Evidence that the Great Unconformity did not Form Before the Strata above it

Not really. If your understanding were correct we could just erode right down into the mantle.The problem you have is that you cannot erode beyond the base level (usually sea level). You can only erode from the areas above that. Why should uplift occur at any particular time?

Since we are talking about erosion and the formation of 'flat' platforms, here is one mechanism: There should be enough notation here to help with the explanation, but if not let's discuss rather than complain. I think this is an important mechnism for the Great Unconformity becuase you can easily imagine it happening as the Cambrian transgression cut into Precambrian rocks on the continent. I have personally seen this on the west coast of N.A., and many of the images we have provided show this mechanism at work.

So you assert.How can you tell? I think you are saying that it is not horizontal, but how do you know that the G.U. was horizontal? Certainly the lower sequence it tilted in many places, so what's to keep the unconformity itself horizontal?Besides, we've given you plenty of examples that are pretty clear as to how they happened. So, what have you got?Do you think this surface was level? And do you think it is smooth? Edited by edge, : No reason given.

That's not what I was asking. I was asking, 'is it a smooth surface'? Well, then, I'm going to say that the GU in the Grand Canyon is 'too weathered to tell what it originally looked like. Let me get this straight.You are saying that the shape of the unconformity has changed since it formed.ETA: Please describe this change at Siccar Point.This is worse than I thought. Is there really any point in continuing here? Edited by edge, : No reason given.

So, it's weathering that caused the unconformity at Siccar point to change after it was buried by the upper sequence of rocks. It went from smooth to rough.And that makes it irrelevant to the discussion.ETA: According to Faith, that is...Edited by edge, : No reason given.

I think it has to do with Faith thinking that the surface, which was obviously smooth and level, has been changed by secondary processes that she refuses to describe or explain. If she did try to do so, she would find that they make no sense.The frightening thing is that understanding Faith is like stepping into Wonderland.

That's a good point. Erosion was probably different at that time. I'm sure the point still stands that you cannot erode below base level with running water.There is another fly in the ointment that I hesitate to bring up because it will probably make us follow Faith down another rabbit hole. But, casting fate to the wind:There are several lines of evidence suggesting multiple phases of glaciation in the latest Proterozoic, just before the Cambrian. Now if you want to have a nice, smooth, planer surface try that on for size.

So, you know how severe the weathering was in the Grand Canyon are was half a billion years ago? That's fabulous Faith. By that reasoning, Faith, every bedding plane in the upper sequence should be battered as much as the unconformity. There should be no original sedimentary features left. So you are comparing a schematic diagram to an actual photograph. How clever! But your little sketch does not show this, does it? I see nice even layering all through both the upper and lower sequences.Once again, you are saying that an ancient unconformity surface is changing in geometry because of modern erosion. I think someone spiked my orange juice this morning...

So, you are saying that you SEE the unconformity changing from smooth to rough? Interesting...

So, the weathering (erosion, actually) that can penetrate the rock mass and change the character of the unconformity, still manages to leave behind clear bedding features in the overlying rock strata.I think I need more of an explanation here...ETA: See how the smooth unconformity in this sketch has been damaged by erosion (according to you) but the upper layers are still intact in the modern picture. Arguably, the uppermost layers of red sandstone have suffered even more erosion than the unconformity plane. Please explain. Edited by edge, : No reason given.Edited by edge, : No reason given.Edited by edge, : No reason given.

The weird thing is that now she's saying that erosion is causing the distrubance...

(Sigh...) Hunh? Explain or show a diagram. It's called a schematic diagram.

You know, it would probably help if you realized that I/we always think in terms of long ages...That's what the evidence tells us.

And how do you know their 'former selves'?But that's not even the point here. The point is that if the weathering is so severe at the unconformity, why is there anything left of the uppermost layers? Think of it this way. Why is the uppermost dashed yellow line still intact? If you were correct, it should be battered to tiny splinters and scattered across the North Sea.By the way, I have outlined in blue some clasts of the lower sequence within the upper. How do you suppose they got there? And all of the time they were eroded, they were protecting the unconformity at this point... Then neither has the unconformity been exposed to the elements for a great period of time.

Then please explain. And remember, just repeating the assertion is not an expalanation. Nor is saying that it's obvious.