Summations Only

Hi Faith,I don't have any problem with you using the term "parallel" when you're talking about something like this: But you're going to confuse people about what you really mean if you use the term "parallel" when what you have in mind is this. You could describe the layers as roughly aligned with one another or as predominantly horizontal, but they're certainly not parallel: You again have to realize how exaggerated are the tilts on diagrams like this where the tilted portions are circled in red: Take, for example, the middle red circle which shows the layers tilting upward from the Vermilion Cliffs to the Grand Canyon, a distance of about 60 miles. Over that distance the elevation increases about 2000 feet to the canyon rim, or about 33 feet per mile. That's less than a 1% grade, 0.625% actually. That's a difference of only 0.36 degrees from the horizontal. If you were standing on a grade of 0.625% right now you'd think you were standing on level ground.So what looks like a dramatic tilt and a dramatic increase in elevation on that diagram is actually almost flat level, and at any significant scale the boundaries between layers are going to appear horizontal and parallel, as you can see in this image of the Grand Canyon: Now, getting back to the original point, we're trying to explain to you that the effects of tectonic forces were not completely absent from the region during the half billion years that these layers were deposited. If major tectonic forces that elevated the entire Grand Canyon region cause a grade of only 0.625%, then we should expect equally unspectacular grades for tectonic forces that occurred before all the layers were deposited and therefore only affected some of the layers.And this is just what we find. We know that the thickness of the Temple Butte ranges from 0 ft in some parts of the Grand Canyon to a couple thousand feet in Nevada around 75 miles west. The angular difference between the top and bottom boundaries of the Temple Butte is therefore 0.5%, just slightly less than that for the tilt for the geography between the Vermilion Cliffs and the Grand Canyon.Of course the top and bottom boundaries of the Temple Butte are unconformities and so erosion confuses the picture of how much of the effect was tectonic, but erosion alone combined with sea transgressions/regressions would be very unlikely to cause that great an angle.--PercyEdited by Percy, : Clarify.Edited by Percy, : Found a Grand Canyon image I liked better.

Hi Faith,Here's what's wrong with your idea about the origin of the Great Unconformity. You're saying we start with this, where the sky blue layer is the top layer of the supergroup: And we all agree that this is what we see today at the Grand Canyon where the tilted layers of the supergroup stop at the bottom of the Tapeats, which is the yellow layer in this diagram: So where did all the material in the first diagram go that is missing in the second? Take, for example, the bottommost layer that is a darkish orange. In the first diagram it stretches from one side of the diagram to the other. In the second diagram it is clipped short at the Tapeats and then below and to the right at the Vishnu Schist. It used to stretch for hundreds of miles in all directions buried beneath a mile of rock, now it's just a short stretch of maybe a mile. Where did all the cubic miles of rock go? That much rock could not help but leave huge amounts of evidence behind telling us what happened to it.--Percy

When I said "clipped" I was describing the image, not geological actions. I wanted to make sure Faith was aware how much the extent of the supergroup layers had been truncated in the second image versus the first, and how much of the supergroup layers had simply disappeared.There was no effort to accurately represent the schist as it didn't seem a relevant factor.--Percy

Even if the material is where it always was, just crumbled up, it would still take up as much space as it always did. Here's the diagram again where the bottom four layers represent the supergroup before it tilted: These bottom four layers extend for hundreds of miles, just like the layers above them, as shown in this familiar Grand Staircase diagram: So in your scenario, the tilted layers of the supergroup on the right side of the diagram at one time were level and extended beneath the Tapeats all the way from Cedar Breaks to the Grand Canyon (and further, of course, since the layers don't just stop at the edges of the diagram). Then tectonic forces tilted them leaving behind what we see today.So if this happened as you say, where are all the cubic miles of supergroup layers that used to underlie the Tapeats? You are self-evidently wrong to claim that that it remains "where it always was, it's just not shown on the diagram," because not only would that much material definitely be represented in diagrams, it would also be copiously described in the geological literature, and it would be whoppingly self-evident to the naked eye. Here's an image of the Grand Canyon Supergroup boundary with the Tapeats. The intersection runs across the center of the image, and there's no layer of crumbled up supergroup at the intersection: Here's a more close up image: The idea of layers rotating while buried under miles of rock is physically impossible and ludicrous on its face, but if we found evidence telling us that's what happened then we'd have to accept it and try to develop theories for how that happened naturally. But besides being physically impossible there's no evidence that any such thing ever happened.--PercyEdited by Percy, : Add a second Great Unconformity image.

I didn't address where you said the supergroup had gotten "metamorphosed into Vishnu Schist" because Edge had already addressed this, but I see now that you've explained to HereBeDragons that you didn't understand that explanation.The reason the Vishnu Schist could not be metamorphosed material from the supergroup is because the two have distinctly different compositions. The material in the Vishnu Schist is definitely not metamorphosed supergroup layers. The supergroup layers are predominately sandstone, siltstone, claystone, mudstone and limestone, while the Vishnu Schist, though highly varied, has a much more granitic and volcanic content.Also, as HereBeDragons has pointed out, were there a tectonic event that metamorphosed most of the supergroup layers and joined them to the Vishnu Schist then we would be able to easily recognize that, both from the junction boundary and particularly from the different composition. The Vishnu Schist is already subdivided by geologists into many different subcomponents, and if one of the Vishnu Schist subcomponents had been contributed by metamorphosed supergroup layers then it would not be possible to miss that.--PercyEdited by Percy, : Forgot limestone in my list of composition types of the supergroup layers, added it now.

