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Author Topic:   Depositional Models of Sea Transgressions/Regressions - Walther's Law
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 513 of 533 (730636)
06-29-2014 1:53 PM
Reply to: Message 511 by Faith
06-29-2014 1:49 PM


So half a million years and what I figured was 20 thousand feet in a million years so now it's down to 10 thousand feet since they were formed and they should still have eroded away to dust by that calculation.
abe: Sorry the second figure makes it a tenth of that time so 2000 feet should be gone. What does that leave?
At its narrowest point, the Channel is twenty miles wide.

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 Message 511 by Faith, posted 06-29-2014 1:49 PM Faith has replied

Replies to this message:
 Message 514 by Faith, posted 06-29-2014 1:55 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 515 of 533 (730638)
06-29-2014 1:56 PM
Reply to: Message 514 by Faith
06-29-2014 1:55 PM


We're eroding the CLIFFS, Dr A., not the channel.
Eroding the cliffs widens the Channel, Faith.

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 Message 514 by Faith, posted 06-29-2014 1:55 PM Faith has not replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 519 of 533 (730643)
06-29-2014 2:22 PM
Reply to: Message 517 by Faith
06-29-2014 2:00 PM


40 to 60 million years is the age given for the rock from which the hoodoos were carved, by the Old Earthers who wrote the article for the National Park Service, whom I suppose to be real people, but I suppose they could be robots programmed to spout OE stuff.
And the age of the rock is different from the age of the hoodoos. This is why I asked you for an instance of someone giving an erroneous date for any given hoodoo, rather that of someone giving an accurate date for the rock.
Do you have some reason to suppose that the hoodoos didn't start eroding at that point?
Yes. For starters, if the hoodoos we have now had started being formed then, they wouldn't still be here.
You can read some interesting stuff about hoodoo formation here.
The hoodoos have limited life-spans. What you see toward the top of the image is remnants of hoodoos, now transformed into the rounded hill erosions one would expect if normal arroyo wash processes had been dominant throughout. As Sprinkel et al. observe, the rim of Bryce Canyon is a passive topographic feature that retreats backward, estimated at about 4 feet per century, which would add up to 12 miles in a million years....

This message is a reply to:
 Message 517 by Faith, posted 06-29-2014 2:00 PM Faith has replied

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 Message 521 by Faith, posted 06-29-2014 2:30 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 520 of 533 (730644)
06-29-2014 2:24 PM
Reply to: Message 518 by Faith
06-29-2014 2:16 PM


Sigh. OK. So it's 450 thousand down to 180 thousand years old, so that means that at the rate given by Percy if they are half a million years old they'd have added ten thousand feet to the English Channel, or at the lower age about 2000 feet since they were formed. Is that feasible?
Yes. Because of the channel being twenty miles wide at its narrowest point, and a mile being 5280 feet.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 523 of 533 (730650)
06-29-2014 2:39 PM
Reply to: Message 521 by Faith
06-29-2014 2:30 PM


But there is no reason whatever to suppose the erosion started recently enough for that to be the case.
Since no Bryce Canyon hoodoo could last for millions of years, we may conclude that no given hoodoo in Bryce Canyon has been there for millions of years. That was your argument. That bit was correct. Where you went wrong was that you pretended that geologists claim that the present Bryce Canyon hoodoos are millions of years old, which they aren't. But you were right to say that they can't be.
The fact that they wouldn't be here if it started when of course it did start, right after the cliffs were formed ...
* sigh *
When were the cliffs formed?
Note that the cliffs are different from the rocks and the time since there was a cliff face is different from the time that any given presently existing hoodoo was carved.
Edited by Dr Adequate, : No reason given.

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 Message 521 by Faith, posted 06-29-2014 2:30 PM Faith has replied

Replies to this message:
 Message 524 by Faith, posted 06-29-2014 2:47 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 525 of 533 (730652)
06-29-2014 2:51 PM
Reply to: Message 524 by Faith
06-29-2014 2:47 PM


So you've explained away the hoodoos and Dover. How are you going to explain away the rate of erosion of the monuments in Monument Valley? I can hardly wait.
What is it you don't understand about Monument Valley? I shall be happy to explain it, or as you would apparently phrase it, I shall be happy to explain away it.
But perhaps now that you've seen how simple and obvious it is to understand erosion you could have a go at this one yourself.

This message is a reply to:
 Message 524 by Faith, posted 06-29-2014 2:47 PM Faith has replied

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