Composite volcano formation

Composite volcanoes are formed at which plate margin?

• constructive

• destructive

• conservative

What is a destructive plate margin?

• when an oceanic plate and a continental plate move parallel

• when a continental and a continental plate meet

• When a continental and oceanic plate meet

What happens when the two plates meet?

• The oceanic plate is pushed upwards to form a volcano

• The oceanic plate sinks as it is more dense

• The oceanic plate sinks as it is less dense

• The continental plate sinks because it is less dense

What happens to the oceanic plate in the mantle?

• the oceanic plate melts and forms high viscosity magma

• the oceanic plate melts and forms low viscosity magma

• the plate remains intact and is forced up through the continental crust

What happens to the high viscosity magma when it rises through the continental plate.

• The magma collects in the magma chamber and then rises up the main vent

• The magma in the magma chamber travels easily through to the crater

• The magma is thick and so sticks in the main vent

• Pressure builds as the magma continued to rise

Why is the eruption violent?

• The high viscosity magma creates a lot of pressure as the magma sticks

• The pressure is released violently in the eruption

• The magma continually flows from the crater

What are the features of a composite volcano?

• steep sided

• wide base

• narrow base

• sloping sides

Theory builder: Why does the oceanic plate melt in the mantle

• the mantle is made of magma

• The mantle is hotter and as it is closer to the core

• There is more pressure on the rock in the crust in the mantle

Theory builder: What is the sinking of the oceanic plate called?

• sinking

• evaporation

• subduction

• dissolving

Why is the magma here high viscosity?

• The plates move apart and the magma comes directly from the mantle

• The magma is slow so it cools and thickens

• As the oceanic plate sinks it pulls down water from the ocean which makes the magma gassy