Earth Science and Geology Glossary

Vocabulary flashcards covering core geological and plate tectonics terms, processes, and structures.

Asthenosphere

A soft, semi molten layer of the upper mantle on which tectonic plates move.

Cementation

The process where dissolved minerals bind sediments together to make a rock

Cleavage

The way a mineral breaks along smooth, flat surfaces

Convergent boundary

A plate boundary where two tectonic plates move toward each other.

Compaction

The squeezing together of sediments by pressure from overlying layers

Convection currents

Currents in the Earth's mantle that cause it to move slowly over time. Hotter, less dense rock moves upwards and colder, denser rock moves down.

Core

The central part of the Earth, consisting of a liquid outer core and solid inner core

Crust

The thin outermost layer of the Earth

Crystallisation

The formation of mineral crystals as magma cools

Deposition

The process by which sediments are dropped and settle in a new location.

Divergent boundary

A plate boundary where two tectonic plates move away from each other

Erosion

The transport of weathered rock and sediment by water, wind, ice or gravity

Fault

A crack in the Earth's crust where movement has occurred.

Fossil evidence

Similar fossils found on different continents that support the theory of plate tectonics

Hot spot

An area where magma rises up through the mantle, forming volcanoes away from plate boundaries

Igneous rock

Rock formed when magma or lava cools and solidifies

Lava

Molten rock that reaches the Earth's surface

Lithosphere

The rigid outer layer of the Earth, including the crust and upper mantle

Lustre

How shiny or dull a mineral looks when light shines on it

Magma

Molten rock beneath the Earth's surface

Mantle

The thick layer of hot rock between the crust and core.

Metamorphic rock

Rock that has been changed by heat and pressure

Mid-ocean ridge

An underwater mountain range formed at divergent plate boundaries

Mineral

A naturally occurring, inorganic substance with a definite chemical composition

Plate boundary

The region where two tectonic plates meet

Plate tectonics

The theory that Earth's lithosphere is divided into moving plates

Rift valley

A valley formed when tectonic plates move apart

Rock cycle

The continuous process through which rocks change from one type to another.

Rock

A naturally occurring solid made of one or more minerals

Sediment

Small particles of rock, minerals or organic material

Sedimentary rock

Rock formed from compacted and cemented sediments.

Seafloor spreading

The formation of new oceanic crust at divergent plate boundaries

Streak

The colour of the powder a mineral leaves behind when scratched on a streak plate.

Subduction

The process where one tectonic plate is forced beneath another

Tectonic plate

A large section of the Earth's lithosphere that moves slowly over the asthenosphere.

Transform boundary

A plate boundary where plates slide past each other

Trench

A deep depression in the ocean floor formed at subduction zones

Volcano

An opening in the Earth's crust through which lava, ash and gases escape

Weathering

The breakdown of rocks into smaller pieces without being transported