But this is just another bald assertion that is contradicted by the evidence. If you read the Wikipedia article on Vishnu Basement Rocks you'll see that the composition of many different portions of it have been analyzed in detail. Were the upper layers of parts of the Vishnu Schist contributed by metamorphosed supergroup layers then the analysis would have showed this, and there would have been an obvious boundary. There's no evidence of anything you claim, which is expected for things that are made up.--Percy

So in a debate you don't think it's kosher to demonstrate that your opponent's views are based upon ignorance?In this age of Internet point-and-click to get a definition, I can't believe you actually complained about vocabulary.Can we assume you'll be using this excuse to once more reset to square one and begin making your arguments from scratch, while of course claiming that you've proved this all before?--Percy

In science, "things that are made up" are never called theories. If you hate science so much, why are you trying to be scientific? Well, now you're just being goofy. The article is full of information about " the source of the various kinds of rocks and minerals in the GC basement rocks." In this excerpt I've highlighted the sections that are specific about origin: Of course, as inconsistent as ever, you go on to reveal that you *did* find information about origin: Do you see anything in there about sandstone or limestone origins, which form a significant portion of the supergroup layers? We're well aware that evidence has nothing to do with how seriously you consider an idea. If you think an idea has Biblical support then you'll never give up on it. Whether it has evidence or not is irrelevant to you.--Percy

I highlighted the exact same text, just a shorter portion of it, the part that explicitly describes the "original deposition" material (to use your words), which is what you said was missing. Are you not able to understand the meaning of this passage you just quoted? Do you not see that it is saying that Vishnu Schist is composed of metamorphosed rock that was originally sedimentary layers from a marine environment?--Percy

Would everyone who sees Edge's contributions in this thread as nothing but incredibly patient and informative please give his Message 305 an upvote.--Percy

Yes. No.When a surface is eroded, the eroded material is absent. It's no longer there, carried away by wind and water. The next sedimentary layer is deposited directly onto the eroded surface.But in your scenario the top of the Great Unconformity is not an eroded surface. For you it's an interface with the Tapeats where somehow the deeply buried supergroup layers tilted, and all that material of the supergroup layers had to go somewhere, and what you said in Message 271 was: And so I responded with images showing that there is no layer of broken material between the tilted supergroup and the Tapeats. Strangely, you looked at the images and seem to believe there *is* broken material between the supergroup and the Tapeats, but there isn't. You must be looking at the scree. Eroded material from above gathers on any available surface. We've been over this before.--Percy

This image is a good illustration of how the direction of cut through tilted layers affects their appearance: A cut parallel to the tilt, the left face of the cube, shows all of the tilt. A cut at a 45 degree angle to the tilt, the middle plane at the top, shows only some of the tilt. And a cut perpendicular to the tilt, the right face of the cube, shows no tilt at all.--Percy

You're going to have to explain how you interpreted him as saying anything supportive of your scenario. What he said was that erosion took the surface down to a basal eroded surface, then when the sea returned it began a process of sedimentation upon that surface, depositing first big chunks of material (very active water), then later sand (a shoreline).When a surface is eroded, the eroded material doesn't remain behind. It is carried away.When sedimentation deposits material onto an eroded surface, the sediments are material that was eroded away elsewhere and then carried there by wind or water.There is no layer of ground-up supergroup material at the Great Unconformity. What you thought you saw earlier was probably scree.--Percy

I didn't say anything about erosion or erosional material. The vast majority of sedimentary material is the product of erosion. The "chunky erosional material" in your video is a sedimentary deposit of material that came from elsewhere. Nobody on the science side in this discussion would ever deny that "chunky erosional material" can be deposited, and as someone already explained, it is precisely what you would expect for energetic waters.The Colorado River does this every year in the spring floods. When the water is at it's most energetic it scours all the way down to the river bed and large pebbles and rocks are carried along in the flow. These large rocks knock loose additional pebbles and rocks which are also carried downstream. When the energetic flow eventually peters out these large pebbles and rocks will be deposited on the river bed, which is an erosion disconformity. If at this point in the time the canyon bottom becomes a region of net sedimentation then that layer of pebbles and rocks will become preserved and will mark the bottommost portion of a new layer of sedimentary deposits, similar to your video.But your Grand Unconformity scenario does not involve erosion. You've been using the word erosion incorrectly, and we haven't really corrected you too much because we understood what you meant, but now it turns out that your use of the term "erosion" has confused you, so it's time to correct you and make sure you don't make this mistake anymore.The process you're actually talking about is one of detachment of deeply buried adjacent sedimentary layers followed by tilting of the lower layer and abrasion and crushing at the contact surface between the two layers. There being no flow of water or wind to carry away the products of friction, abrasion and crushing, those products must still be there. But there is nothing like that there at the Great Unconformity, not in diagrams, not described in the literature, and not in photographic images.Your scenario of the tilting of the deeply buried supergroup layers is contrary to natural physical laws, and there is no evidence that anything as impossible as this ever happened.--PercyEdited by Percy, : Grammar.Edited by Percy, : Clarification.

I should also have included gravity as a force removing eroded materials from their point of origin. Scree in the Grand Canyon is an excellent example of gravity removing eroded flakes and pebbles from the point where they broke off from the canyon face.To clarify for Faith, I didn't mention eroded material remaining at its point of origin because it couldn't be a factor on any surface experiencing significant erosion. This is because once sediment begins accumulating, whether or not the sediment came from the very location where it's being deposited, it protects the surface from further erosion. For the most part, sedimentation and erosion are mutually exclusive processes.--PercyEdited by Percy, : Clarify.