More evidence to digest:
75. Calculations are sometimes put forth in an attempt to show that plumes can rise through the mantle. Usually assumed are unrealistically low values for the mantle’s viscosity and density or unrealistically high values for the plume’s initial temperature and volume. These claims take the position, “We know flood basalts came from the outer core (where most magma resides), so here is how it must have happened.” Others, looking at the physics involved and using the most reasonable numbers, admit they don’t understand how enormous volumes of flood basalts could rise through the mantle. My calculations show that a magma plume rising buoyantly and melting its way up from the core-mantle boundary would initially have to exceed the Earth’s volume for just one drop of magma to reach the Earth’s surface. Others, cited below, have reached similar conclusions.
- “A simple calculation shows that if ascent is governed by Stoke’s law, then the great viscosity of the lithosphere (about 10 25 poise, if it is viscous at all) ensures that the ascent velocity will be about ten thousand times smaller than that necessary to prevent solidification. A successful ascent could be made only by unrealistically large bodies of magma.” Bruce D. Marsh, “Island-Arc Volcanism,” Earth’s History, Structure and Materials, editor Brian J. Skinner (Los Altos, California: William Kaufman, Inc., 1980), p. 108.
- “The question of where the magma comes from and how it is generated are the most speculative in all of volcanology.” Gordon A. Macdonald, Volcanoes (Englewood Cliffs, New Jersey: Prentice-Hall, Inc., 1972), p. 399.
- “All the evidence that has been used so far to support the plume model—geochemical, petrological, thermal, topographic—is equivocal at best, if indeed not contrary. The plume idea is ad hoc, artificial, unnecessary, inadequate, and in some cases even self-defeating, and should be abandoned.” H. C. Sheth, “Flood Basalts and Large Igneous Provinces from Deep Mantle Plumes: Fact, Fiction, and Fallacy,” Tectonophysics, Vol. 311, 30 September, 1999, p. 23.
- “There are no chemical or isotopic data that require deep-plume origins or anomalously high temperatures, and no reliable seismic-tomography results have ever revealed a plume.” Gillian R. Foulger and Warren B. Hamilton, “Plume Hypothesis Challenged,” Nature, Vol. 505, 30 January 2014, p. 618.
- “Deep narrow thermal plumes are unnecessary and are precluded by uplift and subsidence data. The locations and volumes of ‘midplate’ volcanism appear to be controlled by lithospheric architecture, stress and cracks.” Don L. Anderson, “The Thermal State of the Upper Mantle; No Role for Mantle Plumes,” Geophysical Research Letters, Vol. 27, 15 November 2000, p. 3623.
This is referenced in the Evidence to be explained section:
Flood Basalts. Vast amounts of melted basalt rapidly erupted onto the (solid) Earth’s surface, especially in and surrounding the western Pacific. How did this happen, and why was it so rapid?
7. Hydroplate Theory explanation
Magma outpourings resulted from the following chain of events:
- the bulging of the chamber floor in what was to become the Mid-Atlantic Ridge, this bulging produced movements deep within the Earth that resulted in deep faulting (shearing), frictional heat, and melting,
- the contraction of magma below the crossover depth, and the eruption of magma above the crossover depth,
- the resulting subsidence of the Pacific plate, and
- the accelerating of hydroplates away from the rapidly rising Atlantic floor and toward the subsiding Pacific.
(A similar acceleration occurs when a horizontal teeter-totter board, with a massive rock resting at its center, slowly begins to tip. The tipping rate will increase at an accelerating rate, so the rock will rapidly slide—accelerate—down the board and crash.)
This explanation answers all the questions in the
“Volcanoes and Lava” and
“Geothermal Heat” discussions, beginning on page
122. Because these deep faults often intersect the Earth’s surface as linear features, we have many linear island chains, but with different orientations.
Magma rises to the Earth’s surface along deep faults, not in plumes. Rising as plumes presents “severe thermal and mechanical problems.” Magma can rise along faults a million times faster.
73
8. Plate Tectonic Theory explanation:
Over millions of years, plumes of magma can rise from the liquid outer core.
[Response: As explained on page
166, below the crossover depth of 220 miles, magma is too dense to rise. This also means that mantle circulation is a fiction.
This mistaken idea arises because seismic tomography has found more than two dozen examples of magma paths joining the outer core to the Earth’s surface.
74 However, as we have shown, magma (produced by friction along faults that extend from the Earth’s surface to the outer core) drains down below the crossover depth and rises above the crossover depth. Therefore, a magma path does join the core with the Earth’s surface, but magma never rose from the core as a plume.
Even if a hot plume of magma could slowly rise through the entire mantle, the plume would lose heat to colder, overlying rock. This heat loss would exceed the excess heat in the plume. Calculations show that hot plumes cannot rise from the outer core and produce flood basalts.
75 Nor will current processes open cracks in the mantle so a plume can rise. Confining pressures under the crust are simply too great.
An old, now discredited,
76 idea used in popularizing plate tectonics was that fixed “hotspots” exist inside the Earth. Supposedly, plumes of hot, melted rock continually rise from the Earth’s core upward through the mantle. Over millions of years, as a plate somehow slid over a hotspot, the plate melted along a line and produced volcanoes and flood basalts. Yellowstone National park is frequently given as one example.
The Hawaiian Islands were considered the best example of this.
77 Not explained were the long chains of submarine volcanoes that intersected the Hawaiian chain—some at large angles. It is now recognized that if hotspots exist, they must move.
78 Other volcanic chains, such as the Bermuda Rise, are almost perpendicular to the claimed movements of their plates.
79
If the mantle circulates enough to move a plate, why is a hotspot’s plume in that moving mantle fixed? If a chain of volcanoes means its plate is drifting, does an isolated volcano mean that its plate is not drifting? Faster moving plates should have fewer volcanic cones “burned” through them than slower plates. Just the opposite is the case.
80 Also, the chemistry of rocks comprising these “hotspot” chains indicates that the magma originated from the upper mantle, not the lower mantle boundary as claimed by plate tectonics.
81 Endnote
75 explains the most compelling objection to the hotspot idea—the absence of a physical mechanism.]