Subduction Zones and Oceanic Crust

Subduction zones are convergent plate boundaries where oceanic crust, which is denser and composed of basalt, collides with continental crust, which is lighter and composed of granite. The denser oceanic plate subducts beneath the continental plate, driven by mantle convection currents. This process leads to the formation of mountains, active volcanoes, and earthquakes, as well as deep-sea trenches. Subduction zones are characterized by significant volcanic and seismic activity, making them some of the most dynamic regions on Earth.

What is a subduction zone?

• A type of static plate boundary

• A type of convergent plate boundary

• A type of transform plate boundary

• A type of divergent plate boundary

What type of rock primarily composes oceanic crust?

• Granite

• Limestone

• Basalt

• Sandstone

Which crust is denser, oceanic or continental?

• Continental crust

• Both are equally dense

• Oceanic crust

• Neither, they are both light

What type of rock is continental crust primarily composed of?

• Marble

• Granite

• Shale

• Basalt

What happens when oceanic and continental crusts collide?

• Both crusts remain stationary

• The oceanic crust subducts beneath the continental crust

• The continental crust subducts beneath the oceanic crust

• The oceanic crust rises above the continental crust

What geological features are formed due to subduction?

• Flat plains

• Jagged mountains and volcanoes

• Deserts

• Coral reefs

What is a common feature found where two plates meet in a subduction zone?

• Rift valleys

• Plateaus

• Deep sea trenches

• Mountain ranges

What type of activity is common in subduction zones?

• Volcanic and seismic activity

• Tsunamis

• Tornadoes

• Hurricanes

Why are subduction zones considered active plate boundaries?

• They are only found in oceanic regions

• They are stable and unchanging

• They are characterized by extensive volcanic and seismic activity

• They have no geological activity

What is a key characteristic of the surface features in subduction zones?

• Jagged and rugged

• Covered in ice

• Smooth and flat

• Sandy and soft