January 21st, 2011, 02:26 PM
Hi,
I'd like to discuss if someone thinks that what was know as plate tectonics; if this was merely a free fabrication by Alfred Wegener (and others )?
What was, if, lets say, earth shaped, then rain poured down and all of the planets surface that got colder was being inundated?
The Planet would have a full like complete crust instead of single land masses that are swimming on top of the hotter earth interior.
Steve
January 21st, 2011, 02:49 PM
Wegener's theory was continental drift (continents sailing over ocean floor) not plate tectonics.Originally Posted by Steve Miller
hi florian,
continental drift is the opener for the rolling stones vcr live tape 'live at the max'
http://en.wikipedia.org/wiki/Plate_tectonics
No, but seriously. Did you get what I meant? When there was not one initial continent, which cracked and spread?
And I wonder if continental drifts or/and plate tectonics had to result in earth shakes. The same had to go for seaquakes. Both sorts of quakes taking place not only every once in a while, as we witness them to be like, but always steadily ongoing?
Steve
Think more along the lines of the hard sections that form on cooling grease. then keep the rest of the grease just warm enough to prevent solidification.hi florian,
continental drift is the opener for the rolling stones vcr live tape 'live at the max'
http://en.wikipedia.org/wiki/Plate_tectonics
No, but seriously. Did you get what I meant? When there was not one initial continent, which cracked and spread?
And I wonder if continental drifts or/and plate tectonics had to result in earth shakes. The same had to go for seaquakes. Both sorts of quakes taking place not only every once in a while, as we witness them to be like, but always steadily ongoing?
Steve
Hi Paleoichneum,
sorry I don't know what cooling grease does. What was it, or the effect, used for?
Steve
presumably you're thinking about pangaea - which was only some 300 million years ago, long after plate tectonics as we know has been known to exist
think of the initial earth's surface to be totally molten, followed by small cores of continents forming from higher melting components, and subsequent accretion around those cores
once the temperature had decreased far enough for water to become liquid and oceans had formed plate tectonics as we know it now could start, but still with a fairly large number of microcontinents which over time stuck together to form larger continents
Nice scenario. Evidence?presumably you're thinking about pangaea - which was only some 300 million years ago, long after plate tectonics as we know has been known to exist
think of the initial earth's surface to be totally molten, followed by small cores of continents forming from higher melting components, and subsequent accretion around those cores
once the temperature had decreased far enough for water to become liquid and oceans had formed plate tectonics as we know it now could start, but still with a fairly large number of microcontinents which over time stuck together to form larger continents
I'm sorry I cite myself, buthi florian,
continental drift is the opener for the rolling stones vcr live tape 'live at the max'
http://en.wikipedia.org/wiki/Plate_tectonics
No, but seriously. Did you get what I meant? When there was not one initial continent, which cracked and spread?
And I wonder if continental drifts or/and plate tectonics had to result in earth shakes. The same had to go for seaquakes. Both sorts of quakes taking place not only every once in a while, as we witness them to be like, but always steadily ongoing?
Steve
I like to add, taken continental drift or plate tectonics for real, a continent like Australia, a huge isle, shouldn't it tumble and flip over at some point? The cold chunks of grease would. if I get you rightly here.
Not like an iceberg when the most part of ice was below the sealine; about 95 % or more. The earth interior core or the underlying grease where still too hot, so the or land masses or the chunks of grease would melt away again.
I'm getting lost at - the earth be molten when small cores of continents forming from higher melting components .....presumably you're thinking about pangaea - which was only some 300 million years ago, long after plate tectonics as we know has been known to exist
think of the initial earth's surface to be totally molten, followed by small cores of continents forming from higher melting components, and subsequent accretion around those cores
once the temperature had decreased far enough for water to become liquid and oceans had formed plate tectonics as we know it now could start, but still with a fairly large number of microcontinents which over time stuck together to form larger continents
I'm sorry 'marnixR'.
It was very likely a crust formed all over the surface about the same time (due to the spherical shape of the planet and the rotations and revolutions), which cracked at several places.
The forming of these cracks and the emission of heat from the interior earth core by these cracks could be the subsequent reason of the fall of some rain, eventually.
Steve
Noo sleep to Brooklyn....
indeed, it is a scenario of what may have happened, consistent with our present state of knowledge of the early earth
as for continents tipping over : they DO have deep roots, maybe not quite in the same proportion as an iceberg, but still substantial enough to stabilise it
The continent lithosphere is thicker and lighter than the ocean lithosphere. This is why continents are floating on top of the asthenosphere and why oceans are oceans, because the oceanic crust is lower.
When you think about "floating", we have to be careful. All these structures are ductile, but the viscosity is very very high, nothing to do with oil, grease or even butter. However, in the long run, they behave like paste.
About the evidence of plate tectonics, there is first the magnetic inversion symetrical strips on the ocean crust, the GPS measurements etc... This is a pretty done deal, although some mechanisms remains obscur.
Actually, the ocean symmetrical growth was predicted by Mantovani at the eve of the 19th century.
I still love the idea that all the orbs in orbit might have the same cradle. Meaning, they might have been one day like sun.
But they morphed further since sun was existent already.
Now a compleat crust that cooled down as well as that the planet shrank therefore, then had compressed the gas inside of the planet. The clue for the magma which splurts once a volcano is erupting.
Earth might not have been a huge rock once which has been catching fire for the magma to be kinda liquid, however?
No. You have to know that Earth is a growing body. See these discussions: Is Earth growing?, Were the continents once gathered by Equator?
florian,
under circumstances, sure earth might grow. Especailly, as it once has been a gaseous ball and this gas has been compressing by the cooling of its surface.
It could well be the said compression let earth grow in diameter. Though, I personally, would say it does not grow. The once gaseous state might have been altered to a liquid one, eventually. As for the atmosphere, not to be growing has not due to be true here, however.
Lets say, earth was in a process to further cool down, which we could assume I think by better chance, since non further energy was added, the actual planet rater should, slowly but steadily, shrink further. This shrinking could trigger volcanos to erupt and cause sea and earthquakes, as well.
Steve
Steve,
You're assumption is wrong. Earth is not the isolated system you think it is. You obviously failed to read the discussions I pointed to you. Read them or your remarks will remain irrelevant.
That's right florian. If it was, earth crust wouldn't crack, I think. Don't necessarily wait for folks to tell you failed or pass.
It wouldn't get you anywhere.
Did you understand, Australia was not said to be floating on the ocean, but was said to swim in the real hot earth' interior upper mantle?
Please, what do you think what would happen if you'd stick (so please don't do this.. but ) your feet into hot lava? Pretty much would go for Australia, after the due period of time, don't you think?
It simply would submerge at some point, as all the other continents would if swimming on the upper mantle. Just like in some fiery end time scenario. I'm really serious about it. However.
Steve
Steve,
Sorry, but I've a hard time to decipher what you mean?
Why would a continent submerge? They are much less dense that the upper mantle, molten (as you think) or not (in reality).
I think the whole crust of earth was being one, with not several plates drifting. Did this come clear to you? Elevated regions just stick out of the oceans surface just like plateaus.
Steve
When?
