Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 66 (9077 total)
583 online now:
AZPaul3, kjsimons, nwr, Percy (Admin) (4 members, 579 visitors)
Newest Member: Contrarian
Post Volume: Total: 893,968 Year: 5,080/6,534 Month: 500/794 Week: 126/89 Day: 10/14 Hour: 0/3


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Evidence that the Great Unconformity did not Form Before the Strata above it
herebedragons
Member (Idle past 125 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


(2)
Message 211 of 1939 (753666)
03-21-2015 2:41 PM
Reply to: Message 206 by edge
03-21-2015 11:14 AM


More terminology clarification
The term 'quartzite' is often used loosely, but if you want to be precise...

Something else that needs to be clarified... terms like quartzite, granite, sandstone, etc. are general categories for rock classification. Its like the terms fish, insect, mammal, etc. in biology (well maybe not quite that broad, but close). They are classified because they have certain characteristics in common, but there can be considerable variation in their actual make up.

For example, here is the description of the Tapeats Sandstone from the USGS. It is much more than just "sandstone."

quote:
Tapeats Sandstone (Middle and Lower Cambrian)—Brown and red-brown, cliff-forming sandstone and conglomerate. Includes an upper slope-forming transition zone of nearly equal distribution of brown sandstone of Tapeats Sandstone lithology and green siltstone and shale of Bright Angel Shale lithology, and a lower unit of cliff-forming sandstone and conglomeratic sandstone. Lower cliff unit consists mainly of medium- to coarse-grained, thin-bedded, low-angle planar and trough cross-bedded sandstone and conglomeratic sandstone; sandstone beds 6–24 in. (15–60 cm) thick. Unconformable contact with underlying Middle and Late Proterozoic surface that forms the Great Unconformity. The Tapeats fills in lowland areas and thins across or pinches out against young Proterozoic highlands. Variable thickness 0–400 ft (0–122 m)

Quartzite is kind of a strange category, there can be metamorphic quartzite and unmetamorphic quartzite. I think that makes the terminology confusing and it is understandable why Faith thought the Shinumo Quartzite was metamorphic.

Geologists

HBD


Whoever 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.


This message is a reply to:
 Message 206 by edge, posted 03-21-2015 11:14 AM edge has taken no action

  
herebedragons
Member (Idle past 125 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


(1)
Message 212 of 1939 (753668)
03-21-2015 3:00 PM
Reply to: Message 203 by Faith
03-21-2015 3:53 AM


The Tapeats
Another thing to point out real quick.

In Message 211 I quote a description of the Tapeats sandstone from the USGS. Here it is again.

quote:
Tapeats Sandstone (Middle and Lower Cambrian)—Brown and red-brown, cliff-forming sandstone and conglomerate. Includes an upper slope-forming transition zone of nearly equal distribution of brown sandstone of Tapeats Sandstone lithology and green siltstone and shale of Bright Angel Shale lithology, and a lower unit of cliff-forming sandstone and conglomeratic sandstone. Lower cliff unit consists mainly of medium- to coarse-grained, thin-bedded, low-angle planar and trough cross-bedded sandstone and conglomeratic sandstone; sandstone beds 6–24 in. (15–60 cm) thick. Unconformable contact with underlying Middle and Late Proterozoic surface that forms the Great Unconformity. The Tapeats fills in lowland areas and thins across or pinches out against young Proterozoic highlands. Variable thickness 0–400 ft (0–122 m)

I bolded a section in that description that describes how the Tapeats blends into the Bright Angel Shale and both materials are found in nearly equal proportions. Contrast this upper contact to the lower contact with the Vishnu and/or the Supergroup.

HBD


Whoever 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.


This message is a reply to:
 Message 203 by Faith, posted 03-21-2015 3:53 AM Faith has taken no action

  
Faith 
Suspended Member (Idle past 712 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 213 of 1939 (753670)
03-21-2015 3:19 PM


Erosion simply CANNOT explain the flat contact line
In all your ponderings about the Great Unconformity, how long the erosion of the lower surface took etc., why is it that the relative flatness of that surface, where it comes in contact with the strata above, is taken so for granted?

