center of the Earth, but pressure which causes uplift and folding are tectonic in nature (involves the shifting around of earth's tectonic plates). Pressure 'deep beneath the surface' is also caused simply by the enormous weight of the overlying rock.

Did the folding in the strata occur before or after the hardening of the strata?

There isn't any tectonic folding in the Catskills. The beds are simply tilted slightly upward toward the east, the ancient source of the deposits, the Acadian mountain range. However, there is plenty of tectonic folding along the northeast margin of the Catskills, particularly around the Towns of Catskill and Leeds

How did those fossil images on top (and inside for that matter too) of the Grand Canyon survive all that erosion you say occurred?

They will eventually be eroded away, and more and more fossil-bearing layers beneath will be revealed.

Where did the side canyons come from?

Erosion from tributaries I would imagine.

How come archaeologists have to dig?

Is that a serious question?

Did the folding in the strata occur before or after the hardening of the strata?

Although there wasn't any tectonic folding at the location depicted in the photo, folding occurs *after* the rock has already hardened. Hardened rock can and does behave in an almost ductile manner when it is under enormous pressure. It has been demonstrated experimentally that rock will 'flow' under such extreme conditions.

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How a particular rock deforms depends on:

* its temperature and depth;
* the amount, rate, and direction of the stress;
* the rock’s inherent strength;
* and the quantity of water in the rock.

[Photo: Close-up of phyllite showing angular folds.]
This phyllite deformed while it was cool and less ductile, making its folds angular.

http://www.mnh.si.edu/earth/text/3_2_3_1.html

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Also see:

http://earthsci.org/education/teacher/basicgeol/deform/deform.html

I don't know what it is at the precise center of the Earth

I didn't ask whether you knew what was there. (It had better be iron, or we have another one of those contradictions.) I asked what the pressure is. You know: high, low, medium. What? And since we're talking about the center of the earth and all that iron there: where did it come from. I mean I thought the earth was formed from a swirling cloud of hydrogen gas which somehow coalesced. Where did the iron come from and how did it make its way neatly to the center if it wasn't there at the beginning?

You talk about the tectonic plates, but when I was in college we had a guy who believed in that stuff who came to lecture (I wish I could remember his name but I don't.) and as I recall he was considered a quack. (I was a math student, but I like to hear guys with far out theories speak so I attended.)

As for the folding, isn't it neat that you think the rock somehow flows in to fill the gaps that would be created. Flows in from where? Put any of these rock in a vice of sufficient strength and you will crush the rock. It won't flow or bend, at least at normal temperatures.

Tributaries formed the side canyons you say. There are no tributaries. The land is sort of flat and featureless as you approach the Grand Canyon (from the south, at least - I haven't been to the North Rim.) and then, boom, there it is: a huge hole in the earth with a little river running along at the bottom a mile below. You can see it at Google.

Yeah, the question about the archaeologists was serious. To me it looks as if the earth is still accreting, but you have the land washing away. And, oh BTW, how come almost all of the land is in the northern hemisphere? Yasuo Shinozuka had an interesting idea about this, but I stopped hearing from him. I don't know what became of him.

ML/NJ