Topic 8, Lesson 1 - Evidence of Plate Motions

Front

What is sea floor spreading?

Back

Sea floor spreading is the process by which new oceanic crust is formed at mid-ocean ridges as magma rises to the surface and solidifies, causing the continents to move apart.

Front

What causes the movement of Earth's tectonic plates?

Back

The movement of Earth's tectonic plates is primarily caused by convection currents in the mantle.

Front

What happens at mid-ocean ridges?

Back

At mid-ocean ridges, tectonic plates move apart, leading to the formation of new oceanic crust through sea floor spreading.

Front

What are pillow-shaped rocks and how do they form?

Back

Pillow-shaped rocks form when molten material erupts underwater and cools quickly in cold water, creating a distinctive shape.

Front

What theory replaced Wegener's old theory of sea floor spreading?

Back

The theory of plate tectonics replaced Wegener's old theory, providing a more comprehensive explanation of how continents move.

Front

Define convection in the context of plate tectonics.

Back

Convection in plate tectonics refers to the movement of molten rock in the mantle that causes tectonic plates to move due to heat from the Earth's core.

Front

What is subduction?

Back

Subduction is the process where one tectonic plate moves under another and sinks into the mantle, often causing earthquakes and volcanic activity.

Front

What is the significance of mid-ocean ridges?

Back

Mid-ocean ridges are significant because they are the sites of sea floor spreading, where new oceanic crust is created.

Front

Explain the term 'tectonic plates'.

Back

Tectonic plates are large sections of the Earth's lithosphere that move and interact with each other, causing geological activity.

Front

What evidence supports the theory of plate tectonics?

Back

Evidence for plate tectonics includes the distribution of earthquakes, volcanic activity, and the matching of geological features across continents.