Earth Structure and Plate Tectonics

Flashcards about the structure of the Earth and plate tectonics.

Compositional Layers

The layers of the Earth based on chemical composition: crust, mantle, and core.

Mechanical Layers

The layers of the Earth based on mechanical properties: lithosphere, asthenosphere, mesosphere, outer core, and inner core.

Continental Drift

Wegener's theory regarding the movement of continents over time.

Evidence for Wegener's Theory

Shape of continents, fossils of the same species on different continents, and mountain ranges and rock patterns on different continents.

Sea Floor Spreading

The process where new oceanic crust is formed at mid-ocean ridges and gradually moves away from them.

Evidence for Sea Floor Spreading

Underwater ridges, rifts in the ridges, magnetic striping, age of seafloor increasing with distance from ridges, and crust thickness increasing with distance from ridges.

Plate Tectonics

Theory that Earth's lithosphere is divided into plates that move over the asthenosphere.

Asthenosphere

The semi-liquid layer in the upper mantle on which the plates move.

Convection Currents

Movement in the asthenosphere that drives plate motion.

Types of Plate Movement

Diverging, converging, and transform plates.

Diverging Plates

A constructive boundary where two plates move apart, creating new land. Features such as rift valleys, volcanoes (on land), and mid-ocean ridges (under the sea) are found here.

Converging Plates and Subduction Zones

A destructive boundary where plates collide and land is destroyed and recycled. Three types: continental/continental, continental/oceanic, and oceanic/oceanic.