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Thread: Independent convections

  1. #1 Independent convections 
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    The motion of Earth's plates are supposed to be driven by persistent currents of magma. As well, or another way of looking at it, parting and subduction of the plates causes convection, which must continue as long as those plate conditions last. Long chains of volcanoes are formed by a single "hot spot" acting on a plate like a sewing machine on fabric slid across it. Like clockwork, for millions of years. So we can say that, since the breakup of Pangaea, there has been a stable convection regime directly beneath the plates and probably extending far down into the mantle.

    If the convection itself is driving tectonics, which play out over hundreds of millions of years, then we model such a persistent force on grand scale involving the whole Earth as one stable-celled convective system.



    The Earth's magnetic field is supposed to owe to convection currents. The orientation and strength of the field indicates the Earth's dominant convection regime. For the field to invert, or wander as it is now, the Earth's convection system must change. And change rapidly it does, apparently. For since the breakup of Pangaea the magnetic poles have reversed scores of times, seemingly at random.

    We model the convections responsible for the magnetic field as chaotic. They don't seem to relate to anything going on above the mantle.



    How can these two patterns of convection coexist in one mantle and not influence each other?


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  3. #2 Re: Independent convections 
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    Quote Originally Posted by Pong
    The motion of Earth's plates are supposed to be driven by persistent currents of magma.
    If by supposed you mean "allegedly" or "mistakenly believed" then I agree totally.

    As well, or another way of looking at it, parting and subduction of the plates
    There is no such thing as subduction. Subduction is a myth.

    "In the oral session, except for one presentation that was clearly pro plate tectonics, and another one that did not address the issue of global and large scale geology specifically, there was general consensus that subduction, and therefore plate tectonics, is mechanically impossible." -- Stavros T. Tassos (seismologist/geoscientist) and Karsten M. Storetvedt (geophysicist), November 2007

    "Subduction is not only illogical, it is not supported by geological or physical evidence, and violates fundamental laws of physics." -- Lawrence S. Myers, cryptologist/geoscientist, 2005

    "Now that the subduction concept has been developed for almost 30 years, it can be said that it has not been fruitful geologically." -- Yury V. Chudinov, geologist, 1998

    causes convection, which must continue as long as those plate conditions last.

    Long chains of volcanoes are formed by a single "hot spot" acting on a plate like a sewing machine on fabric slid across it. Like clockwork, for millions of years. So we can say that, since the breakup of Pangaea, there has been a stable convection regime directly beneath the plates and probably extending far down into the mantle.

    If the convection itself is driving tectonics, which play out over hundreds of millions of years, then we model such a persistent force on grand scale involving the whole Earth as one stable-celled convective system.

    The Earth's magnetic field is supposed to owe to convection currents. The orientation and strength of the field indicates the Earth's dominant convection regime. For the field to invert, or wander as it is now, the Earth's convection system must change. And change rapidly it does, apparently. For since the breakup of Pangaea the magnetic poles have reversed scores of times, seemingly at random.

    We model the convections responsible for the magnetic field as chaotic. They don't seem to relate to anything going on above the mantle.

    How can these two patterns of convection coexist in one mantle and not influence each other?
    There is no such thing as convection. Convection is a myth.

    "There is no direct unambiguous evidence that mantle convection and/or mantle circulation actually takes place; in fact, there is some evidence to the contrary. Moreover, there is no evidence that oceanic basalt can be repeatedly recycled through the mantle without being substantially and irreversibly changed. Yet, mantle convection/circulation and basalt recycling are fundamental necessities for the validity of plate tectonics. Furthermore, plate tectonics theory does not provide an energy source for geodynamic activity." -- J. Marvin Herndon, geophysicist, 2005


    "The most likely site for error is in the most fundamental of our beliefs." -- Samuel Warren Carey, geologist, 1988
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  4. #3  
    Forum Isotope Bunbury's Avatar
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    Pong,

    The convection currents responsible for the Earth's magnetic field occur in the core, not the mantle. Convection in the mantle is driven by heat from the core. Would changes in the magnetic field of the core have any corresponding effect on the flow of heat? I don't know - just asking.

    It seems to me that even if there is interaction between the core and the mantle, our only direct information comes through weaknesses in the crust. This highly filtered information wouldn't tell us much if anything about what changes are occuring deep below the crust, or would it?
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  5. #4  
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    Quote Originally Posted by Bunbury
    The convection currents responsible for the Earth's magnetic field occur in the core, not the mantle.
    Because that's where the iron is? Makes sense.

