Volcanoes are small mountains formed by magma rising up between the plates and solidifying into rock. There are many types of volcano. these include fissure, shield dome, cinder, composite and caldera volcanoes
Cause and Location of volcanoes
Subducting plates: where two plates are forced against each other. One is forced upwards which lets magma get through in the gaps
Spreading plates: where two plates are forced away from each other which creates a gap for magma to rise to the surface
Most volcanoes are near or on top of the earths plate boundaries
Difference between magma and lava
Magma is the molten rock beneath the earths crust that makes up the earths mantle.
Lava is the molten rock that comes spewing out of the volcano when it erupts.
Igneous rocks are rocks that have been formed by lave solidifying on the earths surface. Some of its characteristics are, being course grained, have many small holes in it, no fossils and are non-porous
Difference between plutonic and volcanic igneous rocks
Plutonic rocks are formed below the earth’s surface
Volcanic rocks are formed when they are shot out of a volcano and cooled on the earths surface
Things that come out of a volcano
Gases - mostly steam - a lava fountain, a rain of ash, a colossal explosion - all depend on how the gas escapes.
Liquids - molten lava - their trapped gasses often explode violently. Basic lavas such as these at Craters of the Moon are fluid. Gases escape easily and rarely with explosive force.
Solids come out as blocks of the old cone, cinders, ash and dust.
Components of volcanic gases
Small jagged pieces of rocks, minerals, and volcanic glass the size of sand and silt erupted by a volcano are called volcanic ash. Volcanic ash is not the product of combustion, like the soft fluffy material created by burning wood, leaves, or paper. Volcanic ash is hard, does not dissolve in water, is extremely abrasive and mildly corrosive, and conducts electricity when wet.
Volcanoes vs. the environment
Volcanic eruptions can be extremely damaging to the environment, particularly because of a number of toxic gases possibly present in pyroclastic material. it contains carbon dioxide and sulphur dioxide gas. These can cause both humans and plants to suffocate.