Structure of the Earth and Plate Tectonics

Flashcards covering key vocabulary related to the structure of the Earth and plate tectonics.

Crust

The outer layer of the Earth, ranging from 5 to 70 km thick, with a density of about 3 g/cm³, divided into tectonic plates.

Upper Mantle

A solid layer of the Earth about 400 km thick, starting beneath the crust and ending at the lower mantle, with temperatures around 1000°C.

Lower Mantle

Approximately 2000 km thick, existing about 3000 km below the surface, behaves like a viscous liquid with convection currents.

Inner Core

The solid innermost part of the Earth, made primarily of iron and nickel, with temperatures between 5500°C and 6000°C, and 1200 km in diameter.

Outer Core

The liquid layer of the Earth next to the inner core, about 2200 km thick, producing Earth's magnetic field through its movement.

Convergent Boundary

Plate boundaries that move towards each other, often forming mountains or causing subduction, e.g., the Himalayas.

Subduction Zone

A type of convergent boundary where denser oceanic crust sinks beneath continental crust, leading to volcanic activity.

Divergent Boundary

Plate boundaries that move away from each other, leading to the creation of new crust, e.g., Mid-Atlantic Ridge.

Transform Boundary

Plate boundaries where tectonic plates slide past each other without forming or destroying crust, e.g., the San Andreas Fault.

Asthenosphere

A semi-solid layer of the upper mantle that allows for the movement of tectonic plates.