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Faith  Suspended Member (Idle past 1470 days) Posts: 35298 From: Nevada, USA Joined: |
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Author | Topic: Evidence that the Great Unconformity did not Form Before the Strata above it | |||||||||||||||||||||||||||||||||||||||
JonF Member (Idle past 194 days) Posts: 6174 Joined: |
I may have put it differently at different times but most of the time I said what I mean: sand won't deposit EVENLY on a slope to form a layer like the strata we know and love
Whatever you may have meant, you said many times that strata can only deposit horizontally. Post that picture again and we'll re-evaluate it. Edited by JonF, : No reason given.
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Admin Director Posts: 13032 From: EvC Forum Joined: Member Rating: 2.1 |
Faith writes: I may have put it differently at different times but most of the time I said what I mean: sand won't deposit EVENLY on a slope to form a layer like the strata we know and love. If it deposits more thickly on the top and bottom approach to a slope it doesn't make a layer like the strata. This doesn't make any sense. When deeply buried and under great pressure, what would prevent the area of the light sand layer that I've indicated from becoming lithified just like the rest of the layer?
About this part:
And remember I "cheated" and evened it out so what you see proves nothing anyway. Unless there was no sand at all on the slope before you "evened it out", it proves that sediments do deposit on a slope.
The question was whether that sagged layer in the road cut had sagged while damp, after the whole stack had been deposited, or got deposited that way. There is no thickening at top or bottom of that layer. If that is what normally happens with deposition on a slope YOUR theory has been disproved, not mine. An equal volume of sediment descending everywhere will accumulate to the same vertical thickness everywhere, including upon sloped surfaces. If instead of measuring vertical thickness you were to measure the thickness normal to the surface then layers upon sloped surfaces will have less thickness, but this is by mathematical necessity because of the greater surface area of the sloped surface relative to level surfaces across the same horizontal expanse. However, the lessened thickness of the sloped sand layer in your experiment is far too great for that to have been a factor. It could only be due to uneven deposition and to the effects of when you "evened it out." But the depth of sediments on sloped versus level surfaces was never part of anyone's "theory". Your objection was that sediments could not accumulate upon sloped surfaces, but quite obviously they can, and they look just like the sediments that accumulate upon level surfaces.
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Admin Director Posts: 13032 From: EvC Forum Joined: Member Rating: 2.1 |
Those posts are so old now that I think it would be best if we just let discussion return naturally. If anyone has specific issues they'd like addressed they can raise them again.
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edge Member (Idle past 1732 days) Posts: 4696 From: Colorado, USA Joined:
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This doesn't make any sense. When deeply buried and under great pressure, what would prevent the area of the light sand layer that I've indicated from becoming lithified just like the rest of the layer?
If you magnify the highlighted area of the photograph, you will see another sedimentary feature that shows how sediments can be deformed shortly after deposition. Note how the tan sand sinks into the underlying brown mud and the mud itself surges upward into the sand. These have a number of descriptive name such as 'ball and pillow' structures or sole marks. If we could see fine laminae in those pillows, they would be warped according to the flow of the sediments. The point here is that these features formed almost immediately upon deposition and didn't wait until the 'entire sedimentary section' was deposited and lithified, as proposed by Faith in some of the earlier photographs that we have viewed in this and other threads.
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edge Member (Idle past 1732 days) Posts: 4696 From: Colorado, USA Joined: |
Whatever you may have meant, you said many times that strata can only deposit horizontally.
Exactly true, and the equivocation we see going on now was predictable from the start. If it were the case that strata could only be deposited horizontally, then the tan layer should pinch out against the brown layer. At least that's the way that it was always presented to us.
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Faith  Suspended Member (Idle past 1470 days) Posts: 35298 From: Nevada, USA Joined: |
If you magnify the highlighted area of the photograph, you will see another sedimentary feature that shows how sediments can be deformed shortly after deposition. Note how the tan sand sinks into the underlying brown mud and the mud itself surges upward into the sand. These have a number of descriptive name such as 'ball and pillow' structures or sole marks. If we could see fine laminae in those pillows, they would be warped according to the flow of the sediments. I'm afraid you've misread the image, edge. That's not mud, that's rather stiff dark gray nondrying clay that nothing could sink into. Although I did my best to get a tight fit between the clay and the sides of the container there was apparently enough space for the very fine sand to filter down between the clay and the container wall. I mention that in my description. It was one of the effects that spoiled the experiment.
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Faith  Suspended Member (Idle past 1470 days) Posts: 35298 From: Nevada, USA Joined: |
It can't make a stratum if at any point the layer deposits more thickly than at another point. I didn't anticipate that so you simply ignore it and confine your definition to the part about the distribution on the slope alone. The whole point was DO STRATA EVER FORM THAT WAY?
