Editing Extrusive rock (section)

== Extrusive bodies and rock types ==
[[Shield volcano]]es are large, slow forming volcanoes<ref name=":2">{{Cite book|title=Petrology : Principles and Practice|last=Sen|first=Gautam|publisher=Springer|year=2014|isbn=9783642388002|location=Berlin|oclc=864593152}}</ref> that erupt fluid basaltic magma that cools to form the extrusive rock [[basalt]]. Basalt is composed of minerals readily available in the planet's crust, including [[feldspar]]s and [[pyroxene]]s.<ref name=":3" />

Fissure volcanoes pour out low viscosity basaltic magma from [[fissure vent]]s to form the extrusive rock basalt.<ref name=":3" />

Composite or [[Stratovolcano|stratovolcanoes]] often have andesitic magma and typically form the extrusive rock andesite. Andesitic magma is composed of many gases and melted [[Mantle (geology)|mantle]] rocks.<ref name=":3" />

[[Cinder cone|Cinder]] or scoria cones violently expel lava with high gas content,<ref name=":3" /> and due to the vapor bubbles in this [[mafic]] lava, the extrusive basalt scoria is formed.<ref name=":2" />

[[Lava dome]]s are formed by high viscosity lava that piles up, forming a dome shape. Domes typically solidify to form the rich in silica extrusive rock [[obsidian]] and sometimes [[dacite]] domes form the extrusive rock dacite, like in the case of [[Mount St. Helens]].<ref name=":3" />

[[Caldera]]s are volcanic depressions formed after an erupted volcano collapses. Resurgent calderas can refill with an eruption of rhyolitic magma to form the extrusive rock rhyolite like the [[Yellowstone Caldera]].<ref name=":3" />

[[Submarine volcano]]es erupt on the ocean floor and produce the extrusive rock pumice.<ref name=":3" /> Pumice is a light-weight glass with a vesicular texture that differs from scoria in its silicic composition and therefore floats.<ref name=":1" />