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Author Topic:   Young earth explanations for Angular Unconformities
PaulK
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Posts: 15825
Joined: 01-10-2003
Member Rating: 2.8


Message 4 of 202 (349904)
09-18-2006 3:18 AM
Reply to: Message 3 by anglagard
09-18-2006 2:00 AM


Re: Answer
Faith has this idea that they somehow happen underground. She's got no idea how it could be possible and no significant evidence, but that doesn't prevent her from asserting that she is correct

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PaulK
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Posts: 15825
Joined: 01-10-2003
Member Rating: 2.8


Message 89 of 202 (424453)
09-27-2007 2:00 AM
Reply to: Message 88 by CTD
09-27-2007 12:34 AM


quote:

Now if something like this here:
http://antwrp.gsfc.nasa.gov/apod/ap060509.html

If something like this were to happen underneath some horizontal rocks, what would the result look like?


Wherever it happened it would be igneous rock, not sedimentary.

If it happened underneath horizontal rock it would be constrained by the presence of that rock - so it wouldn't happen like that.


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PaulK
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Posts: 15825
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Member Rating: 2.8


(3)
Message 141 of 202 (796679)
01-03-2017 2:07 AM
Reply to: Message 140 by Faith
01-03-2017 1:50 AM


The point - which seems rather obvious to me - is that the tectonic events only affected the strata below the unconformity. Also that the surfaces at the unconformity do not show the effects that should have been generated under your scenario.

There is no need for a counterweight as simple experimentation should show you.

Material removed from the surface by erosion is typically carried away - only a relatively small proportion would remain. The problem for your scenario is that the erosion occurs deep underground where that cannot happen.

All this should be obvious.


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PaulK
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Posts: 15825
Joined: 01-10-2003
Member Rating: 2.8


(3)
Message 186 of 202 (796822)
01-05-2017 12:04 AM
Reply to: Message 185 by Faith
01-04-2017 10:18 PM


Re: The decrepitude of both upper and lower blocks of strata
Again it seem obvious. With regard to the rock below the unconformity, erosion removed the weathered material from the surface, thus the material that remained shows relatively little weathering.

Although I have to add that it seems to me that you prefer to judge weathering by looking at cross-sections rather than the surfaces. Since weathering is related to exposure to the elements that is a rather odd thing to do - without knowing when and how the cross-section became exposed you can't even know what weathering to expect.


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PaulK
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Posts: 15825
Joined: 01-10-2003
Member Rating: 2.8


Message 188 of 202 (796824)
01-05-2017 12:22 AM
Reply to: Message 187 by Faith
01-05-2017 12:15 AM


Re: The decrepitude of both upper and lower blocks of strata
quote:

I'm not looking at any cross sections, I'm looking at the usual view of Siccar Point.

Both segments of the unconformity look like they've been subjected to a very great degree of weathering or whatever has left them so desiccated and splintery looking.


The usual view IS a cross-section. That is how you can see the strata. If you were looking down on to the surface you obviously wouldn't see the rock underneath.

quote:

Erosion removed the weathered material....How do you know that?

You seem to forget that I am explaining what Edge is saying. However it is a quite normal occurrence - it's where a lot of sediment comes from.


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PaulK
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Posts: 15825
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(2)
Message 193 of 202 (796855)
01-05-2017 2:17 PM
Reply to: Message 192 by Faith
01-05-2017 1:44 PM


Re: The decrepitude of both upper and lower blocks of strata
quote:

I've been saying from the point I entered this thread that the upper and lower segments of the Siccar unconformity look about equally weathered. The appearance of weathering (or erosion or whatever is the cause of the obvious breakdown of the rocks into their splintery form) is the only comparison I've commented on

Aside from the subjectivity (and failing to check that the rocks are equally hard) it does seem very clear that you are looking at an exposed cross-section rather than the surface.

quote:

The point has been from the beginning that I see no evidence of the usual interpretation of angular unconformities, that there is a difference of millions of years between the tilted lower portion and the upper horizontal portion of such formations.

You are the only one who fails to see it. The evidence that there has been major erosion between the folding and the deposition of the strata above the unconformity is quite clear.

quote:

If that were the case, I argued, the lower section should be utterly reduced to a small pile of splintery rock at a location like Siccar Point with the constant battering of the elements. MILLIONS of years.

Given the fact that quite large amounts of rock were lost between the folding and deposition starting - and that you would need to know that the conditions causing the erosion were so harsh that we should expect more - that really doesn't seem to be much of an objection. Without good estimates of how much has been lost and how much should have been lost you are just guessing.

quote:

The upper segment is identified as Devonian, the lower as Silurian, the usual difference in age between these time periods being in the millions.

The age of the fold would seem far more relevant than the time the greenwacke was deposited. Exposure time is what matters, not age.

quote:

How long does it take? How long has the upper section been there? Even that section should have been reduced to rubble by now according to the usual time spans proposed by standard geology.

As I point out above, that is no more than a wild guess. (However I will note that an inability to account for observed erosion in the Biblical timescale was one of the earliest clues to the fact that the Earth was much older than the Bible suggested)

quote:

The topic is still pretty confused it seems to me.

The confusion is mostly yours.


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PaulK
Member
Posts: 15825
Joined: 01-10-2003
Member Rating: 2.8


Message 199 of 202 (796870)
01-06-2017 2:54 AM
Reply to: Message 196 by Faith
01-05-2017 8:31 PM


Re: The decrepitude of both upper and lower blocks of strata
Thank you for having the honesty to admit it.

Perhaps you should be more careful to avoid knee-jerk assertions in the future. This is hardly the only example, although perhaps it is more obviously wrong than most.


This message is a reply to:
 Message 196 by Faith, posted 01-05-2017 8:31 PM Faith has not yet responded

  
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