I've brought this up many times and all I get is basically Why not? or I see no problem, or That's the way it is as if I'm asking an unreasonable question. But it doesn't matter how many millions or billions of years of erosion were involved there is no way to get such a flattish surface at the top of a lumpy bunch of schist or granite or folded strata.

But in image after image we see the strata above laid down FLAT on these lumpy rocks, so the surface did have to be flattish. There would be no problem if we were talking about the surface of a mesa or butte or tepui, those are flat because the rock itself is flat or the exposed surface is flat. But on top of lumpy Vishnu or uptilted strata, no. Yes we see in some places that the harder rock, such as the quartzite, makes the surface irregular, and there are plenty of examples of less than perfect flatness that can be found, but still, look at the contact line in spite of those irregularities: overall it's flat / straight / horizontal. Flattish. Straightish. Then there are the cross sections, which are of course schematic, but why would anyone draw such inexorably straight lines if they didn't represent the reality well enough to justify it?

So I've picked some examples that are of course familiar just so you'll know what I'm talking about. How-how-how could "erosion" of any type or length of time create such a flat surface? And, one might also ask, why did "erosion" stop where it did at that particular level? Why didn't it just keep on eroding downward, or create this flat surface at some other level?

PLEASE. Erosion CANNOT be the explanation for this flatness.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


Replies to this message:
 Message 215 by herebedragons, posted 03-21-2015 3:45 PM Faith has replied
 Message 220 by jar, posted 03-21-2015 4:22 PM Faith has taken no action
 Message 226 by herebedragons, posted 03-21-2015 5:39 PM Faith has replied
 Message 249 by Dr Adequate, posted 03-21-2015 9:51 PM Faith has replied

  
Faith 
Suspended Member (Idle past 712 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 214 of 1939 (753671)
03-21-2015 3:30 PM
Reply to: Message 204 by herebedragons
03-21-2015 8:31 AM


Re: Surface of the Unconformity
OK, I'm very happy to know that the problem has been solved, and Shinumo quartzite is not metamorphic. One less problem to worry about.

This message is a reply to:
 Message 204 by herebedragons, posted 03-21-2015 8:31 AM herebedragons has taken no action

  
herebedragons
Member (Idle past 125 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 215 of 1939 (753672)
03-21-2015 3:45 PM
Reply to: Message 213 by Faith
03-21-2015 3:19 PM


Re: Erosion simply CANNOT explain the flat contact line
I understand your concern here. We have been over this before and without arguing over what "flat" means again, let me ask you a question...

Can you think of an example in our contemporary setting where the surface of the earth that is exposed to erosion is "flat?"

Remember that image that we went round and round about in the other thread (the one where you said it looks like the rock were lifted out of the Vishnu)? Remember how you said it doesn't look like it had even been subjected to erosion? And I pointed out that even though it may not "look like" it had been eroded, we knew for sure it was eroded. Sometimes our expectations of what geological features should "look like" is pretty subjective.

HBD


Whoever 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.


This message is a reply to:
 Message 213 by Faith, posted 03-21-2015 3:19 PM Faith has replied

Replies to this message:
 Message 216 by Faith, posted 03-21-2015 3:54 PM herebedragons has replied

  
Faith 
Suspended Member (Idle past 712 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 216 of 1939 (753673)
03-21-2015 3:54 PM
Reply to: Message 215 by herebedragons
03-21-2015 3:45 PM


Re: Erosion simply CANNOT explain the flat contact line
You do NOT "understand [my] concern here!"

Can you think of an example in our contemporary setting where the surface of the earth that is exposed to erosion is "flat?"