Note in this diagram of the Kaibab Monocline that the thicknesses of the strata vary slightly along the length of a layer but do not accumulate more thickly on the horizontal parts. Isn't this what should be expected of layers depositing on a slope?
Of course this block of strata didn't deposit on the slope but was deformed all together AS a block by the lifting of the Kaibab plateau. They climb from the Tapeats to the Kaibab or from the pre-Cambrian to the Permian, and one would think that at least the "earlier" layers would have been lithified beyond the ability to deform even if the upper were still soft enough to deform. But that's another subject. Edited by Faith, : No reason given.
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Admin Director Posts: 13032 From: EvC Forum Joined: Member Rating: 2.1 |
Faith writes: It can't make a stratum if at any point the layer deposits more thickly than at another point. I didn't anticipate that so you simply ignore it and confine your definition to the part about the distribution on the slope alone. The whole point was DO STRATA EVER FORM THAT WAY? This again makes no sense. You didn't quote anything I said, I can't tell what you're responding to, and I'm unable to figure out in what way you're misunderstanding this, so I don't know what I could explain that might help you. The evidence from your experiment was unequivocal that sedimentary layers can form upon a slope. The thickness of sedimentary layers can obviously vary for numerous reasons and still be lithified, if that's what you mean by "make a stratum." Unless you can raise objections that I can make sense of, I'm ruling that sediments can form upon slopes, that there is no evidence at the road cut we were discussing to indicate the reason for the change in slope of the layers, and that therefore it could have been original or due to later changes. I'm also ruling that there is no requirement that sedimentary layers always be deposited horizontally. If you'd like to discuss these topics further then I welcome you to propose a new topic over at Proposed New Topics, but we'll no longer be discussing them in this thread.
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Faith  Suspended Member (Idle past 1470 days) Posts: 35298 From: Nevada, USA Joined: |
Lovely. Just rule in favor of your side of the argument. Lovely. No problem, I don't expect fairness here. I used to but I got smart. Sand on a slope does not prove strata can form that way and they don't, but that's all right, it serves you all to think they can.
Edited by Faith, : No reason given.
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Admin Director Posts: 13032 From: EvC Forum Joined: Member Rating: 2.1 |
As I said, if you want to make an argument I can make sense of then I'm all ears, but otherwise we're moving on. Your position never made sense from the beginning, your own experiment proved your position wrong, and unless you can make arguments I can make sense of then that's the end of it in this thread. If you'd like to continue the discussion about sedimentation on a slope then simply propose a new topic over at Proposed New Topics, but we're not going to spend any further time on that diversion here in this thread. This thread will return to discussing its original topic.
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edge Member (Idle past 1732 days) Posts: 4696 From: Colorado, USA Joined: |
I'm afraid you've misread the image, edge. That's not mud, that's rather stiff dark gray nondrying clay that nothing could sink into. Although I did my best to get a tight fit between the clay and the sides of the container there was apparently enough space for the very fine sand to filter down between the clay and the container wall. I mention that in my description. It was one of the effects that spoiled the experiment.
Okay, I see. Nevertheless it does happen in nature.
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edge Member (Idle past 1732 days) Posts: 4696 From: Colorado, USA Joined: |
Of course this block of strata didn't deposit on the slope but was deformed all together AS a block by the lifting of the Kaibab plateau.
Which makes me wonder why you are presenting this in the context of our current discussion.
They climb from the Tapeats to the Kaibab or from the pre-Cambrian to the Permian, and one would think that at least the "earlier" layers would have been lithified beyond the ability to deform even if the upper were still soft enough to deform. But that's another subject.
Virtually all rocks are 'soft enough to deform' under the right conditions. Again, I'm not sure how this bears on the current discussion.
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Faith  Suspended Member (Idle past 1470 days) Posts: 35298 From: Nevada, USA Joined: |
Okay, I see. Nevertheless it does happen in nature. But probably not in the geological column as we know it from the Precambrian to the Quaternary.
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Faith  Suspended Member (Idle past 1470 days) Posts: 35298 From: Nevada, USA Joined: |
I believe I indicated that it doesn't relate to the present discussion. It's a glorious bonus perhaps. to be treasured for its special revelatory value.
Edited by Faith, : No reason given.
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edge Member (Idle past 1732 days) Posts: 4696 From: Colorado, USA Joined: |
But probably not in the geological column as we know it from the Precambrian to the Quaternary.
I'm sure you would know. But somehow there are lots of pictures out there, if one looked.
Edited by edge, : No reason given. Edited by edge, : addition of images
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