Volcanic Eruptions
Describe Pyroclastic material and lava flows
Types of magma
Their are 3 types of magma, Pahoehoe, it forms wrinkly volcanic rock when it cools. Aa forms sharp volcanic rock when it cools. And the last one, blocky lava, it's the most vicious type of lava and forms chunky volcanic rock when it cools. All these three types of magma are of mafic lava. All these three are of magnesium and iron.
Types of pyroclastic material
Their are pyroclastic materials that are called Volcanic ash, Volcanic blocks, and Lapilli. Volcanic ash that is less than 0.25 mm in diameter is called volcanic dust. Pyroclastic materials form when magma breaks into fragments during an eruption because of the rapidly expanding gases in the magma. Some pyroclastic materials that are less than 2 mm in diameter are called volcanic ash. The largest pyroclastic materials are known as volcanic rock. As they spin in the air they develop a round or spindle shape, that is called volcanic bombs. During an eruption pyroclastic materials are ejected violently from the volcano.
Types of Volcanoes
Their are three types of volcanoes. One volcano is called a Shield Volcano, it is cones that are broad at the base and have gently sloping sides. It has layers of hot, Mafic lava that flow out around the vent and harden. Cinder Cones, it has very steep slopes. Made of pyroclastic, material. The last one is Composite Volcanoes, made of alternating layers of hardened lava flows cover the sides of the cones.
Shield Volcano
This is an actual picture of a Shield Volcano that is in Oregon. It is called the Belknap Shield Volcano. A shield volcanoe has mafic magma.
Cinder Cone
It has felsic magma inside. Made up of pyroclastic material, is deposited around the vent. Followed by quiet lava flows.
Composite Volcanoe
Inside it has both mafic and felsic magma,theirs times where it has both, in which that case it will make layers of both.