With the precondition that convection takes place in a regular way, with equal height and width, it is easy to show that the main discontinuities at 410 km and 670 km are found where different convection cell layers meet.
Convection rolls of Earth’s mantle
As shown above, the convection rolls fit exactly to the measured layers. The intersection between the rolls is always of the same proportion.
The lower rolls below 410 km depth are found within the larger rolls of the lower mantle. It explains why volcanic activity can follow the tectonic drift above, for instance the Cameroon line of volcanic activity in Africa.
Published by Steingrimur Thorbjarnarson
I am a geologist, graduated from the University of Iceland, and taught geology for a few years. I have gained some knowledge about Earth's inner structure, so I provide this website as my contribution to answer one of the greatest questions remaining within the realm of geoscience. Experiments show that the mantle should form convection rolls when close to the melting point. I took this literally, and calculated the dimensions and shape of these mantle convection rolls. Then I compare that model with the surface. This makes it possible to provide many interesting examples about geology found on my blog.
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