Volcanic Eruptions

To describe pyroclastic material and lava

What is pyroclastic material

Pyroclastic material consists of fragments of rock that form during a volcanic eruption which has low viscosity and is made up of magnesium and iron . And is also trapped in gases and has a dark color.

Types of pyroclastic materials

Scientist classify pyroclastic materials according to the sizes of the particles. Pyroclastic particles that are less that 2 mm in diameter are called volcanic ash . Some pyroclastic materials form when magma breaks into fragment during an eruption because of the rapidly expanding gases in the magma . These pyroclastic particles are called volcanic bombs . Large pyroclastic particles that are less than 64 mm in diameter are called lapilli.the largest pyroclastic materials form when fragments of erupting lava cool and solidify as they fly through the air.

Types of lava

When mafic lava cools rapidly ,a crust forms on the surface of the flow. If the crust deforms rapidly or grows too thick to form wrinkles the surface breaks into jagged chunks to form Aa. If lava continues to flow a volcanic rock called pahoehoe.block lava has a higher silica content than Aa lava does which makes blocky lava more viscous than Aa lava .

Type of mafic magma

Most Mafic minerals are dark in color and the relative density is greater than 3. In terms of chemistry , Mafic rock are on the other side of the rock spectrum from the felsic rock.

Three types of volcanoes

Volcanic activity produces a variety of characteristic features that form during Both quiet and explosive eruptions. Volcanic cones are classified as three main types. The funnel shaped pit at the top of a volcanic vent is known as a crater. A crater usually becomes wider as weathering and erosion break down the wales of the crater and allow loose materials to collapse into the vent