Origin of the Flood Layers

So, if you are correct, we should be able to find similar occurrences within the Vishnu Schist. The occurrences should have a fragmented appearance with schist on both sides.You may want to do this search, but I'm going to abstain for the time being (likely a very long time).In the meantime, could you explain why we do not have these veins or dikes in the Tapeats? Interesting observation. Why do you think that is that case? What does that material between the clast and the schist seem to be? Why do you suppose it looks different? Is there anything else you can say about that material?

Well it sho' looks like that to me. Looks like air from here.

Actually, I think it's a different material, also. The question is, what is it? It has something to do with the process of creating an unconformity. I don't have a problem with the clasts being transported, just not from those 'depressions', and probably not by the same flow regime that deposited the sandstone. And I don't think they were transported very far. The clasts are what I would call sub-angular, meaning that they have been transported a short distance, but more than simply plucked up and resettled in the same place.You are also seeing something that is interesting to me. You are pointing out a fabric in the softer, shadowed material. How did that form and from what material? Does it look like sand?

Well, according to Faith that seals it. It 'looks like' is pretty solid evidence. I don't know if even Faith would think it was always air, but if the Vishnu at this location has always been exposed to the surface (never buried), you never know...

Not sure what you mean by "fabric", and we don't know much from that photograph about the hardness. IMHO the shadowed area is Vishnu Schist, just a continuation of the un-shadowed area.

Hi Edge,Yeah, you got it, thanks for the clarifications.You were wondering why I chose the scenario of a cliff face towering over a riverbed, and that was because you said, "Probably much the same way as they would look as if they fell out of the cliff face shown and ended up in the river sediments below," and the "cliff face shown" was this one: So in my reply I tried to be consistent with that pictured scenario of a cliff face over a riverbed. I understand it doesn't have to be a cliff face, just a difference in height. But it's the difference in height combined with the transport that is a part of the scenario that I think many people will miss when you say that the material atop the Vishnu Schist is from the Vishnu Schist. I think many will assume you mean it came from that exact spot of the Vishnu Schist, or perhaps just be confused.Also, the material coming off that cliff face can be from other layers above the Vishnu Schist. We can only see Vishnu Schist in that photo, but somewhere above out of view are other layers. It's another part of the potential confusion that when it is said about that clast photo that when clasts from the lower layer are found embedded in the layer above that it is evidence of an unconformity, many will conclude that you mean the clasts always have to be from that lower layer. They don't. They could be from some layer above that layer, and even possibly below that layer depending upon how "interesting" the geological history has been.

Please use PM's if you want to discuss other participants and their contributions.

Sure, all scenarios of topographic relief are valid, and they do happen. That is why I included that image of different types of placer gold deposits. There are differing degrees of transport.And, there is little doubt in my mind that some of the material just above the unconformity is actually part of the schist itself. Exactly. All Jon and I are saying is that if it is incorporated into the sand, its source is older than the sand; and since the sand is a product of erosion, then erosion must be occurring somewhere, probably at a higher elevation.

Not much point in my sticking around either. When an argument is about an observation it helps to have others see the same thing along with you and I'm always just one against many. Takes heat and pressure I would expect, plus the fact that schist is made up of many rocks and minerals including those that form quartz or pegmatite veins.

Some kind of common observation is one of the main requirements of science. If you consistently see something different, could there be something wrong with your sensors? Or maybe your processing is out of calibration? Well, the geological level of the Tapeats isn't much different from the GC metamorphic suite: and the composition of the pegmatites is mostly quartz, so I'm not sure why the Tapeats would be exempt from forming such veins and dikes.Do you think there could be an age difference?

Heat and pressure does it for me.And no, I'm seeing the clasts and the depression correctly, you aren't.

Does what for you? You don't even know what I think about the depressions. I've been careful about that...

So how do you make heat and pressure?How do you get a layer made from very fine metamorphosed mudstone and shale below a layer of far more coarse sandstone?

One of the many difficulties of trying to have a discussion with you is that you NEVER read in context. Heat and pressure does it for me without the factor of great age, about which you had just asked me. Does that clarify or do I need to copy out every quote, even the most recent? I guess I could do that but since this is only one of many difficulties I don't expect it to be worth the time anyway. OK, but didn't you just respond to JonF by suggesting that the material in the depression / shadow is not schist?And please make something else clear: You called the clasts "boulders" at one time, and referred to that little ridge in the Tapeats as a "bedding plane." Did you see Percy's post since then that showed the area of this photo to cover about twenty 100 square inches? ABE: About nine by twelve or so, judging by the size of the woman's hand in Message 322 ./ABEEdited by Faith, : No reason given.Edited by Faith, : No reason given.

I explained the heat and pressure back in that lengthy description I gave of the scenario I have in mind that Percy suggested you should take as my model.As for the question about the laying down of different sediments let's not change the subject, OK?