What are these elevated regions? Continents? Continental lithosphere is a patchwork with different composition than oceanic lithosphere. How do you explain this?Did this come clear to you? Elevated regions just stick out of the oceans surface just like plateaus.
First, ever,
second,
the crust was not being a plane surface, but some regions of this crust were elevated. Rising above the sea level. Thats why our feet stay dry most of the time.
Steve
Sorry, but he difference between oceanic crust and continental crust is not restricted to elevation. The most important differences are related to composition and formation.
Well yes florian this might be. Seen be contemporary 'standards' my statements are hypothetical. But I think, anyway, you're getting the point of what I say. Btw. I didn't write they were.
When you consider the other effects both of the surfaces of the crust were exposed to these differences pretty much come clear. Obviously, below the sea its gonna be different than on shore, somewhere.
Steve
Plate tectonics was a important improvement over previous theories, but it is about to become outdated.
Come back to us when a viable alternative theory is published in reliable peer reviewed journals and accepted by the geophysical community...Plate tectonics was a important improvement over previous theories, but it is about to become outdated.
A scientist has to be able to judge a theory on the evidence presented, published or not in the peer-reviewed literature. If one individual can't, then he's not a scientist (at least from the field).
Besides, paradigm shifts take time to be accepted by entire communities. But of course, it does not prevent a few individuals to be ahead of their time. Actually, without these individuals able to think out of the box, like Faraday, Einstein, Wegener or Carey, paradigm shift would never happen.
Fine. Then start presenting some damned evidence and a theory which explains observations better than existing theory, and which makes falsifiable predictions about what we're likely to see moving forward and why.
How so?
There is already an ongoing thread that was moved to the pseudoscience category by ignorance: http://thescienceforum.com/viewtopic...r=desc&start=0
There, in the last 20 posts of this thread or so, I started to expose why the absolute motion at subduction zones as determined by recent data implies Earth's growth. And please ignore the blahblah from that creationist named WWJD. Such unwanted contribution is what arrives when a discussion is stupidly moved to the pseudoscience category. What a pity...
I looked at the thread. It appears that all of the points were sufficiently addressed, and the arguments for an expanding earth shown bunk. Why is this discussion still occurring?There is already an ongoing thread that was moved to the pseudoscience category by ignorance: http://thescienceforum.com/viewtopic...r=desc&start=0
There, in the last 20 posts of this thread or so, I started to expose why the absolute motion at subduction zones as determined by recent data implies Earth's growth.
Really? then why don't you answer this question: "So, where are the subduction zone relatively to the mantle/crustal displacement, rear? front? side?"
As reminder, this simple question is related to the 2 figures found in this post: http://thescienceforum.com/viewtopic...r=desc&start=4
This is true as a generic statement, yet is largely inapplicable in the context of this thread. Among the members there are close to zero practicing geologists or geophysicists whose speciality is directly immersed in the mechanics of plate tectonics, rather than simply touching upon it. I should be delighted to learn this is not the case, but surprised in equal measure.A scientist has to be able to judge a theory on the evidence presented, published or not in the peer-reviewed literature.
In such an instance peer reviewed literature provides an important critical filter, especially for ideas that are unorthodox. You present an unorthodox idea. This idea has some features:
1. It was considered then rejected fifty years ago.
2. Your principle justification for the hypothesis seems to be that plate tectonics has problems. That approach to justification has parallels with the approach of creationists. I would have thought you would wish to avoid that.
3. Others have pointed out that you have used the Bozo the Clown defence. Again, this is a signature of a pseudoscientific idea.
You have objected that the idea is not being addressed scientifically. Well, that is to be expected when it is not presented scientifically.
I would have expected a scientist to say “I started to demonstrate…”, or “I began to present evidence for…”. The phrase, “I started to expose” reeks of an agenda ridden attitude seeing conspiracy in the community and suppression of ‘the facts’.There, in the last 20 posts of this thread or so, I started to expose why the absolute motion at subduction zones as determined by recent data implies Earth's growth.
If you object to such a suggestion as an attack on you, not an attack on the evidence, then I recommend avoiding such emotive phrases that are commonly associated with hacks.
I shall shortly address your evidence in the other thread, if someone doesn’t beat me to it.
Hi People
I hope you don't mind - this is self-plagiarism unless I say as much. I posted almost exactly this in "why has water stayed liquid on Earth?" a few days ago. Maybe lots of discussions here touch these matters, but here goes:
Conjecture
There was once a time when the Moon had been made and the Earth had cooled so that a skin of solid rock had formed all about the planet.
From far space came a big rock traveling fast, and hit us so hard that the shell of the Earth was smashed into bits.
Time passed.
Mantle currents immediately began to act on the broken pieces. As the newly formed plates moved spreading zones and subduction zones came into being.
Prediction:
Unless Mars has also been smashed by a big rock, we will not find terrestrial-type (tectonic) volcanism.
Possible evidence
Perhaps bits of the re-smashed Earth caused the near-side craters on the Moon.
Once again I hope not to have offended by repeating these remarks. I justify my repetition with the idea that knowledgeable people might see it for the first time and I might learn something.
I think we should leave the discussion of this where you originally posted it. It is considered bad form to repost fringe ideas in multiple threads.
i have learned two things from your post:
1. You are very likely a nice, well meaning, inquisitive guy.
2. You do have a lot to learn.
Thanks Ophiolite
I think that about wraps it up!
M
That's the point. There are no specialists here that know the scientific side of the expanding earth theory sufficiently well. And instead of being prudent, people paint this theory as a pseudoscience. That is unscientific.
For example, did you read the literature on which the rejection was based?In such an instance peer reviewed literature provides an important critical filter, especially for ideas that are unorthodox. You present an unorthodox idea. This idea has some features:
1. It was considered then rejected fifty years ago.
And does the argument still holds 50 years later?
Hmm not exactly. Plate tectonics does not have just problems (every theory has problems), it is plainly refuted. And the expanding earth theory emerges as the natural consequence of the refutation of plate tectonics.2. Your principle justification for the hypothesis seems to be that plate tectonics has problems. That approach to justification has parallels with the approach of creationists. I would have thought you would wish to avoid that.
You play with the words (rhetoric). What I'm doing is obviously a demonstration.You have objected that the idea is not being addressed scientifically. Well, that is to be expected when it is not presented scientifically.
Then I'll see you there.I shall shortly address your evidence in the other thread, if someone doesn’t beat me to it.
It would be more accurate to say that your presentation of the hypothesis has been called pseudoscience. I have cited some of the reasons this conclusion has been reached. I could do a better job of presenting the case for it than you have and I don't believe in it.
The theory was primarily rejected because of the stronger arguments in favour of plate tectonics. I wouldn't say I have read those. I would say I have studied them. It's a subtle difference, but possibly important.
It is even stronger now.
Where has it been refuted? You are picking out some ambiguous observations and wholly ignoring a mutlitude of cases where it is plainly demonstrated. (Here is a hint: that's a classic example of pseudoscience.)
It is a demonstration of your inability, thus far, to present a cohesive, coeherent, convincing argument.
If you know it so well, be my guest.
Wrong. Quite a bad start for someone pretending he studied the arguments. I remark that you propose only general statements instead of giving accurate examples.
