Definitions

These definitions are necessary when reading and discussing the text «ROCK CYCLE»

Weathering – the process by which Earth materials change when exposed to conditions at or near the Earth's surface and different from the ones under which they formed.

Weathered rocks –rocks that have undergone weathering.

Erosion – the set of all process by which particles of rock and soil are loosened and moved.

Transportation- the movement of a particle from one location on the Earth’s surface to another.

Mobile sediments – rock material, which can be moved by water, wind or gravity.

Deposition – physical settling of mineral and other material from water, air, or ice, or chemical or biological precipitation of minerals from water.

Sedimentary sequences – sediments laid down (ex. by slowing water currents, slowing wind currents, melting ice)

Compaction – reduction of pore space between individual particles as the result of overlying sediments or of tectonic movements.

Cementation – the process by which clastic sediments are converted into sedimentary rock by precipitation of mineral cement between the sediment grains, forming an integral part of the rock.

Sedimentary rocks – rocks formed by the consolidation of sediment settled out of water, ice or air and accumulated on the Earth’s surface.

Metamorphism – the processes, which produce structural and mineralogical changes in any type of rock in response to physical and chemical conditions (differing from those under which the rocks originally formed). Regional metamorphism – heat and pressure; thermal metamorphism – heat from an intrusion.

Metamorphic rocks – rocks formed by change in heat and pressure without melting.

Extrusive (effusive) rocks – rocks crystallized from lava (fast cooling) or blasted from a volcano.

Melting – solid rocks becoming liquid.

Magma – molten rock that forms naturally within the Earth; comes from partial melting of the mantle below the crust.

Extrusion – erupting magma at the surface through the volcanoes as lava, ash and blocks (lava eruption, explosive eruption).

Intrusion – forcing of magma into other rocks and solidifying.

Intrusive rocks – rocks crystallized from magma underground.