Final answer:
Subduction is a geological process where denser oceanic plates are forced beneath continental plates at convergent plate boundaries, leading to recycling of crustal material in the mantle.
Step-by-step explanation:
The process of subduction takes place when oceanic plates are forced beneath continental plates. This process occurs at convergent plate boundaries, where the denser oceanic plate is thrust down into the upper mantle beneath the lighter continental plate, often marked by ocean trenches such as the Japan trench.
Subduction results in high pressure and temperature for the subducting plate, eventually causing it to melt and become part of a downward-flowing convection current.
This pattern is part of the cycle that maintains the balance of crustal material on Earth, with the amount of crust destroyed at subduction zones being approximately equal to the amount formed at rift zones, where plates diverge.