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Kinetic energy of (?thermal?) expansion?

 

That is an unconventional way to deal with it. Using strain energy as an intermediate is more usual. Can you explain further?

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Kinetic energy of (?thermal?) expansion?

 

That is an unconventional way to deal with it. Using strain energy as an intermediate is more usual. Can you explain further?

 

studiot, thank you for the correction. In my mind I pictured the outward displacement of the mantle and I assumed it was kinetic because of the movement aspect. Strain Energy, I honestly have never heard that term before. I just Googled it and I'm blown away at what it covers. It fits what I imagined the mantle was enduring as the material was pressed outward against gravity and the mantle's viscosity, stressed and releasing energy as it expands. I am changing the mistake on my site also, I'm a little worried what other force/action/mechanism I may have misnamed. You have me rethinking the description of the energy transfer and storage of post #8, thanks again. arc

Edited by arc

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Strain Energy: If you want a good geologists viewpoint of this subject the little book by professor J C Jaeger is brilliant

 

Elasticity, Fracture and Flow, published by Methuen.

 

Strictly there is a kinetic energy component to consider when a body suffers internal strain and this appears in the formal equations of continuum mechanics.

However this is normally ignored as the movent is slow so the KE is small compared with the stored elastic or plastic strain energy.

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I've read through this and if i missed i apologize but a lions share of Earth's heat comes from radioactive decay, some of it comes from the heat of formation and the rest from gravitational contraction. I see no need to postulate an arc tube like the one that occurs with Jupiter and Io,

 

Other than your assertions can you show any such current loop between the sun and the earth? It should be quite obvious if it were true...

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Strain Energy: If you want a good geologists viewpoint of this subject the little book by professor J C Jaeger is brilliant

 

Elasticity, Fracture and Flow, published by Methuen.

 

Strictly there is a kinetic energy component to consider when a body suffers internal strain and this appears in the formal equations of continuum mechanics.

However this is normally ignored as the movent is slow so the KE is small compared with the stored elastic or plastic strain energy.

 

studiot, It sound's great. But if it's at the level of some of the material I found on the web it may be over my head. I'm shooting from the hip on this. You folks can leave me in the dust just walking to the car.

 

About the mantle's displacement and strain energy, I'm wondering if according to this: http://newscenter.lbl.gov/news-releases/2011/07/17/kamland-geoneutrinos/ the current 22 terawatts of unaccounted internal heat could be the result of a slow strain energy movement in the mantle. And could the current sea floor spreading metrics be used as a value for calculating and verifying the mantles degree of displacement and strain energy thermal release. arc

 

I see no need to postulate an arc tube like the one that occurs with Jupiter and Io,

 

Other than your assertions can you show any such current loop between the sun and the earth? It should be quite obvious if it were true...

 

Hello Moontanman, It looks to me like the classic "rookie overcompensation" mistake on my part, urp..sorry I just threw-up in my mouth. What can I say, first CaptainPanic then Ophiolite I freaked and started throwing everything out there to stop the hemorrhaging. O.k. seriously you people will have to occasionally deal with my "flee market hypothesis" approach. Just dig through the pile of worthless crap until you get something useful.smile.png arc

 

 

 

I've read through this and if i missed i apologize but a lions share of Earth's heat comes from radioactive decay, some of it comes from the heat of formation and the rest from gravitational contraction.

 

The link: http://newscenter.lbl.gov/news-releases/2011/07/17/kamland-geoneutrinos/ gave me the impression that about 22 terawatts out of a total of 44 TW's was a little bit more mysterious in its origin. Quote: Says Freedman, “One thing we can say with near certainty is that radioactive decay alone is not enough to account for Earth’s heat energy. Whether the rest is primordial heat or comes from some other source is an unanswered question.”

 

If its unaccounted then it's up for grabs and I call dibs. arc

Edited by arc

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Well, to be honest I thought this would create a lot more resistance from those committed to the standard model. I had an image of hitting a hornets nest with a stick. I think the hornets are still around I just need a bigger stick. So with that in mind I begin what I think will be a difficult post for some people.

 

WARNING!

The following post may challenge some people's rigid inflexible understanding of the Earth's current and controversial heat flux dynamics.

 

The mantle in this model is displaced by the thermal expansion of the outer core's liquid iron from the increased amplitude of current within the magnetic field's magnetohydrodynamic generator. The mantle's outward movement, against the force of gravity, produces a strain energy response as the mantle's viscosity resists the expansion, creating thermal heating of the mantle material as the strain tension is released.

