Figure 62. Seismic Tomographic sections of Africa, South and North America, Europe showing continuity of brittle lithosphere, Pacific subduction, Mid Atlantic Ridge and Europe/Africa collision geological features.
The slide is an attempt to summarise the AusIMM Webinars on Africa, South America and North America.
The biggest surprise in the African study was finding that the lithosphere was brittle right to the core and that big structures like the East Africa Rift could be seen right down to 600 km depth and it continued right to the core in the sections looked at.
In the South American Webinar it was seen that the brittle structures also extended right to the core and that the mid-Atlantic Ridge dipped flatly east was almost non-existent below the surface.
The other important discovery was what I called The 4 billion-year-old Immovable Boundary under both American continents.
I discovered that the lithosphere was continuous from the surface to the Outer Core from South America to Alaska. It was also continuous across to Africa and Europe.
In all sections a huge, brittle, disrupted arc under the North and South American continents represented the Pacific Plate Subduction Zone. The movement has the structural geology of glacier flow, brittle but quite capable of fast movement.
This subduction has obviously continued since the Pacific plate started moving but has slowly build up over the eons and only the closest area to the Pacific is active at any one time.
There are many brittle structures and curved structures transacting this subduction area under the American continent which provide pathways for rising fluids and magmas (hotspots).
Both American continents are getting pushed to the east by the Pacific plate and to the west by the African Eurasian plate.
The only relief for this pressure is up, forming mountains, or down into the liquid 5,000°C outer core which would slice it off like a laser cutter!
The structure is a perfect ‘pop-up pop down’ structure which forms extension structures right from the core to the surface.
These are seen in the sections as huge flat structures dipping flatly west and flatly east.
24. Summary and Conclusions
25. References
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