Continental Drift and Plate Tectonics

These flashcards cover key concepts and terms related to the theories of Continental Drift and Plate Tectonics, including their evidence, processes, and consequences.

Continental Drift

A theory proposed by Alfred Wegener that suggests continents are mobile and once formed a single supercontinent known as Pangaea.

Pangaea

The supercontinent that existed when all continents were joined together.

Evidence for Continental Drift

Includes the fit of continents, fossil evidence, glacial deposits, rock similarities, and paleoclimate patterns.

Magnetic Declination

The angle difference between magnetic north and true north, varying by location.

Paleomagnetism

The preserved record of Earth’s magnetic field direction in rocks when they formed.

Seafloor Spreading

The process by which new crust forms at mid-ocean ridges and moves outward, subducting into trenches.

Plate Tectonic Theory

A unifying theory that combines Continental Drift and Seafloor Spreading.

Lithosphere

The rigid outer shell of Earth made up of the crust and uppermost mantle.

Asthenosphere

A hot, weak layer of the upper mantle beneath the lithosphere that allows for plate motion.

Divergent Boundaries

Regions where tectonic plates move apart, allowing magma to rise and new crust to form.

Convergent Boundaries

Regions where tectonic plates move toward each other, leading to subduction or mountain-building.

Transform Boundaries

Areas where tectonic plates slide past each other horizontally, such as the San Andreas Fault.

Subduction

The process where one tectonic plate sinks beneath another, contributing to the recycling of the seafloor.

Natural Hazards Associated with Plate Tectonics

Earthquakes, volcanic eruptions, and tsunamis caused by tectonic movements.

Hot Spots

Volcanic plumes independent of tectonic boundaries that create island chains, like the Hawaiian Islands.