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

I don't know much about this formation and to be honest, I can't make out crossbedding in that "stream bed" from the photo. A couple quick comments though How could they be "completely unrelated?" when they are touching each other? It is kind of hard to see the contact line with his yellow line in there (maybe he could post the unedited version?) but it does seem clear that those two sediments are not conformable. It makes no sense to say they are "unrelated." Because the two materials that make up the two strata contact each other unconformably. Another very confusing comment. Of course they are strata... Stratum (pl: strata): is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers.Can you distinguish those two sediments from each other? "possibly including weathering" ??? Of course it has been weathered. I can't for the life of me figure out why you would say this? Yes, it possibly includes a LOT of weathering. Because the two strata contact each other unconformably. What is the exact nature of the unconformity? That is not so clear from the picture, but it is an unconformity - by definition.The point of the "rip-up" portion is that it is comprised of material that was derived from the dolomite (the larger clasts) and at least one other material of which the source is not in the picture along with fine sand and gravel. This looks to me like a mass-wasting or possibly scree at the base of a cliff.A broader picture would be helpful, though.HBDABE: Maybe interesting: The relationship between the Neoproterozoic Noonday Dolomite and the Ibex Formation:Edited by herebedragons, : Added link to paper

I wanted to offer you this explanation about how an uplifted, jagged landscape can be reduced to a level surface. What this does is illustrate what jar has been saying about how material is moved from high places to low places. It is overly simplistic but should give you the idea behind how erosion could work over time to wear down a landscape. This first photo shows uplifted tilted blocks with a valley in between them - very much like what we see with the Supergroup. I have drawn it as an island to keep it as simple as possible. One thing to keep in mind is that we should be talking about energy gradients here; erosion moves material from high energy potential to low energy potential. The water level indicates lowest energy potential, the mountain peaks indicate high energy potential and the valley indicates low energy potential. Image 2 shows how erosion has worked to round off the sharp peaks. Because there is still an energy gradient from the valley to the water level, sediment coming from the peaks will be carried away from the valley through runoff.(A good contemporary example of this is the Adirondacks as compared to the Rocky Mountains. The Rockies have sharp jagged peaks while the Adirondacks’ peaks have been rounded off by erosion) Image 3. When the valley has worn down to the point that there is no longer a sufficient energy gradient to carry sediment away, it begins filling with sediment. Erosion continues at the places where there is still a high enough energy gradient to carry material away. Image 4. When enough sediment accumulates in the basin, the energy gradient increases until sediment can once again be carried away. Sedimentation stops and the valley once again becomes an area of net erosion.The process repeats between image 3 and 4 as energy gradients shift back and forth and the area shifts between net deposition and net erosion. In the end, there is nothing that CAN happen BUT a flat plain created. Eventually, this water will come up onto the land and will further level the landscape by eroding the highs and filling the lows. Image 6 illustrates what would happen if there was continuous and equal erosion on all surfaces. It could not happen this way. A negative energy gradient would be created in the valley and there would be nowhere for erosion products to go. They would HAVE to accumulate - which would take it back to image 3Your images of erosion in Message 345 show what happens when water runs off the surface rapidly and in high volumes, not what happens with normal, long-term erosional processes. (commentary: If a world-wide flood did shape what is now the surface of the earth, this is the type of erosion we should see everywhere. But it’s not instead we see evidence of these slow, long term processes).I think this post illustrates the model as to how rugged landscapes can be worn down to flat plains. It is more than just fantasy, it is based on real, physical processes and principals that we observe.Is this what happened to the surface of the Grate Unconformity? Maybe, maybe not This post is not meant to address that particular question, but to give a model for landscapes being reduced to a flat plain. I realize my model is overly simplistic, but it is the principles you should focus on.The ONLY thing that erosion CAN do is reduce a lumpy, bumpy landscape into a flat plain - because erosion does not act alone but in conjunction with deposition.HBDEdited by herebedragons, : typo

Great find Percy! It makes the scale of the formation much clearer.Your image is enormous though, it takes forever to load and then I have to zoom way out (33% zoom or smaller) to get the full size image to fit on my screen. Could you possibly reload it in a smaller aspect?I have some discussion regarding this formation that I am going to present to edge, but I need to get back to my school work now - so maybe later...HBDEdited by herebedragons, : additional info

