Convection and Plate Tectonics Concepts

What are the three primary forces that interact to create plate motion?

• Volcanic eruptions, earthquakes, and tsunamis

• Convection current, slab pull, and ridge push

• Erosion, weathering, and deposition

• Gravity, magnetism, and solar winds

What is a convection current in the Earth's mantle?

• A continuous flow of water in the ocean.

• The movement of air in the atmosphere.

• A continuous loop of sinking hot, soft rocks caused by energy transfer in the asthenosphere.

• The transfer of heat through direct contact.

How does convection in the Earth's mantle behave similarly to boiling water in a pot?

• Both involve the evaporation of liquid.

• Both create cycles of sinking cold and rising warm materials.

• Both require direct sunlight for heating.

• Both result in the formation of new solid material.

What effect do convection currents circling within the mantle have on the Earth's crust?

• They cause the crust to become thinner and more brittle.

• They push magma up, forming new crusts and causing sea-floor spreading.

• They pull the crust downwards, creating deep ocean trenches.

• They stop all plate movement, stabilizing the Earth's surface.

What happens when colder magma sinks during convection?

• It causes the Earth's magnetic field to reverse.

• It pulls the surface together, leading to subduction of denser crust.

• It creates new volcanic islands.

• It causes continents to drift apart.

Who proposed the theory of mantle convection?

• Alfred Wegener

• Harry Hess

• Arthur Holmes

• Charles Darwin

What is the primary force responsible for plate tectonics according to the Slab Pull Theory?

• Volcanic eruptions

• Gravitational pull on the plates themselves

• Wind erosion

• Magnetic forces

How does a very dense slab behave in the Slab Pull mechanism compared to a less dense slab?

• It rises faster due to increased buoyancy.

• It sinks slower due to greater resistance.

• It sinks faster and exerts greater force due to gravitational pull.

• It remains stationary, having no effect on plate movement.

What is Ridge Push?

• A process where oceanic crust is destroyed at trenches.

• A proposed driving force for plate motion where rigid lithosphere slides down the hot, raised asthenosphere at mid-ocean ridges.

• The upward movement of magma at subduction zones.

• The formation of new continental crust.

What causes the "pushing" on plates in the "gravity sliding" ridge push model?

• The direct impact of meteorites.

• The difference in gravitational potential energy between a plate at its spreading center and subduction zone.

• The expansion of the Earth's core.

• The friction between tectonic plates.