Hot Spots and Differential Rotation
Hot spots like that of the Hawaiian Islands, Iceland and Yellowstone have posed considerable confusion to geologists. There is really little insight as to how or where these phenomena derive from, other than the simple convection theory. However, there is a very strong possibility that these centers of specific volcanic activity, far from plate boundaries may well be due to Tidal Effects and Differential Rotation.
The Earth’s surface is subject to a number of strong gravitational potentials. The two largest and most prominent are the Moon’s gravitational tug, and the Sun’s. Since the Earth rotates, these are never at one place but constantly moving. Both of these forces are experienced daily(or approximately so.)
Their effects on the Tides of Ocean basins are well known. Yet these effects are quite a bit more complex than Newton originally postulated.
With the contributions of Laplace and his tidal equations we have seen that these rises in sea level are rather complex and varied. They are varied simply because the Moon, and Earth and Sun are never quite at the same position. Due to apogee, and perigee, or far and near orbital positions the gravitational attraction is variable, and therefore the tides produced are variable-and either accelerate or decelerate. Moreover, the two tidal forces tend to either augment one another or degrade one another depending on whether they occur in agreement(same time and spatial orientation), or discordance. These factors alone add complexity to sea tides.
However, there are even greater complications to be found.
These include the geometry of sea basis, various bottom terrain, wind directions, currents, vorticity, atmospheric and sea storms, specific gravity at various depths, and thermodynamic effects, or sea temperatures, all of which can complicate things further.
But most complicating in determining the true nature of sea tides is actually the fact that tides do not occur as simple rises in sea level, but in periodic waves. This requires complex Fourier analysis of the resulting wave impulses and periods generated by the revolution of the Earth, orbit of the Moon, and orbit of Earth around the Sun. In the end predicting Sea tides becomes a complicated and difficult task.
We should add that Venus, Mercury, Mars, and Jupiter-possibly even Saturn- will contribute to anomalies in Tidal dynamics when they are in alignment, which though not often, will still generate a disturbance in the wave dynamics of Sea Tides that will to a certain extent be persistent and anomalous.
But in all this one thing is fairly certain, and this is that as these various gravitational forces combine, or dissipate rhythmically, they will create a change of sea level at any point on the sea surface.
Most of these changes will be met with resistance from both the land masses which meet the sea basins, but also adhere to the responsive nature of water. Liquids, depending on their elasticity, will usually revert back to normal after they expend their energy. Therefore, there is tendency at least for the Sea Levels to revert to some kind of normality given both their internal elasticity, and the land barriers which they encounter and are contained by.
However there are really no such bounds for anything below the surface of the Earth. Nor are there any such barriers for the tectonic plates. Any energy imparted to these structures will simply resonate within them. As we can see with Jupiter’s moon Io, this energy will eventually be dissipated as heat.
Moon’s Orbit Increasing Distance
It has long been maintained that the Moon’s orbit is being altered by the revolution of the Earth. Put simply the Moon’s orbit is being accelerated to a further distance while the Earth’s revolution is being slowed. But it has been assumed that these gigantic forces would act uniformly on the Earth’s crust and interior. But this is not a valid assumption.
Even if the Earth’s interior were solid, eventually the resonance of these titanic forces would culminate in particular stresses and fault lines. In other words, the solid would eventually crack to the tug, and due to various resonances that would develop and at times be amplified.
Yet the Earth’s core is not solid after all. It is pliable. It is plastic and we really cannot know just how far down this pliability actually exists. Still, as we see with the theories of George Darwin concerning sea tides, there will be harmonics to account for. Therefore, any pliable material, no matter the degree of plasticity, will be subject to some kind of harmonic resonance if a gravitational force is repeated and oscillations in locale and order occur.
More to the point, such resonance will not be uniform throughout the body. That is the surface will experience a stronger effect than the subsurface. And if the materials are different, therefore if one is semi solid, like the crust, and the other liquid, or semi liquid as is the magma below, there will be differences in the way these materials react to the pull of the Moon and Sun.
The energy released in the deceleration of the Earth’s angular velocity would not be distributed equally throughout the body.
Differential Rotation
It should be understood that the tug of the Moon and Sun will affect the crust in different ways than the way they affect the sub surface, or magma “pool”. The Earth’s crust being higher closer to the Moon, and essentially lighter, or less dense will tend to absorb the Moon’s tug more imminently than the sub surface. Therefore the pull will be stronger. If as we theorize the Earth’s surface “floats” on hot Magma, and this being the cause of Plate Tectonics, then we must add that the Moon’s immediate tug on these floating plates will, after billions of years and billions of revolutions, cause some kind of differential rotation. That is the magma will move faster towards the East-the direction of Earth’s rotation, than will the plates since they will lag due to the Moon’s more imminent pull. Therefore, we can speculate that at least some forcing component of plate tectonics is due to Moon’s tug on these plates, as well as most likely some force from below – due to the rotational dynamics of the core.
