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

I was not talking down to you. You're deflecting. But it's not flat, that was the point of Message 204 which the only thing you took out of that was the point about quartzite. Go back and read the rest of the post that describes the contact surface. A reference that describes the actual contact surface is irrelevant? The point you are making is "it doesn't look eroded" and that you can't see how erosion could produce those features. Those aren't arguments they are personal incredulity.And by the way, you could stop yelling at me.HBD

OK. Red lines show channels filled in with Tapeats Sandstone. Not Flat Red lines shows a cut into the Vishnu filled with Tapeats. I saw a version of this same area before and there are several of these visible. The top is flat, yes. But it looks as if the layers below were laid down at an angle as shown by the blue lines. How were they either laid down on an angle OR how were they truncated by continuous deposition. What is this? Is this supposed to be an unconformity? You can draw straight yellow lines, so what?

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(From Message 204) The maximum height of these monadnocks in the Shinumo quadrangle he gives as 600 feet. Schuchert, after visiting an area farther east, refers to hills up to 700 feet, and Wheeler and Kerr ’ describe one north of Grand Canyon Village which rises approximately 800 feet above the base of the Tapeats sandstone.

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These monadnocks are in the same general area as that photograph. Not flat.By the way, in my post Message 204 my point was not about erosion, but about continuous sedimentation. So if you are claiming there was no erosion, then are you arguing that there WAS continuous sedimentation? How does continuous sedimentation produce those contact surfaces?In Message 205, I showed an image with 4 unconformities. How would any of those unconformities form during continuous sedimentation WITHOUT erosion?HBDABE: So if we ignore the exceptions, such as 800 foot tall monadnocks, then it is mostly flat.Edited by herebedragons, : No reason given.

So, "mitigating factors" would control metamorphosis so that it produces a straight, flat contact line, but erosion can't. That makes no sense. How is everything below your flat yellow line metamorphosed and everything above it remains unmetamorphosed.HBD

I went back and reread this and I guess I really don't understand your point (I guess you were right, I just didn't think about it ) Lumpy rocks had flattish surfaces? So as long as the surface of the rock is flat, then its not a problem for it to be flat? So the Vishnu and the uplifted strata are lumpy at the surface? Wouldn't that be the unconformity? So you are saying the surface of the Great Unconformity is lumpy but it couldn't be erosion that made it lumpy? We have looked at these cross sections before and I showed you how layers pinched out or were truncated by other layers. Some layers are missing within the canyon. Some fill depressions and channels in the surface of another layer. What kind of question is this? Erosion would stop when there is no longer a differential in height or when deposition begins. Those questions make no sense, especially as a rebuttal to an unconformance being a period of non-deposition.Besides all this, we don't need to decide HOW any particular surface came to be the way it is yet. What we need to do first is determine if a contact (the Great Unconformity in this case) is consistent with a period of non-deposition.HBD

So landscapes exposed to the surface should not be flat like this: or how about this: It has monadnock structures just like the ones I have been describing in the Great Unconformity.So your saying that these areas shouldn't be flat? Not anywhere? Why?And stop yelling, it is completely unnecessary.HBD

What argument? That erosion can't make surfaces flat? That lumpy, bumpy rock isn't flat? There is no argument, you don't think erosion can make rocks flat. That's not an argument.You should tell us then, what force of nature could flatten a lumpy bumpy surface into a flattish plane. What force?HBD

I don't think you've made the case that it can't.But, the thing is that I have no idea what other force could do such a thing. If a surface was all jagged and bumpy and now it is flat... the only thing my limited scientific imagination can come up with is erosion.If you have a better explanation, that would be a much better argument. You changed the subject. I was discussing the Great Unconformity and whether it was actually an unconformity or not. If there was continuous deposition and the Great Unconformity does not represent a period of non-deposition, then we need to talk about something other than erosion. We need to talk about how that feature could form during continuous deposition. If that is the case and there was no hiatus in deposition, then I will concede that erosion did not make those surfaces flat.But, if it does represent a period of non-deposition, then we need to talk about what happened during that non-depositional time... was it erosion or something else?HBD

