|
Register | Sign In |
|
QuickSearch
EvC Forum active members: 64 (9164 total) |
| |
ChatGPT | |
Total: 916,902 Year: 4,159/9,624 Month: 1,030/974 Week: 357/286 Day: 13/65 Hour: 0/1 |
Thread ▼ Details |
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
|
Thread Info
|
|
|
Author | Topic: Evidence that the Great Unconformity did not Form Before the Strata above it | ||||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
Most of that is off topic.
|
||||||||||||||||||||||||||||||||||||||||||||
jar Member (Idle past 423 days) Posts: 34026 From: Texas!! Joined: |
Faith writes: Most of that is off topic. In Message 412 did you not post "And what is your model anyway? Just a bunch of suppositions looks like to me. " When I respond to a direct question with links and evidence can it be off topic? Now, since I responded perhaps you can provide the links to support your claim also from that same message that you have already presented the model, mechanism, method, process, procedure that can explain what is seen. And as Percy has requested we repeat pertinent information:
quote: The links I provide contain the full description of how to make schist or sandstone or granite or shale or limestone. That was what you requested.Anyone so limited that they can only spell a word one way is severely handicapped!
|
||||||||||||||||||||||||||||||||||||||||||||
Admin Director Posts: 13042 From: EvC Forum Joined: Member Rating: 2.3 |
Faith writes: If I'm getting you, yes, I'm saying that the presently "exposed cliff face" was eroded after being exposed. But what you've just said, that the cliff face was eroded after being exposed, isn't what people are taking issue with. If that's all you were really saying then everyone would agree with you because every exposed surface is always being eroded, it only being a matter of degree. We're trying to understand what you think happened to transform this from a couple hundred years ago:
Into this today (ignore the blue outlined area):
There are two options:
Or is it something else. Please let us know.
But as I was looking at your version of the picture you marked with the straight line I began to doubt that edge had identified the lower strata correctly anyway. Some of it looks like it belongs in the eroded zone above it. But even if the yellow line were redrawn as you would like, it would still be uneven, right? PS: Edge - Are you deleting photos from PhotoBucket that you've linked to from your messages? And me, too?
|
||||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
Faith writes: If I'm getting you, yes, I'm saying that the presently "exposed cliff face" was eroded after being exposed. But what you've just said, that the cliff face was eroded after being exposed, isn't what people are taking issue with. If that's all you were really saying then everyone would agree with you because every exposed surface is always being eroded, it only being a matter of degree. We're trying to understand what you think happened to transform this from a couple hundred years ago: ...Into this today (ignore the blue outlined area): There are two options: 1.The part of the boundary exposed a couple hundred years ago happened to be straight. In the couple hundred years since, the cliff face has eroded back a number of feet, enough to expose a different part of the same boundary, one that happens to be much more uneven. 2.The cliff face we see today is basically the same one as a couple hundred years ago. In the couple hundred years since, severe weathering has caused the straight boundary to deform and become very uneven Or is it something else. Please let us know. Hard to follow so many different options. But I'll just try to state more clearly what I had in mind. The drawing I posted I believe represents accurately what was actually there: Distinct upper horizontal and lower vertical sections with a straight contact line. To explain edge's photo of the irregular contact line I figure the upper section was partly eroded away from the lower, could be a matter of inches rather than feet but I'm not sure of the scale, exposihg the upper surface of the lower strata to weathering which has made it irregular over the last couple hundred years. ABE: So, rereading, I think your option 2 is closest but it needs the exposure of the upper surface of the cliff face brought about by erosion of the upper section. Edited by Faith, : No reason given. Edited by Faith, : No reason given.
|
||||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
But even if the yellow line were redrawn as you would like, it would still be uneven, right? Somewhat but not a lot.
|
||||||||||||||||||||||||||||||||||||||||||||
jar Member (Idle past 423 days) Posts: 34026 From: Texas!! Joined: |
Something I was thinking about... there is no evidence that land plants had colonized the land even as late as the Cambrian. Of course, that could be an artifact of the erosion that wiped that surface clean, but if that is true, then none of the surface of the GU would have been secured by plant roots and would have suffered extreme erosion, at a far greater rate than we observe today. HBD Lately I've come across several articles along those lines. Here is a letter that was published in Nature a couple years ago that speculates that the Great Unconformity points to one possible trigger mechanism for the Cambrian Explosion.Anyone so limited that they can only spell a word one way is severely handicapped!
|
||||||||||||||||||||||||||||||||||||||||||||
herebedragons Member (Idle past 886 days) Posts: 1517 From: Michigan Joined:
|
Again, as usual, there is some kind of huge disconnect in this discussion that makes no sense to me. After reading today's posts, I again get the impression that you don't understand what we mean by an unconformity. I realize that you think that unconformities form in a different way than we do, but it would be really helpful if we were all talking about the same thing. So at the risk of being patronizing I thought I would put up this image of an nonconformity for you viewing pleasure.
