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

Since you seem to be agreeing with me in this post in answer to the post I addressed to HBD (which I mention not because there's anything wrong with that but because you so often ignore context) although you say you are probably not saying what I think you are saying so I'm not going to try to figure out what that means. Maybe the puzzle will be solved as discussion proceeds, or more likely it will just get weird.But your off topic side note caught my attention: It is relevant, though, if onlyk because it's one of HBD's examples, and my answer is that the only way you could dispute original horizontality in a subsiding basin is by invoking OE theory, certainly not by observation or evidence.Edited by Faith, : No reason given.

Surely Steno's law refers to STRATA, not alluvial fans and dunes.

duplicateEdited by Faith, : No reason given.

Sorry, I guess I need to be clearer, although I did try to make a distinction between HBD's diagrams plus your photo of the road cut in New York, and the straight level contacts in my photos of the G.U. in Grand Canyon.I think all these angular unconformities were formed in the same order: strata all laid down, then tectonic force disturbs the lower part of the stack, sometimes leaving the upper strata more or less intact, sometimes deforming them too, and this force creates the "unconformity" -- between two different kinds of rock at the point where the weight above resists the force from beneath.This doesn't always create the same kind of formation. Sometimes the lower segment is folded or tilted, sometimes it's a different kind of rock like the schist in the GC or the gneiss in New York, sometimes the contact is amazingly level as in my original photos, which argues against an erosional surface and in favor of shearing, and in that case the upper strata were remarkably preserved intact and horizontal; but sometimes the contact is pretty rough as in HBD's diagrams where the strata were deformed by a large rock pushing up into them; as well as the NY photo, where the upper strata were also deformed by the tectonic disturbance, and part of it sagged into a depression in the gneiss. In this latter case it's the general deformation of the strata and especially its sagging instead pf filling up the depression that shows it was already there when the surface of the gneiss was roughed up.So there is no shear in your NY photo and HBD's diagrams. Thought that was clear but apparently it wasn't.Edited by Faith, : No reason given.Edited by Faith, : No reason given.Edited by Faith, : No reason given.

I'm not sure "bogusity" is fair, a poorly chosen example maybe.Sediment will "drape" over an obstacle,I was just trying to introduce that point, but maybe a subsiding basin was a bad choice. I think I did a better job of explaining the idea later up-thread, but I probably should have waited to post about that topic until I had time to look for an appropriate example and provide an appropriate explanation.HBD

I'm not sure what you mean here?

quote:

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Strata: is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers. The "stratum" is the fundamental unit in a stratigraphic column and forms the basis of the study of stratigraphy.

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Why would buried dunes and alluvial fans not be considered strata?HBD

Compromised?? You crack me up. Could it be that we have learned new things since the 17th century. Steno didn't write the Bible on geology, you know.HBD

Thanks for providing a link to the resource that proves your assertion false. This is a pretty common YEC tactic and fun to watch.From your link:

quote:

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As one of Steno's Laws, the Principle of Original Horizontality served well in the nascent days of geological science. However, it is now known that not all sedimentary layers are deposited purely horizontally.

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Nicely done.JB

Well, I think that Moose is right on this. I erred in comparing the locations. And the fact that the diagram shows ages of rocks rather than rock types or formations is a clue. However, I would like to say that I was mainly looking at the variable thicknesses of the units and how they would sag into the basin as they dewatered.And it is also a fact that a given formation can be highly variable in thickness, and even 'pinch out' completely, so we know for a fact that the upper and lower formation boundaries cannot be parallel.It should also be pretty obvious that in a transgressing situation, the leading edge of the formation has to be thinning toward land at any given instant in time.So, the point still stands that there is often a visual draping effect around transgressing formations, particularly around pronounced high points such as islands of Shinumo Quartzite.

I understand completely what you are saying, but it makes no sense. This is probably because no one can imagine a form of deformation where this would occur and form the kind of structure that we see (or in the case of your scenarion we do not see). If the underlying sequence is uplilfted, how do you get a 'straight and flat' surface extending outward from the point of uplift??Please draw a diagram or something to show this. Shearing that is not in evidence.But it must be there, right? Evidence? Evidence? What is your evidence that the sagging was tectonic? Because it 'looks like it'?

Faith, do you not even read your own citations? If you did, you would have seen this: ABE: Reading just a bit further into the article (it's not even very long...): Thank you for doing this research for us, Faith. Edited by edge, : No reason given.

Since you've had more explanation of this now and had time to learn more perhaps you can elaborate on what you mean by it being a coincidence.It is a "coincidence" that occurs all over the world. Are you suggesting that it all occurs by just chance? Or are you suggesting something else?

A nice view of strata deposited with an original inclination from glacial outwash in Quebec. Each of the inclined layers represents the top of the deposit at one point in time, becoming younger to the right. Coarse grained material such as this, is more likely to have an original inclination. The inclined layers are truncated at the top by erosion and subsequent deposition of another deposit. Note how flat the erosional surface between the two deposits is in this picture. There is a shovel at the right side for scale.

Wait, that can't be true! According to faith that defies the law of gravity and the most basic law of geology.I'm seeing evidence that Faith lacks understanding of the law of gravity along with the laws of geology. But yeah, that's funny that it comes from her own link.JB

I read the whole thing and even commented that unfortunately the principle has been compromised. You obviously didn't read all of my post though.