Biology 210 with Walsh at Trident Technical College *. * The material on this site is created by StudyBlue users. StudyBlue is not affiliated with, sponsored by or endorsed by the academic institution or instructor.
Mid-ocean ridges (eg. Mid Atlantic Ridge) are formed at constructive plate boundaries, where magma is welling up between two diverging plates and forming new plate materiel. Trenches (eg. Marianas Trench) are formed at destructive plate boundaries where an ocean plate is being subducted below a continental plate.Chariotmender Â· 8 years ago.id Atlantic Ridge) are formed at constructive plate boundaries, where magma is welling up between two diverging plates and forming new plate materiel. Trenches (eg. Marianas Trench) are formed at destructive plate boundaries where an ocean plate is being subducted below a continental plate. Chariotmender Â· 8 years ago.
Sometimes a deep ocean trench swallows more oceanic crust than a mid-ocean ridge can produce. Then, if the ridge does not add new crust fast enough, the width of the ocean will shrink. In the Pacific Ocean, subduction through the many trenches that ring the ocean is occurring faster than new crust can be added.