Non sense, because there is an expansionist interpretation for each observations used to support plate tectonics. The contrary would be surprising for a theory that is correct. And actually, most interpretations are shared by both theories.
Note that I proposed to discuss one of the difference in interpretations. But thus far, you ignore this proposition.
The fact that you continuously evade the discussion on mantle flows makes me doubt that you have the background to understand the argument at all. And why don't you continue the discussion in the other thread?
Sorry to draw parallels to creationism again, but this could also be said of creationist theories. There are interpretations in creationism that explain evidence, and a certain amount of hand-waving and "goddidit". What there is not in either creationism or expansionism, but there is in plate tectonics, is evidence to suggest that this interpretation is accurate.
Essentially this stance you're taking is akin to "you can't prove I'm wrong", and as Ophiolite has said, this is the classic pseudoscience approach.
There is a huge difference. Creationists always use non refutable arguments at some point. Non refutable arguments do not make a scientific theory.
Actually, most arguments used against the expanding earth theory are non refutable arguments. Like that mass origin issue is a non refutable argument. How can you prove that there are no unknown physical mechanism explaining that growth? you can't.
That's why I absolutely want to focus on those arguments that clearly refutes plate tectonics as a whole. But curiously, ophiolites does not seem to want to go there.
Not as huge as you might think.
Nobody (as far as I am aware) is saying that it is impossible for the Earth to gain mass. What they are saying, however, is that you have neither demonstrated that; A: there is a real, measurable increase in mass; or B: there is a scientifically sound mechanism whereby the Earth could gain mass over time.
Not that this would necessarily be a barrier to a theory being accepted, of course. But given that you fail to demonstrate that the Earth is expanding, demonstrating that the Earth is increasing in mass and providing a feasible mechanism would add significant weight to your hypothesis.
You could also suggest some experiments to measure how the mass of the Earth changes over time, or find some experiments done in the past that are relevant.
You could then compile all of this into a scientific paper, and submit it for peer-review.
It has been done already.
Regarding the quantification of the growth. James Maxlow made reconstruction of the Earth back in time using the geological map of the world assuming that recycling of the oceanic lithosphere was negligible compared to MOR accretion and intracontinental extension (See his PhD thesis). Then he tested his reconstructions against different set of data to verify that both the data and the model are consistent. And they are consistent.
So, he made an hypothesis (lithosphere recycling is negligible), made prediction from this hypothesis (reconstruction of early earth models), and tested the prediction with hard data. It results that his predictions are validated, and thus that his hypothesis is correct. Note that there are other independent means to prove that his hypothesis of negligible recycling is valid.
hypothesis->prediction->validation: this is the scientific method. Quite different indeed from plate tectonics that is more a scenario than a theory (interpret observations in a unified framework, but where are the verifiable predictions?). I mean, even evidence of plate tectonics before the neroproterozoic are now seriously questionned in the general literature (See this recent paper by hamilton).
And many others have written papers on the expanding earth. I cited already many papers in the other thread. I could cite again this one:
"Mantle plumes and dynamics of the Earth interior — towards a new model" by Stefan Stefan Cwojdziñski, (2004) Geological Review, vol. 52, no. 8/2, 2004, p817
Anyway, yes I have a paper in project. But first there is a important workshop that I may attend in Erice, Sicily, this fall (see announcement here)
Do you think the assumtion that lithosphere recyclic is negligible is a reasonable one? Really, considering it is widely accepted that it is very much not negligible?
I fail to see how this is different to a creationist assuming that the Earth is only 10,000 years old and explaining data in terms of this.
It is assumed not to be negligible. Because it was earlier assumed that Earth's surface does not change. You should read Le Pichon (1968) JGR 73, p3661, a funding paper of plate tectonics, very striking. Basically, this is classical circular reasoning.
So the question is: is it negligible? To answer this question, one has to understand what is a benioff zone, in which context it does form. This is what I would like to discuss.
Hypothesis->prediction->verification of the prediction. Did you miss that part?
It is unfortunate because this is the basis of the scientific method.
An assumption based on natural law - namely, the first law of thermodynamics. If you want to demonstrate that this law is not being violated, you need to demonstrate a mechanism whereby the Earth can increase in mass over time, and hence lithosphere recycling can be negligible.
You see, it's not so much that your ideas aren't fully supported; it's that they actually violate fundamental laws of physics.
So while the assumption made in plate tectonics is based on a highly successful physical law, the counter-assumption you are making is directly in violation of it.
Sure, go for it.
See above.
First. I was specifically talking about lithosphere recycling. So don't mix thing.
Secondly. It appears that you don't understand that your argument about a violation of conservation laws is speculative, i.e., not scientific.
You can't prove that a growth mechanism not violating any conversion law does not exist, very much as you can't prove that pink unicorn do not exist. Do you understand that?
In this case, you must rely on Ockam's razor except if there are other evidence (direct or indirect) that such a mechanism must exist to explain what is observed.
So the discussion must focus on these evidence.
Then I will repost what I posted earlier in the other thread.
So let's start again with these two similar examples (Agean sea/turkey and Scotia sea).
The first figure represents the GPS-measured displacement in the oriental mediterranean sea. Europe is the referential.
So, What is in motion here and relatively to what? Where is the subduction zone relatively to displacement observed? rear? front? side?
The second figure represents the age of ocean floor in the scotia sea, in between South America and Antarctica, red=young, blue=old:
Same questions as precedent. Where is the subduction zone?
However, sea-floor spreading is clearly occurring, so without significant recycling of the lithosphere at subduction zones, we might very well assume (as you have) that the Earth is expanding.
Again, this is not what I am saying. I'm saying that we do not know of any growth mechanism nor have the appropriate theoretical framework to allow one to exist at this time, whereas we can observe that continents are being pushed apart at sea-floor spreading zones, and we can show empirically that energy must be conserved.
To add to this the assumption that there is some unnecessary, unseen, unmeasured and alltogether undetectable effect at work is not scientific. It is also oddly akin to citing religious deities.
My denial of the existance of this mystery force is purely out of the healthy skepticism we need to have when discussing matters of a scientific nature. If you want this mystery force to be accounted for, you have to demonstrate that it actually exists; otherwise the natural scientific position would be that it does not.
Just so we're clear on this - the above observations don't in any way invalidate plate tectonics, nor validate expansionism. In fact, they have little to do with the validity of either hypothesis/theory.
I'm guessing, since you stated above, that the motion is relative to the Eurasian plate. The other reference often used, is the motion relative to satellites in a geosynchronous orbit.
Front/rear/side of what exactly? The location of the subduction zone isn't clear from the diagram you've posted, and in any case we're probably looking at an obduction prism. You may find it more useful to use seismic surveys and the history of earthquakes in the region to locate the subduction zone.
Again, the diagram doesn't show enough information to locate the subduction zone and seismic and gravitational profiles would be more useful for this purpose.
But since you bring it up, and as I'm not actually familiar with this example, I'm guessing that we're either looking at an obduction prism again, or an extinct plate boundary?
It's worth remembering that plate movement changes over geological time.
Lastly, case studies where the geological history of an area is unclear are very common in every field of geology. If complicated examples were enough to cause us to question the theories we have, we would have a complete overhaul of every field in science every couple of weeks.
