Tectonics 1.4 - Earth's Conveyor Belt

Which of the following is a key element of the theory of plate tectonics?

• Earth's internal structure

• Mantle Convection

• Palaeomagnetism

• All of the above

What process is associated with a constructive plate margin?

• Subduction

• Volcanic eruption

• Earthquake

• Sea floor spreading

What generates most of the heat within the Earth's mantle?

• Friction between tectonic plates

• Solar radiation

• Radioactive decay

• Heat from the Earth's core

What is the asthenosphere?

• The outermost layer of the Earth's atmosphere

• A semi-molten weaker zone between the crust and mantle

• The innermost layer of the Earth's core

• A layer of solid rock just beneath the Earth's crust

What allows the Earth's crust to move?

• Gravitational forces from the moon

• Magnetic fields from the sun

• Convection currents in the asthenosphere

• Rotation of the Earth on its axis

What happens at constructive plate margins?

• The plates collide and create mountains

• The plates slide past each other causing earthquakes

• The plates move apart and magma forms new crust

• The plates sink into the mantle and melt completely

What is formed when magma cools at a constructive plate margin?

• A trench

• A mountain range

• A ridge

• An island

What is the significance of Earth's Magnetic Field (EMF) in palaeomagnetism?

• It causes the Earth's poles to reverse every 200,000 years

• It aligns magnetic minerals in lava as it cools

• It prevents the Earth from losing its atmosphere

• It generates convection currents in the mantle

What is the result of polarity reversals in Earth's magnetic field?

• Random patterns of magnetic minerals in rocks

• A symmetrical pattern of mineral changes on either side of mid-ocean ridges

• The destruction of the existing magnetic field

• Immediate flipping of the north and south poles