This differential rotation, as stated before, will of necessity affect all layers of the Earth right down to the core. The further away an atom is from the Moon, the less it will be affected, putting aside Newton’s ideal summations on the geometry of gravitational forces. Therefore tides are formed at each “sheet” of Earth’s depth. True there may tensile forces that keep the sheets together, but these forces do not in any way dissipate the tug of either the Moon or the Sun as the Earth revolves around its axis. These lunar and solar gravitational forces will at some point cause friction in the different layers, and this will cause heat to be released.
Any liquid, no matter how thick, will eventually rotate as excited particles will seek the most convenient path of least pressure and least resistance. The supposed structure of the Earth’s interior would no doubt be subject to differential rotation since in one way or other the materials involved are ductile, or simply put, liquefied as plastic.
Since heat is generated, and dissipated, we must theorize that there is an “organization” to this that the simple convection theory cannot account for.
It should also be understood that these phenomena, although perhaps similar to rotational atmospheric phenomena, are probably on a time frame of millions, or even hundreds of millions of years. Therefore if gusts similar to those that occur in a tornado, or thunderstorm were to occur in the Earth’s interior rotation, their life cycle would be on the order of a hundred million years rather than minutes. Therefore a “plume” would not arise directly from the core, but from the rotation, and would be tangential to the rotation rather than be at right angles to the core and last for many millions of years. This tangential forcing would strain the crust, and eventually break it open to the surface of the Earth resulting in the Hot Spots that we see. This is especially true since the magma would rotate to the East at a higher speed than the crust.
But this differential rotation would account for the so called Hot Spots, at least in part. Since any rotation of magma that adheres to the crust would eventually force an opening or crack in the crust and would probably move east relative to the fixed crust as we see with most Hot Spots since relative to the magma subsurface the crust is moving West, and the Hot Spots East(relatively.) However, due to turbulence, lasting for millions of years, we may not say that this would necessarily be a “rule” but only subject to probability, as no wind gusts could ever be correlated to a particular direction so it would be that no magma “gusts” would be subject to a particular direction always. There will most likely be occasional anomalies.
Both core rotational turbulence, and deformity of the crust itself could well supply the inlet for magma intrusions. That is to say if there were a deformity in the crust that captured a particular gust or impulse of magma, then there would be an intrusion and an eventual opening to the surface and would result in what we see at Yellowstone, Hawaii or Iceland.
We should add that strains on the crust from either the Moon’s, and Sun’s gravitational tug(over billions of years), as well as core differential rotation and implied thermal dynamics would tend to stress and break the surface crust open. Therefore we should not be so certain that the Missouri Earthquakes of 1811-12 were simply an anomaly, they could well be indicative of a new rift valley in creation-similar to that in East Africa. So where there are cracks or stresses in the crust, you will almost certainly see volcanic activity. Large cracks will result in known volcanic hot beds, these being the Mid Atlantic Ridge, East Africa and others. But small magma protrusions would result in so called Hot Spots. The Icelandic Hot Spot would simply be a “convenient” arrangement where an existing large crack in the sea basin encountered a “gust” or plume from the core rotation and therefore remained and grew large.
We are often told that subduction in plate tectonics results in volcanic fields, but we are not quite as often reminded that one possible cause is that when there is a differential rotational speed(Westward) between plates(most likely due to altitude and the gravitational tug of the Moon and Sun) there will of necessity be stress cracks, and vacuous formations in the crust which will allow the Earth’s magma to protrude. There would also be increased turbulence from below due to the differential rotation and difference in tangential velocity. As well as melting of the sinking crust.
In general we can surmise that some kind of differential rotation is occurring. Though it should not be confused with the kind of differential rotation we see in the Sun, where the equatorial regions are moving faster than the polar regions. Rather we can be fairly certain that the surface of the Earth is moving towards the West relative to the sub-surface due to the gravitational pull of the Moon and Sun. The internal dynamics however, will remain mysterious since we cannot know for certain what the source of the thermodynamic impulse is.
To be sure that layered differential rotation provides at least some frictional heat to the core, but whether that is all the heat being produced we cannot be certain. There may in fact be a nuclear component to the heat source, but it may not be what is now imagined. What exists at the Earth’s core may well be enough for even more exotic processes of heat generation. The Electromagnetic fields at the core must be exceedingly powerful. There is no telling what processes might have emerged there after billions of years. We should be certain that there is much more dynamism at the Earth’s core than we have yet to surmise.