Welcome to
Science a GoGo's
Discussion Forums
Please keep your postings on-topic or they will be moved to a galaxy far, far away.
Your use of this forum indicates your agreement to our terms of use.
So that we remain spam-free, please note that all posts by new users are moderated.


The Forums
General Science Talk        Not-Quite-Science        Climate Change Discussion        Physics Forum        Science Fiction

Who's Online
0 registered (), 58 Guests and 1 Spider online.
Key: Admin, Global Mod, Mod
Latest Posts
Is there anybody out there?
by True
01/07/20 09:26 AM
Top Posters (30 Days)
True 1
Page 1 of 3 1 2 3 >
Topic Options
#44134 - 07/05/12 12:24 AM Global Tectonics
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Why am I starting a new thread about tectonics when there are already numerous threads into which the subject would fit? The answer is that the other threads contain a lot of distracting elements, and I am hoping that it might be possible to focus the discussion, at least for a while.

This is not intended as an attack on Kevin Mansfield’s theory, but, obviously, there is considerable overlap.

Time has not been as readily available as I had hoped while I have been without the net; so the information is not as organized as I would have liked. This may not be a bad thing, though, as past experience suggests that posting too much all at once is not the best course of action. My current estimate suggests that there will be three or four parts, but a lot may depend on the response from others, which I hope will be plentiful and constructive.

With any luck, the first bit will be ready tomorrow.
_________________________
There never was nothing.

Top
.
#44138 - 07/05/12 02:42 AM Re: Global Tectonics [Re: Bill S.]
preearth Offline
Senior Member

Registered: 05/22/10
Posts: 370
This is the theory (Kevin Mansfield's) mentioned above by Bill 6.

Mansfield's Earth Theory & Proof that
various accepted Earth theories are wrong.


Mansfield's Earth theory, is that the Earth formed from the collision of two smaller planets (which, before their collision, were of a similar size and formed a double planet system, much like the Earth and Moon today, except that the previous moon had about thirty-five times the mass of our current Moon).

It is said, that you can tell a good theory by its explanatory power.

The collision theory of Dr. Kevin Mansfield explains all of the following:

[1] It explains the existence of the Pacific Basin.
[2] It explains the existence of the Pacific Ring of Fire.
[3] It explains the (impact) mountains that ring the Pacific Ocean.
[4] It explains why the Earth has continents.
[5] It explains how, and why, the continents moved apart.
[6] It explains the existence of the ancient continent of Pangea.
[7] It explains why Pangea fits neatly within a circle.
[8] It explains why Pangea had a large split called the proto-Tethys Ocean.
[9] It explains how continental crust formed and where it came from.
[10] It explains why continental crust covers only 40% of the Earth's surface.
[11] It explains why continental crust is so different from oceanic crust.
[12] It explains why the Earth's core is rotating faster than the rest of the planet.
[13] It explains why the Earth has a relatively strong magnetic field.
[14] It explains why the Earth's magnetic field is rapidly decreasing.
[15] It explains why the Earth has a global surface layer of clay.
[16] It explains how the ice-caps were able to build to such a size.
[17] It explains why no evolution occurred in India while a separate continent.
[18] It explains why the severity of volcanism has decreased.
[19] It explains the bimodal distribution of elevation.
[20] It explains the geologically mysterious Gamburstev Mountains.
[21] It explains why magnetic reversals have not caused mass extinctions.
[22] It explains why only the top 500 meters of the sea-floor has a significant magnetic anomaly.

Also, with further assumptions, it provides,

[23] new possibilities regarding the formation of the Moon,
[24] can explain the tremendous size of dinosaurs, pterosaurs, etc, and
[25] can explain the large amount of Ar40 in the atmosphere.

Current theories explain only two (numbers five and thirteen) of the above (and both of these explanations are wrong).

The official explanation for (5) is called plate-tectonics.

Plate-tectonics, is the belief that many of Earth's geological features, such as mountains, are caused by currents of solid rock which circulate in the mantle. These extremely slow flows of rock, are thought to be maintained by convection. The convection is claimed to be due to the temperature difference (about 3,000 degrees) between the top and the bottom of the mantle.

The basic idea, is that the rock at the bottom of the mantle, on being heated by the core, becomes lighter, and thus, rises (in a gigantic up-welling) to the top of the mantle. The rock current, then flows (away from the up-welling and) under the Earth's surface, but parallel to it (carrying the continents with it), until it cools. On cooling sufficiently, the rock becomes heavier and sinks (in a gigantic down-welling) back to the bottom of the mantle, and on doing so, completes one lap of a circuit.



However, it is a fact that seismic studies have allowed scientists to determine the density of rock at all levels of the mantle, and laboratory experiments have given reasonable estimates of the temperatures (briefly, the deeper the rock is, the hotter and more dense it is). In particular, we know the densities of the cold rock at the top of the mantle and the hot rock at the bottom.