 

The strain energy response and thermal release increases proportionally to the distance from the mantle-core boundary, culminating at the crust-mantle boundary with maximum expansionary movement and strain energy thermal heating. The mantle's outer boundary surface area is stretched out and torn producing localized pressure reduction thus allowing melting of the surrounding surface area materials.

 

This thermal heating of the crust-mantle boundary coincides with the expansionary movement of the crust by the displaced mantle, giving researchers a way to measure and calibrate the thermal forcing of Earth's ocean and atmosphere to historic periods of plate tectonic expansion and contraction.

 

As an example, the extension of the Basin and Range Area is dated to the Miocene Epoch (5.3 - 23.03 MYA). The province is believed to be the result of tectonic extensional processes that began around 17 MYA (million years ago) in the Early Miocene. It was considered a warmer climate period than the following Pliocene and Pleistocene Epochs that were cooler periods of climate that coincide with the Himalayan and Andes mountain building periods. These structures would require large scale subduction and displacement of crustal gravitational potential energy into the folded and raised rock strata. These mountain structures occurred while the Earth's climate went into a period of Ice Ages.

This model gives significant, but not unambiguous, evidence that the thermal variability of the outer core produces coordinated geologic restructuring and climate forcing. arc

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WARNING!

The following post may challenge some people's rigid inflexible understanding of the Earth's current and controversial heat flux dynamics.

 

The mantle in this model is displaced by the thermal expansion of the outer core's

This model gives significant, but not unambiguous, evidence that the thermal variability of the outer core produces coordinated geologic restructuring and climate forcing. arc

 

 

Marc

I Do not know if you have seen it yet. A big eruption in philipines Mayon Volcano 212 miles S.E of Manilla

 

. Blew out ROCKS the SIZE OF CARS

 

Spewing ,and throwing rocks towards 30 climbers 5 Killed others injured

 

Attached picture from Paper. Does your theory relate to this area.

 

post-33514-0-63608800-1368060409_thumb.jpg

 

mike

Edited by Mike Smith Cosmos

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This eruption looks to be, by volcanic standards, a small steam related event. It looks like some prior rain was deposited in the crater where gravity and an inclined terrain provided a means to load a charge of propellant into a makeshift chamber of a steam driven cannon. The rain water was able to quickly flow into a deposit of extremely hot ash producing the explosive eruption. This appears to be more of a secondary response by an outside trigger to an existing thermal content in the crater.

 

Island Arc volcano's are a difficult mechanism to understand.

 

post-88603-0-81163300-1368072106_thumb.jpg

 

This 3-D sketch (left) shows a cross-section of the Mariana Arc with some of its main structures and features. The numbers represent the speed of sound in the various layers beneath the arc measured by the precise timing arrivals from earthquakes and man-made sources. Higher velocities represent more dense material. Note that there is old ocean crust descending in the trench at the same time new crust is forming along the island arc (from deep melting of the down going plate) and in the back-arc spreading center (from extension behind the arc). Modified from Plate 2 of Fryer and Hussong (Proceedings of the Deep Sea Drilling Project, Leg 60, pp. 45-55, 1981). Image and text courtesy NOAA Ocean Explorer.

 

In both the standard and my model the descending ocean plate is melting into the asthenosphere, the accompanying friction adding to the melting of the surrounding rock into magma, some of which is forced to the surface building up the volcanic island chains.

 

In my model there is an additional mechanism that produces the observable phenomena of island arcs and may actually allow for larger eruptions. Picture in your mind that image above. The mantle is slowly moving down, unloading the crust's gravitational potential energy into the trench in an ebb and flow of movement over millions of years. The compression loading up and then slowly relieving then repeating over and again. The trenches rate of resistance varying as the surrounding mantle is heated from the increasing compression. This in turn will decrease resistance and increase movement.

 

The increase of compression will increase the curvature of the ocean plate at the trench, moving it towards the island arc and compressing the island arc structure all the way to the back arc spreading center, decreasing magma flow to the surface in the entire complex. This compression in the ocean plate is what is also producing increased friction, pressure and melting. The thermal energy builds as the kinetic changes into compression.

 

The stage is now set for a volcanic eruption when the compression is relieved as the ocean plate melts away. As the compressed ocean plate relaxes the volcanic vents release the pent up energy of the lower regions. This cycle would fit nicely to the historic record of island arcs.

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This eruption looks to be, by volcanic standards, a small steam related event. It looks like some prior rain was deposited in the crater where gravity and an inclined terrain provided a means to load a charge of propellant into a makeshift chamber of a steam driven cannon. The rain water was able to quickly flow into a deposit of extremely hot ash producing the explosive eruption. This appears to be more of a secondary response by an outside trigger to an existing thermal content in the crater.

