Lesson 3: Theory of Plate Tectonics

What is a transform fault boundary?

a plate boundary where two plates slide past each other and lithosphere is not created or destroyed

If a plate moves at a rate of 10 cm per year, how far will the plate move in 20,000,000 years?

2000 km

In your own words, briefly explain the theory of plate tectonics.

According to the theory of plate tectonics, large pieces of Earth's lithosphere, called plates, move slowly over Earth's surface driven by convection currents in the mantle. Plates can include oceanic and/or continental lithosphere. Plate interactions help cause earthquakes, volcanoes, and mountain building.

Suppose you could view the Great Rift Valley in Africa millions of years from now. How might the region have changed?

After millions of years, the Great Rift Valley could widen and form a new ocean basin similar to the Red Sea.

What forms when oceanic lithosphere collides with continental lithosphere at a convergent boundary? Explain.

Because the oceanic lithosphere is denser than the continental lithosphere, a trench forms, and the oceanic lithosphere is subducted beneath the less dense continental lithosphere.

How do rift valleys begin to form?

Rifts begin when the lithosphere is stretched and a plume of hot rock from the mantle weakens and then splits the lithosphere.

Why is a divergent boundary considered a constructive plate margin?

because volcanic activity along divergent boundaries produce new oceanic lithosphere

List the three types of plate boundaries.

convergent boundaries, divergent boundaries, and transform boundaries

What caused the Himalayas to form?

the collision of two continental plates