The cold rock (930 K) at the top (about 40 kms down) of the mantle has a density of 3,370 kg/m³.

The hot rock (3,740 K) at the bottom (about 3,700 kms down) of the mantle has a density of 5,560 kg/m³.

So, one of the many, many, many problems with the mantle currents scenario (plate-tectonics), is that, contrary to assumption, the hot rock at the bottom of the mantle is much heavier than the colder rock anywhere above it. Thus the hot rock at the bottom of the mantle will never rise, it will just sit at the bottom of the mantle, forever.

Consequently, mantle currents, do not, and cannot, exist.

Seismic studies have revealed mantle details, such as, the 410 km, 520 km, and 660 km, density discontinuities. These discontinuities are related to chemical, and or, phase changes in the rock, and the discontinuities are globally found to be within a few kilometers of the depths that they are named after. If giant rivers of rock were really flowing through these structures, there would be significant distortion of them, but these discontinuities are always found close to the depths that they are named after.

Seismic studies have told us much about the Earth's interior. They have told us, that at a depth of about 660 km, the density of mantle rock changes suddenly (over about 4 kms) from 4,000 kg/m³ to 4,380 kg/m³. High-pressure studies in the laboratory have revealed that the main component, Mg2SiO4, of olivine (olivine comprises about 60% of the upper mantel and is a solid solution of Mg2SiO4 and Fe2SiO4) undergoes a reversible change to a mixture of MgSiO3 and MgO. This new structure occupies a smaller volume (which accounts for the density change) and is only stable at pressures, corresponding to depths greater than 660 km.

In the mantle current scenario, lower mantle rock is continuously being raised through the 660 km discontinuity. As it rises above 660 km, the reduced pressure allows the MgSiO3 and MgO to recombine as Mg2SiO4. This is accompanied by a decrease in density and an increase in volume. The increase in volume can be found from the density change, and is about 10%. This massive increase in volume of rock, around the up-welling, would cause the Earth's surface to swell and would be accompanied by almost continuous earthquakes, of tremendous magnitude, as existing rock is moved, many kilometres, to accommodate the newly created volume.

On the opposite side of the mantle current (which may be 3,000-4,000 kms away) upper mantle rock is continuously being forced downward through the 660 km discontinuity. As the Mg2SiO4 changes to MgSiO3 and MgO, the rock suffers a large decrease in volume, which would lead to a subsidence of the Earth's surface and would be accompanied by almost continuous earthquakes. Since, none of this is observed, the mantle currents scenario cannot be correct.

To overcome this, and other problems, some geophysicists have suggested that the mantle has stacked convection currents, one circulating above the 660 km discontinuity and another circulating directly below it. But, of course, this new model has serious problems of its own.

That geophysicists cannot tell you whether the mantle has stacked convection current loops, or single loops, shows how very little they actually know about these mythical convection currents. Of recent years, some geophysicists have tried to downplay convection as the main power source of these currents and tentatively suggest that they are really caused by slab push and slab pull, but this is equally hopeless.

There are other arguments against plate-tectonics, that, while not proving it wrong, do render it less plausible. For example, it is claimed that, 200 million years ago, the single continent Pangea covered about 35% of the surface of the Earth, with the remaining 65%, covered by ocean. Obviously, any ocean sea-floor from this time, still existing today, must be more than 200 million years old. However, it is well-known that there is no sea-floor, existing today, that is more than 180 million years old. This tells us that none of the ocean sea-floor that covered 65% of the Earth, 200 million years ago, still exists as sea-floor today. So, what happened to 65% of Earth's surface? Did it just disappear into thin air?

The official answer (from qualified geologists) is that, over the last 200 million years, 65% of the Earth's surface has fallen down various holes and disappeared. So, the disappearing into thin air, answer, is closer than one may have thought. In the language of geology; 65% of the Earth's surface has been subducted. How easy is it to believe that, over the last 200 million years, 65% of entire surface of the Earth has fallen down holes and disappeared?

The official explanation for (13) is called the geo-dynamo theory.

The geo-dynamo theory, is the belief that Earth's magnetic field is caused by convection currents which circulate the molten iron of the outer core. The fact that the outer core is a true liquid, means that if convection really occurred, the outer core would have reached a uniform temperature, a very, very long time ago. The reason this hasn't happened, is that convection cannot actually occur. And this is because the cold liquid iron at top of the outer core weighs 9,900 kg/m³, while the hot liquid iron at the bottom of the outer core weighs 12,160 kg/m³, and the heavier material at the bottom, has absolutely no incentive to rise into the lighter material above it.

It is worth noting that even if the outer core had a uniform temperature, the material at the bottom would still be heavier than the material anywhere above it. This is simply due to gravitational compression.

Consequently, convection in the outer core, does not, and cannot, exist.

So, the geo-dynamo theory, like plate-tectonics, is fatally flawed.

I have only presented difficulties that can be described in a few sentences, but the list of problems with these two theories is very long and thick books could be written on the subject. I have been absolutely stunned by how easy it has been to find significant holes in these theories. But, I guess, this is what one should expect from false theories.

