Terrane accretion generally occurs along a boundary between a continental plate and an oceanic plate.

Answer; 
Terrane accretion generally occurs along a convergent boundary between a continental plate and an oceanic plate.

Explanation; 
Terrane accretion occur at convergent plate boundaries, however, it may be possible for a terrane to be brought from an exotic location along a transform plate boundary.
Additionally, it is also likely for a new divergent plate boundary to develop that rifts a continent apart.