OK I think I know what you are trying to get at. Here is some pictures that Percy posted back in Message 88You're saying that erosion could not have caused this process.Here's the first problem... if we show you images of angular unconformities where it has been flattened, it the same situation; erosion could not have done it. If we show you images of tilted blocks in the process of being eroded (which is not practical because everything but the erosional surface will be buried) that is not evidence because it is still all bumpy and lumpy. By your standards nothing is evidence that erosion could wear a mountain range into a flat plain.The second problem is... how do you know that erosion couldn't do this? You don't think it could. That's not evidence, that's not an valid argument. The way we know (or at least think that it could) that erosion can wear a mountain range down to a flat plain is that we see evidence of it in the rock record.The idea seems strange to me too, it's hard to picture. But the evidence suggests that what happened.You start with the premise that erosion can't reduce a mountain to a plain and then reject the evidence of it in the rock record.If you are interested in the evidence of this, we can continue discussing why the Great Unconformity is actually an unconformity.The other direction this could go is propose a way other than erosion that the Great Unconformity could form.HBD

I think it could... you think it couldn't. So we are on equal footing here. Are we going to discuss it or are you going to assert it? I have not asserted that erosion is the force that made "it" flat. I said what alternative is there? I said how do you know that erosion couldn't do that? I said we don't need to even discuss erosion if the GU is not even an unconformity; erosion is right off the table if the GU is not an unconformity. I bet there is... How about we check?Now is the Great Unconformity an unconformity or not?HBD

Declaring there is no evidence is nothing but evasive. Of course there is evidence. Maybe there is not enough evidence to come to a conclusion; maybe the evidence doesn't support the premise; maybe what evidence there is supports a different hypothesis besides erosion... but there certainly is evidence.We could compare two competing hypotheses and see which one better fits the evidence. If the erosion hypothesis has no evidence to support it, then the competing hypothesis should find at least some support.What you are saying is that you don't want to discuss the evidence, you just want to make unsupported declarations. You pretend that you have brought down the conventional view of geology and therefore any unsupported hypotheses are just as valid. That's nothing but basic denial.HBD

The point Dr. A, edge and myself are trying to get across is that those surfaces you say couldn't be brought down by erosion because they are so flat are not flat.So the question becomes "Can erosion make a lumpy, bumpy surface into a lumpy, bumpy surface?" You're the worst one for this. When we "misunderstand" your point you just keep repeating the same thing over and over often resorting to yelling and name calling. I try different approaches trying to get at what your saying, you just keep up the same mantra "declaration X is right, just think about what I said." over and over.Sheesh yourself.HBD

I am not sure why it can't have strata above it. Does the strata above somehow flatten it? But how about these? They all have tilted strata, no horizontal strata on top of them and are as flat as the GU.What else?HBD

I would like to hear what this "something else" might be. I have an idea what you have in mind, but would rather you describe it before I guess at what you're thinking.Also keep in mind that any surface exposed to erosion today is in the process of being eroded. Erosion is not finished sculpting it. Deposition will not begin until the surface is low enough to begin accumulating sediment.HBD

No doubt. I'm not sure this is the situation exactly. I am thinking that she is suggesting the the slip - folding is what caused the "perfectly" planar surfaces, rather than erosion. It is not a scenario you can find in any textbook, so it is something I was thinking about drawing up to show why it's not a feasible mechanism. I think two major problems come into play (not just with any one person specifically, but with "floodists" in general). A rejection of standard geological explanations - basically, if the explanation involves long periods of time, it must be wrong. And looking at problems piece-meal - geology (and the GC in particular) are huge subjects with multiple lines of reasoning. Basic geology is not particularly difficult (I assume it can be very difficult at levels above what we are doing here) but is rather involved and requires looking at the big picture. When you look at only one piece at a time (like that image so much time was spent arguing about and whether there was ever layers on top of it) it makes it very easy to see things that don't make sense. Geology, as a whole, is a big picture exercise in my opinion.HBD

Odd, the first one was my favorite example. Are you looking at the ridge in the background? It is very Grand Canyon - like. I the farm (actually a church, but whatever) picture, you can't actually see the strata from the side view, but it should be clear they are practically vertical. Now why would you guess that? If you are saying what I think you are saying, you are still right that erosion can't flatten tilted strata but these were flattened by another process, buried and then unburied. Now they look like eroded tilted strata but really aren't. Worse concession speech ever.HBD