Only on the top of a mesa or butte or tepui as I already said, or on a single-sediment deposit such as the great salt lake, or where the surface of a rock layer was washed clean and exposed, such as the Kaibab in the GC area. WHERE THE ROCK IS ALREADY NATURALLY FLAT! OTHERWISE NO! And neither can you! PLEASE stop treating me like a child and think about the point I'm making!

FLAT is defined by the pictures I've posted.

Remember that image that we went round and round about in the other thread (the one where you said it looks like the rock were lifted out of the Vishnu)? Remember how you said it doesn't look like it had even been subjected to erosion? And I pointed out that even though it may not "look like" it had been eroded, we knew for sure it was eroded. Sometimes our expectations of what geological features should "look like" is pretty subjective.

IT DID NOT LOOK ERODED, but that is NOT the same thing as I'm talking about here. It turned out that was a vertical surface that was not at all evident on the photo we were discussing, and only a few inches of it were seen there too. And I'd ask the same question about the actual contact line there as well, which can only be seen when the whole context is included in the picture: HOW ON EARTH COULD EROSION HAVE CREATED THAT STRAIGHT FLAT HORIZONTAL CONTACT LINE?

Again, PLEASE stop talking down to me and think about the point I'm making! You have NOT addressed it, you've merely dismissed it with an irrelevant reference.

All your detail does NOT deal with such basic questions!

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 215 by herebedragons, posted 03-21-2015 3:45 PM herebedragons has replied

Replies to this message:
 Message 217 by herebedragons, posted 03-21-2015 4:09 PM Faith has replied

  
herebedragons
Member (Idle past 125 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


(2)
Message 217 of 1939 (753674)
03-21-2015 4:09 PM
Reply to: Message 216 by Faith
03-21-2015 3:54 PM


Re: Erosion simply CANNOT explain the flat contact line
I was not talking down to you. You're deflecting.

And I'd ask the same question about the actual contact line there as well, which can only be seen when the whole context is included in the picture

But it's not flat, that was the point of Message 204 which the only thing you took out of that was the point about quartzite. Go back and read the rest of the post that describes the contact surface.

think about the point I'm making! You have NOT addressed it, you've merely dismissed it with an irrelevant reference.

A reference that describes the actual contact surface is irrelevant? The point you are making is "it doesn't look eroded" and that you can't see how erosion could produce those features. Those aren't arguments they are personal incredulity.

And by the way, you could stop yelling at me.

HBD


Whoever 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.


This message is a reply to:
 Message 216 by Faith, posted 03-21-2015 3:54 PM Faith has replied

Replies to this message:
 Message 219 by Faith, posted 03-21-2015 4:19 PM herebedragons has replied
 Message 315 by Admin, posted 03-23-2015 8:06 AM herebedragons has replied

  
Faith 
Suspended Member (Idle past 712 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 218 of 1939 (753675)
03-21-2015 4:18 PM
Reply to: Message 202 by Minnemooseus
03-21-2015 2:01 AM


Re: Sorry, but there's so much wrong here
As Edge said in the previous message, there's no way to shut off the metamorphism, especially that radically, at the contact. The sediments would have shown some signs of pressure and heat effects.

I would think it would depend on mitigating factors such as the presence of a cooling agent in the vicinity to retard the heat before it reaches the contact. Simple distance from the source of course already reduces its effect as it moves upward and outward.

However, I think movement between the upper and lower rocks still has to be considered an important factor. And there may be other factors yet to be considered.

From THIS SITE:

If a lava erupts into water it will cool much more quickly than if it erupts on land into the air.

And if we're talking magma released underwater so much the more quickly.

You would not go from high grade metamorphsim to little or no metamorphism at the contact that is the nonconfromity. Not even if the lower rocks were dry, and the upper rocks were water saturated.

