Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum What are the main problems with plate tectonics?

Here are some questions concerning the formation of the Earth;

Today, the continental crust covers only 35% of the globe.

1) When did the continental crust come into being?
2) How did the continental crust come into being?
3) How much of the Earth did it originally cover?
4) If it originally covered the entire Earth, where did 65% of it go?
5) If it didn't originally cover the entire Earth, how did it grow to 35%?

Note that, according to plate-tectonics believers, continental crust cannot be subducted as it is the lightest. So, once continental crust is created it is almost impossible to destroy by plate-tectonics.

Apparently, plate-tectonics has no answers for the above questions.

Another question regarding plate-tectonics;

The single continent Pangaea covered 35% of the surface of the Earth.

Ocean covered the remaining 65%.

Pangaea is more than 300 million years old.

Therefore, the Pangaean era oceanic crust, if any were still to exist, would be more than 300 million years old.

Geologists claim that none of todays oceanic crust is older than 200 million years, therefore, none of it is Pangaean era oceanic crust.

Summarizing;

1) Pangaean era oceanic crust comprised 65% of Earth's surface area.
2) Pangaean era oceanic crust would be more than 300 million years old.
3) Todays oceanic crust is less than 200 million years old.
4) There is no Pangaean era oceanic crust left today.

So, where did all that 300 million year old oceanic crust, go?

Where did 65% of the Earth's entire surface vanish to?

Yeah, geologists must say that 65% of the Earth's entire surface has been subducted.

How easy is it to believe that 65% of the Earth's entire surface has been subducted?

The above is a slight update on comments I posted at

http://geology.about.com/b/2010/08/13/the-expanding-earth-illusion.htm

If you wish, you can also discuss this at my forum:

http://www.preearth.net/phpBB3/search.php?search_id=newposts

Continental crust has been forming, and re-forming ever since magmatic differentiation became possible.



Continental crust formed through partial melting of basic material, and magmatic differentiation.



What do you mean by “originally”?



Why would you think it might have covered the entire Earth?



Answered in (1) above.



There is good evidence that some subduction of continental crustal material takes place, along with oceanic crust. E.g. in some types of andesitic formation.




Perhaps answers have to be sought with a degree of impartiality.




Accepted.




Oceanic crust is constantly being re-cycled.





Perhaps geologists have less of a problem with this than with some other suggested scenarios. Given the processes and vast expanse of time involved, it seems quite reasonable.
However, if your philosophical/theological beliefs preclude that length of time, it might be important to find some other explanation.

Hey preearth,

You wrote:

"Geologists claim that none of todays oceanic crust is older than 200 million years, therefore, none of it is Pangaean era oceanic crust."

Not so. Pangea was here less than 200mya. It broke apart in fits and starts throughout the Mesozoic so it's a subjective view about when Pangea "ended."

Here's an illustration of Pangea from around 200mya:

http://www.scotese.com/jurassic.htm

Laze

Bill S. said; "Continental crust has been forming, and re-forming ever since magmatic differentiation became possible."

What is "magmatic differentiation?"

It is the melting and re-solidification of magma (silicate rock).

When the magma melts and re-solidifies, lighter components of the melt precipitate out at the top of the melt, and heavier components precipitate out lower.

When did magmatic differentiation became possible?

Magmatic differentiation first became possible when the original, molten Earth, cooled.

The lighter components of the melt precipitated out near the surface, as "continental crust."

The heavier components of the melt precipitated out lower, as the "mantle."

So, if magmatic differentiation works at all, it would have initially produced a thin layer of light material, i.e., continental crust, across the whole surface of the Earth. Note, continental crust would have originally covered 100% of the surface of the Earth.

So, how come continental crust only covers 35% of the Earth's surface, today?

Magmatic differentiation does not explain how the oceanic crust came into being.

In particular, it does not explain why there is no lighter continental crust covering the heavier, oceanic crust.

The only theory that gives a satisfactory answer to these questions is that of planet collision, as in;

http://preearth.net/evidence.html

You may find fault with other parts of the Mansfield's planet collision theory, but it satisfactorily answers all of the questions I asked above.

And Laze is wrong, geologists do claim that none of todays oceanic crust is older than 200 million years. I have personally asked many geologists about this.

Laze said; "so it's a subjective view about when Pangea ended."

