Plate Tectonics & Continental Drift Lecture

15 vocabulary flashcards summarizing key terms and evidence from the lecture on plate movements and continental drift.

Continental Drift Theory

The idea that Earth’s continents were once joined in a single landmass and have slowly moved to their current positions.

Pangaea

A supercontinent that existed about 250 million years ago, containing all present-day continents in one massive landmass.

Alfred Wegener

German meteorologist who proposed the Continental Drift Theory in his 1915 book “The Origin of Continents and Oceans.”

Plate Movement

The motion of Earth’s lithospheric plates, including convergence, divergence, and transform sliding.

Convergent Plate Boundary

A place where two tectonic plates move toward each other, often forming mountains or subduction zones.

Divergent Plate Boundary

A boundary where two tectonic plates move apart, creating new crust as magma rises (e.g., mid-ocean ridges).

Transform Plate Boundary

A boundary where plates slide horizontally past one another, causing earthquakes along faults like the San Andreas.

Continental Jigsaw Puzzle Evidence

The visual fit of coastlines (e.g., South America with Africa) supporting the idea that continents were once connected.

Fossil Distribution Evidence

Identical fossils found on widely separated continents, indicating those landmasses were previously joined.

Glossopteris

An extinct fern whose fossils on South America, Africa, Antarctica, India, and Australia support continental drift.

Mesosaurus

A freshwater reptile whose fossils on Africa and South America show those continents were once connected.

Cynognathus

A Triassic land reptile whose fossils on separate southern continents back Wegener’s theory (poor swimmer, limiting dispersal).

Lystrosaurus

A land-dwelling herbivorous reptile found on Africa, India, and Antarctica, reinforcing the concept of continental drift.

Rock Types & Structures Evidence

Matching mountain ranges and rock formations on opposite continents (e.g., West Africa and eastern South America).

Ancient Climate Evidence

Signs such as glacial deposits in now-warm regions and coal in present polar areas, showing continents have shifted latitudes.