Convergent oceanic-continental

• The oceanic lithosphere plate is saturated with sea water and subducts beneath the continental lithosphere - this subduction is sped up by slab pull
• In the Benioff zone, sea water is driven out by increasing temperatures and pressure, lowering the melting point of rocks in the mantle wedge, forming magma which rises upwards
• This magma is high viscous due to fractionation, which means that gas bubbles cannot escape easily - pressure then builds up creating an explosion eruption
• As the plates are subducting, ocean trenches are formed - such as the ‘Mariana trench’ located in the Pacific Ocean, which is 36,000 ft deep