Leftovers from Theia?
Did they find leisure suits and platform shoes?
Good point!
Nothing puzzling at all about these molten plumes. The ones discovered are located somewhere beneath the slowly separating plates that are cleft beneath the Atlantic Trench and the Mariana Trench, where the depths are the greatest and the earth’s crust are presumed thinnest.
Fluids being acted upon by immutable physical forces. Eventually, there will be an enormous discharge of the internal pressures and a new equilibrium will be established.
Can’t say much for the survival rates for any plant or animal organisms in the immediate area, though, and secondary effects would have world-wide effects. One or more supercaldera volcanoes will be formed.