The "thing" we are referring to as the "unconformity" or the "surface of the unconformity" is the surface in figure C that has grass growing on it. That surface is the unconformity. It is not exposed to erosion after the upper sediments are laid down. Figure D would be a depiction of the face, or cross section, that is exposed to erosion and what is visible to us. The thin line is the unconformity (in cross section) but the surface that has been overlain with horizontal sediment (in Fig C) is THE unconformity. If I am wrong and you understand this, I apologize, but why would the surface of the unconformity that is buried many feet back from the exposed face be subject to erosion? If you have some other understanding of an unconformity, what is it?? HBDWhoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for... I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca "Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem. Ignorance is a most formidable opponent rivaled only by arrogance; but when the two join forces, one is all but invincible.
|
||||||||||||||||||||||||||||||||||||||||||||
herebedragons Member (Idle past 886 days) Posts: 1517 From: Michigan Joined: |
Just for the record, if I were thinking in terms of half a billion years I would expect the Grand Canyon long since to have dissolved into a pile of dust. But you don't think erosion can reduce a landscape to dust even in a hundred billion years, so why would you expect the GC to be "reduced to dust." And besides, the GC has been reduced to dust. HBDWhoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for... I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca "Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem. Ignorance is a most formidable opponent rivaled only by arrogance; but when the two join forces, one is all but invincible.
|
||||||||||||||||||||||||||||||||||||||||||||
Admin Director Posts: 13042 From: EvC Forum Joined: Member Rating: 2.3 |
Faith writes: The drawing I posted I believe represents accurately what was actually there: Distinct upper horizontal and lower vertical sections with a straight contact line. Is this the drawing you mean:
The contact point between the upper and lower layers appears very similar to Edge's photo, fairly straight to the right, fairly uneven to left:
The diagram was drawn from a different angle than the photo, accounting for some of what appear to be differences but probably aren't. Here's an image with some people in it to give you some perspective:
To explain edge's photo of the irregular contact line... Both the diagram and Edge's photo show irregular contact lines, so you need to explain both.
...I figure the upper section was partly eroded away from the lower, could be a matter of inches rather than feet but I'm not sure of the scale, exposing the upper surface of the lower strata to weathering which has made it irregular over the last couple hundred years. ABE: So, rereading, I think your option 2 is closest but it needs the exposure of the upper surface of the cliff face brought about by erosion of the upper section. I'm still not sure what you're saying. Do you mean that the lower layer at the boundary was eroded more than the upper layer, and that the boundary is still straight, it's just that there's now the appearance of being uneven? Here's the image without the yellow line - it might help because it gives a better idea of which layers stick out from the cliff face more than others:
Edited by Admin, : Clarify last para.
|
||||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
I spent a little time on that photo and came up with the following: the only part of the lower section that remains above the straight line you drew is the small piece to the right of the dike. My own squiggly yellow line falls below yours. I also outlined in lt. blue the zone that looks more like erosion than like either of the strata sections.
' Edited by Admin, : Remove the URL from the image - it makes zooming the image very inconvenient.
|
||||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
But you don't think erosion can reduce a landscape to dust even in a hundred billion years, so why would you expect the GC to be "reduced to dust." Not flat level dust.
And besides, the GC has been reduced to dust. That's a lot of solid organized dust if so.
|
||||||||||||||||||||||||||||||||||||||||||||
dwise1 Member Posts: 5952 Joined: Member Rating: 5.2 |
This is an ordeal with a malfunctioning space bar. Must have splashed something on it.
Or there might be something lodged underneath it. That happened to me once with the shift key I normally use to type my password when I start my computer. After the first flash of panic, I noticed that the key wasn't travelling down fully. After I gave it a blast of canned air, it worked fine. Could be a bread crumb or a seed or a clump of lint. It can make even more of a difference on a laptop whose keys have very little travel. If you have canned air, try that. If not, then you could your own breath, but that can be difficult to keep dry. Or you could tilt the keyboard in various directions and either shake or tap (ie, like somebody menacingly slapping a club into the palm of the other hand, though much more gently).
|
||||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
Perhaps my basic rejection of the idea of how such an unconformity develops makes it too hard for me to think in such terms at all. Certainly I think I get that it's the horizontal surface that cuts across the folded strata but I reject the whole idea of the order of things presented in your diagram. Maybe that is causing all the miscommunication? Perhaps it would help if you applied your diagram to Siccar Point with a view to explaining where we are misunderstanding each other.
|
||||||||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
Thanks. Could be that I guess. I've blown on it but no change. I do have canned air but never used it. They say to remove a certain tab but the likely candidate doesn't want to come off.
|
||||||||||||||||||||||||||||||||||||||||||||
New Cat's Eye Inactive Member |
Perhaps my basic rejection of the idea of how such an unconformity develops makes it too hard for me to think in such terms at all. How are you going to provide evidence against something if you can't even think it its terms?
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024