I am certainly not the first to claim that plate-tectonics is simply wrong. That honour belongs to the renowned Australian geologist, Professor Warren Carey. I particularly like his simple observation that there are no subduction zones in, or around, Africa (and similarly for Antarctica). This deficiency in plate-tectonics theory, is so hard to explain, that it is just ignored.



The problem is clear. If there is no subduction, in, or around, Africa, then there is no feasible arrangement of the mantle currents below the African plate.

Returning to Mansfield's Earth theory.

Evidence for this theory is presented in the articles; When Worlds Collided, and Evidence supporting Mansfield's Earth Formation Hypothesis, both of which can be found on the websites named below. A senior geophysicist from the University of Auckland has read the above mentioned articles, and for the first of them, kindly contributed a number of pages of suggestions, and helpful comment. Unfortunately, he believes that plate-tectonics is much too well established, for any competing idea (as different as mine) to be true.

Whether Mansfield's Earth theory is correct, or not, it certainly warrants careful consideration. Any theory that explains such an array of otherwise unexplained facts, is likely to be correct. From a parochial viewpoint, Kevin Mansfield is a New Zealander, who can attract significant attention to New Zealand science. And with attention, comes funding.

Dr. Kevin Mansfield has a BSc(Hons) [mathematics and chemistry] from the University of Auckland and a PhD [mathematics] from the University of New South Wales (Sydney, Australia). His mathematical research involves the study of certain algebraic structures with normed topologies (these being of interest as a framework, in which both relativity and quantum theory, may eventually find a compatible home).

Websites: www.preearth.net; 21 March 2011.

PDF version.
_________________________
Earth formed from a collision
www.preearth.net

Plate-tectonics is wrong
www.preearth.net/plate.html

Top
#44149 - 07/05/12 12:46 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
(In best possible imitation of Joyce Grenfell)

“Thank you, Kevin. We had noticed it in other threads!”

Just for the record; I'm Bill S.
_________________________
There never was nothing.

Top
#44150 - 07/05/12 12:58 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Global Tectonics (part 1)

Tectonics is a field of study within geology concerned generally with the structures within the lithosphere of the Earth. Strictly speaking, it would also involve the study of the lithosphere of other planets, but for the purposes of this study, we will restrict ourselves to the Earth.

The currently accepted theory of how the lithosphere behaves is plate tectonics. There are plenty of excellent books available that recount the history of plate tectonics, and explain how scientists believe it works. It is not my intention to duplicate these books, and certainly not to try to improve on them. Rather, I propose to look at the whole question of the lithosphere and to ask questions such as: Why is the concept of plate tectonics so widely accepted? and: are there any reasonably credible alternative theories?

There is a tendency among geologists to consider proposed alternatives to plate tectonics as the work of crackpots, but one must not lose sight of the fact that when Alfred Wegener proposed the theory of Continental Drift, geological academia in general condemned it as a singularly crackpot idea. However, a few decades and a change of name turned it into the leading contender for an explanation of the way in which the world works. Apart from the fact that Wegener was a meteorologist and therefore had no right to be telling geologists their business; there was the problem of a power source. I suspect that few, if any, geologists really thought that Wegener was actually suggesting that solid continents ploughed through the even more dense underlying rock. Geologists were quite familiar with the idea that rock could act as a brittle solid under some conditions, such as sudden impact or rapid compression; whereas the same rock would act as a plastic solid if subjected to steady, persistent pressure over a long period. The concept of isostatic equilibrium was well understood. Continental material, formerly, often referred to as “sial” was less dense than the underlying, more basic rock, known as “sima”. Thus a column containing both sial and sima would have to have a greater vertical extent than a similar column containing only sima, in order to achieve isostatic balance. If material at the surface was moved, the underlying rock could move vertically, or even be displaced horizontally to maintain this balance. Even the accumulation or melting of great thicknesses of ice could bring about vertical movement of the underlying rock. Indeed, Scandinavia, Greenland and other areas are still rising as a result of the removal of ice cover at the end of the last ice age.

The initial stumbling block was therefore not an inability to appreciate that solid rock could flow; it was rather the apparent lack of any force capable of causing such mass movement in a horizontal plain. Gravity provided the force necessary for isostasy, but what could move vast continents about on the Earth’s surface? The problem must have been compounded by the fact that continental masses were known to have “roots” which logically should anchor them.

Improvements in the study of seismic waves and the way in which they propagated through the Earth led to greater understanding of the nature of the Earth at depth. This led geologists to think that convection within the mantle might be possible, and that this might provide the necessary driving force for tectonic movement.

One has to ask how reasonable it might be to suggest that convection within the mantle could be possible. The following quote from (http://www.platetectonics.com/book/page_4.asp) certainly seems to argue that it is.