 

Island Arc volcano's are a difficult mechanism to understand.

 

attachicon.gifxsection_600.jpg

 

This 3-D sketch (left) shows a cross-section of the Mariana Arc with some of its main structures and features. The numbers represent the speed of sound in the various layers beneath the arc measured by the precise timing arrivals from earthquakes and man-made sources. Higher velocities represent more dense material. Note that there is old ocean crust descending in the trench at the same time new crust is forming along the island arc (from deep melting of the down going plate) and in the back-arc spreading center (from extension behind the arc). Modified from Plate 2 of Fryer and Hussong (Proceedings of the Deep Sea Drilling Project, Leg 60, pp. 45-55, 1981). Image and text courtesy NOAA Ocean Explorer.

 

In both the standard and my model the descending ocean plate is melting into the asthenosphere, the accompanying friction adding to the melting of the surrounding rock into magma, some of which is forced to the surface building up the volcanic island chains.

 

In my model there is an additional mechanism that produces the observable phenomena of island arcs and may actually allow for larger eruptions. Picture in your mind that image above. The mantle is slowly moving down, unloading the crust's gravitational potential energy into the trench in an ebb and flow of movement over millions of years. The compression loading up and then slowly relieving then repeating over and again. The trenches rate of resistance varying as the surrounding mantle is heated from the increasing compression. This in turn will decrease resistance and increase movement.

 

The increase of compression will increase the curvature of the ocean plate at the trench, moving it towards the island arc and compressing the island arc structure all the way to the back arc spreading center, decreasing magma flow to the surface in the entire complex. This compression in the ocean plate is what is also producing increased friction, pressure and melting. The thermal energy builds as the kinetic changes into compression.

 

The stage is now set for a volcanic eruption when the compression is relieved as the ocean plate melts away. As the compressed ocean plate relaxes the volcanic vents release the pent up energy of the lower regions. This cycle would fit nicely to the historic record of island arcs.

 

 

Under The illustration above it says

 

 

Note that there is old ocean crust descending in the trench at the same time new crust is forming along the island arc (from deep melting of the down going plate) and in the back-arc spreading center (from extension behind the arc).

 

.This new crust that is forming, :-

 

Is this " new crust" that's building up , counted as Continental crust or Oceanic crust. ?

 

As I thought Continental Crust was less dense than Oceanic Crust and that the mineral make up of continental crust was different to Ocean crust. ( More Iron content ?)

 

And that was why Continental crust floated (as it were on top ) and Oceanic crust was more dense so sub-ducted (and sunk as it were ) , under the continental crust. I might have this wrong Marc , Could you clarify.

 

Thanks. Mike

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I know this may be very basic, but what is the density of the crust compaired to the mantle?

 

If it's higher it may well sink into it but if its' lower then the primary drive for plate movement must not be the weight of the crust droping into the mantle.

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Under The illustration above it says

 

 

 

.This new crust that is forming, :-

 

Is this " new crust" that's building up , counted as Continental crust or Oceanic crust. ?

 

As I thought Continental Crust was less dense than Oceanic Crust and that the mineral make up of continental crust was different to Ocean crust. ( More Iron content ?)

 

And that was why Continental crust floated (as it were on top ) and Oceanic crust was more dense so sub-ducted (and sunk as it were ) , under the continental crust. I might have this wrong Marc , Could you clarify.

 

Thanks. Mike

 

Hi Mike;

The back-arc spreading center, to the left in the image, is a divergent spreading process similar to the mid-ocean ridges. But as I described above it would be activated by the ebb and flow of the subduction process during contraction of the core-mantle from decreased current amplitude, in addition to being separated during extension of the crust by the mantle during the periods of increased thermal expansion. I would expect the subduction driven spreading to be small while the expansion spreading would be conciderably more. Its movement is due to the subducted plate sections expanse producing proportionate kinetic energy movement as described in post 7. According to Wikipedia; Spreading rates vary from very slow spreading (Mariana Trough), a few centimeters per year*, to very fast (Lau Basin), 15 cm/year. This infill material would be ocean crust like any other.

 

*As a side note; this low level of movement of the Mariana Trough is due to the decoupled and fractured end of that ocean plate section to the east (see post 6) that slips and reduces the ocean plates ability to acquire the tension needed during thermal expansion to pull the spreading center open.

 

The other "new" crust material is being deposited on top of the existing historic ocean crust that underlies the axis of the island arc chain. "new crust is forming along the island arc (from deep melting of the down going plate)" ​ This material is forming the sub-surface volcanic structures that may break the ocean surface and eventually combine to form large island arc structures similar to those like Japan, Philippines and Malaysia.

