🌊Alluvial Fan

A fan-shaped deposit of sediment formed where a stream slows.

💧Aquifer

An underground layer of rock that holds and transmits water.

🌊Asthenosphere

The semi-fluid layer of the upper mantle beneath the lithosphere.

🕳️Caldera

A large crater formed by the collapse of a volcano.

🏞️Canyon

A deep narrow valley with steep sides, often carved by a river.

🕳️Cave

A natural underground hollow large enough for human entry.

🐒Cenozoic

The current geologic era, beginning about 66 million years ago.

🌍Continental Drift

The gradual movement of continents across Earth's surface.

➡️Convergent Boundary

A plate boundary where plates collide.

🔥Core

The central region of Earth, composed mostly of iron and nickel.

🥣Crater

A bowl-shaped depression at the top of a volcano or from impact.

💠Crystal

A solid material whose atoms are arranged in a highly ordered structure.

🔺Delta

A landform at a river mouth formed by deposited sediment.

📥Deposition

The laying down of sediment by water, wind, or ice.

↔️Divergent Boundary

A plate boundary where plates move apart.

🌍Earth's Crust

The outermost solid layer of Earth, composed mainly of rock.

🌍Earthquake

A sudden shaking of the ground caused by tectonic movement.

🌌Eon

The largest division of geologic time, lasting billions of years.

⏱️Epoch

A subdivision of a geologic period.

📅Era

A major division of geologic time composed of periods.

🌊Erosion

The wearing away of soil and rock by wind or water.

🪨Erratic

A rock transported and deposited by a glacier far from its origin.

〰️Fault

A fracture in Earth's crust where rock masses have moved.

📚Foliation

Layering in metamorphic rock caused by directed pressure.

🦴Fossil

Preserved remains or traces of ancient organisms in rock.

⚗️Geochemistry

The study of the chemical composition and processes of Earth.

🗺️Geologic Map

A map showing the distribution of rock units and structures.

⏳Geologic Time Scale

A system dividing Earth's history into named intervals.

🏞️Geomorphology

The study of landforms and the processes that shape them.

🧲Geophysics

The application of physics to study Earth's structure and processes.