“One idea that might explain the ability of the asthenosphere to flow is the idea of convection currents. When mantle rocks near the radioactive core are heated, they become less dense than the cooler, upper mantle rocks. These warmer rocks rise while the cooler rocks sink, creating slow, vertical currents within the mantle”.

Whilst this kind of simplified explanation may be all that is sought by the majority of people who might read this, it is, with some justification, open to the criticism, not least, because it suggests neat cells spanning the full depth of the mantle. In spite of their one time popularity, such cells are probably unlikely.

Let us look first at temperature: We find that the temperature at the bottom of the mantle is about 3,740K, and the temperature at the top is about 930K. Increased temperature leads to decreased density, so one might expect the mantle to be constantly convecting, like a pot of simmering soup. However, gravity causes density to increase with depth, so we must look also at relative densities. We find that the density of the material at the bottom of the mantle is about 5,560 kg/m3, while at the top it is about 3,370 kg/m3. This seems to suggest that material at the bottom should stay at the bottom, and material at the top should stay at the top. However, things are rarely that simple.

In part 2 I propose to look more closely at the reasons why this simple convection picture might not be "that simple".
_________________________
There never was nothing.

Top
#44163 - 07/06/12 08:19 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Well, part one has not been greeted with murmurs of agreement or howls of protest. Perhaps, as a gentle introduction it is lacking in controversial material. Let’s see if part 2 stirs any feelings.

Part 2

Is mantle convection possible? The first thing to recognise is that convection does not necessarily require that the rock at the bottom of the column be less dense than the rock at the top. All that is needed to start convection is for the rock at any point in the column to become sufficiently less dense than the rock directly above it; or to become sufficiently more dense than the rock directly below. In fact, even horizontal differences in density can initiate convective movement. Once started, the rate at which convection will proceed depends to a great extent on the plasticity of the rock. In general, the hotter the rock in any given environment, the more readily it will flow, and the more easily convection should progress.

Consider first rock towards the top of the mantle where pressure is a less important factor than it would be at the base. Local variations in temperature may occur, caused, perhaps by inhomogeniety in radioactive elements. Theory maintains that the hotter rock will be lighter than the colder rock, so, given that the material is sufficiently plastic, the hotter rock will rise, relative to the colder. Obviously the colder rock must sink in order to maintain isostatic balance.

At greater depth in the mantle gravity plays a more important role. The downward pressure exerted by the overlying column of rock at any given point increases with depth, as does the temperature. To decide whether convection will occur, it is necessary to balance increased density due to compression against decreased density resulting from heating.

Let us assume that if the mantle were homogeneous, evenly heated from below, and uniformly cooled from above, a state of balance would eventually be reached in which hot heavy rock would remain at the bottom and light cool rock would remain at the top. Heat transfer would be by conduction, and everything would be stable. This is what the Earth’s mantle would be like if these conditions prevailed. However, such is not the case. The study of seismic waves has shown that the mantle is not homogeneous. In particular, seismic tomography has revealed marked inhomogeniety in the upper and lower regions of the mantle.

One factor that may add to doubts about mantle convection is that many simplified explanations of the process, such as that cited above, tend to suggest that it is a straightforward case of Rayleigh-Benard convection. Such explanations often draw a parallel between mantle convection and a “pot on the stove” situation. It must be remembered that in Rayleigh-Benard convection heating is from below, and cooling from above. While it is undoubtedly true that the mantle is cooled from above, heating is by no means solely from below. A significant portion of the mantle’s heating is from within, and the source of this heat, radioactive material, is not evenly distributed.

Although it is true to say that the mantle is cooled from above, this cooling is most certainly not uniform. Again seismic tomography provides valuable information. The deep ocean trenches and island arcs that plate tectonics theory identifies as areas in which oceanic plates are being subducted, have been studied extensively. Traces of relatively cold material that in terms of proportions and angle of apparent descent fit the theory of subduction have been identified. These reach down to considerable depths in the mantle.

It is widely accepted in scientific circles that although there is now ample evidence that tectonic plates move about the Earth’s surface, the actual mechanism is not fully understood. To some extent this leaves scope for a range of other theories such as the expanding Earth and Kevin Mansfield’s “collision” theory. Possibly professional geologists in general lack the time and inclination to give more than a cursory glance towards non-standard ideas, in addition to any potential damage to their careers that seeming to entertain crackpot theories might bring. We amateurs suffer no such constraints, so perhaps we have a “duty” to question everything, including established wisdom.

It has been argued that if there were convection cells in the mantle discontinuities would be significantly displaced by the ascending and descending limbs. This seems like a logical line of reasoning, but it may be based on an over simplistic view of nature of the mantle.

One possibility is that there is more than one level of convection. For example, there is a major discontinuity at about 660 km depth. It has been suggested that convection may occur below that, with a separate set of convection cells above that level. The chemical composition of basalts from mid-ocean ridge systems indicates that the magma from which they are formed may have originated at no great depth. Although this has been used as an argument in favour of layered convection, such may not actually be the case. Mantle convection would not necessarily require melting to the point of magma formation. There is good evidence that mineralogical changes are brought about by changing pressure at different levels in the mantle. Thus the composition of the magma may reflect the level at which melting took place, rather than the depth at which an ascending limb started its journey.