 

post-88603-0-94862400-1368150884_thumb.jpg

Image courtesy NOAA Ocean Explorer.

 

Imagine the compressed and subducted ocean plate where it bends at the top of the trench. (see image) The subducting crust is pushed by the compression towards the overriding plate. This causes the overriding plates vertical movement that produces a fore arc structure and the tension fracturing of that plates underside that will precipitate the movement of magma through those fractures to the sea floor surface where it will accumulate to form the growing island arc structures, notice the volcano above the "Zone of Melting". The accumulation of crustal deposits that are scraped off the surface of the subducting plate form the accretionary wedge that contributes to the fore arc development. Thanks, arc

I know this may be very basic, but what is the density of the crust compaired to the mantle?

 

If it's higher it may well sink into it but if its' lower then the primary drive for plate movement must not be the weight of the crust droping into the mantle.

 

post-88603-0-57728900-1368160380_thumb.jpg

 

Hello Tim, I'm glade to hear from you again.

I think that is a fundamentally important question and it never occurred to me, I should have investigated it.

If you look at the image you will see some numbers like 6.5 - 7.9 k/s. These are seismic velocities indicating the speed in kilometers per second. The higher the number indicates more distance per second which I believe also indicates greater densities. It looks like the mantle is the highest density.

Thanks, arc

Edited by arc

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Hi Mike;

The back-arc spreading center, to the left in the image, is a divergent spreading process similar to the mid-ocean ridges. But as I described above it would be activated by the ebb and flow of the subduction process during contraction of the core-mantle from decreased current amplitude, in addition to being separated during extension of the crust by the mantle during the periods of increased thermal expansion. I would expect the subduction driven spreading to be small while the expansion spreading would be conciderably more. Its movement is due to the subducted plate sections expanse producing proportionate kinetic energy movement as described in post 7. According to Wikipedia; Spreading rates vary from very slow spreading (Mariana Trough), a few centimeters per year*, to very fast (Lau Basin), 15 cm/year. This infill material would be ocean crust like any other.

 

*As a side note; this low level of movement of the Mariana Trough is due to the decoupled and fractured end of that ocean plate section to the east (see post 6) that slips and reduces the ocean plates ability to acquire the tension needed during thermal expansion to pull the spreading center open.

 

The other "new" crust material is being deposited on top of the existing historic ocean crust that underlies the axis of the island arc chain. "new crust is forming along the island arc (from deep melting of the down going plate)" ​ This material is forming the sub-surface volcanic structures that may break the ocean surface and eventually combine to form large island arc structures similar to those like Japan, Philippines and Malaysia.

 

attachicon.gifxsection_600.jpg

Image courtesy NOAA Ocean Explorer.

 

Imagine the compressed and subducted ocean plate where it bends at the top of the trench. (see image) The subducting crust is pushed by the compression towards the overriding plate. This causes the overriding plates vertical movement that produces a fore arc structure and the tension fracturing of that plates underside that will precipitate the movement of magma through those fractures to the sea floor surface where it will accumulate to form the growing island arc structures, notice the volcano above the "Zone of Melting". The accumulation of crustal deposits that are scraped off the surface of the subducting plate form the accretionary wedge that contributes to the fore arc development. Thanks, arc

 

attachicon.gifxsection_600.jpg

 

Hello Tim, I'm glad to hear from you again.

If you look at the image you will see some numbers like 6.5 - 7.9 k/s. These are seismic velocities indicating the speed in kilometers per second. The higher the number indicates more distance per second which I believe also indicates greater densities. It looks like the mantle is the highest density.

Thanks, arc

 

So is the crust illustrated ................. named OLD Ocean Crust the Continental Crust, as it appears to lay under the land there. Or will there be a different Continental crust further into Asia. I am a bit Mixed up ,in my head with What lays under continents like Europe and what lays under the area of illustrated.?

Mike

Edited by Mike Smith Cosmos

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So is the crust illustrated ................. named OLD Ocean Crust the Continental Crust, as it appears to lay under the land there. Or will there be a different Continental crust further into Asia. I am a bit Mixed up ,in my head with What lays under continents like Europe and what lays under the area of illustrated.?

Mike

 

Hi again Mike;

This is some of post 10 and gives a starting point of how ocean crust is built at divergent centers. (think of them as expansion joints) During a period of thermal increase the crust is required to continually move independent of the mantle to release what are primarily tension stresses. The Atlantic for example has two opposing continentally attached ocean crust sections that are slowly and incrementally being separated by the expanding mantle. This is simply a very large tension relieving mechanism that back-fills with magma.

