Plate tectonics, mountain building, and the Flood

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Originally posted by John Solum:
The structures in the Colorado Plateau have certainly been looked at, but the problem is that the amount of vertical uplift is not equivalent to the height of a feature. Determining the total amount of uplift during a mountain building event isn’t too difficult, and for major events it’s on the order of 10s of kilometers. Finding rocks exhumed from depths of ~30 kilometers is pretty common, but that doesn’t mean that the mountain ranges were 30 kilometers tall. The height of a mountain range is limited by the strength of the rocks that the mountain is composed of. The rocks at the bottom of the mountain are weighed down by the overlying rocks, and if you piled up enough rock, the stress would be too great for the mountain to support. The highest a mountain can be is around 9 kilometers. This means that mountains will grow until the hit that 9 km mark, and after that, instead of continuing to grow vertically, they will start to grow laterally. This is what’s going on with the Himalayas today; India and Asia are still colliding, so mountain-building stresses are still being generated, but the Himalayas can’t get any higher, so they’re expanding laterally. This is why there are active extensional faults in the Himalayas despite the fact that the stresses in that region are compressional. Phrased another way, the rocks aren’t strong enough for the mountains to get any higher, but there’s still deformation going on, and so the rocks have to accommodate that deformation somehow, and they do that is that the mountain belt expands laterally instead of vertically (this process has been given the dramatic name synorogenic collapse).

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There’s evidence of synorogenic collapse of ancient mountain belts too, in particular I’m thinking of the 1.2-1.0 billion year old mountain belt that I’ve mentioned before. This means then, that these mountains were 9 km high at some point, since they’d have to be that tall in order to cause the collapse. Since these mountains are Precambrian, and since to the best of my knowledge most young earthers would place the Precambrian in the time interval before the Flood, this is a pretty strong indication that the earth wasn’t flatter before the Flood.

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Just a couple of notes here regarding the height of mountains, etc. First, one has to accomodate the fact that there are differences between oceanic and continental crust. Perhaps the greatest reason for topographic relief on the earth is this difference. Of course, I have to assume that there were continents in pre-Noahic times...Second, there is another way of estimating relief for some mountains. Stratovolcanos have a fairly predictable profile that can be seen in some of the ramparts of older volcanic arcs. By projecting them to the known profile we can estimate that some, such as the predecessor of Mt. Lassen, were still on the order of 10-14,000 feet above the current sea level. I can't remember the age or name of this peak, but I'm pretty sure it is quite older than 6000 years (or 4000 years, if the flood supposedly caused the volcanism).I suppose, as John has indicated, that one might look at the amount of crustal thickening in some mountain ranges and calculate how high such a crust might extend above sea level. Certainly we have some information on detachment surfaces that might lead to an idea of total relief. We might also judge the thickness of the crust necessary to generate the metamorphic assemblages that we see and then make some calculations as to how high such a crust might ride on the asthenosphere.Personally, I think that the geological record indicates a constant supply of coarse-grained, terrigenous sediments from large areas of erosional unconformity. This is strong evidence to me that there has been some emergent land mass at all times in the earth's history since formation of the crust (I assume that this happened before the first humans inhabited the earth).As far as we know there is no significant difference in the materials or processes that create mountains today from those that created mountain ranges in the past. I would say the onus is on the smooth earth people to show that there is some reason to think differently.

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Originally posted by TrueCreation:
--The vary geophysical processes Meert uses are the ones which the Global Flood harnesses as the reason the continents became inundated. Tell me, what do you think is going to be the effect of a ~150m ocean basin?

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Why does it matter?

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Originally posted by TrueCreation:
JS: "Nowhere in Joe's article does he state that the ocean floor was shallow. His point is that if the ocean floor is 6,000 years old then it ought to be a uniform 15 meters deep."

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--And you don't call that shallow?

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Hunh? Would you mind terribly explaining the reasoning behind this question?

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JS: "Quite clearly the ocean floor isn't 15 meters deep, and so the present bathymetry can't be reconciled with the idea that the ocean floor is 6,000 years old."

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--You should read Meerts source T & S - Geodynamics and find the sections where it explains the principle of isostatic balance. After that, you will see that ocean bathymetry will not stay in such condition.

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Thank you for the lesson, but I think that is what we are saying. When the oceanic crust cools, it will sink. In 6000 years, it will not cool enough to sink as far as it has.

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--To make this clearer for you, ...

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Ah, good! Another lesson from TC who has read a few geology papers.

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... a mainstream analogy: Eustatic levels in the Cretaceous (80 Ma) were 300m higher than it is today, and water flooded about 40% of the present area of the continents.

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(Hmm, that still leaves 60% of the continents, but who's counting, eh?)

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Such eustatic changes are due to this same process directly associated with Meerts calculations. And Sea levels in the past imply larger values of the mean oceanic heat flux. Were not at that present level are we, bathymetry rebounded.

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Yes, and it has been doing so for a long period of time. In fact, some of the oceanic crust has been cooling for 80 My, which accounts for the present ocean depths. The point, which you have predictably missed, is that your flood scenario does not account for the existing depths.

