How is crust destoyed?

Answer 1

Old crust can be destroyed by

subduction, or the pushing down of an oceanic plate below an

overriding plate at a convergent boundary. The initial phase of a

divergent boundary is a rift valley, which progresses to form an

oceanic basin with a mid-oceanic ridge.

Answer 2

Old crust can be destroyed by

subduction, or the pushing down of an oceanic plate