 

During each thermal cycle the width of the plates is continually increasing from the magma infill, as it has since their creation during the break-up of the super-continent. As it does this, the continually increasing tension from the drag or friction of that additional material imposes proportionally increasing tension stresses at the continental ends of the ocean plates. Eventually, when the plates are maybe twice as wide, the ocean plates will fracture from that tensional stresses, adjacent to where they meet the continents.

 

These new stress fractures will begin the process of becoming subduction zones during the following contraction portions of the cycles, and will develop trenches with depths proportionate to the drag created by the ever growing plates. The Pacific Plate and its now subducted twin the Farallon likely began in this manner. The Pacific Plate succumbed to this tension stress, probably shortly after the creation of what is now the oldest seafloor in the Pacific at maybe 180+ MYA.

 

These ocean plates eventually get over ridden on one end and subducted on the other, imposing tensional forces that create structures like the Mariana Trench and the Basin and Range and developing stress relieving mechanisms such as the San Andreas Fault. This give and take of the thermal cycle will continue until the two opposing and closing continents meet, forming once again a combined continental structure.

 

So the continents seem to be the longer lasting of the two crusts, and generate the seafloor anytime a rift is developed from thermal expansion. As the continental sections separate seafloor is created, as they come together seafloor is destroyed, sometimes taking a little continental crust with it. But that is replaced there or somewhere else by an accretionary wedge of crustal deposits that add to continental land mass like the Himalayas, Alps or anywhere else an ocean basin is bulldozed up onto or under the continental edge. A lot of the accretionary wedge material is the sedimentary outflow of river systems, so the material is just recycled continental material anyway. All the while, volcanic processes rebuild volcanic mountain arcs like the Cascades of the western U.S. and the central Andes, continually restoring their continental inventory. arc

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Arc,

 

The computer won't let me cut+paste. Pretend I have put in the bit about 7.9 k/s.

 

If the crust is less dense than the mantle it will not sink into it as it is boyant. It will float on top of it. Something else has to be the driving force pushing the crust under other bits of crust.

 

7.9 k/s ..... ummm, is that the cubic volume of rock which moves in one event or the speed of the shock wave or what? I don't see how the actual rock could move so quickly. It's over half the needed escape velocity from earth. I think we would have noticed if the rock was fired about at that speed.

 

I know I am not able to keep up with the talk about strain energy or whatever but occaisionally I am the one who points out the King has no cloathes on.

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Arc,

 

The computer won't let me cut+paste. Pretend I have put in the bit about 7.9 k/s.

 

If the crust is less dense than the mantle it will not sink into it as it is boyant. It will float on top of it. Something else has to be the driving force pushing the crust under other bits of crust.

 

7.9 k/s ..... ummm, is that the cubic volume of rock which moves in one event or the speed of the shock wave or what? I don't see how the actual rock could move so quickly. It's over half the needed escape velocity from earth. I think we would have noticed if the rock was fired about at that speed.

 

I know I am not able to keep up with the talk about strain energy or whatever but occaisionally I am the one who points out the King has no cloathes on.

 

post-88603-0-34482200-1368378287_thumb.jpg

 

Hi Tim,

These are the speeds that shock waves such as those generated by earthquakes can travel through the various material layers. The denser the material the faster the speeds. Sand would be slow, while basalt (ocean crust) or granite (continental crust) would be substantially faster. It looks to me that even though the mantle's material is a higher temperature with a plastic nature as compared the overlying or subducting crust, it maintains a higher seismic velocity.

 

According to the image, the mantle shows the highest seismic velocities which leaves me to conclude it has the highest density. Would the current model require the crust to overcome this differential through hanging enough mass over the edge to create gravitational pull? Gravity driven kinetics would have to overcome both the friction of the extended crust section, which may be as wide as the Pacific, and the resistance of the mantles greater density to the subducting crust's intrusion. The current models gravity mechanism would need sizable intrusion to produce the gravitational energy needed, yet it seems the melting away of the subducted crust would be needed to overcome the density problem of allowing movement of the crust into the trench.

 

As I mentioned before I do not possess the math skills to properly express this phenomena but my intuition tells me there is something wrong with the current models explanation of this. arc

Edited by arc

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Google says that the density of the earth's crust is 2.7 to 3 and the mantle is 3.3 to 5.7.

 

The crust will not fall into the mantle. It will float upwards if it's in it.

 

Something is driving the plates into and over each other that is not the crust falling down into the earth.