It does not matter when Pangea ended. Take, e.g., 201 million years as the point of reference.

All ocean sea-floor existing at that time is 201 million years old, or older.

All of todays ocean sea-floor is less than 200 million years old.

Therefore, none of the ocean sea-floor existing 201 million years ago, about 65% of the entire Earth's surface, currently exists. It has all disappeared.

Supposedly, it has all been subducted.

Of course, since magma is molten silicate rock, it would have made more sense to say;

"It is the melting and re-solidification of silicate rock.

When silicate rock melts and re-solidifies, lighter components of the melt precipitate out at the top of the melt, and heavier components precipitate out lower."

Also, later, it would have been better to say;

"It does not matter exactly when Pangea ended."

This would be true if you assumed that the entire surface of the Earth was molten at the same time, and that it remained still while cooling. Next time you make a rice pudding, try stirring continually while it is cooling and see if you get an even covering of skin.



This is true only if the process is slow and undisturbed.



This is true only if you chose to ignore all other theories and close your mind to the real problems of planet collision, but these have been fairly well covered elsewhere, so there seems little point in raking over cold ashes.

Hey preearth,
You wrote:

"And Laze is wrong, geologists do claim that none of todays oceanic crust is older than 200 million years. I have personally asked many geologists about this."

You have to go back and reread your and my statements. Nowhere did I state that today's oceanic crust is older than 200my. To me more precise, all of the the oceanic crust that is in the ocean today is less than 200my old. Of course,the oceanic crust that is over 200my old that has not been subducted (i.e.,some ophiolites) are still here.

What I stated you were wrong about is the following statement you made:

"Geologists claim that none of todays oceanic crust is older than 200 million years, THEREFORE, NONE OF IT IS PANGEAN ERA OCEANIC CRUST."

Laze

Preearth, would I be right in thinking that your statements: "The single continent Pangaea covered 35% of the surface of the Earth." and, "Today, the continental crust covers only 35% of the globe" imply a belief that there was the same volume of continental crust present at both times? If so, you would need some evidence about the average thickness at both times.

Yes, that is what is usually assumed. For example, this is always assumed in modelling the hypothesized Theia collision.

Although, since geologists presently have no real theory for the development of continental crust, a number of different proposals (some contradictory) are current.


No. The molten globe can be as (self)-mixed as you want.


I understand that you have a limited background in science, but you should really think about what you read.

Your analogy is extremely poor.

One major problem is that you have a solid-liquid mixture that is essentially of one density which has no propensity to separate out in layers at all (this is very different from the Earth).

Another major problem is that the crust comes from dehydration caused by it being heated for a long period (this is very different from the Earth).

A better analogy would be a mixture of oil, water and mercury solidifying (freezing),... you can stir it as much as you like. At least, these elements have different densities and do have a propensity to separate into layers (somewhat more like the Earth).


I doubt you have any idea what the real problems of planet collision actually are and your mind is certainly closed to the real problems of mantle currents. The truth is that mantle currents are a figment of scientists imagination and in the course of time will be proved to be exactly that.

Over the years, quite a number of well qualified geologists have already stated that mantle currents are just so much trash.


If you are talking about the Geeks dribble, it is so full of holes and wrong-headed ideas (and even lies) that only a religious person (like yourself, your religion being the standard version of whatever you are told, by whatever authority (god)) could come close to the words,... "fairly well covered."


No.

Pretty much every one of the Geek's comments in:

http://www.scienceagogo.com/forum/ubbthreads.php?ubb=showflat&Number=35758#35758

(the 2nd post #35758) is wrong. After weeks of argument with the Geek, something akin to bashing one's head against a wall, just to prove his first claim wrong, his line 3, I decided I couldn't be bothered any more.

However, after claiming above that his reply was completely full of holes and wrong-headed ideas (and even lies), I figured I should once again take up the task of pointing out his errors.

We move on to his lines 5 & 6.


This is another example of the Geeks misleading replies

In fact, there is no smiley that can express my derision at the unscientific nature of the Geek's reply.

POINT ONE; Even though the Geek ignores it, the velocity of the projectile is important. For example, a bullet travelling near the speed of light would split the apple into subatomic particles. The Geek shows you what a high velocity bullet does to an apple.