The model I presented is obviously very simplistic. You are right that there are energy gradients below sea level and that there are erosional forces also at work. However, in such a simplistic model as I presented (especially one that deals primarily with land processes), we need to think in terms of NET erosion and deposition. Surfaces below water level would experience net deposition -although of course, there would be regions of erosion as well.The point would be that erosion would move materials from land to the sea, down the energy gradient. The energy gradients on land deal primarily with erosion while the energy gradients in the ocean would primarily deal with sedimentation.HBD

I think Faith is right in asserting that a flood of that magnitude would behave in ways that might not fit our models of localized flooding exactly. But there is a generalized pattern we should observe if there were a single, global flood event:erosion --> deposition --> erosionUnconformities are problematic in that they create a pattern that is more like:erosion --> deposition --> erosion --> deposition --> erosion --> deposition --> erosionWhich strongly suggests multiple, smaller events rather than just one massive, single event.(and by "strongly" I mean inescapably conclusive )HBDABE: I think Faith has one of the better approaches to this problem - trying to explain unconformities with an alternate mechanism, rather than erosion, in an attempt to reduce the problem of multiple events into the single event sequence (erosion --> deposition --> erosion). Of course, I think it is ultimately futile but so is trying to restrict the flood event to a narrow segment of geological history. Edited by herebedragons, : ABE

Just that the evidence doesn't suggest that there was such a single event of erosion --> deposition --> erosionbut rather multiple events producing multiple cycles of erosion and deposition Well... that's part of what this discussion is about... unconformities challenge that pattern. The presence of unconformities suggest multiple erosion / deposition events rather than a single, linear progression. (ie. erosion --> deposition --> erosion) It's an interesting approach, I just think it goes against all the evidence. Most creationists say that the Great Unconformity is the pre-flood surface, which is fraught with problems of it's own.HBD

Ok then... none of them. HBDI'll have to come back to all this later

What form do you imagine all these sediments were in prior to the flood?Keep in mind that we assume that all the sediment existed before the flood, but you have deep, deep layers of unconsolidated (or at least, unlithified) sediment piled up on the earth. DEEP! Like miles deep of what? sand? coccolithophores? Foraminifera? "Basement" would probably be a better term, since that refers to the metamorphic base which all the sedimentary rock sits on. Well that explains one continuous transgression. The problem is we see not only multiple transgression events, but also regressions. I think this is where your "wave idea" came in.The other problem is that in order for there to be a transgression, there needs to be a land mass. The water first has to rise enough to strip all of the land of its sediment and then at the same time lay down a transgression sequence. Once you strip all the land off the basement, you have no land left with which to begin a sea-level transgression.Or to put it another way, why would you think the energy level of the water would be low enough to begin deposition during the first 40 days? That would be the most violent part of the flood. This would be your stage 1 erosion. Once the 40 days are over, the water settles down and THEN deposition begins. But there is no land mass except deep underwater with which to invoke Walther's Law on.What you might get is Walther's Law sequencing as the water regresses, but then you need it to also be eroding.Darn , so much to do - such a short time to do it in.HBD

I thought about that, but figured it could be explain away as having been created that way without the need for erosion. But really that doesn't make a lot of sense, that God would have created the earth with a mile deep, uhh ... whatever (dirt, sand, loose gravel).Well, then there is the scripture in Matt 7 where the wise man built his house on the rock and the fool built his house on the sand ... I don't think we want God building on sand... The earth was probably rock... just sayin'HBD

