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

Well, I wouldn't say that there is a lot of deformation related to the unconformity.What is interesting is that the composition of the gneiss varies across the outcrop. The place where there is some irregularity in the unconformity is different from the rest of the cut. This could easily be due to differential erosion.Still remembering my caveat about not being there... I would say that this is an accurate portrayal. The beds do not have to be horizontal, nor do they have to be inclined.

I'm pretty sure that it is both deformed and eroded. Just look at the layering in the gneiss and you will see that appears to be going in different directions.This would, of course, be a problem for most people professing a young earth scenario because you've got sedimentation, dynamic metamorphism (deformation), more sedimentation (the Supergroup in the GC), faulting and then more erosion even before the Great Unconformity even formed. Ah, yes, this sends us full circle back to the Grand Canyon, incised meanders and formation of flat erosional surfaces...

There are ways of doing it, but there is always evidence that it has happened.What is your evidence?

Hopefully to clarify, stretching does not imply a volume change. To get a volume change there are basically two ways:-- add or subtract to the rock mass
-- compress or expand the existing rock massExamples of the first are expulsion of water, or intruding an outside material such as a magma. There is always evidence such processes.The second is mainly done by changing the confining pressure and would be governed by Poisson's ratio for the rock. This is probably not what we are talking about. Edited by edge, : No reason given.

This is a good analogy.What Faith should show us is the addition of material to the volume of rock in question. She could do this by showing that the sandstone has undergone some kind of chemical reaction to expand its volume, perhaps; or maybe some kind of flow features (after all, it's plastic, right?) into the sandstone mass.However, by her own model of 'gaps' in the lower layers, maybe there should be gaps in the upper layers also. Just smaller ones...We can actually see such things in some mining operations, but there is usually pretty good evidence that it has happened. Like mining equipment laying around...

I see what you mean now. This discussion has gone down so many rabbit holes that I'm completely confused at times.

Exactly. I believe that there is some relief on the gneiss surface, and that is only evidence that the surface is irregular. I think Faith's logic here is that the surface is irregular due to 'intrusion' of the basement, but that the evidence for intrusion is the irregularity. Here is a photo of meanders and abandoned meanders in the Imuruk Basin of the Seward Peninsula. It gets pretty flat out there...

Heh, somehow, I never found this link before:http://www.gly.uga.edu/railsback/VFT/VFTManitou.htmlFaith should read the whole thing if only to show that there are crazy people outside of this Forum.Brainwashing college students... scandalous...

A good find. We should keep this demonstration handy for future reference...ABE: The only difference I can see with this demonstraton and the situation in the GC is that the Tapeats is a transgressive sand deposit; but the detailed motion of sand grains would be comparable. /ABEI had thought about flowing water forming sand bar-type deposits, but never about density currents or storm surges forming those non-horizontal, draped sand deposits.It looks like as long as there is some kind of existing topography, forming drapes with pinch-outs and a sagging appearance is rather trivial in sedimentary systems.This should overcome some of Faith's doubts regarding what sedimentation can do.So, we are back to the original question. What is the evidence that overturns the mainstream view and supports a tectonic origin of the unconformity surface?ABE: The only difference I can see with this demonstraton and the situation in the GC is that the Tapeats is a transgressive sand deposit; however, I don't see a real problem hereEdited by edge, : No reason given.

Silly me...I might just emphasize here that the facts shown support a sedimentary origin for draped sediments and non-horizontality of some deposition.We can quibble over the details, but both of these facts fly directly in the face of Faith's proposition.Is this debate going anywhere?

And you seem to forget that you said sediments could not be deposited on a slope.I'm not sure what you mean by "all those in the strata formations". Actually, I read your post correctly, all it was intended to show is that strata can be deposited on a sloping surface. It is a bonus that you can see the low areas being filled in and the upper layers becoming more horizontal and even.That's kind of like the McKee diagrams and the road cut photos.The only commentary on the mechanism by the video is that inclined layering can be accomplished by sedimentary processes, and tectonism is not necessary.

Okay, 'somewhat'...I'll take that as a 'yes'. Just as we have been saying all along. The thicknesses are variable, thinning toward the high points. As shown in the photographs and in the McKee diagrams... Actually, I see thickening of the layers in the direction of the deeper parts of the basins. Not sure what you are talking about here. Again, I don't understand what you are talking about here. I see drapes consecutively overlapping the older drapes as we go up the slope on the basement rocks. If you are talking about how they pinch out, yes, I would expect that when the basement high points extend out of the water as shorelines and islands.

But that's not what we see at the base of the Tapeats near the monadnocks. We see thinning in the upslope direction Again that is not what we see in the McKee diagrams. If you are talking about up in the Redwall or the Coconino, fine, but those are way up in the section where the video shows that the layers would be even. That would be a non-current flow situation. But it doesn't matter because in the upper parts of the demonstration, the layers are flat and even regardless of what the base was like.

Why do you capitalize the word 'strata'?It makes me think you are talking about something different from the rest of us.

This is true and it is one reason that I have never seen a violation of superposition, regardless of the convolutions YECs generate to refute it. The relevance to this discussion, however, is that things like the Lewis Thrust show evidence of their existence. What is your evidence that tectonism is responsible for the sedimentary drapes?