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Faith  Suspended Member (Idle past 1444 days) Posts: 35298 From: Nevada, USA Joined: |
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Author | Topic: Motley Flood Thread (formerly Historical Science Mystification of Public) | |||||||||||||||||||||||||||||||||
edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
If you pile a lot of loose sediment on top of a dry salt lake you'll get a lot of loose sediment in the cracks and not much effect on the straightness factor. If you pile a lot of loose sediment on top of a broad flat field with grass and other green things growing on it you'll get a lot of dead grass under the sediment. or rotted grass if it's wet.
Not much grass growing on the bottom of the GSL.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
And if this later of sediment is 100ft deep, or 100m, or 1m? What then?
Here is an image of the perfectly flat bedding that Faith is talking about:
[/sarcasm]
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
May I ask about Valles Marineris? It's a much bigger canyon than the Grand Canyon. Was this caused by a divine flood too?
Please tell me you didn't really ask this question...
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
LOOK AT THE STRATA IN THAT PICTURE. JUST LOOK,. NO LAKE BED, NO SALT FLAT, NO FIELD, NO BEACH, IS THAT FLAT. JUST LOOK.
However, they are lake bottoms And they are flat. And why couldn't they be muds rather than salt? In fact, many are.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
THE GC AND THE MAP OF ENGLAND SHOW EXACTMPLY WHAT I'M TALKING ABOUT, ALL THE TIME PERIODS ATTACHED TO THEIR RESPECTIVE SLAPS OF ROCK IN PLACE FROM CAMBRIAN TO HOLOCENE, ...
Actually, some are missing.
... AFTER WHICH ALL THE EROSION OCCURRED AND NOT BEFORE,
Actually, incorrect. These two locations do not represent the entire world.
AFTER WHICH ALL THE TECTONIC DISTURBANCE OCCURRED AND NOT BEFORE.
Again, demonstrably wrong. Siccar Point is an example of deformation before the most recent sediments.
THAT IS EVIDE3NCE THAT THE GEO COLUMN HAS COME TO AN END.
Not really. You cannot predict what is going to happen in the future as sea level changes.
THE EROSWION MARKS THE END, THE TECTONIC DISTURBANCE MARKS THE END. THAT DID NOT OCCUR DURING THE LAYING DOWN, IT OCCURRED AFTER IT WAS ALL LAID DOWN.
Again, the process is ongoing. We only see a snapshot in human terms. Erosion is acting as it always has and tectonism is very much alive as it has been for the last half billion years. I am surprised that you have not yet figured this out.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
i WAS HOPING SOMEONE HERE MIGHT ACTUALLY BE ABLE TO SEE HOW THOSE CANNOT POSSIBLY BE LAKE BEDS.
That's pretty much what your science consists of ... hoping. Recent lake beds look exactly like the ones in your picture. The sediment cores from Lake Suigetso are also similar. This image shows the upper layers in the upper left of the image as kind of vague and obviously of very low strength, usually uncountable. The layers seem to blend together rather than show sharp contacts.
This is similar to your image where the bedding, while flat, is still vague and gradual in some cases.
I TRIED TO AVOID ANYTHING THAT I THOUGHT MIGHT SOUND INSULTING. BUT OF COURSE THE INGRAINED HABITS WOULD PREVAIL EVEN IF THEY ARE TOTALLY WACKO. i
Irrelevant, but I understand that your habits are hard to break. Edited by edge, : No reason given.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
You said the layers in the hill are limestone and volcanic ash.
Yes, same question. Why couldn't they just as soon be limestone and volcanic ash?
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
When first considering this I figured that erosion at the plateau edges was just a form of incision and recession. I thought the plateau edges would gradually recede north, expanding whatever plateau is south of the Colorado Plateau. But after a little thinking I realized that you're probably saying that the Mogollon Rim is an example of an orogeny that requires erosion for exposure. Sounds, weird, but do I have that right?
An interesting way of putting it, but yes.
You're killing me. Like Faith I know that certain things are true, like that the Rocky Mountains were thrust into the sky by an orogeny to stand high and gleaming above the surrounding landscape, but unlike Faith I can go to Wikipedia and disabuse myself of misconceptions like this. After reading the geology section of the Wikipedia article on the Rocky Mountains I'm just confused. First it says the southern Rocky Mountains were thrust up through overlying Pennsylvanian and Permian layers, then it says the Rockies were once a high plateau like Tibet and that erosion gradually exposed the mountain range. How does unevenly thrust up underground rock cause a flat plateau at the surface?
By being eroded to the local base level. Below base level erosion can't occur (except possibly by glaciers), so you end up with a 'peneplain'.
