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

I don't know what trust has to do with anything... Rather than addressing my character, address the argument.If the mounded hill was pushing up into the layers of sandstone and gravels were being stripped off the hill, why would they be forced out away from the surface? Why would they not be pressed against the surface of the hill?If the gravels are settled between the layers, away from the hill, in a line that follows the upper surface of the layer... doesn't it make more sense that they fell off the hill and landed on an exposed surface and were then buried by the next layer?You claim the gravels as evidence of "drag folds" or uplift and deposition, but the logic of what that observation suggests is completely backwards. I didn't make a wouldacoulda speculation about anything.HBD

I'm sorry to hear that. It must be frustrating. I don't want to be flippant or insulting about a condition that is beyond your control, but I wonder at the wisdom of arguing so vehemently about what you see in a picture when you have such trouble seeing in the first place. How could you distinguish between uplift of the right side and "sagging" of the left side. How can you tell that is not a near-shore deposit that tapers off near the water's edge? How can you tell? There is no "gaping contact line." That's what I am talking about. You think you see that, but it's not there and instead of admitting that it could be an artifact of your vision problems, you call us "untrustworthy." There is NO gap between those layers, it is shadows cast by an uneven surface. What would go a long way to improving discussion is if you would just admit when your wrong and not blame us. There is no "gaping contact line."HBDEdited by herebedragons, : spelling

I didn't highlight that image, Percy must have...but anyway, here is what McKee says about coarse fragments at the base of these hills

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Monadnocks which persisted as rocky islands in many parts of the Cambrian sea during early stages of deposition show definite evidence of a shore environment. Walcott reports that the flanks of some of these hills are covered with large rock fragments which obviously were broken off from near-by ledges, probably through the action of the sea, and were buried in drifting sand where they fell. Later geologists working in the region have recorded other excellent examples of coarse materials, especially large angular blocks, on the sides of various Ep-Algonkian monadnocks (pl. 3c). In many places these boulder accumulations grade off into conglomerates containing gravels which are subangular or rounded, doubtless as a result of pounding and rolling by waves, and still farther away, at what presumably was the gravel limit, they grade into normal sand of the formation. Sharp has also described what is believed to be a marine slide breccia, located at Ninety-one Mile Canyon. It appears to have been caused when oversteepening by wave action of the slopes on a monadnock flank resulted in a great mass of material breaking loose and sliding into the sea, moving out over fine beds and deforming them locally.

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Other evidences of wave action are found in the profiles of hills on the Ep-Algonkian surface. An undercut carved in a monadnock of Shinumo quartzite and preserved in cross section beneath the Tapeats sandstone in Hotauto Canyon is considered by Noble to be an ancient sea cliff, and is described in detail by him. Other hills of Pre-Cambrian rock on which the slopes have been sharpened and the profiles modified, apparently by wave action, are mentioned by Sharp, and the flat top on one monadnock, believed to be the result of marine planation because it forms a sharp angle with the steep hill slope below, has been pointed out by him as especially significant.

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From Cambrian History of the GC - pg 122It is a really poor quality image, but here is plate 3 which show some of the coarse sediment being described above.I spent some time the other day using Google Earth to try and find some of the structures McKee illustrated, but it is just to hard to tell from photos. There are some great 360 degree panoramas though.

Did I not mention somewhere back there that whether Faith excepted the principal of superposition depended on the circumstance? The principal of **erosion --> deposition --> erosion** supersedes principal of superposition. We can't have **erosion --> deposition --> erosion --> deposition --> erosion --> deposition --> erosion** can we? Reminds me of Alex the Lion from Madagascar talking about his steak... "Come on, look at this. you won't find any of this in the wild. This is the kind of refined, food-type thing that you do not find in the wild."HBD

This is the impression I have gotten as well, like strata comes in sheets that are laid down all at once. Even if the general idea is that individual grains are deposited one at a time, the whole thing has to happen so rapidly, that it would appear as being dropped all at once. Imagine 300 - 400 feet of sandstone spread out over a hundred square miles being deposited in a matter of a week or so...HBD