Here, is a video of a slightly slower bullet hitting an apple;

http://www.youtube.com/watch?v=zV4X_O_Rrrs

where most of the skin is unscathed (i.e., still recognizable as skin and, in this case, the unscathed skin has not even split into pieces).

Another example of this type of thing, is a bullet hitting a human skull. The bullet rips through the skull, leaving most of the skull (and skin, etc) around the entry wound unscathed,... Same basic idea.

POINT TWO; The Geek's claim that "Unscathed skin is nowhere to be found." is, of course, false.

Even in this instance of a high velocity bullet, the apple skin is still recognizable as apple skin. It has just been split into pieces, just as the continental crust was still recognizable as continental crust, and was just split in pieces (called continents, which then expanded apart).

If you are considering a career in mind reading, I suggest you hang on to the "day job" a bit longer. In fact I like to keep an open mind about "non-standard" theories (e.g. those of Mark McCutcheon, Louis Savain, Fred Alan Wolf, Chapline & Mazur, João Magueijo etc.)
However, I find that asking questions is the best way of developing an understanding. I make no apology for asking questions of you. If my questions are too naive for you to consider them worth answering, say so,I can accept that, but please try to avoid "mind reading".



You exhort me to think, yet you become irritable when I think about/question your statements.

Possibly the rice pudding was not the best analogy. Perhaps you make yours with skimmed milk. I prefer full-cream milk which does have a propensity for separation. I am a little puzzled as to why you should consider three immiscible substances to provide a better analogy, when the components of a silicate magma are clearly able to combine, as well as separate.



You believe I am a religious person because.....?

Personally, I think that if we are ever going to do anything positive with this discussion we should stick to the subject matter. Perhaps deal with one point at a time.

Lets go back to an earlier question:
Preearth, would I be right in thinking that your statements: "The single continent Pangaea covered 35% of the surface of the Earth." and, "Today, the continental crust covers only 35% of the globe" imply a belief that there was the same volume of continental crust present at both times? If so, you would need some evidence about the average thickness at both times.
Your "No", while obviously an answer, does not approach answering the real question, because, surely, if the volume was different at the different times, then the percentages you quote have no real relevance.

I wasn't irritable. Your mind reading went a little astray on that one.


Because you do not display an open scientific mind and your beliefs (dogma) are just the standard set of beliefs that are delivered to you by those in authority (your god).


I just made it up in response to your rice-pudding analogy. I would be very happy if you suggested a better analogy.


Actually, I didn't understand your question and thus thought it irrelevant. Of course, the 35% is a surface area, not a volume. I didn't imagine anyone thinking of it as a volume,... but I should have, because the Geek made exactly this unusual mistake.

Your post contained bold type = shouting. Shouting suggests anger. Irritable = charitable inference, not mind reading.



Would you have come to that conclusion if I had accepted your "dogma" without question?



Perhaps we should stick with magma, to avoid confusion.

Thanks for the clearer response to the continental crust question. I understand that it was surface area you were talking about, but that is where I have a problem. Perhaps it is my lack of scientific qualification, but a comparison of volume, rather than just surface area seems to be a more relevant comparison, in terms of knowing how much continental crust was present at each time.

Nearly all my comments contain bold type. The bold highlights what I consider important. Not that you would notice.


There are many, many problems with "plate tectonics." Why is it you haven't even found one of them.

I guess it is because you are a true believer in "plate tectonics".

I guess it is because you accept "plate tectonics" by faith.

A scientific mind would point out the problems for discussion and resolution. A religious mind, like yours, will try to hide problems from discussion, so that people will not even find out about them, let alone discuss them. You certainly seem to have a religious mind.


You seem to be forgetting the big iron ball in the center of the planet. The mercury was meant to represent this.


A comparison of volume is silly. It doesn't make sense for the situation being discussed.

Who says I haven't found any?

Looking back through your posts I find that you have a strong tendency to respond to questions as though they were attacks on your beliefs.

You accuse me of trying to hide problems rather than discuss them. How can we discuss things if you are not prepared to accept that my questions are honest attempts to learn.

Your responses remind me of those of religious bigots I have tried to discuss things with in the past. I gave that up, and, sadly, it looks as though I may have to do the same here. It's a shame, because I think you have some interesting things to say.

Funny you should say that,... because your responses remind me of those of religious bigots that I have tried to discuss things with in the past, and gave up on.