Instead of citing examples where the tesctonic history of the area is ambiguous, why don't you look at cases where it's straightforward?
Here is your mistake. It is not assumed that earth is growing. The growth of Earth is implied by both sea-floor spreading and the absence of significant recycling. Then follow the secondary implication that the growth in size is fuelled by a growth in mass.
So the growth in mass is not an assumption at all. It is an implication derived from the observations. And this growth in mass implies that a physical mechanism must exist to explain it. Obviously, this unknown mechanism must be in agreement with the known laws of physics.
So again, nothing is assumed it is just chained implications.
Of course, if recycling is not negligible, then the logical chain breaks. That is why I insist on the demonstration that recycling is truly negligible. So could we please progress in this direction?
Yes, but is it limited to the eurasian lithosphere? what about the african lithosphere?
Oh, ok. I assumed that you knew the area and the location of the subduction zone. I post this second figure of the region for clarifications. The subduction zone is highlighted by the orange dashed line extending from the south of cyprus to the peloponnese.
Ok. The sandwich islands form a volcanic arc, and the subduction zone is located just east of the arc.
On the contrary. These are very active regions (not boundaries) as highlighted by GPS measurements, high seismicity and the young age of the seafloor (for scotia). There is a prism, but this is secondary.
Funny remark. I use these examples because they are straightforwardInstead of citing examples where the tesctonic history of the area is ambiguous, why don't you look at cases where it's straightforward?
The fact remains that somewhere along the lines, you have made a groundless assumption. Whether this is with the recycling of the lithosphere of the increase in mass, is irrelevant. In either case, you have to assume that there is some unexplained effect taking place, which you cannot demonstrate, measure or observe.
Therefore, there is no scientific value to the hypothesis.
Presumably, yes. But there is no known mechanism, nor any need for one. The data doesn't even come close to excluding all other possibilities, so there is no need to invent an effect.
Absolutely.
Can I ask exactly what the relevance of these case studies is? I'm not getting your point...
First, the fact is that we can really observe and measure the growth for Earth.
Second, you're wrong again. I insist that there is actually no assumptions. Only observations and their implications. I suppose that you understand the difference between an assumption and an implication?
Now, Frankly, why would I spend my time on a theory that would be based on just an assumption? And why do you focus on an hypothetical physical mechanism if you've not yet examine the observations that lead to the conclusion that Earth is in fact growing. It does not make any sense. First look at the evidence, then look at the implications, not the other way around.
I mean, that is science 101, and the specular aspect of the theory should not divert people from rigorous objective scientific reasoning.
The aim is to demonstrate that recycling is negligible and that the concept of plate is irrelevant. The concept of mantle flow is much more relevant for every active region.
Show me a study then?
I fail to agree. You have yet to demonstrate that subduction does not occur. You showed me two cases where plates are converging and are not producing large uplifted areas, and where there is intermediate volcanism in an arc along adjacent to where the plates appear to meet. This is all consisten with plate tectonics.
Here is a gravity profile of the hellenic arc and trench:
Here is a plot of seismic activity in the region (admittedly not the best example I've ever seen):
Also worth mentioning is the Troodos Ophiolite Complex on Cyprus - I am curious as to how you believe ophiolites form? Actually come to think about it, I am curious as to what you think drives magmatic differentiation? What caused continental crust to form?
I did plan to say quite a lot more... But it's 3:23 am, my thoughts are all over the place, and I'm going to bed.
Just a few posts above I wrote:
So why do you ask it again?
Are you familiar with the rubber duck effect? If not, then let me explain you what it is. You can try to push down a rubber duck in your water bath as long as you want, it will always pop back up. It looks like the same thing happens with your questions. I can answer them as many time as possible, but you will always come back again with the very same questions. This is the kind of rhetoric that pseudoscientists like creationists often use.
At this point, I assume that you're not a pseudoscientist, so please avoid the repetition of questions that were already answered or I will call you creationist-like sooner than later
Non sense, subduction does occur. I repeat again what I wrote in the other thread. The discussion is not about the existence of subduction, the question is about the amount of lithosphere that get recycled in the subduction process.
And why would you consider that this is not consistent with the expanding earth theory? You apparently misunderstand most of the concepts related the expanding earth theory. But you're not alone. So, back to the point to fix this.
Beautiful profile. Now please discuss the location of the region showed in the profile relatively to the lithosphere in motion as shown in the GPS figure. Is the continental lithosphere active or passive? Is the oceanic lithosphere active or passive? In short, is the continental lithosphere running over the oceanic lithosphere?Here is a gravity profile of the hellenic arc and trench:
Indeed, not the best example. And we loose too much information by representing these regions in 2D. I prefer 3D representations. See for example this 3D representation for the whole mediterranean basin.
By uplift and overthrusting. How else?
There are many possible mechanisms, various amount of partial melting, crystal fractionation... I fail to see see the link between this question and the current discussion.
Continental crust forms when mantle meets water-rich lithosphere. For example when a slab got buried by a mantle wedge, and releases its water content in the wedge. That's the only relation I find with the current discussion.
Please, don't try to divert the discussion again. You're more slippery than a fish.
I need to take exception to these remarks.
I am not evading a discussion of mantle flow. I am at a loss to see what its relevance is to demonstrating your argument. However, all you asked me was, essentially, am I familiar with the concept of mantle flow. The answer to that is a definitive yes.
Now ask what you will, or make what ever points you wish. Be aware of this however: your questions and presentations are so obtuse that it is difficult to know exactly what you are asking or saying. That means I have to revisit your posts several times before constructing a response that hopes to hit the mark.
Excellent. Then I'll be glad if you join the discussion.
I understand that my questions might appear obtuse because I know where I'm going while you don't. That's actually quite common when two people discuss the same observation using a different paradigm. But once you get hit by "eureka", everything becomes crystal clear. It happened to me, there is no reason that it won't happen to you.
The point to discuss is that in the plate tectonics theory, every piece of the lithosphere is considered as being a plate or a part of a plate. Accordingly, the aegean sea region is classically described as a microplate. But my point is that the concept of mantle/crustal flow is much more appropriate to describe what's going on in this region. That's especially striking from the GPS data. The same remark applies for the scotia sea.
Do you agree that the concept of plate should be abandoned for this region in favor to mantle/crustal flow? Your agreement is a very important initial step to understand the implications.
Note that the recent literature is going toward this direction (not there yet but closing). As an example, I could cite two recent papers: Bai et al (2010) Nature Geoscience 3; 358-362 and Facenna and Becker (2010) Nature 465, 602-605.
I'll respond to the rest later, but this has to be addressed now. I've run across Becker's work in a literature search. I find his work supports the conventional position, not yours. If the gap is closing it may only be because your eyes are enlarging from shock.
Of course his work supports the conventional position! And this last paper does so as well in many aspects. What did you expect? But he introduces new concepts that will lead to the expanding earth theory. But you won't understand why before you get familiar with some concepts belonging to the expanding earth
And there was me expecting you to explain some relevant information in terms of isostatic equilibrium :P
Oh, fair enough. Most of the rest of my post was aimed at demonstrating subduction lol
It may very well be. But it all comes back to the fact that Expanding Earth Theory relies on the assumption that the lithosphere is not recycled (or negligibly). In the absence of a feasible mechanism for the expansion to occur by, and considering the first law of thermodynamics, and considering the observed plate movement and the geophysical profiles of subducting slabs, it is far, far more sensible to accept that recycling does occur.