Your logic puzzles me... If the orange lines and yellow lines were once parallel and the orange lines "sagged" or pivoted down to the left after the whole (or most of the) stack was already above it, shouldn't there be "gap" somewhere between the orange and yellow lines?? Instead that contact is seamless, barely even a crack between them.HBD

Sure, but its not a simple 1 deposition and 1 tectonic disturbance scenario. Plus you would need to do the sand deposition experiment to see how sediments look when they form on a sloping surface, otherwise you won't except what we see as having happened. You seem to have the impression that all rocks go through a stage where they are "clay-like." I don't think that is right. Clay has special properties because of the extremely small particle size. The particles are also electrostatically charged and when combined with charged ions have strong adhesive properties.Sandstone doesn't have these properties. Unlithified or "soft" sandstone is grains of sand compacted tightly together. They don't have the adhesive properties that clay does. It is the water molecules that bind the grains together until they are cemented. Use wet beach sand to mold a tower, it holds its shape (until it dries) but if you try to deform it, it crumbles - it does not bend like clay would. Sandstones require mineral "cements" to hold the grains together.Do the experiment with the sand and the fish tank, Faith. I thought about doing it for you - I have the materials or could get them readily, but I am afraid it would be a waste of time because you wouldn't believe my results. But if you want me to, I will - I will just have to take pictures, probably not take video footage (maybe I could??)HBD

This whole issue of "soft" rocks is bothering me too. I addressed it a little bit in Message 1593, but maybe you could address it in a bit more detail. Especially (I am curious as well) how sandstone would be expected to behave if it was only partially lithified - like say 10% of the grains were cemented or 20%, something like that. It wouldn't be hard like fully lithified rock, but it wouldn't be like clay either.And are there examples of rock that has only been partially lithified? I suspect not since it needs to be buried deeply for the process to happen and so is unlikely to be exposed before completion, but I suppose it could happen. I do realize there are poorly cemented sandstones, but I think that is different than partially lithified, right?HBD

I would say that in general, her lines are representative of what I see there as far as layering goes. You're right though that it is difficult to be completely sure without standing there (just like that little hump in the middle is probably not there based on the Google Map images).What her drawing does not capture is that the angle of the layers she represented with orange lines get progressively steeper. The layer above it is not as horizontal as the yellow line, but not as steeply angled as the orange lines. The contact between the grey stone and the tan stone is even more steeply angled.This is consistent with what we should expect if this was deposited on a slope - the slope being the tan unit.HBD

This is what the experiment (demonstration) is needed for!!! I hope she gets to it soon.HBD

Great find Percy!! This is exactly the kind of demonstration I looked and looked for. Too bad it is in Spanish, it looks like there is more good information in the rest of the video as well.I especially like this image It shows the directionality of the flow much like this image What I would have done as a demonstration would have given an even distribution across the whole system and so would not have captured the directionality that is demonstrated here, just the layering effect. So this is much better.They use a slightly different system than would have formed the Tapeats, since the Tapeats was supposed to be a transgression, and they use a silt which would be transported much further than sand would be, but it captures the general idea very well! Of course, one source we looked at suggested that the Tapeats sea was actually a deeper system than previously thought, so maybe not so far off.Excellent! I'm not sure it is even necessary to do the experiment now... I guess we'll see what Faith thinks of this.HBD

I don't see why it doesn't match well enough. After 5 or 6 layers there is still a high spot under the arrow where the sediment is draping over the peak. That is drape on drape. 7 layers above the peak of this hill, there is still a bit of a dip in the layer, it is still being affected by the draping effect. Drape on drape, no? The particles used in this experiment are much finer than what we should expect sandstone to be formed from, but it still shows the basic effect.Also when sediment is referred to as "fluid" this is what is meant. Note how the sediment influx "flows" over obstacles. But as it settles, it "sticks" to the slopes and "drapes" over high spots. More sediment filled the low spots in this demonstration because the sediment could "flow" more easily into those low spots.Although I am not particularly surprised that you don't find this demonstration convincing, I simply can't understand why... You will need to give me some clue as to what you would find convincing. I get the impression that nothing will. I would be willing to do an experiment or demonstration, but not for you to just say "Nope, that doesn't do it."HBD