Well, let's say you had found one (or many) of the problems with plate tectonics, then why haven't you written about them here for all to read? What's holding you back?

Could it be because, that religious minds, like yours, really do try to hide problems with their dogma from discussion, so that people will not even find out about them, let alone discuss them?

Plate tectonics has a very long list of serious problems, but you refuse to, or perhaps can't, even mention one of them.

Preearth, perhaps I am over optimistic, but I cling to the hope that you will eventually answer some questions, rather than continue with these pointless personal attacks.

If you would care to point out to me which of my responses remind you of "religious bigots" I will do my best to rectify any misunderstanding that might have caused that.

Perhaps we could return to my last question:

"Thanks for the clearer response to the continental crust question. I understand that it was surface area you were talking about, but that is where I have a problem. Perhaps it is my lack of scientific qualification, but a comparison of volume, rather than just surface area seems to be a more relevant comparison, in terms of knowing how much continental crust was present at each time."

While your dismissive statement that this "is silly" may well be true, it is hardly a response calculated to inspire confidence in your willingness to engage in discussion. Perhaps the question is too naive for you to deign to answer it. If that is the case, please say so, and I will leave you in your intellectual "ivory tower" to preach to those who may accept your views without question.

Well, let's say you had found one (or many) of the numerous problems with plate tectonics, then why haven't you written about them here for others to read about? What's holding you back?

A very serious bias,... is what is holding you back.

You have some weird plate tectonic religion, which you accept by faith,... it must be by faith,... as you have made it clear that you are not at all interested in points of view differing from the official/standard line.

Plate tectonics has a very long list of serious problems, but you refuse to even mention one of them.

The passage below hints at a few holes in plate tectonic theory. Why don't you expand upon it and turn it into a full-blown argument against plate tectonics?

The power source of plate tectonics.

This power source that moves continents thousands of kilometers and raises the Himalayas to great heights is "radioactive shine," that is, heat from the radioactive decay of material that is much less radioactive than your body, or your surroundings. In fact, a segment of the Earth stretching 6371 kilometers from a point at the center, to a one meter square at the surface, generates only 0.08 watts of heat (with radiogenic heat from the mantle comprising about 30% of this total). This is about one ten thousandth the power of sunlight on a dull day. It is true that if you let "radioactive shine," shine for a few hundred million years, it adds up to a lot of energy, and much more so, if you let sunshine, shine for a few hundred million years. To use this, widely distributed, extremely dilute power, you have to first, stop it from escaping, then, concentrate it where the work will be done. We are told that the Earth and mantle currents can do this, but some doubt it.

From: http://preearth.net/evidence.html

Alternatively, you could demonstrate exactly how such an extremely dilute power can be kept from escaping, concentrated, and used to raise mountains.

Maybe, to begin with, you could use sunshine (which is ten thousand times as powerful as the radioshine of plate tectonics) in your demonstration/analogy.


I can't see that the volume is important. Why don't you explain why you think the volume is important. Then maybe I won't think the idea so silly.

Could it be significant that you labelled this as "silly" before trying to understand what I was asking about?

If you had cared to answer an earlier question, we might have been able to make more progress in this area, so let's have another go.

I asked: "Preearth, would I be right in thinking that your statements: "The single continent Pangaea covered 35% of the surface of the Earth." and, "Today, the continental crust covers only 35% of the globe" imply a belief that there was the same volume of continental crust present at both times? If so, you would need some evidence about the average thickness at both times."

Bill, I did answer this question of yours. I answered "NO."

I later asked you to explain why you think the volume is important (if you explained why you think it is important, I may be able to answer your question).

But you didn't bother to answer it, did you?

If you are going to insist that I answer your questions, perhaps you should answer mine (especially since that would help me answer yours)?

I have tried to make it clear that I was looking for information, rather than just being critical. A simple "NO" is not the most helpful in that scenario. However, I accept that it is an answer of sorts.





I thought a comparison of volume, rather than just surface area seemed to be a more relevant comparison because surface area alone does not necessarily reflect the amount of crustal material present.

Yeah, but if you continue to refuse to help me, help you, by answering a simple question to establish what you are actually asking, then what can one say,....

Can anyone else add to the list of flaws in plate-tectonics?

What did you not understand about the above answer to one of your questions?



Do you consider that surface area alone would reflect the volume of material present? If so could you explain the relevant maths in reasonably simple terms?