Actually I do apologise for my sleep-deprived rant. I thought you were completely denying that lithosphere is subducted, which apparantly you weren't :PPlease, don't try to divert the discussion again. You're more slippery than a fish.
Interesting fact: during the recent "Mega-quake" in Japan, the Pacific Plate was thrusted up to 60m underneath the Eurasian plate in the areas where maximum slip occurred, as recorded by GPS measurements.
Hey, why not. And actually, it will be very relevant to this discussion.
The layman thinks intuitively that when there is a mantle upwelling, it should systematically results in the formation of a high topography region. But he forgets that the mantle is so dense that isostatic equilibrium is attained at a relatively low level, so that there is actually formation of an oceanic basin.
Now, the situation is much more interesting when the point of isostatic equilibrium is overshoot because the whole column of mantle is rising rapidly, pushed at the base by low density material. In this case, the upper part of the column will reach a higher elevation despite being denser than the surrounding area. This happens for salt diapirs as well. So what will happen to the upper part of the column? will it stay up there forever?
You make different errors with this statement. Negligible recycling is not an assumption, and the Expanding Earth Theory does not rely uniquely on this aspect. There are many different line of evidence that prove the growth. But I want to discuss the recycling aspect because it is particularly striking. Once understood that recycling is negligible, the expanding earth theory comes very naturally.
Did you look at the solution found at UCSB available here? The forearc moved up to 20 m over the Pacific lithosphere (Fig 5.2) with a vertical uplift up to 9 m just east of the hypocenter (Fig 5.1). Very impressive. So the forearc moved away from the arc, toward the Pacific and up. This is also very relevant to our discussion.
Just to be clear, are you denying the existence of subduction zones?
Once again, no. But I'm refuting the large scale recycling of lithosphere that is traditionally associated to them.
So you agree they exist, but you feel that they do not do a very good job of subducting.Once again, no. But I'm refuting the large scale recycling of lithosphere that is traditionally associated to them.
How do you explain the relatively young age of oceanic lithosphere at subduction zones?
Feel? what do feelings have to do with tectonics?
And the correct wording is "They do not do a very good job of recycling."
Oceanic lithosphere at subduction zones is of any age. Or you meant the lithosphere in the back arc? Please be more specific.
And please comment the figures posted above in this thread.
I used the word "feel" as a nice way to point out that it is your opinion, as opposed to hard fact.Feel? what do feelings have to do with tectonics?
And the correct wording is "They do not do a very good job of recycling."
I used the word subduction because it is less ambiguous than the word recycling -- it has a more clearly defined meaning in the context, and is more pertinent to a "discussion" on whole earth expansion. Actually I don't think subduction zones are fantastic at recycling -- recycling is a bad word to use. Certainly a lot of the material that is subducted goes deep into the mantle and probably never comes back up. In fact, there is good evidence that slabs pile up at the core mantle boundary.
It is the fact that material goes down (whether or not it gets recycled), which is the important factor in this discussion. Afterall, it is the fact that material goes down (at the same rate that it comes up) which prevents the Earth from expanding (or shrinking).
Let me rephrase the question as I realise it is more complicated than it need be.Oceanic lithosphere at subduction zones is of any age. Or you meant the lithosphere in the back arc? Please be more specific.
Why is oceanic lithosphere so much younger than continental lithosphere?
There is little or no oceanic lithosphere beyond the age of about 300 Ma, yet it is not hard to find continental lithosphere more than 10 times that age, so I hope we can agree that oceanic lithosphere is younger.
Surely in an expanding Earth, with negligible subduction, the oceanic lithosphere would be just as old the continental lithosphere?
Except that this is not an opinion because it is precisely based on hard facts. The facts that I'm presenting in this thread. So using the word "feel" is misleading. And I do not think that you used that word innocently. I'm afraid that such an attempt of misleading is incompatible with an objective and respectful discussion. So you were not so nice and in return, I may be not very nice either. You've been warned.
In plate tectonics, Subduction is all about recycling, because I remind you that the subducting slabs are the descending flows of a complex convective system. The amount of time necessary to achieve a full cycle is irrelevant to the discussion.
The question was not complicated. It was ill-formulated as your question was exactly: "How do you explain the relatively young age of oceanic lithosphere at subduction zones?"Let me rephrase the question as I realise it is more complicated than it need be.Oceanic lithosphere at subduction zones is of any age. Or you meant the lithosphere in the back arc? Please be more specific.
Yes the oceanic lithosphere is younger, because the oceanization of Earth is increasing in relation to the increase in the growth rate. As the formation of oceanic floor is just due to the exposure of mantle at the surface, it simply means that the mantle has been inflating so rapidly that it is now directly exposed at the surface where there is lithosphere extension and thinning. Something that was less common 250 millions years ago and before, because extension basins had the time to fill up with sediments.
Note that the amount of continental lithosphere has also been increasing in surface with time, but over billion years, not hundred millions like the oceanic lithosphere. All of this is consistent with a growth rate regularly increasing, with a first stage were continental crust formation was dominant because the inflation of the mantle was too slow to allow the mantle to be exposed at the surface, and a current stage in which the formation of oceanic lithosphere is dominant due to rapid mantle inflation.
Anyway. Discussing this does not make much sense as long as no agreement is obtained on the amount of recycling.
So could we focus on the recycling issue please? I thank you in advance.
The system will eventually reach equilibrium, why do you ask?
From what you've posted so far, I would say that it is.
True, there are a number of other assumptions based on this.
So far you've shown us that plates converge and subduct. You haven't specifically mentioned, but it can be seen from GPS measurements, that the plates around the world are converging at similar rates to which plates diverge at spreading ridges.
I still fail to see the appeal in assuming that subduction does not lead to significant lithospheric recycling.
Actually I just happened to be reading about it in an old issue of New Scientist...
You do realise that it is quite possible to base opinions on hard facts?
Not that your hard facts go any way whatsoever to back up your opinion.
I tremble in wait.You've been warned.
What is the style of mantle convection? Is it layered or whole mantle? Or is it some combination?In plate tectonics, Subduction is all about recycling, because I remind you that the subducting slabs are the descending flows of a complex convective system. The amount of time necessary to achieve a full cycle is irrelevant to the discussion.
The slabs that go down have been seismically imaged to penetrate through the transition zone into the lower mantle at some locations and not at others. At some locations it is imaged all the way down to the base of the mantle where it piles up.
How about the upwelling mantle? At the base of the mantle there are vast swaths of hotter denser material, so called "super plumes", from which plumes seem to rise from crests and ridges, pushing their way right up to the surface. Mantle upwellings related to smaller scale convection patterns in the upper mantle push up material in a state of "dynamic topography". While natural buoyant upwelling of material in other regions seems to be responsible for creation of new ocean crust in other places without the need for plumes.
It is by no means obvious that subducted slab material is efficiently recycled in this system. In fact, at the core mantle boundary we see evidence to the contrary.