Convection is much more likely to be possible in the mantle if the dominant mineralogical changes are structural, rather than compositional. Compositional changes would require the addition or removal of chemical elements; whereas structural changes require only readjustment of existing elements. Let us look at the dominant mineral type of the mantle; olivine. Common olivine is stable down to a depth of about 410 km, at which point pressure causes it to convert to wadsleyite. (Temperature plays a part in the transformation, but the prime mover is pressure). Wadsleyite is stable down to about 520 km where it transforms into ringwoodite. All these minerals share the same chemical composition; only the structure is different. Transformation in either direction can take place easily given the necessary changes in pressure; however, these transformations produce discontinuities, and it has been argued that if convection occurred in the mantle these various discontinuities would be displaced either up or down by the rising or falling limbs of each convection cell. One has to ask if any evidence of this has been found.

Seismic tomography has revealed that beneath the Japanese trench the 660 km discontinuity is displaced downward by about thirty kilometres. The descending material is cooler than the surrounding mantle, suggesting that it is a subducting plate that is causing the depression of the discontinuity. If, as geologists seem increasingly to be thinking, subduction is the major driving force of plate movement, it would be reasonable to expect the downward displacement of discontinuities to be more marked, and easier to detect than upward displacement.

One might wonder why displacements of this nature are not detected more commonly. In fact it is much more likely that seismic tomography will trace a descending plate down as far as the 660 km discontinuity. A probable reason for this might be that the spinel to perovskite transformation that takes place at about 660 km depth is endothermic; thus it would be likely to decrease the temperature of the mantle locally, therefore increasing the relative buoyancy of the descending material.

In part 3 I propose to look at the question of vanishing oceanic crust.
_________________________
There never was nothing.

Top
#44174 - 07/08/12 08:18 AM Re: Global Tectonics [Re: Bill S.]
preearth Offline
Senior Member

Registered: 05/22/10
Posts: 370

"Consider first rock towards the top of the mantle where pressure is a less important factor than it would be at the base."

First, the pressure from overburden is important throughout the entire mantle.

Even the top of the mantle has somewhere between 10 and 70 kms of rock sitting on it and that creates huge pressure.

So, you ALWAYS have to consider gravitational compression.

"Local variations in temperature may occur, caused, perhaps by inhomogeniety in radioactive elements."

There is absolutely no evidence for this.

To be fair, almost nothing concerning the distribution of radioactivity is known for sure, so who knows? The levels of radioactivity are just educated guesses. There is no direct evidence for the levels of radioactivity currently assumed to exist in the mantle and significant contrary evidence for the levels of radioactivity that some have assumed for the core (the best educated guess for radioactivity in the core seems to be zero).

It is a fact that globally, the heat from any radioactive decay is leaking faster than it is being produced and thus there is no buildup of temperature. To account for the current rate of heat loss from the Earth, you have to add a sizeable chunk of "secular heat" (about 65% of the total heat) to that produced by the supposed radioactivity (about 35% of the total heat).

"Theory maintains that the hotter rock will be lighter than the colder rock, so, given that the material is sufficiently plastic, the hotter rock will rise, relative to the colder."

Your proviso, that the material is sufficiently plastic, is unwarranted. Mantle rock is the least plastic material on the planet (excepting the iron of the solid core) and thus is NOT sufficiently plastic.

"Theory maintains that the hotter rock will be lighter than the colder rock, so, ...., the hotter rock will rise, relative to the colder."

This is simply not true. Hotter rock will not rise, relative to the colder, even if you ignore gravitational compression.

There are these things called chemical bounds which hold all solids together. For convection to occur in a solid, quadrillions of chemical bounds must be broken and reformed. Breaking these chemical bonds is called melting the material.

Any rock where convection might occur, has to have most of these chemical bounds broken, i.e., it has to be at least partially molten.

As it is, the mantle is (everywhere) stiffer than the strongest steel. Nowhere in the mantle is it sufficiently plastic for convection to occur, even locally.

And, it should be noted that local convection can not explain the movement of the continents.

If you heat one end of a long (very wide) rock pillar to a few hundred degrees and keep the other end at zero, then convection will NEVER occur. This is because, for convection to occur those quadrillions of chemical bounds must be continually broken and reformed as one portion of the solid rock moves through another portion of it.

Unless temperatures approach the melting point of the material, the temperature difference cannot provide enough energy to break these bonds. Also, it is impossible to maintain large local temperature differences, for long periods of time, as the heat will escape by conduction. This, by itself, implies that local convection is impossible.

Although convection cannot occur, continuous massive pressure over a long period of time will cause even the stiffest steel to deform. Similarly, continuous massive pressure (provided by gravity) over long time periods, will cause some small movement of pieces of the (solid) mantle.