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phys.org/news/2013-05--earth-center-sync.html

 

The earth's core is rotating at a different speed to the mantle.

 

That will give you all the driving mechanisim you need.

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Tim the plumber

Posted Today, 01:12 AM

Google says that the density of the earth's crust is 2.7 to 3 and the mantle is 3.3 to 5.7.

 

The crust will not fall into the mantle. It will float upwards if it's in it.

 

Something is driving the plates into and over each other that is not the crust falling down into the earth.

 

Tim we may be on the wrong track on this. I located another thread;

 

Density and Seismic Velocity

Started by OSHMUNNIES, Aug 30, 2011
"density and seismic velocity inversely proportional to one another" - OSHMUNNIES
The Answer!...? Fri, 09/09/2011 - 02:00
OSHMUNNIES posted on this site and gave a better explanation of the phenomena.
After discussing this with my geophysics prof., I've learned that although seismic velocity and rock density may be inversely proportional in mathematical theory, they don't actually have that relationship anywhere in nature.
- OSHMUNNIES
OK, I think were back on track. But what you want to discuss is extremely complex, there are so many variables that I don't believe I have the proper educational back ground to navigate it successfully.
Tim, do you feel that my model does not provide a viable solution to subduction in using the raised crustal mass to drive the subducting plate into the resistive mantle? This is a very efficient mechanism, vary simple with more than enough force and more importantly traction, to overcome the resistance in the mantle and the friction during the plates movement down. A higher density in the mantle would not be an issue with this level of gravitational potential energy as the engine. And remember if the kinetic movement exceeds the trenches rates of resistance, the energy will be diverted into the building of mountain structures. Go back and read the beginning of this thread post # 4,5,6,7,8. arc


phys.org/news/2013-05--earth-center-sync.html

 

The earth's core is rotating at a different speed to the mantle.

 

That will give you all the driving mechanisim you need.

 

Tim, can you elaborate a little on this hypothesis? How does the mechanism move the plates? Is there subduction?

Edited by arc

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I may have misunderstood your model.

 

I understand that the weight of the crust moving over the one being subducted is what is supplieing the force to push the lower one down into the mantle but that still requires a suficent force pushing the plates into collision in the first place.

 

The idea that the weight of the decending crust can drag the rest after it is wrong. It might be my misunderstanding of your model there. If the upper crust plate was magically removed the lower one would float up. There is no force draging the crust downwards.

 

If the inner core is rotating at a different speed to the crust then there must be friction between the various layers of the earth. This will supply horizontal forces to the underside of the crust plates. Mountain ranges which stick up into the air also have deep "roots" which stick down into the mantle. These supply the boyancy within the mantle to stop the mountains sinking into the mantle. They will also drag in the moving mantle more than the flatter low oceanic crusts. This will provide different horizontal forces acting on the underside of the various crust plates. This will set up the situations of collision and ripping appart.

 

More mathsy scientific stuff is beyond me but that must be the basic situation given a differential rotation speed of the inner core.

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I may have misunderstood your model.

 

I understand that the weight of the crust moving over the one being subducted is what is supplieing the force to push the lower one down into the mantle

 

Tim, that is not my model. You need to read posts 4-8. This is the main context of #4;

 

Lets imagine that there is a small current/temperature variable over millions of years in the Earth's magnetohydrodynamic field generator ( that could and probably would also be expected in the current standard model I think) and it slowly raises the outer core's temperature a fraction of a degree over those millions of years. A fraction of a degree over millions of years. I believe almost everyone would expect the liquid outer core to thermally expand a proportionate amount to the degree of temperature rise. Now what would you expect from the mantle? Do you think it could contain the molecular level expansion forces of the core's liquid iron? The mantle is under extremely high pressures and temperatures especially the deeper you go. Would you think that it would move out a little making a little more room in its interior? Unlikely, I think in either model most would expect the mantle would show a reflex at its outer boundary. But how much? I would think it would resemble the current seafloor spreading metrics.

So lets say this continues over a couple of million years building up a nice little slice of new divergent plate infill in the worlds entire divergent inventory. Now we start into that lower level part of the cycle with the core going down a fraction of a degree over millions of years. As the liquid iron lowers imperceptibly the mantle responds and moves in tandem. What will the crust do? It would likely move with the mantle but it can't because of the nice new slice of seafloor that now blocks its pathway down. The plates begin to preload like a Roman arch, slowly sliding to the opposite direction into the trench. Something neat is happening here tho, the plates all have different masses, from some of the largest like the Pacific or say Eurasia to the smaller down to the micro plates. The larger plates take the longest amount of time to unload while the smaller may be able to even slip some on the edges to release even faster.