Is it that the orogeny is slow, and so any high spots created at the surface are worked on by the forced of erosion, thereby maintaining a flat surface? Something else?
Sure, think of it as competition between erosion and uplift. High relief means rapid erosion (generalizing here) and low relief means slow erosion.
Checking the Himalayas, I see they formed pretty much the way I thought, colliding plates thrusting up mountains, but you have destroyed my illusions about the Rocky Mountains. I was fond of them.
Well, the are much more attractive having been eroded.
Geez, just as I'm getting familiar with Arizona you change states on me!
Well, then it's time to move on to the Roraima Plateau. This area is very high plateau rising out of the Amazon-Orinoco jungle as the 'Grand Sabana'. It's very close to flat and it collects a huge amount of water that drains off the edges in places like Angel Falls. At the edges of the plateau, erosion has created very narrow, spire-like mesas called tepuis wich inspired the novel 'Lost World'. There are no 'mountains' as we think of them, just a giant high plateau with outliers.
But aren't Mount Evans and Pikes Peak unique as mountains, unassociated with any orogeny?
Well, they are discrete mountains now. But at one time they were planed off to maybe near sea level and then rose again. In fact, there is speculation that such a peneplain is the reason that so many peaks reach an elevation of 14,000+ feet elevation but none at 15,000'. The peneplain has simply been uplifted and then dissected by streams and glaciers. In fact, if you look at the top of Longs Peak, it's kinda flat. Check out some pictures on line.
Even if we had draped a giant canvas over the Pikes Peak area to protect it from erosion during uplift and after, wouldn't it still tower over the nearby landscape, just covered with the less resistant rock that used to be there?
Not sure, but you still have all of the other Fourteeners to contend with. Why do the only reach that elevation? And actually, most of the erosion is probably due to rock structure: faults and fractures controlling erosion more than rock type. Please remember that I did say this is a bit philosophical. One could simply argue that since erosion occurs along with uplift, that mountains form immediately, and I'm full of baloney. But I'm still saying that erosion is a huge part of the deal in forming mountains.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
Right, we're all trying to explain the width of the canyon at its widest point, and the explanation has to include why the canyon is so wide here and not at other places. Faith's explanation is that the river was at one time 18 miles wide at this widest point, but of course rivers flow fast in narrow portions and slowly in wide portions. To have the deepest erosion at the widest point where the river was most quiet is impossible.
Well, it's fairly simple. Since the GC rocks are not (in the upper levels) composed of strong rocks they have to attain an angle of repose above the river level. So, the deeper the canyon the wider the canyon. But why so wide here and not elsewhere? Why is the Grand Canyon so much wider than Marble Canyon or the western reaches of the canyon? More later.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
The concept of rocks "swelling up" is something to contemplate, but I imagine it's just a poetic way of saying they got pushed up, but it's the "due to underground folding" ...
Actually, these are not Dickinson's words. They do not occur in quotation marks in the article and are not recognized geological terms. The only logical conclusion is that they are descriptive terms written by a journalist for a lay audience.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined:
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The notion that the 'geological column' is 'over and done with' is as sillly as they come. One of the things we learn from events like the eruption of Kilauea is that geological processes that have gone on for at least the last half billion years continue today. Sedimentation driven by tectonism, erosion and deposition continue as before. Mountains rise, water erodes and sediments are carried to the sea.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
OK. io what about the "due to underground folding."
I have never heard of such a term.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
I don't divide anything, I find them deformed in blocks, meaning whole segments of strata deformed together as a unit, not as separate strata.
Of course this does not apply to the Grand Canyon block, right? As you allege, the rocks above and below the GU deformed separately even though they are in the same block at the same time.
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
Well it's very simple English that conveys something easy to visualize it seems to me.
That's the point.
We know what folded rocks are, and we know what "underground" means.
Except that there is no evidence that the rocks are folded due to the Kaibab uplift.
The journalist characterizes Dickinson as saying that folded rocks deep underground are the cause of the uplift.
Except that he characterizes wrongly. To prove my point. I'll ask you how this uplift happened. In other words, what is the dynamic interpretation?
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edge Member (Idle past 1706 days) Posts: 4696 From: Colorado, USA Joined: |
The big problem with relying on diagrams is that they can be misleading. That is especially true if the diagrams are based on early work, and quite possibly get things wrong.
Look how 'straight and flat' the contacts are! And the Great Unconformity, too!
The reality is rather more complicated: A diagram published in 1910 showing a cross-section from Snowdon to Harwich. Even if it is hard to read the fold of older rock at the right should be very obvious. This diagram certainly doesn’t suggest that everything happened at once. This will show those dumb geologists! Edited by Admin, : Inserted image from the link in [msg396] into this post.
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