However, any large scale movement of one part of the mantle through another part of the mantle requires that the mantle be (at least) partially molten (as it would have been in the Mansfield's collision hypothesis). Any convection in a non-molten mantle is just a daydream.
_________________________
Earth formed from a collision
www.preearth.net

Plate-tectonics is wrong
www.preearth.net/plate.html

Top
#44175 - 07/08/12 01:05 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Thanks, Pre, that has to have been the best answer I've ever had from you smile. I'll try to do justice to a response before posting the next part of the "saga".
_________________________
There never was nothing.

Top
#44177 - 07/08/12 07:07 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
This is not an attempt at a full response, but perhaps a few points can be cleared up.

Quote:
the pressure from overburden is important throughout the entire mantle


Agreed, but I did say “less important”, not unimportant.

Obviously, bodies of rock can move vertically with respect to surrounding rock, without melting, otherwise it would not be possible to maintain isostatic equilibrium.


How do you explain the apparently descending bodies of rock with increased seismic wave velocities detected by seismic tomography in what current thinking identifies as subduction zones?

Out of time, unfortunately. More later.
_________________________
There never was nothing.

Top
#44212 - 07/10/12 07:32 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Quote:
"Local variations in temperature may occur, caused, perhaps by inhomogeniety in radioactive elements."

There is absolutely no evidence for this.


There is considerable evidence for mantle inhomogeniety, both in chemistry and temperature. Eg. in L. Wen, et al: Seismic evidence for a thermo-chemical boundary layer at the base of the Earth's mantle, Earth Planet. Sci. Lett. 189 (2001) 141^143.

Does your theory provide a better explanation for temperature variations than associated variations in heat producing elements?

Obviously, I do not rule out endothermic and exothermic phase changes here, but in order for these to produce thermal anomalies there would have to be some vertical movement of mantle material, which you might be unhappy about.
_________________________
There never was nothing.

Top
#44213 - 07/10/12 10:05 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Quote:
The levels of radioactivity are just educated guesses.


Recent studies of antineutrinos from within the Earth indicate that the previous estimate of the contribution of radioactive decay to the Earth’s overall heat-loss needs to be revised slightly.

Previous estimates, based on the bulk silicate Earth model, proposed a total of 20 TW, of which 8 TW was from the uranium-238 decay chain; 8 TW from the thorium-232 decay chain and the final 4 TW from potassium-40.

The more recent figures, based on the study of antineutrinos, indicate that the combined uranium-238 decay chain and thorium-232 decay chain produce 20 TW. This experiment cannot detect the lower-energy antineutrinos from potassium-40 decay, so educated guessing is not entirely eliminated. However, if this applies to little more than 16% of the heat from radioactive decay, it is probably no longer justifiable to claim that it is all an educated guess.
_________________________
There never was nothing.

Top
#44214 - 07/11/12 01:32 AM Re: Global Tectonics [Re: Bill S.]
preearth Offline
Senior Member

Registered: 05/22/10
Posts: 370

Just for the record,....

The 2nd post above was written to point out some of the shortcomings of the current theories of Earth formation. It was printed and delivered to some 600 academics in the Auckland area (New Zealand) towards the end of March, 2011. It was added to http://www.preearth.net in December, 2011.

Mantle currents, and thus plate-tectonics, is wrong.

Those who push plate-tectonics are so amazingly stupid, that they never even bothered to check whether, or not, the hot rock at the bottom of the mantle was really lighter than the colder rock above it, as is required by their theory. And, this is though most geology books actually tell you that the hot rock, 3740 K, at the bottom of the mantle has a density of 5,560 kg/m³, and that the density decreases almost linearly from 5,560 kg/m³ to 3,370 kg/m³ as one approaches the top of the mantle (3,370 kg/m³ is the density the cold rock, 930 K, at the top of the mantle, about 40 kms down).

This, totally contradicts the assumptions of the theory of mantle currents/plate-tectonics (that is, contrary to known fact, plate-tectonics assumes that the rock at the bottom of the mantle becomes hotter, and thus lighter than the colder rock above it, and consequently rises).

How could scientists be so stupid? Well, whatever the reason, they certainly are extremely stupid.

I also note that, various scientists have now had a year to come up with some sort of answer to this problem (and the other problems presented below) but they have not.


From: Why was the continent Pangea circular?
http://www.scienceagogo.com/forum/ubbthreads.php?ubb=showflat&Number=39820
_________________________
Earth formed from a collision
www.preearth.net

Plate-tectonics is wrong
www.preearth.net/plate.html

Top
#44215 - 07/11/12 01:36 AM Re: Global Tectonics [Re: Bill S.]
preearth Offline
Senior Member

Registered: 05/22/10
Posts: 370

"Agreed, but I did say "less important", not unimportant."