 

Refering to this claim; Plate tectonicists insist that the volume of crust generated at midocean ridges is equaled by the volume subducted. But whereas 80,000 km of midocean ridges are supposedly producing new crust, only 30,500 km of trenches exist. Even if we add the 9000 km of "collision zones," the figure is still only half that of the "spreading centers" (Smoot, 1997a).

​In my model this would indicate that the subduction lags behind the expansion portion of the cycle. It takes longer for the plates to melt into the asthenosphere than it does to create the infill that leverages the plate into the trench. So the answer to why is there some subduction happening now? Would be because not all of the plate compression (probably the largest ones) has bled out into the trenches before this current expansion cycle started. The outer core thermal cycle is variable throughout its cycle, even from one maximum to the next in both timing and duration.

 

Now lets say we have a extra long thermal expansion cycle and the divergent plate boundaries build up a very large infill, one of those that only happens every 20 or 30 million years. When the outer core begins to cool and initiates the plates subduction the trenches will be, like before, slower to receive the plate material than the mantles withdraw.

The compression begins building on the plates, being only able to over come the trenches rates of resistances to a point. As the mantle continues down the plates are subjected to loads that require vertical movement of rock strata to relieve to massive compression building on the plates, this compression is in proportion to the length of time and degree of expansion in the previous cycle in relation to the degree of cooling in this cycle.

 

Again, go to my profile page and then go to my Plate Tectonic site that's listed there. You will see the predictive power that this simple mechanism gives to geology.



If the inner core is rotating at a different speed to the crust then there must be friction between the various layers of the earth. This will supply horizontal forces to the underside of the crust plates. Mountain ranges which stick up into the air also have deep "roots" which stick down into the mantle. These supply the boyancy within the mantle to stop the mountains sinking into the mantle. They will also drag in the moving mantle more than the flatter low oceanic crusts. This will provide different horizontal forces acting on the underside of the various crust plates. This will set up the situations of collision and ripping appart.

 

More mathsy scientific stuff is beyond me but that must be the basic situation given a differential rotation speed of the inner core.

 

I think you may find some answers here-

 

http://www.scienceforums.net/topic/72123-is-there-heat-generation-at-the-center-of-the-earth/

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I get the idea that the changes in internal temperature could cause the crust to have to expand and contract and this would cause cracking of the crust which would be infilled with new lava which then forms new crust.

 

But, America is slowly and steadily moving westwards away from Europe. It's doing it faster than the earth is expanding. Something is pushing it along.

 

If the central core of the earth is rotating at a different speed to the crust then this is exactly what I would expect. The friction of the various layers of the earth will cause the top most crust to fracture and slowly float about on the more liquid layers benith. The speed of this has to be ponderous as the visocity of semi-molten rock 200km thick is a lot. It will however slowly sludge along carrieing the much thinner surface with it.

 

I am not at all saying that the earth has no internal "weather" and that your idea of changes in temperature are not valid but the primary thrust to move continents has to be currents pushing them from below.

 

If your idea of the thermal expansion and contraction was all there was then the crust would look like sea ice when it is fairly newly frozen and there are flat plates with ridges where they push against other such plates. The ridges are all around the flat plates, not the result of subduction and don't show the long term growth of mountains on one side of the plate of ice.

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If your idea of the thermal expansion and contraction was all there was then the crust would look like sea ice when it is fairly newly frozen and there are flat plates with ridges where they push against other such plates. The ridges are all around the flat plates, not the result of subduction and don't show the long term growth of mountains on one side of the plate of ice.

 

Tim,

Most analogies used to explain physical similarities between two examples have limits that increasingly tests the analogies validity as the analogy is forced. Your use of ice could be used to bolster or refute my thesis based on the accurate applications of the physical properties involved. One of the key factors in my thesis is the curvature of the Earth and the loading of gravitational potential energy in the form of the mass of the crust. I would use a different analogy to explain this.

 

When a bridge is designed to span a distance and the particulars do not call for center supports the span if not to great can be accomplished by a simple curved deck fitted between to immovable abutments. This is the mechanism that is at play in my thesis. The crustal plates are the curved deck loaded with its own mass that will dissipate its energy as movement into the abutments on either end. As the mantle recedes, incrementally loading energy into the crust's raised mass, the energy will divert as kinetic movement into the trenches and mountains as the gravitational potential energy dissipates. Trenches and mountains are simply compression relieving devices, just as the mid-ocean ridges, aka divergent plate boundaries, are a tension releasing device. Your analogy is missing this key component and therefore is a weak example of the physics involved. arc

 

But, America is slowly and steadily moving westwards away from Europe. It's doing it faster than the earth is expanding. Something is pushing it along.