Why do you make that distinction? ALL the rocks would have been saturated in the Flood, upper AND lower. The magma that intruded from below would have been released into soaked sediments. ABE: Surely, even if you consider the Flood to be a fantasy you can entertain such a hypothetical scenario.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 202 by Minnemooseus, posted 03-21-2015 2:01 AM Minnemooseus has taken no action

Replies to this message:
 Message 222 by herebedragons, posted 03-21-2015 5:10 PM Faith has taken no action

  
Faith 
Suspended Member (Idle past 712 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 219 of 1939 (753676)
03-21-2015 4:19 PM
Reply to: Message 217 by herebedragons
03-21-2015 4:09 PM


Re: Erosion simply CANNOT explain the flat contact line
But it's not flat,

Blatant denial.

You aren't thinking about the pictures I posted.

ABE: You can bring up all kinds of exceptions, as I already acknowledged, but the problem is still how to explain the vast majority that exhibit such a flat horizontal contact -- and even the exceptions are MOSTLY flat and horizontal.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


This message is a reply to:
 Message 217 by herebedragons, posted 03-21-2015 4:09 PM herebedragons has replied

Replies to this message:
 Message 221 by herebedragons, posted 03-21-2015 5:01 PM Faith has taken no action
 Message 223 by edge, posted 03-21-2015 5:16 PM Faith has replied

  
jar
Member
Posts: 33957
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.3


Message 220 of 1939 (753677)
03-21-2015 4:22 PM
Reply to: Message 213 by Faith
03-21-2015 3:19 PM


Erosion does explain the flat contact line
Of course erosion explains flat surfaces. In fact erosion must produce flat surfaces.

Erosion and weathering move materials from the high points to the low points.

If you stop and think about the process at all you must see that the result will be a flatter surface than before the erosion or weathering.

Erosion most certainly can and does explain flat surfaces.

Sorry Faith but it really is that simple.

Edited by jar, : fix sub-title


Anyone so limited that they can only spell a word one way is severely handicapped!

This message is a reply to:
 Message 213 by Faith, posted 03-21-2015 3:19 PM Faith has taken no action

  
herebedragons
Member (Idle past 125 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


(1)
Message 221 of 1939 (753681)
03-21-2015 5:01 PM
Reply to: Message 219 by Faith
03-21-2015 4:19 PM


Re: Erosion simply CANNOT explain the flat contact line
Blatant denial.

You aren't thinking about the pictures I posted.

OK.

Red lines show channels filled in with Tapeats Sandstone. Not Flat

Red lines shows a cut into the Vishnu filled with Tapeats. I saw a version of this same area before and there are several of these visible.

The top is flat, yes. But it looks as if the layers below were laid down at an angle as shown by the blue lines. How were they either laid down on an angle OR how were they truncated by continuous deposition.

What is this? Is this supposed to be an unconformity?

You can draw straight yellow lines, so what?

quote:
(From Message 204) The maximum height of these monadnocks in the Shinumo quadrangle he gives as 600 feet. Schuchert,” after visiting an area farther east, refers to hills up to 700 feet, and Wheeler and Kerr “’ describe one north of Grand Canyon Village which rises approximately 800 feet above the base of the Tapeats sandstone.

These monadnocks are in the same general area as that photograph. Not flat.

By the way, in my post Message 204 my point was not about erosion, but about continuous sedimentation. So if you are claiming there was no erosion, then are you arguing that there WAS continuous sedimentation? How does continuous sedimentation produce those contact surfaces?

In Message 205, I showed an image with 4 unconformities. How would any of those unconformities form during continuous sedimentation WITHOUT erosion?

HBD

ABE:

ABE: You can bring up all kinds of exceptions, as I already acknowledged, but the problem is still how to explain the vast majority that exhibit such a flat horizontal contact -- and even the exceptions are MOSTLY flat and horizontal.

So if we ignore the exceptions, such as 800 foot tall monadnocks, then it is mostly flat.

Edited by herebedragons, : No reason given.


Whoever 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.