Yes I believe that the volume of continental crust present at both times is about the same.

There is good reason for believing this.

1) the (surface) area of continental crust present during both periods are much the same.
2) since 99% of the continental crust and mantle is solid there is little chance of the continental crust being added to or subtracted from.

Thanks, Preearth; this is really what I was trying to get at.



This must assume that the concept of plate tectonics is incorrect.

It must be my that english thing again?

How can continential crust be anything less than 100% what do you have if you don't have crust ... lava or a hole????

There is 30% coverage of water but there is still a crust beneath the water I hope!

I must be missing something in this conversation.

Orac, of course, you are right there is crust under the oceans, but the thing you are missing is that there is a difference between continental crust and oceanic crust. Continental crust has, on average, a higher silica content and tends to sit on top of the heavier oceanic crust.

Preearth will probably point out, with some justification, that that's an over simplification.

You say that Heaven crashed into the pre-earth like a bullet rips through an apple leaving the apples skin intact.

hogwash.
the earth is more like a water balloon.

then theres the triangular impact crater on your web site.

was Heaven a huge pyramid?
did Heaven stay inside the earth or become a part of the earth as you say.




why do you sudgest that it was Heaven?
it seems to me that if your claims are correct it should in fact be hell that crashed into the earth.
or at least you would use hell as the projectile and not Heaven because hell is underground not Heaven.

could it be that the originator of this concept had seen this somewhere in a ancient drawing or heard of this from the ancestors of a people who once had a belief that this happened.



maybe we should search in the backwards Google to find answers.


Can you think of a religion that believes that hell was cast down FROM Heaven?

You can use the non-backwards Google to find that answer.

all I can find is that satan was cast down from Heaven and he lives in a place called hell and cannot physically leave hell.

I assume this is not a Biblical "waters under the Earth" thing; so are you suggesting that the proposed collision would have liquified the Earth?

Bill; Let me guess where you are headed:

Suppose the Earth was once (completely) covered with a layer of continental crust 13 kms thick.

Since continental crust now only covers about a third of the Earths surface, where is the unaccounted for

2/3 * 510,000,000 * 13 = 4,420,000,000 km³ of continental crust.

Are you interested in the volume of continental crust so you can account for the "missing" two thirds by stacking it up in 39 km high blocks (interestingly, Alfred Wegener suggests exactly this).

But, if you say that it is now incorporated in 39 km high blocks of continental crust, then who picked up the 13 km thick blocks and stacked them 39 km high,.... maybe, God?

What incredible force lifted and stacked these blocks.

Or, what even more incredible force might have compressed 13 km thick blocks into 39 km thick blocks?

Since no sufficient force is postulated (within plate tectonics) the idea of finding the missing continental crust in this way is flawed.

(Of course a planetary collision would have had the energy to do this, but in my theory the missing 2/3's is accounted for by the mushing of a large amount of continental crust in the mantle, the expansion of the oceans and the fact that one started with the continental crust completely covering a smaller planet.)

By the way, plate tectonics never claims to have done such (compressing or stacking of continental crust).

It is claimed that plate tectonics has raised mountains, however, these mountains are but a small surface feature on such blocks and comprise a very small percentage of the mass of the block.

How these huge blocks of continental crust came about, has never been explained (by traditional theory).

What caused them to be about 40 km high, has never been explained.

What caused the sides of these blocks to be nearly vertical, has never been explained.

Why these blocks only cover 1/3 of the Earth's surface, has never been explained.

In fact, only the PreEarth-Heaven collision explains these last four things.

As to whether you need a crust or not. Assuming the word crust, is here describing something like the shell of an egg, then the planet does not require a crust. However, as Bill has said, both the continental and the oceanic areas have a crust.

The two crusts are quite different in composition (and thus properties).

The oceanic crust averages about 8 kms in thickness, whereas, continental crust averages about 40 kms in thickness.

of course!

if I rub my hands together they get hot , but rubbing or colliding two planets together would get slightly hotter.

actually there are thousands of us paul's , we are everywhere some of us live on mars and some live on the dark side of earths moon.
some of us live in the past , some in the future , and some in the now.

besides how do we know that your not just some computer program making the post that you make.

and just what gives you the right to question others validity.

What ever gave you that idea?