Your statements are so full of proviso's they often say nothing at all. Another example;

"Theory maintains that the hotter rock will be lighter than the colder rock, so, given that the material is sufficiently plastic, LIKE, e.g., THINNER THAN WATER, the hotter rock will rise, relative to the colder."

Well, yes.... the statement is true but says nothing. The statement loses all meaning. It's like saying; If steel was as plastic as water then hot steel would rise (in convection?), relative to colder steel.

You must be ImagingGeek, or genetically related to him.

"There is considerable evidence for mantle inhomogeniety"

Nobody said there wasn't. What was said was that there is absolutely no evidence for inhomogeniety in radioactive elements.

So you seem to have trouble understanding what you read.

So you are ImagingGeek then,..... :>)

"How do you explain the apparently descending bodies of rock with increased seismic wave velocities detected by seismic tomography in what current thinking identifies as subduction zones?"

The impact pushed large chunks of the original crust/surface material all over the place. It pushed some of it down into what are called subduction areas, where it remains.

"Does your theory provide a better explanation for temperature variations..."

The evidence for your temperature variations is exceedingly tiny, to non-existent. For example, estimates of the temperature of the centre of the Earth vary be a couple of thousand degrees and you claim that small local differences are well-established,... I don't think so.

"Recent studies of antineutrinos from within the Earth..."

Yes I know of these studies. Basically they don't tell you where the radioactive material is, so they tell you nothing about the distribution of the radioactive materials, which is what you are talking about.

And, as to the overall levels of radioactivity in the mantle, they are still educated guesses, just a tiny bit more educated than before the antineutrino experiments (the last I heard the antineutrino experiments were unable to differentiate between any of the proposed Earth models).

Around 2004 various antineutrino experiments were proposed that would determine the angular distribution of antineutrino intensity. This would give a load of valuable information concerning the distribution of the radioactive materials,....

However, the antineutrino experiments seem to have "gone cold". I have heard nothing about them for many years now. If you know some recent papers please let me know about them. Maybe the antineutrino experiments are giving the "wrong" results and are thus being "forgotten".
_________________________
Earth formed from a collision
www.preearth.net

Plate-tectonics is wrong
www.preearth.net/plate.html

Top
#44222 - 07/12/12 12:26 AM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Quote:
Your statements are so full of proviso's

You prefer dogma? BTW, Ellis, this has to be one for your collection!
Quote:
LIKE, e.g., THINNER THAN WATER

Not something I said. I hope you are not suggesting that a substance needs to be thinner than water in order to flow. Take a look at the windows in, for example, some very old churches. You will find clear indications of flow marks in the glass, with no history of melting.
Quote:
"There is considerable evidence for mantle inhomogeniety"
Nobody said there wasn't. What was said was that there is absolutely no evidence for inhomogeniety in radioactive elements.

What was said was: “There is absolutely no evidence for this.” That could equally well be construed as saying there was absolutely no evidence for local variations in temperature.

Quote:
It's like saying; If steel was as plastic as water then hot steel would rise (in convection?), relative to colder steel.

You think I have difficulty understanding what I read?

Quote:
The impact pushed large chunks of the original crust/surface material all over the place. It pushed some of it down into what are called subduction areas, where it remains.

How likely is it that it would still be cooler than the surrounding material if it had been in that position for so long?
_________________________
There never was nothing.

Top
#44223 - 07/12/12 12:30 AM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Part 3

One argument put forward in Kevin Mansfield’s theory is that some 70% of the Earth’s surface area is oceanic crust, none of which is more than 200 ma old. Mansfield seems to think it unlikely that this amount of crust could disappear “down a hole” within that time scale. However, a closer look at the situation reveals that this is possible.

Earth’s surface area = 5.1 x 10^8 km^2

Area covered by oceans is approximately 71% = 3.61 x 10^8 km^2

The oldest oceanic crust is 2 x 10^8 years old.

It seems reasonable to suggest that the ratio of oceanic crust to continental crust was not lower 2 x 10^8 years ago than it is today.

Recent estimates of the global subduction rate = 3 km^2 pa.

If this rate has been constant over the past 2 x 10^8 years, and as far as I am aware there is no evidence to suggest that the subduction rate has been significantly lower in the past, then there would have been time for 6 x 10^8 km^2 to have been subducted. This is a figure approaching twice the amount that would need to be subducted to achieve a complete change of oceanic crust in two hundred million years.

A point worth mentioning here is that if Mansfield’s theory is correct, and the current tectonic movements are just relict activity from the collision, it would be logical to reason that the rate of movement would be slowing with time. Thus, there would be scope for even greater turnover of oceanic crust than the above calculation indicates.
_________________________
There never was nothing.

Top
#44381 - 07/26/12 02:16 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Life’s too short to waste time flogging dead horses. I might be tempted back into one of Pre’s threads in the future, but they do seem just to go round in circles. Perhaps SAGG is not the place for geology.

Amen.
_________________________
There never was nothing.

