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If you look at those cross-sections of the Grand Staircase - Grand Canyon area you can see that the uplift over the GC is in a mounded shape, and that the tilted layers of the Supergroup I've been asking you about occur at the bottom of the canyon area directly under the uppermost height of that mounded area. It looks to me like there is a relation between the uplift and the Supergroup that hasn't been dealt with yet so I would like to get explanations, such as

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When did the uplift occur in relation to the tilting/erosion of the Supergroup?

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Looking at the diagrams I don't see any direct connection. The tilting seems to have come before the uplift, probably by a long time.In this drawing - the least stylised - - it appears that the later strata were laid on top of the GCS, after it had tilted and eroded. The Shinumo Quartzite sticking up into the upper strata is rather telling, and the fact that the fault between the two sections of the GCS doesn't continue upward - in my opinion - also suggests that the fault occurred before the upper strata were deposited.The rise on the ground also starts well before reaching any portion of the GCS, and the tilt of the GCS doesn't exactly agree with the slope.In this diagram, presumably showing a different section ! - we see slopes in opposite directions. The strata of the GCS slopes up right-to-left, while the ground slopes up left-to-right (the surface of the GCS does have a small left-to-right upward angle, and I suppose THAT could be due to the later uplift).So I'm not seeing any reason to suppose a connection in either.

You don't mention it explicitly, so just so no one's confused, in your first image north is to the left, and in the second it is to the right.--Percy

I understand you share Percy's view of how the tilting of the Supergroup was created, so you've abandoned your earthquake explanation, but I still have the question about when you think the uplift of the whole canyon occurred in relation to the formation of the Supergroup. Since I've asked the same question later on you may have answered it later already.Edited by Faith, : No reason given.Edited by Faith, : No reason given.

(my bolding)Yes. Yes, my argument too, different mechanism and time frame of course from yours, which follows: (my bolding)Question: Is there some relation between the elevating landscape and the Colorado's eroding through it that you haven't spelled out? That is, how did erosion cut through the elevating land to cause the canyon? Seems to me more likely that a relatively small amount of water like the Colorado River would just run off the slopes of the mounding uplift rather than cutting into it. Or if it did cut into it, it wouldn't be in an east-west direction but north-south because that's the direction of the slope.(I've been picturing this mounded area as continuing more or less the entire length of the canyon east-west, so that my illustration of a balloon beneath the area should be a sausage-shaped balloon, and the canyon would have cut lengthwise or east-west through the layers mounded over the balloon or uplift. But again the sloping is north to south, so it's hard to see how a river would have cut east to west.) So the idea you are laying out is roughly this:The Supergroup was formed according to the tectonic stretching that builds range-and-basin mountains, first faulting separating sections of a long block of horizontal layers, then tilting of the separated sections so that they form separated tilted blocks, the tiliting due to the space created by the faulting, so that a sequence of tilted blocks of strata becomes a mountain range.Then after all the layers above were in place -- that according to OE theory accumulated over many millions of years, even a billion or so -- after they were all laid down, then deep processes in the earth raised the entire stack from right beneath the Supergroup into a mound shape, and the strata already laid down above formed that mounded shape right over the Supergroup itself, as can be seen on the cross-sections, the Tapeats or lowest layer sort of draping itself over the Supergroup and all the layers above following suit. And the Colorado River at the top of the mound then began its slow cutting of the canyon east to west (which I question above because of the direction of the slopes.)According to this scenario, the uplift occurred some billion years after the lowest layer over the Supergroup was laid down as it would have taken that long to lay down all the layers up to the Kaibab, and yet it was pliable enough to follow the contour of the uplift without breaking, and so were all the layers that built on top of it. Because as you've argued, even solidly lithified rocks can stretch to that great an extent.That's sort of a slow-motion version of how I'd been thinking about the sequences except I've had the Supergroup tilting / Great Unconformity created at the same time as the uplift. Although I still tend to think that, right now I can't prove it, but at least I am in agreement with you about the basic sequence of things after the formation of the Great Unconformity. Of course I'm highly doubtful that the rocks would have been pliable enough to follow the contour of the uplift after multiple millions of years, and also doubtful that an ordinary river could have cut lengthwise into a mounded sausage-shaped uplift.\ I'll have to see what others have to say about it.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : Sorry for all the edits, just trying to be as clear as possibleEdited by Faith, : No reason given.

