No Mantle Convection
In 1931, Holmes  introduced the concept of mantle convection (figure at right) as a motive force for Wegener's continental drift . In Holmes' mantle convection idea, the rocky part of Earth, the mantle, is assumed to circulate in great loops, like conveyer belts, dragging the continents along. The mantle-convection assumption later became a critical part of plate tectonics. But, in eight decades there has been no unambiguous, independent corroborating evidence to show that mantle convection actually exists.
In science, advances are made, not by cataloging a theory's successes, but by revealing its short-comings. Too often people think that mantle convection "must" exist because plate tectonics seems "correct", rather questioning whether there might be a problem with mantle convection, asking "What's wrong with this picture?" J. Marvin Herndon, pictured at left, did in fact question mantle convection and found a serious problem [2, 3]. Indeed, the critical assumption of mantle convection is truly the Achilles heel of plate tectonics.
When a fluid is heated from beneath, it expands becoming lighter, less dense, than the fluid above it. This top-heavy arrangement is unstable, so fluid motions result as the fluid attempts to restore stability. The top-heavy arrangement occurs because the temperature at the bottom is hotter than at the top. This is convection. Not only is the Earth’s mantle not a fluid, but the weight of over-burden rock causes compression within the mantle, which increases with depth. Matter at the bottom of the mantle is about 62% more dense than at the top, as shown in the figure at right. Heating bottom-rock causes a miniscule increase in volume, hence miniscule decrease in density, much, much less than 1%. This is far, far too little to make the "parcel" of bottom-mantle light enough to float to the top, not enough to make the mantle top-heavy; the result is no mantle-convection at all. Moreover, the tacit assumption that the solid mantle behaves as an ideal gas with no viscous loss, i.e., adiabatic, is incorrect as evidenced by earthquakes at depths as great as 660 km.
Often Earth-mantle convection is (wrongly) "justified" by calculating a high Rayleigh Number. But, as discovered by Herndon, Lord Rayleigh's derivation was based upon constant density except as altered by thermal expansion at the base and, thus, is not applicable to the Earth's mantle .
Plate tectonics is seriously flawed by its necessary reliance on mantle convection. Herndon has set forth a new indivisible geoscience paradigm, called Whole-Earth Decompression Dynamics, that explains the myriad of observations usually attributed to plate tectonics without requiring mantle convection. See the following
New Indivisible Geoscience Paradigm (click here)
Whole Earth Decompression Dynamics (click here)
Preface to Indivisible Earth (click here)
Quick Overview of Herndon's New Indivisible Geoscience Paradigm (click here)
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|1.||Holms, A., Radioactivity and Earth movements. Trans. geol. Soc. Glasgow, 1931, 18, 559-606.|
Wegener, A. L., Die Entstehung der Kontinente. Geol. Rundschau, 1912, 3, 279-292.
|3.||Herndon, J. M., Uniqueness of Herndon's georeactor: Energy source and production mechanism for Earth's magnetic field. 2009, arXiv:0901.4509 (click here for pdf)|
|4.||Herndon, J. M., Geodynamic basis of heat transport in the Earth. Current Science, 2011, 101, 1440-1450. (click here for pdf) (click here for pdf)|
|5.||Lord Rayleigh, On convection currents in a horizontal layer of fluid where the higher temperature is on the under side. Philosophical Magazine, 1916, 32, 529-546.|
|6.||Herndon, J. M., Whole-Earth decompression dynamics. Current Science, 2005. 89(10), 1937-1941. (click here for pdf)|