Figure 8. Northern Hemisphere EagleEye enhanced seismic tomography structural geology sections showing the subduction zones and extensional rifts and ridges.
This figure is one that I have never seen in any textbook or paper. Have you? Why not?
It shows seismic tomography cross-sections around the Northern Hemisphere. It shows brittle structures down to the Outer Core right around the Earth. The main features are the North American Pacific (upper-left) and the Eastern Asia and Japan (lower-right) subduction zones (blue arrows) getting pushed down into the liquid Outer Core.
The image shows the mid-Atlantic Ridge (top-right) as a shuffled, but brittle structural system that goes subvertically to the Outer Core and an incipient, internal plate boundary in the centre of Asia (mid -right) that extends from the surface to the Outer Core. It also shows that the Europe/Africa collision (mid-top-right) extends to the Outer Core.
The result of this subduction tectonic activity is the cutting off of this blue, cooler, subducted descending material (~2,500 °C) by the Outer Core (~ 4,500°C) which has differential movement to the mantle.
Calculation of the volume of this Pacific Ring of Fire material added to the core suggests that the continents should rise orders of magnitude greater than is observed. Why does this not happen and what happens to the excess material?
This newly melted material adds to the volume of the liquid Outer Core which becomes pressurised and exerts a immense upward force on the overlying mantle, lithosphere and crust. This causes the Earth to fractionally expand creating an Earthwide extensional regime which creates, and opens up the subvertical structures like Mid Atlantic Ridge, Plate Margins’ and also cracks the subduction zones themselves. The pressure can be relieved up these available weak zones and superheated fluids and magma (red arrows), containing heavy minerals from the core, now have a path to the Earth’s surface.
It is also clear from the tomographic (colour) and the structural evidence that there is no global conveyor-belt Mobile Mantle operating as the intra-mantle material transport system from the subduction zones to the centre of the Pacific and Atlantic oceans as is drawn on the current Plate Tectonics diagrams.
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