Rhyolitic Magma

"Rhyolitic Magma"

What is Rhyolitic Magma?

A type of magma formed by differentiation from basaltic magma in combination with assimilation ofsiliceous material, or by melting of portions of the earth's sialic layer.

These viscous lavas have relatively high aspect ratios (thickness/area), generally > 1/100, and some are thick enough to form as lava domes. Andesite commonly erupts from stratovolcanoes, where they form small-volume flows that typically advance only short distances down the flanks of a volcano.

Rhyolite is a felsic extrusive rock. Due to the high silica content, rhyolite lava is very viscous. It flows slowly, like tooth paste squeezed out of a tube, and tends to pile up and form lava domes. .Rhyolite is the volcanic equivalent of granite.

2000 vv e know that a caldera resurgence that began during the SEE with conduit opening and alkaline trachytic to rhyolitic magma emission near the caldera margins, initial volcanism was not explosive in nature: magma could reach the surface after complete volatile release through conduit permeable walls, promoting anorthoclase and sanidine nucleation rate increment and amphibole and mica stability reduction, which generated corrosion and opatization borders in mafics.

How does it forms?

It flows slowly, like tooth paste squeezed out of a tube, and tends to pile up and form lava domes. If rhyolite magma is gas rich it can erupt explosively, forming a frothy solidified magma called pumice (a very lightweight, light-coloured, vesicular form ofrhyolite) along with ash deposits, and / or ignimbrite.

Non explosive eruptions are favored by low gas content and low viscosity magmas(basaltic to andesitic magmas). ... When magma reaches the surface of the earth, it is called lava.