Wouldn't all the violent rushing water that is stripping the surface of the earth off mix those things up? Land and ocean originates all mixed into one big slurry? Right. Your model can't explain huge amounts of deposits (limestone), so just ignore that detail. Not necessarily. Waves laying down hundreds of feet of sediment like a paint brush? Think about what it would take for a wave to deposit sediment as rapid as this. Ok. So you are saying that it rained for forty days but the waters continued to rise for the full 150 days. I guess you could read the story that way. So it was during that continued rising ~ 110 days worth that the depositing was happening. Walther's Law requires a variation in depth, from deep to shallow. That is what causes that pattern of deposition. The rising water would not have an edge if there was no land deposited to create a shore.So how deep was the water after 40 days? It had to be at least as deep and the highest land mass - remember it has all the sediment from the land suspended in it. Material in suspension takes up more volume than material that has settled, so it needs to way higher than the land.So let's say there was 1000 feet of rock pre-flood (above bedrock). In order to erode that all away, the water would need to rise to 1000 feet above the "bedrock". Now the water keeps rising and sediment begins falling out of suspension. But there is only 1000 feet of sediment available, so the water will always be higher than that, so how does it have a "shallow forward edge."Now we need to go back to the sorting problem. All this stuff is mixed together. How does it deposit in nice neat layers. Previously your answer was something like "the flood water picked up a type of sediment and deposited it somewhere else" but now the sediments are not even in neat layers when you start. How could they possibly get sorted?It's just hard to get my head around what you are envisioning here.HBD

Wow. This thread has REALLY become a mess in the last couple days. Just a quick read through and I see at least a dozen topics that could be spun off into new threads. I would love to discuss this whole issue of "species" and "races" etc. But I think this thread is supposed to be about how the Great Unconformity (and unconformities in general) formed, and as far as I know, that issue has not been resolved.Do unconformities form by erosion or by tectonic forces sliding the blocks underneath? Have we come to a consensus yet? I don't think we have.I would like to ask for you to do a simple project. Draw a step by step process for how you envision tectonic forces acting on a block and how it would cause it to rotate under a larger stack and create an unconformity like we see at the GU. Use a process similar to what I did for erosion in Message 540 or Percy did in Message 88. (I drew mine on paper and then scanned it into my computer. if you don't have a scanner, I guess you could use paint, but I think it is awkward)This will not only illustrate to us exactly what you have in mind, but also will give you the opportunity to fully think through your idea. If I were to draw what I think the situation is, it will probably not be what you had in mind, so better for you to do it yourself.Keep in mind a couple parameters. 1) the sediment is not fully lithified, but in a semi-hardened state. 2) You need to account for the movement of materials (if "rock" is being sheared off, where does it go?) 3) don't skip steps, show the intermediate stepsThis should go a long way to concluding this discussion about unconformities. All the latest discussion is doing is muddying the waters (no pun intended) - there is just no way to discuss all these different topics at one time.HBD

That would be in an open system, that is the material has a place to go (ie. to a basin). Folding under the strata would be a closed system, the materials should be trapped in the system. If you have an idea as to how they could get out, that would definitely help.from your blog (bold mine)

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Then tectonic or volcanic forces tilted or folded a block of the LOWER strata, which were sheared off at the top under the weight of higher strata that remained horizontal though they may have been raised by the force.

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This "sheared off" material is what I am talking about.

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I really think we could put QED to this here.

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Hardly, Faith.HBD

Sheared off rubble accumulated under the Tapeats and turned to schist leaving a flat and level contact - the kind of contact you find impossible for erosion to accomplish? That's the BEST explanation????But there are more problems than that... but they are hard to explain, I'll have to draw a picture which will take me a couple days to have time to get to. But essentially, the volume of sheared off material would take up more volume than can be accounted for with schist at the contact plane.Why would the Super group not also be metamorphosed? It is below the plane of the GU...Wouldn't there be evidence of heating at the contact surface? In other words, why doesn't the Tapeats show evidence of heating? The material less than 1 inch below it was hot enough to metamorphose, why wouldn't that show up in the Tapeats?HBD

But it looks nothing like the contact at the GU. It is similar in that it is two layers of rock, the upper resting uncomformably on the lower, but that's about the only similarity in that contact.I have highlighted some features below Look at how the grain is distorted. You can even tell which direction this block was sliding. (The upper block was sliding to the right relative to the lower block)The area in the circle is really distorted - it may even had been plastic (not molten) heated from friction.That's the thing, sliding cause a lot of friction - A LOT. Friction causes heat. Heat causes deformation. Deformation is recognizable in the contact.No such deformation in the GU.HBD

Here are those calculations regarding earthquake motion and heat generated by rapid plate movement Message 9Message 25Plates moving at 10 feet per day IS supersonic ~30,000 times faster than current rate.HBD