Earth's Layers and Tectonic Plates

These flashcards cover key vocabulary related to Earth's layers, tectonic plates, and geological processes.

Layers of Earth

The different strata of the Earth, including the crust, mantle, and core.

Crust

The Earth's topmost layer; it is the thinnest layer made mostly of solid rock.

Continental Crust

The part of the crust that covers land; it is thicker and primarily composed of granite.

Oceanic Crust

The part of the crust that forms the ocean floor; it is thinner and primarily made of basalt.

Tectonic Plates

Large pieces of the Earth's lithosphere that move on the asthenosphere below.

Divergent Boundary

A tectonic boundary where two plates move away from each other, often forming new crust.

Convergent Boundary

A tectonic boundary where two plates push against each other, often forming mountains.

Transform Boundary

A tectonic boundary where two plates slide past each other, causing earthquakes.

Pangea

A supercontinent that existed when all continents were joined together.

Ring of Fire

An area in the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur.

Mantle

Earth's second layer; it is made of solid and molten rock and is under high pressure.

Outer Core

The liquid layer of the core responsible for Earth's magnetic field.

Inner Core

The solid center of the Earth, extremely hot and under immense pressure.

Continental Drift

The theory that explains how continents move over geological time.

Earthquake

A sudden shaking of the ground caused by the movement of tectonic plates.

Volcano

An opening in the Earth's crust through which molten rock, ash, and gases escape.

Lithosphere

The solid, outer layer of the Earth, comprising the crust and the uppermost part of the mantle. It extends to a depth of about 60 miles (100 km) and is divided into tectonic plates that float on the semi-fluid asthenosphere beneath it.

Asthenosphere

The asthenosphere is a mechanically weak and ductile region of the upper mantle of Earth, lying beneath the lithosphere. It extends from approximately 100 to 700 kilometers (62 to 435 miles) below the Earth's surface and is believed to be much hotter and more fluid than the lithosphere, playing a crucial role in plate tectonics by allowing the movement of tectonic plates above it.