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

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.

The GC doesn't get anywhere near as severe weather as Siccar Point, and much of the GU we see in the GC doesn't get much exposure to weather anyway, such as in the side canyons, but I'm sure it's true that there has been some deterioration of the original GU there too. I'd expect that the contact used to be even more flat than it is now. I'm saying the rock has been so battered by the weather at Siccar Point that it isn't clear that there was originally a straight contact between upper and lower sections, as illustrated by that drawing at my blog I just posted to jar. In your picture the sandstone is almost shredded by the weathering, reduced to splinters. The lower strata no longer have the straight upper surface that is shown in that drawing.Siccar Point is the barely skeletal remains of what must originally have been a much broader and deeper stack of strata, but most of it was destroyed, leaving this small pile of heavily weathered rocks. Perhaps not, if a simple obvious point escapes you.Edited by Faith, : No reason given.

Except it isn't. Those in the GC are but Siccar Point isn't. Weather has been battering this small rock formation from all sides for thousands of years and there is no protection left.

Of course! It wouldn't have been DEPOSITED in that messy condition.

Again, as usual, there is some kind of huge disconnect in this discussion that makes no sense to me. I don't *want* any particular thing, I simply SEE the flatness and levelness and I think it's very clear how it has been lost in some cases by disturbances after it was all laid down, earthquake displacement perhaps, volcanic disturbance perhaps, and in the case of Siccar Point, both those (that light colored column is a magma dike) plus severe weathering. If anybody lives in Wonderland, it's you guys.

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...

You know, it would probably help communication if you realized that I NEVER think in terms of millions of years. I ALWAYS have around 4500 years in mind for the age of all these formations.Just for the record, if I were thinking in terms of half a billion years I would expect the Grand Canyon long since to have dissolved into a pile of dust. And wouldn't that be in keeping with the idea that erosion over such an enormously long time supposedly explains how the surface of the Vishnu and the tilted Supergroup got level enough for all those strata to build on them as horizontally as they did even from the nice neat flat Tapeats? The "upper sequence" being the horizontal strata above the vertical? But it certainly IS that battered: those rocks are barely a shadow of their former selves, nothing left but splinters basically. And surely there was once a huge stack of strata above them too, just as in the GC, long since destroyed by tectonic and other forces. And do try to remember: I don't think of each bedding plane as having been exposed for any great period of time. Well they didn't have photography in those days and those who made such drawings, Lyell for one, did aim to draw what was actually there. A couple hundred years of weathering since then should be sufficient explanation for the greater deterioration we see in your picture. I'm sure much of your problem must be due to your habit of thinking in terms of millions of years. If you'd just recognize that I don't, it might help you see better what I'm saying. It's "ancient" yes, but only in thousands, not millions, of years. Edited by Faith, : No reason given.Edited by Faith, : No reason given.

Your yellow line in this case may not really define the contact line but a deterioration of what is left of it. The upper section in the photo doesn't even look like it's resting on the lower section, it sort of looks like it's collapsed behind it.Why would Hutton's drawing show a straight contact line if it wasn't there?

Well there's your problem; you don't even know your enemy.

(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.