|
Register | Sign In |
|
QuickSearch
Thread ▼ Details |
Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
|
Thread Info
|
|
|
Author | Topic: Origin of the Flood Layers | |||||||||||||||||||||||||||||||||||||||||||
Admin Director Posts: 13029 From: EvC Forum Joined: Member Rating: 2.1 |
I just briefly read through today's messages. I know the lack of time I can devote to this is a contributing factor, but much of what people have written today is difficult to follow, and some of it is drifting off into personal comments again. I think both sides need to find ways to make it more clear what they think happened.
|
|||||||||||||||||||||||||||||||||||||||||||
JonF Member (Idle past 193 days) Posts: 6174 Joined: |
You call that smooth?
What are you looking at? The vertical frontal edge of the sandstone that I've outlined looks pretty smooth to me, as opposed to being at all ragged from erosion. But what is so special about "right there?
Yep, that's the question. Why did your alleged flow stop there?
I wouldn't have expected sandstone to have a viscous stage either, but this photo and the one of the Danxia formation in China certainly suggest something of the sort. Something that occurs during its laying down as a wet sediment, not during lithification.
Wet sediment ain't gonna form a near-vertical ragged edge.
I wasn't clear what you were seeing in that photo, perhaps you could mark it to bring out what you see there? But I'll get back to that post in a minute.
Don't have the time ow to mark it up, but you are looking at the Tapeats sandstone (forming a near-vertical ragged wall) above the Vishnu forming a near-vertical ragged wall lining up with the edge of the Tapeats. I.e an eroded near-vertical surface encompassing both formations. You can see small white clasts in the Tapeats right at the junction.
and if that's the case then the sandstone itself pulled them out
I.e. it's just a fantasy and is impossible in the real world.
Wow, maybe we should be using unpowered sandstone instead of electrically powered vacuum cleaners. Apparently sandstone has undetected but exremely powerful suction. Who knew?
Something to do with the relative looseness of the quartz and the relative stickiness of the sandstone and the dryness and hardness of the schistSeriously, pulled out? Really? What generated that puling force?
|
|||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
JonF, Edge:
Here's that picture again with new markings:
The part I've circled in light blue shows it most clearly: It's BLACK underneath the sandstone and there isn't even a clast there to cast a shadow. It is just as black beneath the bottom of the sandstone all the way to the right, which is now outlined in orange, both where there are clasts to cast a shadow and where there are not. That's a depression or a trench, not a shadow. Edited by Faith, : No reason given. Edited by Faith, : No reason given.
|
|||||||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1731 days) Posts: 4696 From: Colorado, USA Joined: |
OK but that leaves the striping, which is pretty unusual whatever their colors.
Normal tilted bedding with intensive erosion.
Where else does that phenomenon appear?
You mean like here in Nevada?
Perhaps it does somewhere but that formation in China hit me like something from another planet when I first saw it and I've still not seen anything comparable anywhere else.
I dare say that there are a lot of things on this planet that you have not yet seen. And, of course, the gaudy colors are attention grabbers.
You said something about photos from Mexico though -- perhaps something similar there?
There are lots of similar locations, but all are somewhat different, so I doubt you would accept any photos that I have.
AND the main thing about the formation in relation to what I've been saying isn't the color anyway but the way the sandstone looks like it was squeezed out of a tube.
And I noticed the other day that the rocks along the highway looked like they formed in the same way as the paving operation going on between here and Boulder. So, that must be it: continental paving.
Nobody ever talks about sandstone as having a viscous quality at any stage of wetness that I know of, but both the Chinese formation and that picture of the Tapeats with the quartz chunks stuck in it suggest something along those lines.
I know what you mean. The flat-lying sandstones look like the layers laid down by the paving company. I'll work on this theory a little bit more tonight, but in the meantime, it seems plausible.
So does The Wave, but that's the only other one I can think of.
There are more things out there than you can imagine...
|
|||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1469 days) Posts: 35298 From: Nevada, USA Joined: |
Thank you for the picture of the formation in Nevada. It's striped like the Chinese formation and curved like the Wave and I hadn't known about it.
The carved formation at the bottom is a different kind of thing than I'm talking about. I don't think you've said anything to explain the appearance of viscosity in either the Danxia formation -- especially those barrel-shaped forms lying on their side in a row -- or the Tapeats we've been discussing. Neither is "normal tilted bedding." Jut for reference here again are the barrel shaped forms mentioned:
Thanks anyway. Edited by Faith, : No reason given. Edited by Faith, : No reason given.
|
|||||||||||||||||||||||||||||||||||||||||||
JonF Member (Idle past 193 days) Posts: 6174 Joined:
|
You'd need to explain the other pictures more, perhaps mark them to indicate what the descriptions refer to because it isn't obvious to me, and I'm not sure what point you are trying to make with them anyway.
The point is that there are many pictures of many locations where the Tapeats contacts the Vishnu and clasts are in the Tapeats and the near-vertical face of the Tapeats is obviously from erosion and not from magic flowing sandstone.. I'm not going into a long explanation, I've been down that road before. Perhaps someone else will.,
|
|||||||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1731 days) Posts: 4696 From: Colorado, USA Joined: |
Would somebody please explain the significance of "this point?"
It's where the picture was taken.
All I see is a trench left after the vein of quartz was removed from it.
