The Amazon area is mostly found within a large polygon marked by the division lines of each side of a single convection roll of lower mantle. The main hub of downwelling forms the esturary of the Amazon River, the largest river in the world. At the other side of the continent, the division line (wide red) between convection rolls does cross the Andes Mountains under the volcano Tuguruahua.
The exact 30° span along equator from the trench in the east to the estuary in the west is an outstanding manifestation of the predicted interval between convection rolls of the lower mantle.
Magic Magma 