 

The current movement of North America is due to the mantle's displacement of the crust through slow thermal expansion, allowing magma to incrementally fill the tension releasing mechanism of the divergent plate boundary as it is moved apart. This slow expansion is happening concurrently with the various rates of subduction in some trenches as the larger plates are still unloading their compression from the earlier mantle contraction period. There is no large scale displacement or mountain build during during this time. Just movement as the crust adjusts to equalize crustal energies.

 

Additional and large scale subduction is during the contraction portion of the cycle when the gravitational potential energy in the crust is incrementally unloaded as kinetic movement into the trenches and more importantly mountain complexes.

 

Tim, the validity of a thesis is in its ability to predict observations. This is where your thesis will live or die.

Edited by arc

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Arc,

 

Do you agre that the earth's core is moving at a different spin rate to the crust?

 

Do you think that this will cause/be part of currents of moving molten and smi-molten rock within the various layers of the earth?

 

Do you think that this will create friction on the underside of the crust?

 

Have you included this idea into your model?

 

I think you have a strong point about the variability of the size of the earth. I do however, think you need to include other mechanisims in there as well.

 

You can have a theory which gives the right answer and yet is still wrong. Lense theory for instance has been show to not be right as light is a particle. It works so every one uses it but....

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Tim, nature requires that all processes be done with a "conservation of energy", the efficiency law built into every atom in the universe. I am not a physicist and should stay away from the complexities of that field. But I know that you will not find in nature any unneeded mechanisms and processes, nature seeks to find equilibrium and balance throughout its domain and does so expending as little energy as is required to do the job.

 

With that in mind, my theory if correct should describe in simple terms the least number of energy transfers or conversions needed to explain completely the observed phenomena. The inclusion of extra or complicated mechanisms to bridge inconsistencies in the thesis is an indication that the concept is inaccurate at the very least to completely wrong if it requires a string of complicated and/or numerous mechanisms, most being below surface, unseen and only imagined.

 

This NASA article is a good place to start. http://science.nasa...._magneticfield/

 

post-88603-0-36133300-1369023282_thumb.gif

A supercomputer model showing flow patterns in Earth's liquid core.

Dr. Gary A. Glatzmaier - Los Alamos National Laboratory - U.S. Department of Energy.
This article states that globally the magnetic field has weakened 10% since the 19th century. And according to Dr. Glatzmaier; "The field is increasing or decreasing all the time," "We know this from studies of the paleomagnetic record." According to the article; Earth's present-day magnetic field is, in fact, much stronger than normal. The dipole moment, a measure of the intensity of the magnetic field, is now 8 × 1022 amps × m2. That's twice the million-year average of 4× 1022 amps × m2.

My theory simply requires that the molten iron of the Earth's magnetic field generator will vary over million year time periods, and that is verified in the above. An increase in amperage will always include an increase in temperature. The temperature increase will in turn always produce thermal expansion of the molten iron. This will displace the mantle and release strain energy in the form of heat during its outward expansion. The slow increase in the mantles circumference will require the crust to separate and adjust to release the continual tension.

 

When the field generator's cycle changes to a lower amperage the process reverses to slow contraction with the crust now loading up its raised mass as gravitational potential energy that will be displaced into the trenches by the divergent plate boundaries recent infill. If the cycles are widely spaced, the extra infill or a long decrease in temperature will produce excessive kinetic movement. The resulting increased crustal compression will surpass the trenches rates of resistance and redirect the energy to the vertical displacement of rock into mountain complexes.

 

That's it, 179 words. Plain and simple with everything based on the most basic principles of thermodynamics.

 

Tim, do you see any place you need to insert a current or convection cell? A rotating fluid or thick magma?

 

You should work out your model, find someone to help you with the complex maths and physics and see if it can provide predictions of observations. I am satisfied that I have been accurate in my model, its simplicity is in a way a validation. I will change it very little except to describe it more clearly, such as when studiot helped me with the correct terminology of strain energy, sharpening my thesis' cutting edge so to speak. arc

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wouldnt the ice melting at the poles lft the poles and cause the other side of the plate to sink?

wouldnt the stress of the missippi filling to flood stage put stress on the plate causing quakes in washington dc and missouri?

could these things add to plate tectonic stresses?

my theory is that about thirty days after the ol miss recedes to normal level there will be a quake in the areas i first mentioned.

Edited by robomont

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