So extension should be by far the dominant tectonic regime on Earth. This should be seen in the geolocigal record as an abundance of normal faults. We can check it by looking at the world stress map.Yes the oceanic lithosphere is younger, because the oceanization of Earth is increasing in relation to the increase in the growth rate. As the formation of oceanic floor is just due to the exposure of mantle at the surface, it simply means that the mantle has been inflating so rapidly that it is now directly exposed at the surface where there is lithosphere extension and thinning. Something that was less common 250 millions years ago and before, because extension basins had the time to fill up with sediments.
Normal Faulting is in red. This map is not overly dominated by red. So your theory has failed. Sorry, but that's science.
I'm not convinced the recylcing issue is at all relevant to the debate.So could we focus on the recycling issue please? I thank you in advance.
Indeed, it will reach equilibrium, by gravity spreading/gliding. If the whole column is not in isostatic equilibrium, it will continue to rise and the top will continuously spread away from the uplift center thus forming a flow. Let's call it a tectonic flow. As the front of this tectonic flow runs over lithosphere, the latter flexes down and get progressively buried in the mantle, thus forming a Benioff zone. When the tectonic flow is channeled, its sides are delimited by transform faults.The system will eventually reach equilibrium, why do you ask?
Now look back at the figure posted earlier representing GPS measurements in the eastern mediterranean basin:
It is a perfect illustration of what tectonic flows are. In this case, the center of uplift is located in eastern Turkey because GPS vectors in eastern Turkey are significantly shorter than in anatolia, thus implying extension. The North anatolian fault, a megatransform fault, delimits the northern margin of the tectonic flow.
The Benioff zone along the peloponnese and Crete (hellenic trench) marks the front of the tectonic flow.
Africa, the mediterranean sea and Europe constitute a stable platform. Indeed, the vectors of displacements are null or close to null, from the balkan region north of the N. anatolian fault, to Italy, to Libya and to Egypt.
So this tectonic flow is currently running toward Africa and at the current rate (about 4 cm/year) it will reach the margin of Africa 200 km to the south in about 5 millions years. Then one can expect the formation of a beautiful mobile belt.
How much mediterranean seafloor will be recycled in the process? Just the 200 km separating Crete from Libya.
How much Mediterranean "tethyan" seafloor got recycled under this flow up to now? Logically not more than the region between the uplift center and Crete and probably not more that the area corresponding to the aegean sea. So not very much.
If you understand all of this, then you will have made a very important step to understand the growing earth theory.
I'm sorry, what?
The flow path.I'm sorry, what?
No, you're missing my point. How can you determine how much lithosphere has been recycled in this case, unless you base your estimate off past plate motion (i.e. by assuming a plate tectonics context), and extrapolate the original extent of the subducting plate?
I don't see where you're getting your estimate from.
What point can you make by writing something as vague as:"I'm sorry, what?"
The estimate is based on the extrapolation back in time of the current displacement of the tectonic flow among the stable lithosphere region. The concept of plate is useless here.How can you determine how much lithosphere has been recycled in this case, unless you base your estimate off past plate motion (i.e. by assuming a plate tectonics context), and extrapolate the original extent of the subducting plate?
And how do you estimate the current displacement without a) Assuming no tectonic plate setting or b) Assuming no recycling of material?
The concept of microplate is replaced by the concept of tectonic flow: the lithosphere does not move as a plate, but flows. A good analogy would be a glacier. So the current displacement is estimated by comparing the displacement of GPS monuments located on the flow to that of monuments located around the flow, as illustrated by the figure above showing measurements in the oriental mediterranean basin.
The amount of recycled lithosphere is simply the surface of lithosphere that was on the tectonic flow path. Note that it can't be larger than the size of the flow itself, hence the limited consumption/recycling of lithosphere.
Ok... I'm not sure we're on the same lines here. Lithosphere is recycled into the asthenosphere at subduction zones, not just into the surrounding lithosphere. Where lithosphere has broken off and sunk into the asthenosphere and lower portions of the mantle, surface measurements are useless at determining the amount of lithosphere that has been subducted/recycled. And we can see this happening from seismic surveying.
So I'm not really sure what you're talking about...
Well, you're right, we're not on the same lines. You miss the point. So I made a figure to help you understand how it works:
According to the plate tectonics scenario, the slab of lithosphere gets denser than the upper mantle by eclogitization, and it sinks, dragging the lithosphere to which it is attached into the mantle in a manner similar to a tablecloth sliding off a table entrained by its own weight. So, as the lithosphere is dragged by the slab the distance between a and b decreases. A return flow induces extension in the back arc so that the distance between b and c increases. But extension in the back arc is not correlated to the lithosphere displacement toward the trench, and overall, the distance between a and c decreases. So there is a net decrease in surface and lithosphere consumption.
According to the flow tectonics scenario, a mantle upwelling spreads at the surface. As the flow progresses (to the left), it overruns the lithosphere on its path, burying it in the mantle. So the arc (b) and the trench move toward a but this displacement is correlated to the spreading flow and the back-arc extension, and thus the distance between b and c increases of at least the same amount than the distance between a and b decreases. So in net, there is no lithosphere consumption or even lithosphere creation.
The later scenario is what is observed in the case of the oriental mediterranean basin: a tectonic flow spreading in the middle of fixed lithosphere, without any net decrease in surface.
This behaviour has been broadly modelled in the context of plate tectonics without the need to invoke an expanding earth. It's called slab rollback.
According to the plate tectonics scenario, the slab of lithosphere gets denser than the upper mantle by eclogitization, and it sinks, dragging the lithosphere to which it is attached into the mantle in a manner similar to a tablecloth sliding off a table entrained by its own weight. So, as the lithosphere is dragged by the slab the distance between a and b decreases. A return flow induces extension in the back arc so that the distance between b and c increases. But extension in the back arc is not correlated to the lithosphere displacement toward the trench, and overall, the distance between a and c decreases. So there is a net decrease in surface and lithosphere consumption.
According to the flow tectonics scenario, a mantle upwelling spreads at the surface. As the flow progresses (to the left), it overruns the lithosphere on its path, burying it in the mantle. So the arc (b) and the trench move toward a but this displacement is correlated to the spreading flow and the back-arc extension, and thus the distance between b and c increases of at least the same amount than the distance between a and b decreases. So in net, there is no lithosphere consumption or even lithosphere creation.
The later scenario is what is observed in the case of the oriental mediterranean basin: a tectonic flow spreading in the middle of fixed lithosphere, without any net decrease in surface.
See for example this video at 1:50. http://jupiter.ethz.ch/~pjt/GFD_Video_768.mov
I note you didn't have an answer to the global stress project. It's a shame when real data blows your model, huh?
Nope. This is not strictly equivalent to a slab rollback. A slab rollback is driven by the sinking slab. Here, the driving force is the mantle upwelling. And mantle upwelling are driven by the inner growth.
Because your starting hypothesis that extension stress should be dominant is simply naive and wrong. This would be true if it was a simple expansion in volume at constant mass, but not in this case, with an accumulation of material inside, material that is expelled toward the surface. As already written, when material reaches the surface but overshoot the point of isostatic equilibrium. It spreads. And spreading leads to compression at the front of the spreading material.