This message is a reply to:
 Message 219 by Faith, posted 03-21-2015 4:19 PM Faith has taken no action

Replies to this message:
 Message 316 by Admin, posted 03-23-2015 8:21 AM herebedragons has taken no action

  
herebedragons
Member (Idle past 125 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 222 of 1939 (753685)
03-21-2015 5:10 PM
Reply to: Message 218 by Faith
03-21-2015 4:18 PM


Re: Sorry, but there's so much wrong here
I would think it would depend on mitigating factors such as the presence of a cooling agent in the vicinity to retard the heat before it reaches the contact.

So, "mitigating factors" would control metamorphosis so that it produces a straight, flat contact line, but erosion can't. That makes no sense.

How is everything below your flat yellow line metamorphosed and everything above it remains unmetamorphosed.

HBD


Whoever 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.


This message is a reply to:
 Message 218 by Faith, posted 03-21-2015 4:18 PM Faith has taken no action

  
edge
Member (Idle past 974 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 223 of 1939 (753687)
03-21-2015 5:16 PM
Reply to: Message 219 by Faith
03-21-2015 4:19 PM


Re: Erosion simply CANNOT explain the flat contact line
ABE: You can bring up all kinds of exceptions, as I already acknowledged, ...

So, how many exceptions do you need?

... but the problem is still how to explain the vast majority that exhibit such a flat horizontal contact -- and even the exceptions are MOSTLY flat and horizontal.

Flat surfaces are common in eroded areas. Just look at vast expanses of the Canadian Shield, or what do you think the Amazon Basin is going to look like an a few million years?

The point is that the unconformity is not flat everywhere which is what we would expect if your scenario were correct.


This message is a reply to:
 Message 219 by Faith, posted 03-21-2015 4:19 PM Faith has replied

Replies to this message:
 Message 224 by Faith, posted 03-21-2015 5:22 PM edge has taken no action

  
Faith 
Suspended Member (Idle past 712 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 224 of 1939 (753688)
03-21-2015 5:22 PM
Reply to: Message 223 by edge
03-21-2015 5:16 PM


Re: Erosion simply CANNOT explain the flat contact line
IT SHOULDN"T BE FLAT ANYWHERE! NOT ANYWHERE! IT'S A LUMPY BUMPY POKY SPIKY IRREGULAR SURFACE. IT SHOULD NOT ERODE FLAT ANYWHERE, LET ALONE AS FLAT AS YOU CAN SEE IT IS IN THE PHOTOS I POSTED.

This message is a reply to:
 Message 223 by edge, posted 03-21-2015 5:16 PM edge has taken no action

Replies to this message:
 Message 225 by jar, posted 03-21-2015 5:30 PM Faith has taken no action
 Message 227 by herebedragons, posted 03-21-2015 5:50 PM Faith has replied
 Message 317 by Admin, posted 03-23-2015 8:25 AM Faith has taken no action

  
jar
Member
Posts: 33957
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.3


(2)
Message 225 of 1939 (753689)
03-21-2015 5:30 PM
Reply to: Message 224 by Faith
03-21-2015 5:22 PM


Erosion simply does explain the flat contact line
Faith writes:

IT SHOULDN"T BE FLAT ANYWHERE! NOT ANYWHERE! IT'S A LUMPY BUMPY POKY SPIKY IRREGULAR SURFACE. IT SHOULD NOT ERODE FLAT ANYWHERE, LET ALONE AS FLAT AS YOU CAN SEE IT IS IN THE PHOTOS I POSTED.

Shouted nonsense is still nonsense Faith.

If erosion/weathering moves material from high points and deposits it in the low places why would the suface not change from lumpy to smoother?


Anyone so limited that they can only spell a word one way is severely handicapped!

This message is a reply to:
 Message 224 by Faith, posted 03-21-2015 5:22 PM Faith has taken no action

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2018 by EvC Forum, All Rights Reserved

™ Version 4.1
Innovative software from Qwixotic © 2022