Why is magma viscous?

Gevraagd door: Tamara Mack

The solid rocks located at depth ( km) and subjected to high pressure and temperature conditions, partially melt (partial melting) and form the magma, more or less viscous depending on its chemical composition and silica richness, which will slowly migrate upwards.

Qu’est-ce qu’un magma visqueux ?

The magma is viscous: an explosive eruption
Loaded with gas, the magma can reach a temperature of 750°C. Viscous magma contains a lot of silica, an acid component. The viscous magma presses the gases and the lava can’t flow out and blocks the exit. When the gases are released, they make everything explode.

Why is the magma molten?

Magma is the origin of the formation of volcanoes. This molten rock, bubbling in the crater, comes from a partial melting of the Earth’s mantle.

How is the viscous magma of explosive volcanoes formed?

An effusive volcano forms when two tectonic plates collide (converge) or when they move apart. The magma then rises through cracks in the earth’s crust and when it comes out, it forms a dome.

What are the two types of magma?

Basaltic and granitic magmas
There are roughly two main types of magma: granitic and basaltic. A granitic magma is a magma formed by the fusion of rocks rich in silica, it is thick and viscous. A basaltic magma, less rich in silica, will be much more fluid.

Why is the magma hot?

It is the natural radioactivity (uranium in particular) which causes this release of heat. Ah well, it is the natural radioactivity which is at the origin of a magma in fusion?

What is the difference between lava and magma?

1. What are the differences between magma and lava? Magma = molten rock, composed of a mixture of liquid, solid and dissolved gases Lava = magma that has lost a large part of its gases Magma is located at depth while lava is at the surface.

Why shouldn’t the lava touch the sea?

Acidic clouds « The clouds generated by the interaction of sea water and lava are acidic » and « can be dangerous if we are too close », explained to AFP Patrick Allard, of the Institute of Geophysics of the Globe in Paris.

Why is the lava red?

The lava of a volcano is composed of molten rock, i.e. rock brought to a temperature such that it has melted (700 to 1200°C), forming what is called magma, red as embers.

How to explain the magma?

Formation of magma
Magma is formed at high temperature and high pressure by partial melting of the crust or mantle of a rocky planet. Less dense than the solid rock at depth, it is dragged upwards by the Archimedean thrust.

Comment se forme un magma ?

Magma forms at high temperature and high pressure in contexts such as subduction by partial melting of the earth’s crust or mantle. However, the pressure opposes the thermal agitation, which is the main factor in the fusion of rocks.

What is the composition of magma?

In the volcanic field, magma refers to molten rock located deep underground, in what are called magma chambers. It is composed of dissolved gases, liquids and solid elements, such as crystals. As long as it remains underground, it is also called « plutonic rock ».

What resists the magma?

Rhenium is used in tungsten alloys up to a level of 22%, it improves high temperature resistance and corrosion resistance.

What is the temperature of the molten magma?

As far as molten rocks go, mafic magmas are quite liquid, with viscosities ranging from molasses to peanut butter. They are also the hottest variety of magma, reaching temperatures between 980°C and 1200°C.

Why is there lava in volcanoes?

When the magma reaches the surface, it comes into contact with air that is much colder than it is: it becomes thicker and then forms lava. This lava will flow around the volcano and gradually cool to form rock. »

What are the three kinds of magma?

Magmas are generally composed of a mixture of liquids, volatile matter and solids. The most common are of 3 types: basaltic, granitic and andesitic.

How can we explain the difference in magma outpouring at the time of the eruption?

A low silica content produces fluid magmas, whereas, at the other extreme, a high silica content greatly increases the viscosity of the magmas which then have difficulty flowing. Mafic magmas contain little or no silica; they are therefore fluid and produce lavas that flow easily.

How does a volcano die out?

How do volcanoes die out? Little by little, the faults through which the magma rises are blocked one after the other. In the depths of the volcano the magma slowly cools down. The volcano dies out.