I do not see a trench, nor a vein. Those are fragments of a vein or intrusive.
That's how it LOOKS to me. It still looks that way. Somebody will have to show clearly that it's better explained some other way, and probably show me on the photo itself.
Do you understand cross-sections?
All I can say is that it just doesn't LOOK LIKE that to me.
I understand. That's why I'm proposing the continental paving theory.
The "pebbles" don't look like they are sitting, they look like they are stuck in the sandstone and suspended above a depression out of which they came.
I have shown you where they came from. It doesn't look like this picture.
OK, that's something to wonder about. But what, in your opinion, explains that vertical edge of the sandstone in which the quartz is stuck?
Probably just a fracture surface modified by erosion. Hard to tell in a photograph like this. But the point is moot anyway. We know that there have been faults and erosion prior to deposition of the Tapeats based on superposition, cross-cutting features and the fragmentation of the pegmatite.
No comprendo Senor.
Never mind. It's an esoteric point anyway.
That's what the evidence I just gave you shows until something shows me I'm misreading it.
The evidence shows that the clasts came from various veins and dikes, not from irregular depressions in the Vishnu that just happened to be at the contact between the Vishnu and overlying Tapeats.
If you are talking about the picture in Message 247, no, they look like veins of quartz in a wall of schist. If something caused the quartz to come out of their veins then they might look like clasts either lying on the schist or stuck in sandstone and not lying on anything.
And that would be erosion...
|
|||||||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1731 days) Posts: 4696 From: Colorado, USA Joined: |
Thank you for the picture of the formation in Nevada. It's striped like the Chinese formation and curved like the Wave and I hadn't known about it.
I don't know what to tell you. I see continuous bedding in very soft sedimentary rocks that have been eroded into rather fanciful forms. In the foreground the bedding is vertical and in the distance it is tilted to the left.The carved formation at the bottom is a different kind of thing than I'm talking about. I don't think you've said anything to explain the appearance of viscosity in either the Danxia formation -- especially those barrel-shaped forms lying on their side in a row -- or the Tapeats we've been discussing. Neither is "normal tilted bedding." In the descriptions of the site, there is nothing abnormal except the presence of pseudokarst, but I've seen that elsewhere too.
|
|||||||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1731 days) Posts: 4696 From: Colorado, USA Joined: |
The point is that there are many pictures of many locations where the Tapeats contacts the Vishnu and clasts are in the Tapeats and the near-vertical face of the Tapeats is obviously from erosion and not from magic flowing sandstone.. I'm not going into a long explanation, I've been down that road before. Perhaps someone else will.,
It would seem fruitless and rather unnecessary. There is ample evidence without getting into the details of photographs which have odd artifacts due to lighting and lack of depth.
|
|||||||||||||||||||||||||||||||||||||||||||
JonF Member (Idle past 193 days) Posts: 6174 Joined:
|
The part I've circled in light blue shows it most clearly: It's BLACK underneath the sandstone and there isn't even a clast there to cast a shadow.
Yup, there's obviously a depression there, and no matching clast or place where a clast was. So that's a shadow of the sandstone itself.
It is just as black beneath the bottom of the sandstone all the way to the right, which is now outlined in orange, both where there are clasts to cast a shadow and where there are not.
Yup, the underside of the sandstone is undercut so its shadow shows up. I still don't see any depressions matching the clasts. Back to the other picture:
Note the near-vertical edges of the Tapeats and Vishnu. The Vishu face is rougher than the Tapeats, but the Tapeats face ain't no billiard table. Edited by JonF, : No reason given.
|
|||||||||||||||||||||||||||||||||||||||||||
jar Member (Idle past 419 days) Posts: 34026 From: Texas!! Joined: |
Your picture also shows that the Visnu Schist has been uplifted and eroded before the Tapeats sandstone was laid down. Also it shows that there is an angular unconformity.
Anyone so limited that they can only spell a word one way is severely handicapped!
|
|||||||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1731 days) Posts: 4696 From: Colorado, USA Joined:
|
{ABE} I sure don't see any way to interpret this as a fluid sandstone [sic] flowing across and stopping at the Vishnu. Pretty obviously both were eroded to expose this cross-section. Note the clasts in the sandstone.
I'm not sure it's clear to Faith, but this is the exact location where her photograph of the unconformity came from.
Thank you for tracking this down.
|
|||||||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1731 days) Posts: 4696 From: Colorado, USA Joined: |
I'm trying to find an image of the granite dikes terminating against the unconformity and forming a pebble trail along the unconformity. This one isn't quite what I wanted, but it does show the relationship of the dikes (the irregular pink lines on the black wall) being cut off by the unconformity. They do not extend upward into the flat-lying sedimentary rocks.
|
|||||||||||||||||||||||||||||||||||||||||||
JonF Member (Idle past 193 days) Posts: 6174 Joined:
|
Nicelyl labeled. Except for the misspelling. :-)
Oh, and we can tell she's the youngest one in the picture because her hand is intrusive in both. Edited by JonF, : No reason given.
|
|||||||||||||||||||||||||||||||||||||||||||
edge Member (Idle past 1731 days) Posts: 4696 From: Colorado, USA Joined: |
Nicelyl labeled. Except for the misspelling. :-)
New geological term.
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024