Erosion through rock takes time, but uplift also takes time and is usually very slow, perhaps something on the order of a centimeter per year, but not at a constant rate. Whenever uplift outstrips erosion then water pools but eventually spills over and creates a rapid flow, perhaps even a falls, and the fast moving water can erode quickly backward upstream. Niagara Falls is a good example of retreat of a waterfall - it has retreated upstream about 7 miles in the last 10,000 years.The uplift of the region around the Grand Canyon is not thought to have been continuous but episodic and to have taken millions of years.--Percy

No, movement along a fault IS an earthquake. Percy's explanation was a little more complete. An earthquake happens when the stress built up in rocks from tectonic pressures is released. No, I hadn't gotten to that point yet. You have layers bent by uplift that were sedimentary, so their tops should have been relatively level (certainly should appear so from your distant vantage point). So any bending of those layers would have to happen later.If I were to speculate (not being a geologist) I would think that there were two plates in collision, one subducting under the other, and this caused the tilting and faulting of the supergroup, then the sliding stalled and pressure built up resulting in the uplift.But there also had to be time for the supergroup to sink into the sea to have the marine sedimentary layers added before the uplift.It certainly appears that the whole set of mountains there down the west coast are caused by such plate subduction and uplift, a process seen in many places around the world.If you look at that animation of plate movement and concentrate on west coast north america you will see a period where there is a fairly linear inland sea dividing the mountains from the plains. Wish it went slower.Enjoy.

To add to what Percy said, it is thought that the river existed before the uplift, and thus was already constrained by it's floodplain.This is why you see typical floodplain switchbacks in a part of the canyon: Note that this particular shape cannot be developed by rapid runoff by any rational stretch ...As the uplift occurred the slope of the river was increased, and with it the speed of the water, allowing it to keep pace with the gradual uplift.EnjoyEdited by RAZD, : .

Can't picture what you have in mind here, but a river already established would divert AROUND any uplifting of land, not erode through it, and besides, this mounded uplift has a north-south slope, so it's hard to see how water could have eroded the mound east to west. There is apparently an east-west slope down through the canyon now that the river runs down, but the question is how it could have cut in a westerly direction through the upper part of the uplift at all in the first place, right when the uplift was occurring. I'm not sure what rapid runoff you have in mind but if you are referring to my idea that a huge amount of water had to have carved the canyon, I don't explain the meanders or switchbacks as being caused by that initial cataract of water, but by the river that resulted after the great volume of water had decreased to river size. It is rivers that create those formations, not great cataracts of the size I've had in mind that opened the canyon in the first place. I picture that flowing in from all sides of the canyon, not just the eastern end, but there is clearly enough of an east-west slope for the river to run down now.But if you are picturing the river on a flood plain before the canyon existed at all, and attribute the cutting of the canyon to the river's erosive effects as the uplift was occurring, this doesn't seem possible, since the uplift into which the canyon cut is this mounded east-west sausage shape, not to mention that a river would go around any kind of uplift, not through it. So you need an explanation for how that river made its way along the line of the canyon at all, since the slope of the mound where the canyon now is, runs south, not west.By the way I just drew a rather klutzy diagram of what I'm trying to describe, and posted it at my blog (not sure how to post it here) which is HERE . But again, the uplift appears to be in a mound shape sloping north to south, in a sort of sausage shape that extends at least some great part of the length of the canyon east to west, yet the canyon is cut east to west through the south side of the slope, where as I said it looks to me like the water would INTIALLY have had to run south, not west. Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.

Well, yeah, but water flows into lower channels and a lower channel in the direction of the eventual canyon seems to be precisely what is lacking in this scenario no matter how you reduce the height of the uplift. But I guess we can just assume that it did find a way since there it is at the bottom of the canyon. I just did a quick calculation with a centimeter-to-inches calculator based on a centimeter a year and I get roughly 30 thousand feet per million years so it must have taken a lot of long breaks. Yes, that could work I suppose. Plausible enough based on your OE assumptions, considering that we're all guessing.Edited by Faith, : No reason given.

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Can't picture what you have in mind here, but a river already established would divert AROUND any uplifting of land, not erode through it, and besides, this mounded uplift has a north-south slope, so it's hard to see how water could have eroded the mound east to west.

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You're ignoring the time factor here. It's the level of the river bottom that matters. If the uplift is so slow that erosion will keep up with it, keeping the river bottom at about the same level as it started, the river won't divert.And I'm not sure what direction has to do with it. The direction of the river is already fixed by its course - why should it not cut into the rising land, no matter what the direction of the slopes.

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I don't explain the meanders or switchbacks as being caused by that initial cataract of water, but by the river that resulted after the great volume of water had decreased to river size. It is rivers that create those formations, not great cataracts of the size I've had in mind that opened the canyon in the first place.

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So practically the entire depth must have been cut by the river, AFTER it had acquired the meanders and the switchbacks. Think about that one.

Yes, apparently everything depends on the slowness of the uplift, and of course at a centimeter per year its height isn't going to offer any appreciable obstacle. Yet the uplift is a MOUND and the canyon is cut into the south side of it along its length so it slopes north-south no matter what its depth. You simply have to assume that the water was already running in that direction anyway and had enough volume so that the rising land really made no difference whatever. I still need to picture a channel for it to seek and I can't find one on the south side of that mound even at a centimeter in height, but I guess that's just me. Water seeks a lower level, it doesn't cut into rising land, UNLESS of course it's a ginormous amount of water that overwhelms everything in its path. Even then it would seek the lowest level to flow in. But a centimeter wouldn't stop it so that takes care of that. [qs]I don't explain the meanders or switchbacks as being caused by that initial cataract of water, but by the river that resulted after the great volume of water had decreased to river size. It is rivers that create those formations, not great cataracts of the size I've had in mind that opened the canyon in the first place. I can't even think about it because It doesn't make enough sense to begin to think about it. The huge volume of water I've thought did the cutting and sculpting of the canyon occurred at the beginning; the river is what was left at the end, so the original cataracts of water did the major work of scouring out the canyon and the river just cut out its own river bed at the bottom of the canyon after all that enormous amount of water had drained away.

