What might happen to mantle convection currents beneath a continental-continental convergent boundary?
The convection current meet head on. This will cause the currents to force the plates they are carry upwards while the currents go down.
Diverging boundaries are where the convection currents move upwards.
Converging boundaries are where convention current move downward.
When a ocean plate meets a continental plate in a convergent boundary the mantle current carrying the ocean plate is forced downward.