Mantle convection is a circulation of the heat emitted by the earth's core crust lithosphere atmosphere

Mantle convection is a circulation of the heat emitted by the Earth's core. The core, found in the center of the Earth, is made up of extremely hot, molten metal, which heats the mantle in a convection current.

The zone your looking for is the intertidal zone.

It was said to have happened by earthquakes, the shifts in the tectonic plates moved everything