No one has claimed that "worldwide strata formed in any way other than horizontally." What has been claimed is that layers in images like those below were deposited as shown and need not be bent by tectonic forces. The sediment, where it deposits against a slope, would deviate from horizontal. That's the claim. Nothing about "worldwide strata." The experiment you were going to run doesn't need to involve "worldwide strata" it only needs to address the interface between the layer and the topography of the surface it is being deposited on.But I see you have already rejected the outcome as irrelevant regardless of the results.HBD

I am not going to have time to participate much right now (summer was supposed to slow down somewhat for me but it hasn't worked out that way) but it seems to me Faith's hypothesis all goes back to the original topic of this thread which is that the Great Unconformity is not an erosional feature; that it formed during the flood's deposition of the strata - even AFTER most of it was in place.IMO, the only way this thread could possibly move forward is for her to provide a detailed description/model for how that could possibly be the case. That would require some diagrams that detail the steps involved and where material would be displaced to. This is the type of thing she should be encouraged to provide if there be any hope of this thread moving forward... otherwise, it may as well go into summation and simply wait for a year or so until she brings it up again as if none of this thread ever happened.So, is her argument nonsense? Sure, I think it is total nonsense. I think it was made crystal clear in the last 1800+ posts that the Great Unconformity IS an erosional surface. However, she holds that it has not been adequately demonstrated and that her hypothesis better explains the observations. So the next step is obviously for her to provide an unambiguous description of the hypothesis (that is, how the Great Unconformity formed while under a mile of sediment), otherwise we keep guessing and she keeps complaining that we are all crazy (like thinking that sediment can deposit on a slope was madness). Yea, that is exactly how we get dragged into so many rabbit holes. I realize that she will say that she HAS provided that description many times over in this thread, but if so, perhaps it could be pointed out? The "descriptions" I have seen are vague and unclear and need to be explained better and some of the details worked out.HBD

What I said was that *I* think it was crystal clear. Obviously you do not. I acknowledged that you don't find it convincing. Proof is not really an issue, what is at issue is convincing, logical and realistic arguments. I (and I assume others as well) find the idea that 'ALL the layers were deposited and then *somehow* the strata was deformed in such a way as to produce a contact that has the characteristics of an erosional surface' very, very hard to swallow. That it was once an erosional surface seems (at least to me) to be the simplest and most obvious explanation. Your explanation for how it formed seems silly and nonsensical (at least to me). I don't think asking us to go to your blog is appropriate. But yes, you have described your hypothesis before. What is missing is the details. I guarantee if I tried to draw a diagram as to how your hypothesis describes the formation of the GU, you would just accuse me of misrepresenting your argument. This is where you need to step up. Rather than vague statements regarding how you "think" it might have happened, give us specifics, details and illustrations. Those would be good details to further explore. What evidence of surface erosion is missing? "Looks flat" is a lousy argument (especially when it is not flat). What evidence of a massive debris flow IS there and how does that explain the GU? I don't see how debris flow can explain the tilting of the Supergroup or how it occurred after all the strata was in place, but hey, give it a go. But we haven't dismissed the principle of original horizontality, we have just acknowledged that there are conditions where layers are not deposited horizontally. Plus if you look at the internal structures of layers you will see there is very little actually horizontal. As petophysics pointed out all deposits are on a slope. However, the principle of original horizontality is still a useful principle, but only at a macro level. When you look closer, it is not so useful.Besides, you yourself just acknowledged that sediment can drape over existing structures and can deposit evenly along a slope so why are we mad for thinking that it can happen?HBD