Oh right I apologise sincerely. You see I thought we were talking about geophysics here, and thus we had to keep the discussion within the bounds of known physics.Nope. This is not strictly equivalent to a slab rollback. A slab rollback is driven by the sinking slab. Here, the driving force is the mantle upwelling. And mantle upwelling are driven by the inner growth.
Because your starting hypothesis that extension stress should be dominant is simply naive and wrong. This would be true if it was a simple expansion in volume at constant mass, but not in this case, with an accumulation of material inside, material that is expelled toward the surface. As already written, when material reaches the surface but overshoot the point of isostatic equilibrium. It spreads. And spreading leads to compression at the front of the spreading material.
But now I realise that we are talking about a world that doesn't abide by the laws of physics. I mean, why not have a world that grows in mass? Sure it breaks a few fundamental principles, but, hell, we can use it to make up weird theories about the Earth.
That's so cool.
:wink:
Science is about making discoveries that extend our knowledge. What is unknown today will be familiar tomorrow.
And yes, That's so cool.
The model may break down across an individual plate margin, indeed, because each plate margin is part of a complex system of plate boundaries, not an localised occurrance. Try looking at the net effect worldwide, rather than across a single subduction zone?
Should I understand that you agree on the lack of surface consumption in the eastern mediterranean basin?
I agree that this region may appear very complicated from a plate tectonics point of view. But from a flow tectonics point of you, it is not so complicated, because it appears as being simply shaped by flows of different age and spreading directions. The new game becomes what flow was active at what time, and what print it left that is still visible, i.e., not overprinted by more recent flows. That alone demonstrates the power of the model.
If your answer to the question above is yes, then we can move to another region.
I'm willing to accept that the back arc may be diverging at a greater rate than the plate is subducting at this location, yes.Should I understand that you agree on the lack of surface consumption in the eastern mediterranean basin?
You simplify a single example by creating a model that ignores the rest of the system. This does not mean the whole system is as simple as your model suggests.
No, not another single example viewed only in the context of itself. The whole planet: if your model is correct then we would expect to see divergence occurring at a greater rate worldwide than convergence; we do not see this therefore your model is flawed.
A prediction cannot said to be correct if it is only correct in certain cases.
Your terminology is not very well adapted here, but as long as you accept that the mediterranean seafloor, africa and europe are all passive and nothing is moving except what makes the flow, that'll be good enough.
What does the model ignore? What simplification was made? It's quite weird that you judge a model based on 3 dimensional flows, and very dynamic in nature, as a simplification compared to a model based on 2 dimensional rigid plates rotating around Euler poles.
One last remark regarding the mediterranean region. As a reminder, the western mediterranean basin is quiet at this time, but underwent massive extension for the last 30 millions years. In the eastern basin, we just saw that Europe and Africa are currently stable relatively to each other with just a tectonic flow running from Turkey to Africa. And we also know that there is current extension in the red sea at the north east of Africa. Overall, there is no convergence between Africa and Eurasia.
It is much better to follow a step by step demonstration. So let's proceed with 2 other regions.
On the left, we see an intrusion of the Pacific mantle into the Atlantic. It is very similar to the aegean flow, except it is undersea. And the only lithosphere that disappeared, is that found on the flow path. A negligible amount at the planet scale.
Do you agree?
On the right, the philippine sea cannot be easily explained using plate tectonics but it is very simple to understand with flow tectonics. It is a region where multiple mantle extrusions occurred, spreading in different directions, the younger overprinting the older. And what amount of lithosphere disappeared due to these extrusions? Not much, just the western part of the old pacific lithosphere that is less than 150 millions years. The older lithosphere up to 175 millions years is untouched at this time.
Here again, the amount of older lithosphere that got destroyed by the intrusions is very limited at the planet scale.
Do you agree?
Not accepted. Demonstrably not the case, in fact, by satellite measurement. The seafloor, Africa and Europe are in fact all in motion.
It falsely assumes a closed system around the plate margin.
It would be much better demonstrated by applying your hypothesis to the observed motions of all of the Earth's lithospheric plates, and creating a model to see whether either one of convergence or divergence is dominant worldwide.
Showing me that in certain cases, nearby extension is occurring more rapidly than subduction is irrelevant, because plate tectonics is not divided into seperate, closed systems of subduction zones and back arcs.
Hmm, If you're stuck here, then we must solve this before generalising to other regions.
The seafloor Africa and Europe are in motion at the surface of the globe if they are not used as the referential. But, according to the geodetic measurements shown above (GPS), the european lithosphere, apulian lithosphere, mediterranean seafloor and northern Africa lithosphere are in fact not in motion relatively to each other. So all this lithosphere must be considered as a unique entity from a geodynamic point of view. There is a single feature in the move relatively to this entity, and it is the anatolian tectonic flow.
Do you agree with this, including the terminology?
Which plate margin? Anatolia is not a plate but a tectonic flow, Apulia, Europe and Africa are immobile pieces of lithosphere relatively to each others. So which plate margin?
Agreed. The Arabian plate, however, is moving Northwards relative to the African and Eurasian plates, and is considered the main cause of the Westward motion of the Anatolian plate.
No. "Tectonic flow" is a piece of terminology you have seemingly invented (and therefore has a definition unknown to me), and the accepted view is that the Anatolian plate is indeed a plate.
But hey, assuming all the surrounding plates are motionless relative to each other: what does this prove? If this were the case, this shows only that the Anatolian plate (or "tectonic flow") is being subducted at the same rate that it is being formed. So where exactly were you going with this?
Call Anatolia whatever the hell you want. Your previous posts appear to assume that the whole of Anatolia (including the subduction zone beneath the African plate) act completely independantly of the rest of the planet.
Your argument is becoming increasingly ambiguous. What exactly are you trying to demonstrate here?
Is considered, but there is actually a transverse fault separating arabia and anatolia (east anatolian fault in post 86). This fault is in the continuity of the Jordan rift and the Red Sea MOR and will likely evolve to a rift in the future.
Tectonic flow=crustal/mantle flow. Anatolia does not behave as a rigid plate of lithosphere, it is flowing lithosphere.
Tectonic flows are not subducted. They subduct the lithosphere they meet on their path.
Let's try a very childish analogy for clarification.
If you pour a lot of ketchup on a kitchen table, then the ketchup will spread on the table. And obviously the table is not "subducting" under the ketchup, the table is passive, and the ketchup is active.
This is strictly equivalent with the situation in the eastern mediterranean basin. The mediterranean seafloor (table) is not subducting under the anatolian flow (ketchup). But the anatolian flow is spreading over the mediterranean seafloor.
Now, if ketchup is spreading over a table, does that reduce the surface of the system table+ketchup? of course not! (actually the surface is strictly increased compared to the flat table)
Similarly, when the anatolian flow spreads over the mediterranean seafloor, there is no decrease in the surface of the system anatolian flow+mediterranean seafloor.
Hopefully, you will get it now, because I'm afraid that I can't explain better than that at this time.
Ohhhh, that's what you were trying to say... Also, sorry, I said the Anatolian plate is being subducted, I meant that the African plate is being subducted under it.
