Around the 64.75°N parallel the polygons are suspiciously marked by volcanic zones. It becomes quite appearent when colouring them red.

The central division line (wide black line) of lower mantle large convection rolls thereby has three polygons at each side most affected by the flow of magma to the east and west from that line at the depth of 410 km and thereunder.
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Published by Steingrimur Thorbjarnarson
I have a BS degree in geology, BA in anthropology, graduated in Chinese language and as a certified tourist guide. I provide this website about my contribution to answer the greatest question remaining about our Earth. I have analyzed the convection rolls within the Earth's mantle and how they affect the surface. This makes it possible to provide many interesting examples about geology found on my blog.
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