    Quote Originally Posted by Bunbury
    Convection in the mantle is driven by heat from the core.
    So it fuels it but doesn't direct it. A lively hearth fire still drives steady draft up the chimney.
    Quote Originally Posted by Bunbury
    It seems to me that even if there is interaction between the core and the mantle, our only direct information comes through weaknesses in the crust. This highly filtered information wouldn't tell us much if anything about what changes are occuring deep below the crust, or would it?
    There appears to be a core-mantle-boundary. Yet that boundary - to our sketchy observation - looks irregular. It's not the smooth sphere shown on pictures. I think the shape would reflect both mantle convection on the outside, and core convection on the inside... analogous to ice floes eroded by both wind and current. The result is highly chaotic. Maybe if this boundary is relatively inflexible, it could also promote chaos by hysteresis? I wonder how far it lags behind the two convection systems? Do the convection systems ever chance together to rupture it? Such an event must really stir things up!
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  6. #5 Re: Independent convections 
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    Quote Originally Posted by Pong
    The motion of Earth's plates are supposed to be driven by persistent currents of magma.
    Not quite. Magma is a liquid whereas the mantle is (mostly) a plastically deforing solid.
    There's more than one mechanism thought to drive movement and the relative amounts they contribute isn't agreed upon. See here: http://webspinners.com/dlblanc/tectonic/mechansm.php

    Long chains of volcanoes are formed by a single "hot spot" acting on a plate like a sewing machine on fabric slid across it. Like clockwork, for millions of years.
    Pretty much, but hotspots seem not to be perfectly fixed, just relatively stationary compared to the plates.

    If the convection itself is driving tectonics, which play out over hundreds of millions of years, then we model such a persistent force on grand scale involving the whole Earth as one stable-celled convective system.
    Two or three celled, depending on what model you look at. The mantle may convect as one or two units according to the most widely accepted models, and the outer core as a separate system.
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  7. #6 Re: Independent convections 
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    Quote Originally Posted by The Matt
    There's more than one mechanism thought to drive movement and the relative amounts they contribute isn't agreed upon.
    Why I said, "another way of looking at it, parting and subduction of the plates causes convection". I imagine feedback - where plate effects cause convection cells to follow the plates, and convection causes the rifts, so the plates move... maybe. :?

    I still don't see how a molten/plastic "boundary" could keep conventions isolated from each other. If the core has some hot regions (and it must if it's convecting metals), those must impart some extra heat to the mantle above, no? And the converse. So why don't the systems fall into sync? They don't, yet "boundary" seems like wishful thinking, and a lame explanation. How else do we get several systems acting out of step and even generating chaos as seen in our fickle magnetic field and our crazy continents?

    Why don't these systems settle into a stable pattern?
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  8. #7 Re: Independent convections 
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    Quote Originally Posted by Pong
    I still don't see how a molten/plastic "boundary" could keep conventions isolated from each other. If the core has some hot regions (and it must if it's convecting metals), those must impart some extra heat to the mantle above, no? And the converse. So why don't the systems fall into sync?
    Where do you get the idea that they don't sync-up in some way? It's a year or two since I did any research on this, but as far as I can remeber, while it was fairly well accepted that the mantle convects to some degree, the jury was still out on how much and in what pattern. One of the options suggested was that while material may not pass between the upper and lower mantle, the points of upwelling between the two wer pretty closely linked.
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  9. #8 Re: Independent convections 
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    Quote Originally Posted by The Matt
    Where do you get the idea that they don't sync-up in some way?
    See opening post. If the magnetic field provides a clue to what our core is up to, all we can say about that is: WTF. It's like, perversely chaotic. Then it takes these fantastically long breaks that don't relate to anything either. 50 million year hysteresis maybe?

    Well I'm sure thousands have tried relating the field to something. It's maddening.
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  10. #9  
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    Quote Originally Posted by Bunbury
    It seems to me that even if there is interaction between the core and the mantle, our only direct information comes through weaknesses in the crust. This highly filtered information wouldn't tell us much if anything about what changes are occuring deep below the crust, or would it?
    http://www.geocities.com/CapeCanaver...ass-stress.htm
    "The most likely site for error is in the most fundamental of our beliefs." -- Samuel Warren Carey, geologist, 1988
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  11. #10 Re: Independent convections 
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    Quote Originally Posted by The Matt
    depending on what model you look at
    You can say that again.
    "The most likely site for error is in the most fundamental of our beliefs." -- Samuel Warren Carey, geologist, 1988
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