Since the continental crust density is the same, when both of them collide, there will gradually occur a huge mountain chain cause of the uplifting of the collision point and it's surrounding area, today known as the Himalayan mountains, the highest in the world (note: if measured from sea level) with it's peak Mount Everest (Sagarmatha) at 8848 m above sea level (it is estimated that it grows 8 cm per year).