Top
#44387 - 07/26/12 06:02 PM Re: Global Tectonics [Re: Bill S.]
Bill Offline
Megastar

Registered: 12/31/10
Posts: 1858
Loc: Oklahoma, USA
Originally Posted By: Bill S.
Life’s too short to waste time flogging dead horses. I might be tempted back into one of Pre’s threads in the future, but they do seem just to go round in circles. Perhaps SAGG is not the place for geology.

Amen.


Actually geology would be a perfectly acceptable subject for discussion. It is just that you can't get a sensible answer from Pre about anything you question in his posts.

As an example: What is the relationship between fracking* and earthquakes? There seems to be a significant increase in minor earthquakes in areas where there is a lot of fracking going on. If you ask a half a dozen different experts you will get a half a dozen different answers. It seems that most of the answers that say there is no problem come from people who have an interest in using fracking. That includes our state leaders here in Oklahoma. Many of the other answers are from people who just think it must be bad because we never did that way before. And there does seem to be an increase in the number of earthquakes.

*Definition: Fracking - the use of high pressure water to fracture deeply buried rock formations to allow the easy extraction of natural gas.

Bill Gill
_________________________
C is not the speed of light in a vacuum.
C is the universal speed limit.

Top
#44390 - 07/26/12 08:52 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Quote:
Actually geology would be a perfectly acceptable subject for discussion. It is just that you can't get a sensible answer from Pre about anything you question in his posts.


This is a large part of why I started a new thread. I had hoped that others might see it as an opportunity to discuss the mantle without, necessarily, waiting for answers from Pre. Obviously, his contributions would be welcome; which is just as well, because until today he was the only one to respond in any way.

Anyway, I assume the thread will remain in place, so if anyone wasnt to join in I will be glad to respond. I'm not going off in a huff; just a little disappointed, but still here. smile
_________________________
There never was nothing.

Top
#44402 - 07/27/12 03:19 AM Re: Global Tectonics [Re: Bill S.]
preearth Offline
Senior Member

Registered: 05/22/10
Posts: 370
Bill S; So, you have not satisfactorily answered a single one of my complaints concerning mantle currents (plate tectonics) and you say (on one of the other threads) that you are about to run away from geology. I guess that is an admission of total defeat.

A comment concerning your part 3.

"Recent estimates of the global subduction rate = 3 km^2 pa."

Bill finds it quite acceptable that 65% of the entire surface of the Earth (about 330,000,000 km^2) has fallen down holes and disappeared in the last 200,000,000 years. In fact he is prepared to accept much more.

In any case, Bill clearly finds it quite acceptable that 1,650,000,000 km^2 (3.25 times the surface area of the entire planet) has fallen down holes and disappeared in the last billion years.

Yes, Bill finds it easy to accept that 3.25 times the surface area of the entire planet has fallen down holes and disappeared in the last billion years.

Or, since some believe that plate tectonics began 3 billion years ago, Bill is quite happy to have, 5,000,000,000 km^2, that is, TEN times the surface area of the planet, falling down holes and disappearing, during the "tectonic history" of the Earth.

Bill believes in fairies as well (smile).
_________________________
Earth formed from a collision
www.preearth.net

Plate-tectonics is wrong
www.preearth.net/plate.html

Top
#44406 - 07/27/12 09:07 AM Re: Global Tectonics [Re: preearth]
Orac Offline
Megastar

Registered: 05/20/11
Posts: 2819
Loc: Currently Illinois, USA
As opposed to the garbage preearth sprouts with scant evidence and won't discuss the HUGE AND SERIOUS short comings of his belief.

Better to believe in faries than be off with them like Preearth.
_________________________
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.

Top
#44415 - 07/27/12 03:09 PM Re: Global Tectonics [Re: Bill S.]
Bill S. Offline
Megastar

Registered: 08/20/10
Posts: 3570
Loc: Essex, UK
Originally Posted By: Pre
you say (on one of the other threads) that you are about to run away from geology. I guess that is an admission of total defeat.


Wrong again. There is a big difference between abandoning geology and distancing myself from the sort of crap that masquerades as answers to questions about your theory.

Take, for example, your comment concerning Part 3. It fails to address any salient point in P art 3, and is no better than the sort of “school yard put-down” one would expect from a bully who thinks (incorrectly) he knows it all. You have shown you are capable of better than that, but if you find it necessary to resort frequently to such tactics, then I feel I have better things to do than to continue involvement.

I continue to be interested in ideas that differ from accepted “wisdom”, but am not interested in slanging matches with anyone.
_________________________
There never was nothing.

Top
Page 1 of 3 1 2 3 >



Newest Members
debbieevans, bkhj, jackk, Johnmattison, RacerGT
865 Registered Users
Sponsor
Facebook

We're on Facebook
Join Our Group

Science a GoGo's Home Page | Terms of Use | Privacy Policy | Contact Us
Features | News | Books | Physics | Space | Climate Change | Health | Technology | Natural World

Copyright © 1998 - 2016 Science a GoGo and its licensors. All rights reserved.