Rock Cycle Test

Cementation

The gluing together of sediment by new mineral crystals. Cementation can cause sediment grains to stick together, forming sedimentary rock.

Compaction

The squeezing of sediment by the weight of overlaying layers. Compaction can cause sediment grains to stick together, forming sedimentary, forming sedimentary rock.

Crust

The outermost layer of Earth. The crust is made of solid rock and is 5-70km thick. It is thickest underneath the continents.

Continental Crust

Crust that lies beneath a continent. Continental crust is about 25-75km thick and is less dense than oceanic crust.

Erosion

The wearing away and removal of rock. Eroded sediment is transported by wind, water or ice.

Fossil

The ancient organism preserved in rock. Fossils provide information about how life evolved and how Earth’s surface has changed.

Geologist

A scientist who studies the Earth. Geology is the scientific study of the process that change the Earth and their history.

Igneous rock

Any rock formed by the cooling of magma and lava. The size of the crystals in an igneous rock indicates the speed at which it is cooled.

Inner core

The innermost layer of Earth. The inner core is a solid mixture of iron and nickel at extreme pressures and temperatures.

Lava

Hot liquid rock located above the Earth’s surface. When magma rises up from underground and flows on the surface it is called lava.

Magma

Hot liquid rock located below the Earth’s surface. Magma can rise to the surface to form volcanoes.

Mantle

The thickest layer of the earth, between the core and crust. The mantle rock is made of solid and partially melted rock. It can flow over very long timescales.

Melting

A change of state from solid to liquid. When rock is heated deep underground, it melts to form magma.

Metamorphic rock

Any rock that has been changed by intense heat and pressure. Heat and pressure can change the types of minerals and the size and shape of the crystals.

Mineral

A natural substance usually found as crystal in rocks. Minerals are the building blocks of rocks. Quartz is a common rock-forming mineral.

Outer core

The layer of Earth that lies between the mantle and inner core. The outer core is a mixture of iron and nickel. Its flow generated Earth’s magnetic field.

Parent rock

The original rock from which a metamorphic rock formed. Parent rocks may be sedimentary, igneous or metamorphic.

Pressure

The amount of force applied over a certain area. Pressure can be measured in the units pascal (Pa) and gigapascal (GPa).

Rock cycle

The set of changes that turn one rock type into another. Rocks can change between igneous, sedimentary and metamorphic types over millions of years.

Sediment

Small rock fragments such as mud, sand or gravel. Sediments form when rock is exposed to weathering and erosion.

Sedimentary rock

Any rock formed when sediment is compacted or cemented. Sedimentary rocks can also form from the remains of living things.

Solidification

A change of state from liquid to solid. When magma cools quickly, it solidifies to form a rock with small crystals.

Volcanic eruption

A release of magma at the Earth’s surface. The eruption of hot liquid rock forms natural hazards such as lava flows and ash clouds.

Weathering

The breakdown of rocks into small grains or soil. Rocks at the surface are weathered by wind, flowing water, heat and other processes.