Continental Drift and Plate Tectonics

Flashcards covering key concepts related to continental drift, seafloor spreading, and plate tectonics.

Continental Drift

A theory that suggests continents have moved over geological time and were once joined together as a single landmass.

Alfred Wegener

The scientist who proposed the theory of continental drift and gathered various evidence to support it.

Circumstantial Evidence

Indirect evidence that suggests a conclusion but does not directly prove it.

Fossil Evidence

Fossils found on different continents that support the idea of continental drift by showing similar ancient life forms.

Law of Superposition

A geological principle stating that in undisturbed layers of rock, the oldest layers are at the bottom and the youngest are at the top.

Intrusion

A geological process where magma from the earth's interior moves into existing rock layers and solidifies.

Seafloor Spreading

The process by which new oceanic crust forms at mid-ocean ridges and older crust moves away from the ridge.

Divergent Boundaries

Plate boundaries where tectonic plates move apart from each other, often resulting in mid-ocean ridges.

Convergent Boundaries

Plate boundaries where tectonic plates collide, which can lead to the formation of mountains, trenches, and volcanic activity.

Subduction Zone

An area of the Earth's crust where one tectonic plate is being forced under another, leading to volcanic activity.

Transform Boundaries

Plate boundaries where two tectonic plates slide past each other, often causing earthquakes.

Hot Spots

Fixed locations in the mantle where molten material rises to the surface, creating volcanoes as tectonic plates move over them.

Supervolcanoes

Volcanoes that can produce extremely large and explosive eruptions, forming calderas.

Caldera

A large depression formed when a volcano erupts and collapses into itself.