Magma is a liquefied mixture of rock, crystals and dissolved gas. While this fits the general description of magma, it has three distinct observed types: basaltic, rhyolitic and andesitic.Continue Reading
Magma types tend to consist of mixtures of silicon dioxide, or molten sand/glass, combined with a varying mix of iron, magnesium, calcium, sodium and potassium, according to Tulane University. This variance is what determines magma's classification. Basaltic magma is high in iron, magnesium and calcium but low in sodium and potassium, while rhyolitic magma is the opposite.
Gases in magma consist mostly of water and carbon dioxide, with small amounts of sulfur, chlorine and flourine gas. This gas is kept dissolved within the magma due to the high pressure involved but escapes to the surface should the pressure on the magma be relieved. Gases emerging from magma are what create its volatile behavior, and in turn, they are largely what cause eruptions. The gas content in different varieties of magma can vary, with rhyolitic magma carrying a very large measurable amount.
Magmas of different types have varying properties, such as viscosity and the observed temperature at which they commonly erupt. Magmas that have higher viscosity have a greater chance to erupt at lower temperatures due to the amount of gas found within them, for instance.Learn more about Volcanoes
Volcanism is the eruption of magma to the surface of a planet. Molten rock wells up through a vent in the planet's mantle, spewing lava, gases and volcanic material into the surrounding area. Over time, this material hardens and accumulates, creating cone-shaped volcanoes and other structures, such as craters.Full Answer >
Rocks formed from magma in the Earth's mantle are called igneous rocks. However, there are different types of magma. Lava rocks can be basalt, andesite or rhyolite.Full Answer >
The catastrophic Mount Saint Helens volcanic eruption that took place on May 18, 1980 was the result of several factors that began with an accumulation of magma within the mountain's edifice earlier that year. A resulting bulge on the mountain's north flank was further weakened when an earthquake triggered a debris avalanche that relieved the pressure that had been acting as a counter-force to the magma buildup. Relieving the pressure resulted in the water that was contained within the system turning into steam, which then forced its way out explosively through a landslide scar.Full Answer >
When a volcano erupts, magma from beneath the Earth is forced out of the volcano's mouth in the form of molten lava. Large amounts of gases and ash can also be released with the lava, depending on the type of eruption.Full Answer >