Editing Geyser (section)

=== Form and function ===
[[File:Steamboat Geyser in Yellowstone.jpg|thumb|upright=1.1|alt=Water and steam erupting from rocky, barren ground, and fir trees in the background|[[Steamboat Geyser]] in [[Yellowstone National Park]]]]

Geysers are nonpermanent geological features. Geysers are generally associated with areas of recent [[magmatism]].<ref name=annrev>{{cite journal |url=https://www.annualreviews.org/content/journals/10.1146/annurev-earth-063016-015605 |journal=Annual Review of Earth and Planetary Sciences |volume=45 |year=2017 |title=The Fascinating and Complex Dynamics of Geyser Eruptions |first1=Shaul |last1=Hurwitz |first2=Michael |last2=Manga |issue=1 |pages=31–59 |doi=10.1146/annurev-earth-063016-015605 |bibcode=2017AREPS..45...31H}}</ref> As the water boils, the resulting pressure forces a superheated column of steam and water to the surface through the geyser's internal plumbing.<ref name=annrev/> The formation of geysers specifically requires the combination of three geologic conditions that are usually found in volcanic terrain: heat, water, and a subsurface hydraulic system with the right geometry.<ref name=annrev/>

The heat needed for geyser formation comes from [[magma]] that needs to be close to the surface of the Earth.<ref>{{Cite book |url=https://books.google.com/books?id=ljXMs4rkv3gC&q=heat+for+geyser+formation+comes+from+near+surface+magma&pg=PA127 |title=Quakes, Eruptions, and Other Geologic Cataclysms: Revealing the Earth's Hazards |last=Erickson |first=Jon |date=14 May 2014 |publisher=Infobase Publishing |isbn=9781438109695}}</ref> For the heated water to form a geyser, a plumbing system (made of [[fracture]]s, [[ground fissure|fissures]], porous spaces, and sometimes cavities) is required. This includes a reservoir to hold the water while it is being heated.<ref name=annrev/>

Geysers tend to be coated with [[geyserite]], or [[siliceous sinter]]. The water in geysers comes in contact with hot [[silica]]-containing rocks, such as [[rhyolite]]. The heated water dissolves the silica. As it gets closer to the surface, the water cools and the silica drops out of solution, leaving a deposit of [[amorphous]] [[opal]]. Gradually the opal anneals into [[quartz]], forming geyserite.  Geyserite often covers the microbial mats that grow in geysers. As the mats grow and the silica is deposited, the mats can form up to 50% of the volume of the geyserite.<ref>{{cite web |title=Geysers—what exactly are they made of? |work=Yellowstone Volcano Observatory |publisher=USGS |url=https://www.usgs.gov/news/geysers-what-exactly-are-they-made |date=23 March 2020}}</ref>