Volcanic pipe

Volcanic pipes, also called volcanic conduits, are special underground structures made by very powerful volcano eruptions. These eruptions happen faster than the speed of sound, shooting magma from deep inside the Earth up to the surface. The magma then cools and hardens, forming a narrow, carrot-shaped cone deep underground.

These pipes are made of special rocks called kimberlite or lamproite, which tell us about the deep places where magma comes from. These places are rich in magnesium, an important element found in the Earth. Volcanic pipes are interesting because they are the main way diamonds come to the surface. Miners dig in these pipes to find and collect diamonds.

Even though many types of magma reach the surface, volcanic pipes are not very common. They are important for science because they help us learn about the Earth's deep layers and how volcanoes work.

Formation

Volcanic pipes are formed by very strong eruptions from deep-underground volcanoes. These volcanoes start much deeper than most others, and the melted rock, called magma, they push up contains a lot of magnesium and gases like water and carbon dioxide. When this magma moves closer to the surface, the gases turn into steam very quickly because the pressure drops. This makes the magma shoot up very fast, creating a powerful eruption.

Kimberlite pipes are a special type where the eruption throws material from above right over the magma. Instead of making a tall mountain, they create a ring of rocks around a bowl-shaped hole. Over time, this ring can wear away and fill in the hole. These pipes are important because they contain many diamonds and other valuable stones.

Lamproite pipes work in a similar way, but the steam and gases in the magma can wear away the rock above. This creates a wide cone shape that fills with ash and other materials. The magma then pushes up through this cone, making a flat-looking deposit of volcanic material on the surface.