The Anatolian Plate is acting as a rigid block of lithosphere, being pushed Westwards by the Arabian plate to the East due to its Northwards movement. Where it meets the African Plate, the denser African lithosphere is subducted underneath it. The only volcanism associated with the plate's movement is at the Hellenic and Cyprus arcs; there is no divergent boundary/mantle upwelling. All of this is consistent with Plate Tectonics. Where exactly is the problem?
This neatly encapsulates my problem with florian's arguments. I have been reading extensively on this topic over the last two weeks and despite putting on my Devil's Advocate pajamas I just cannot get any of the research to provide support for expansion rather than conventional tectonics.You simplify a single example by creating a model that ignores the rest of the system. This does not mean the whole system is as simple as your model suggests.
No, not another single example viewed only in the context of itself. The whole planet: if your model is correct then we would expect to see divergence occurring at a greater rate worldwide than convergence; we do not see this therefore your model is flawed.
A prediction cannot said to be correct if it is only correct in certain cases.
In detail plate tectonics is complex. That, for me, explains all of the anomalies florian claims exist. I simply fail to see where the problem is. Now may be that's because I'm not too bright, or maybe it's because there is no problem.
False dichotomy, no? Those two are not mutually exclusive (despite the fact that I clearly lean toward the latter as the more accurate description of the situation here).
Great, so now we need to rewrite fluid physics as well as thermodynamics.
('Because of their low temperature, rocks in the lithosphere do not significantly deform on time scales of up to 10^9 years.' Geodynamics, Turcotte and Schubert)
This gets better and better
The African lithosphere is not moving as a block to the North to meet the aegean sea. Therefore it is not subducting. But it is subducted by the aegean flow. It is about what is active and passive.
False. The GPS vectors change progressively of magnitude and direction from east to west. This is not what is expected from a rigid block.
False. Arabia is parting from Africa and GPS vectors are shorter in eastern turkey along the east anatolian fault compared to western turkey, which implies that there is extension between both region and not compression.
Yes, the mediterranean seafloor is subducted (passive), not subducting (active).
This is the expected type of volcanism when mantle flow overun old lithosphere, so what?
This conclusion denies all the observations.
I think that the problem is that you're using a paradigm that does not fit the observations, but still feels it is "OK". For your defence, it's quite usual when there is a paradigm shift (read Kuhn, the structure of scientific revolutions). I mean, I'm talking about "oxygen" and you're talking about "phlogiston"...
Indeed. I suggest you to read the literature on crustal flows, because obviously, you've never heard of it and so do not know what I'm talking about.[
Great, so now we need to rewrite fluid physics as well as thermodynamics.
('Because of their low temperature, rocks in the lithosphere do not significantly deform on time scales of up to 10^9 years.' Geodynamics, Turcotte and Schubert)
This gets better and better
Seriously, where have you been for the last fifteen years?
Citation please. FYI, that's not the same as an opinion.
we've been over this before. The frigging plates are not rigid. Over the long term, in many circumstances they can be conveniently thought of as rigid, but in the short term and the absolute, they are not. They are friggin compressible and extensible. Do you deny this? I doubt anyone currently engaged in plate tectonic research would deny it.False. The GPS vectors change progressively of magnitude and direction from east to west. This is not what is expected from a rigid block."...
Wordplay.
Citations please.This conclusion denies all the observations."...
1st: Amazing that you cannot analyse by yourself such a simple figure as that showing GPS-measured motions in the eastern mediterranean, which interpretation is straightforward.
2nd: "Subduction occurs because the upper plate (Greece) is overriding the lower plate Africa faster."
Doglioni, C., Carminati, E., Cuffaro, M., and Scrocca, D. (2007). Subduction kinematics and dynamic constraints. Earth-Science Reviews 83, 125-175.
Yes we've been other this before. The plates need to be rigid blocks or not rigid depending on the context and this is a major issue in plate tectonics because it renders the theory totally unfalsifiable and thus not scientific. You can't have it both ways claiming that the anatolian plate is rigid so that it is moving as block pushed by arabia (drowsy turtle's claim, demonstrably wrong) and claiming that it is not rigid, to fit the GPS data, but still support the plate tectonics principle (your schizophrenic claim).we've been over this before. The frigging plates are not rigid. Over the long term, in many circumstances they can be conveniently thought of as rigid, but in the short term and the absolute, they are not.False. The GPS vectors change progressively of magnitude and direction from east to west. This is not what is expected from a rigid block."...
These conflicting assumptions are a clear hint that the model is inappropriate.
This is exactly the same kind of issue that Gill Foulger describes for deep mantle plumes in his "Plates vs. Plumes: A Geological Controversy" (a must read IMHO). She argues convincingly that plumes are not falsifiable, but interestingly, she does not connect the dots regarding the same issues that plagues the current state of plate tectonics.
Here, a much better model, in agreement with all the data, is that the lithosphere of Anatolia and the Aegean sea is carried by a mantle flow, which translates into brittle flow of the upper crust (aka crustal flow), and overthrusting at the front of the flow (aka Benioff zone).
I think that you persist in denying this improved model simply because its implications render plate tectonics obsolete. A kind of natural defence.
I assume to be a cold-hearted scientist for that matter. When a model is not in agreement with data, I trash it without any regret. On the contrary, your attachment to plate tectonics is rather irrational. It was just a nice scenario after all, but at some point, you have to let it go. :wink:
It doesn't matter what is active and passive, and what is moving relative to what. The African plate is being subducted, as shown by the trace of the benioff zone and the associated anomalies.
Actually, it is, or what we expect from what we consider rigid blocks in geology. Plastic deformation is surprisingly common in solid, rigid rocks over long time periods. This is how folding occurs. It's also worth considering faults in the plate interior (not sure how relevant they are, could probably look it up for this case study).
Irrelecant to what I said.False. Arabia is parting from Africa
GPS vectors represent a snapshot in geological time. Major slips occurring in the West can easily have skewed these figures; the "extension" is more likely the release of built up stress.
Irrelevant play on words. The mediterranean seafloor lithosphere is forced downwards into the asthenosphere due to plate convergence.
So, even if no lithosphere is being recycled into the rest of the mantle, no new lithosphere is being formed, making this example non-sequitur with regards to your original hypothesis.
It does not. There is no obvious mantle plume-type volcanism, there is no plate divergence, there is no lithosphere being produced. All the boundaries involved are convergent or transform.This conclusion denies all the observations.
You're yet to raise an actual issue with plate tectonics, and you're yet to offer evidence that suggests the EArth is expanding. I would say I'm successfully using a paradigm, that does fit the evidence... And I'm pretty sure everyone else who's following this thread would agree with me.
The irony is, the book you're referencing makes a very convincing case for explaining intraplate volcanism in terms of plate tectonics.
I've read some of her book, and been to some of her lectures here in Durham. None of her work that I'm aware of leads to the conclusion that plate tectonics does not accurately explain the observed evidence; quite the reverse - she quite clearly states that the evidence can be better explained by plate tectonics (specifically intraplate tension and stress) than by mantle plumes.
Except that you have no spreading centre for new lithosphere to form, and this convergence/overthrusting has not lead to large regions of high elevation away from the centre of convergence that would be expected. Instead, it has clearly lead to the African plate being pushed down into the mantle, as predicted by plate tectonics.
I fail to see what about this example would lead you to believe the Earth is increasing in diameter and mass.
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