Oh and while we're at it, Paul, do YOU think, as Percy does, that strata stacked a mile deep would be pliable enough after a billion years to bend over the contour of that mound over the GC that can be seen in the cross-sections? That continuous long stack of strata that runs north-south from the GC to the GS in both diagrams is a mile deep, and on OE theory the bottom layer (the Tapeats) that is the first layer above the Supergroup is something like a billion years old. Edited by Faith, : No reason given.Edited by Faith, : No reason given.

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Yes, apparently everything depends on the slowness of the uplift, and of course at a centimeter per year its height isn't going to offer any appreciable obstacle. Yet the uplift is a MOUND and the canyon is cut into the south side of it along its length so it slopes north-south no matter what its depth. You simply have to assume that the water was already running in that direction anyway and had enough volume so that the rising land really made no difference whatever. I still need to picture a channel for it to seek and I can't find one on the south side of that mound even at a centimeter in height, but I guess that's just me.

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So long as it follows an existing channel - as the meanders indicate - that really isn't a problem. So long as you understand that with uplift being matched by erosion of the river bed the river will follow the original course the shape of the mounding doesn't seem to be an issue.

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Water seeks a lower level, it doesn't cut into rising land, UNLESS of course it's a ginormous amount of water that overwhelms everything in its path. Even then it would seek the lowest level to flow in. But a centimeter wouldn't stop it so that takes care of that.

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If the lowest level is it's existing bed then it will follow that. The cutting KEEPS the riverbed low enough for it to continue on it's existing course.

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I can't even think about it because It doesn't make enough sense to begin to think about it. The huge volume of water I've thought did the cutting and sculpting of the canyon occurred at the beginning; the river is what was left at the end, so the original cataracts of water did the major work of scouring out the canyon and the river just cut out its own river bed at the bottom of the canyon after all that enormous amount of water had drained away.

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But according to you, this initial rush did NOT sculpt the meanders at all. They formed later. Which means that the meanders - with all their depth - must have been cut by the river as it developed over time. Like I said, you have to think about it.Edited by PaulK, : No reason given.

Paul, you've got things seriously out of order here. The meanders occur at the very end of the carving of the canyon, whether on OE theory or YEC theory. The meanders were carved by the RIVER at the BOTTOM of the Canyon, that on MY scenario wouldn't have existed as a river until after the entire canyon had been scoured out by the huge volume of water I've kept describing as spilling into cracks in the uplift from all sides until it's carved away miles and miles of strata and sent it west and out of the canyon.And on the OE theory the current river bed with its meanders also wouldn't have existed, in that case for millions of years because it would take that long for the river to carve out the canyon and it wouldn't get so deep until very recent time. Um, sure, but you have to assume you've got a river bed anywhere in the vicinity of today's canyon, when the canyon didn't yet exist and was no deeper than a rather shallow river bed and how it could get that deep under the circumstances is rather puzzling to. I find it hard to suppose a riverbed could have existed at all along the south slope of that sausage shaped uplift no matter how high the uplift. I think you are mixing things up, in some way it's hard to pin down. The meanders did not exist AT ALL until toward the very end of the formation of the canyon, that is after millions of years on OE theory, and at the very end of the draining of the Flood waters on YEC theory.The problem is your phrase "the river as it developed over time." But there is no river in my scenario at all until all the Flood waters had drained away. On OE theory you have a river but it doesn't get around to cutting those meanders until the whole canyon is finished forming either.Best I can do to resolve what seems to be a confusion.Again, sure, but again, getting a riverbed established at all along the south slop of the uplift, still strikes me as highly unlikely. You seem to keep picturing the current riverbed at the bottom of the canyon but I'm picturing it all before there was any canyon, only a shallow riverbed following the course that would eventually become the canyon, and that's what seems unlikely to me. But sure, if you HAVE a riverbed there, certainly the river will keep cutting into it.ABE: This post seems to have come apart at the seams and I'm not sure how.Edited by Faith, : No reason given.

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Oh and while we're at it, Paul, do YOU think, as Percy does, that strata stacked a mile deep would be pliable enough after a billion years to bend over the contour of that mound over the GC that can be seen in the cross-sections?

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Provided the bending is done incredibly slowly, under high pressure, yes. There is good evidence (distorted fossils) of such things happening elsewhere. And, after Percy's reply it seems that this represents bending more extreme than the examples you are proposing.Edited by PaulK, : No reason given.