No. You just made that up. You're doomed Pre-earth, you'll get more and more hardheaded about your idea, and take yourself down more ridiculous paths trying to prop it up. But somehow you will never bother to actually study the existing knowledge or do any useful investigation. You believe you're special and you don't need to work to demonstrate your idea, just do some high-school level calculations and write a lot of ramble.

Common behavior of 99% of cranks. Why don't you see the signs? I notice you tried to distance yourself from "expanding earthers", but why? They're just like you.

All the concerns you have about the existing theories can be solved by researching them. No need to ask people. Go to the literature. If you can't understand the math/prior work, go to the text books. But you won't do that because you don't really want know. You just want to pretend nobody knows.

Take a step back and consider why it all started. It was simply noticing a pattern in the shapes of continents. That's all. Without that you certainly won't be promoting the idea of a giant forklift picking up continents and laying them on top of each other.

Preearth, thanks for the detailed response.

Actually, I wasn't heading towards a major crustal stacking scenario, I tend towards James Hutton's idea that the present is the key to the past, so I am inclined to look for past mechanisms that jibe with present processes, rather than Kallog's giant forklifts.



Whilst willing to "suppose" this for the sake of discussion, I would have to ask why continental crust rather than the more basic oceanic crust?

I can accept that the process of crustal formation might have been so slow that it allowed time for sufficient magmatic differentiation to take place, and continental crust to develop, but that would raise a question as to why we have two quite distinct forms of crust now, and how the patches of continental crust acquired their positions on top of oceanic type crust. I know they are lighter, so isostatic processes come into play, but that would imply at least some local softening of the now underlying oceanic crust.

Paul (whoever you are); if the collision liquified the Earth, then presumably it also liquified the other planet?

Would I be right in thinking that your reasoning would say that if that had happened, and plate tectonic mechanisms had not intervened, we would now have an Earth that was completely covered with one type of crust?

Woah ...



Do you have any idea how hard and unlikely that is to have happened?

Do some basic gravity calculations and try to get orbital stability for both the pre and post crash ... have you tried?

Forget everything else at the moment you would have to show me that you could get stability for both configurations which is very very very unlikely.

Examples 6,7 and 8 on here will show you how ahrd this is going to be
http://faculty.ifmo.ru/butikov/Projects/Collection1.html

Interesting link, Orac; lots of questions; for instance:
In example 8 the three bodies appear to be in syzygy at the start, at 0.5 orbits and 1 orbit.
The divergence seems not to start until almost 1.5 orbits. What initiates the deviation?

I would think that earth already has 1 type of crust.

like fresh water is basicaly the same as sea water.

the earths crust is also basicaly the same as far as chemical composition is concerned , it is the difference in the amounts of chemicals found in basalt and granite that cause the two to seem really different.

an active basalt flow



granite collums



they are both igneous volcanic rock , or cooled lava

the earth has two types of crust basalt and granite and both types are igneous rock



my guess is that if that would have happened the entire forming mass would be too hot to remain solid , even the two cores would form a single core , after several million years of cooling then the crust would be taking shape , remelting , taking shape , etc.. for a few million more years.

Plate tectonics would have come about during the cooling process.

That is the point Bill S the instability is caused because the system at start was inherently unstable and that is the issue to get a long term stability of more than a few laps which is ultimately unstable is extremely difficult. It has to be so fractionally out of balance it takes a long time to break the stability which is sort of what preearth is suggesting they were stable for a long time then the collided.

I would also add the Earth-moon tug-of-war value to the sun is 0.46 (http://en.wikipedia.org/wiki/Double_planet).
As Isaac Asimov said in some ways



The likelyhood of being able to able to switch between the different conditions is incredibly long odds you would much more bet on Earth smashing into another body orbiting the sun than a double twin planet.

I would suggest that there is only 1 mathematical solution to the proposition given and you should be able to even calculate the masses and stable/unstable times because the balancing act would need to be so precise.

I also view the tectonic plates exactly as Paul did in his post so you have alot of hurdles to get me across this line.

Edit: I should add this really is not much different to the (http://en.wikipedia.org/wiki/Giant_impact_hypothesis) except it adds in a whole new orbital stability issue and the theories difficulties are summed up as probably the same as the above.

Having read "Mansfield's Earth Formation Hypothesis: Update." I realise there is an answer to this question there. I withdraw it for the present.

So many unanswered questions out there.