Plate Tectonics & Continental Drift Lecture Notes

Question-and-answer flashcards covering key terms and concepts related to continental drift, tectonic plates, and Earth’s internal layers.

Who proposed the Continental Drift theory?

Alfred Wegener, a German scientist.

What supercontinent did Wegener propose once existed?

Pangaea.

Into which two large landmasses did Pangaea first split?

Laurasia and Gondwanaland.

Which present-day continents originated mainly from Laurasia?

Asia, Europe, North America, South America, and Africa (northern-hemisphere continents).

What are the huge slabs of solid rock that make up Earth’s outer shell called?

Tectonic plates (or simply plates).

Why are tectonic plates described as "tectonic"?

Because they are capable of movement and tectonic activity.

Name three major geologic features or events produced at plate boundaries.

Volcanoes, earthquakes, mountain building, and deep-ocean trenches (any three).

What layer lies directly beneath the lithosphere and allows plates to glide?

The asthenosphere.

From what Greek word is "asthenosphere" derived, and what does it mean?

From "asthenes," meaning "weak."

How does the asthenosphere behave despite being solid?

It flows like molten plastic, exhibiting plasticity.

At what approximate rate do tectonic plates move over the asthenosphere?

From less than 1 cm to about 16 cm per year.

What does the division of the lithosphere into plates imply about Earth’s surface?

Earth’s surface is dynamic, with plates that collide, separate, or slide past each other, shaping geological features.