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Originally posted by TrueCreation:
"How do you account for the present bathymetry of the ocean floor?"
--The fact that it has cooled for the past couple thousand years.

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So, don't you think someone would have notice that sea level has dropped thousands of feet in the last 2k years?Unbelievable! Your scenario is getting sillier and sillier all the time.More later... I need recovery time from that one![This message has been edited by edge, 01-19-2003]

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Originally posted by Tranquility Base:
I agree with everything you've written. I'll just point out that you are yet to come up with any hard data on heights.

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Perhaps you can give us an idea what you consider 'hard data' by showing us what you've got to indicate a smooth earth.

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Your cited 9km is really a theoretical/extrapolated expectation. In our sceanrio these warpings and uplifts happened catastrophically simultaneously with huge flood sruges. So the uplifts could have occurred shattering rock that was catastrophically carried away.

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How was it catastrophically carried away? Remember, you have to transplant trees into a growth position and leave them standing with the ebb flow of these surges.Where is the evidence of these catastrophic erosion events? Where are they in the geological record?Have you calculated the strain rates necessary in your scenario? Why do we see folded rocks and metamorphic terranes at all?

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It may never have reached the heights you understandably expect even though the left over warping is compatible with such heigths.

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The point here is that the onus is upon you to show that things were different. We have reason to believe that there were mountains prior to the last 4000 years. You have nothing but a biblical myth that carries no evidence of a smooth earth. The smooth earth is strictly a construct that you have created by necessity.

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Originally posted by Tranquility Base:
Quite true although I got the impression that on average there may have been fewer high mountains in the Paleozoic/early Mesozoic. I may be wrong.

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I am curious as to where you got this 'impression.' John has given you the example of at lest three orogenic episodes for the Appalachians alone. And all are in the Paleozoic. It is curious that these mountains actually appear more mature than other mountain ranges that have undergone more recent episodes of uplift. How do you explain this? I would say, 'yes,' you may be wrong. (I can just imagine your subtext, to borrow from Charles Barkley, "... but I doubt it..")

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Like I said, I've searched for the data and come up empty handed.

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Do you think this might be telling you something?

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I have learned quite a bit from John S on the issue and that will help me next time I venture out into the geo-lit on this issue.

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Somehow, I am concerned that your only learning is where you have to come up with more ad hoc sub-theories to fill in the numerous cracks in your flood scenario. At some point, most of us would say that it is time to abandon a theory that so consistently lets you down.

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Originally posted by TrueCreation:
--Its difficult to do these things without hundreds of other scientists even having the interest, things don't get done for us as fast as the mainstream.

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Once again, perhaps this is a hint that you should heed.

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Edge: "So, don't you think someone would have notice that sea level has dropped thousands of feet in the last 2k years?"

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--No they wouldn't because whatever the mechanism, such a rapid deceleration in heat flow hasn't been observed.

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Once again, you make no sense whatsoever. Could it be that since it hasn't been observed that it is impossible?

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Originally posted by TrueCreation:
"Once again, perhaps this is a hint that you should heed."
--Heed to who or what?

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Well... maybe you need more than a hint.

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"Could it be that since it hasn't been observed that it is impossible?"

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--I don't see evolution taking place on macro scales, and I haven't seen any 'big bangs' lately either. Sure it could be so, any scientist will say this about unanswered questions.

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You leave out the tiny fact that there is evidence for evolution and there is evidence of the big bang. And, no, not everything is possible.

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Originally posted by Tranquility Base:
As an excesize, can someone here post a clear summary of the evidence that a Paleozoic mountain chain was entirely uplifted prior to the Mesozoic being deposited?

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Yes. The Appalachian orogenies were succeeded by Triassic extensional basins.

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Let us look carefully at the actual data. In our sceanrio the uplift could have been occurring gradually during the flood ...

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TC, nothing like this can happen gradually when confined to a one year period. You contradict yourself. A few posts back you were talking about the tectonic plates pulverizing themselves...

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.... with its peak being achieved only after the 100% covering.

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Exactly when was this?

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Can we really identify the height prior to the Mesozoic or is it actaully a lot of guess work?

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To an absolutist, no. However, we can show that there were mountain ranges and they were likely very simlar to those of today. This is a damn site more than you have... Why do you badger us for exact heights of the mountains while you haven't even an iota of data saying that the earth was smooth? This is hypocritical and sophomoric, and I am extremely disappointed in your progress.

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Originally posted by TrueCreation:
"Well... maybe you need more than a hint."

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--I still don't know what your talking about, heed to what?

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That there is a reason, no one is researching this. It makes no sense to do so.

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"You leave out the tiny fact that there is evidence for evolution and there is evidence of the big bang."

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--I was being sarcastic, you missed my point. I didn't say there wasn't evidence for it, I said we arent observing it occuring today.

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Let's see, could it be that is because it never happened? Why do you assume that because we cannot see it today that it must have happened and various laws of physics must have been violated before we could have seen them? I am sorry, but if the oceans receded thousands of feet between 4000 and 2000 years ago, we would have some record of it, and possibly a verbal record.