Editing Magma (section)

=== Magmatic gases ===
{{Main|Volcanic gas}}
The concentrations of different [[volcanic gas|gas]]es can vary considerably. [[Water vapor]] is typically the most abundant magmatic gas, followed by [[carbon dioxide]]<ref>{{cite journal
| last1 = Pedone  | first1 = M. | last2 = Aiuppa | first2 = A.| last3 = Giudice | first3 = G. | last4 = Grassa | first4 = F.| last5 = Francofonte | first5 = V. | last6 = Bergsson | first6 = B.| last7 = Ilyinskaya | first7 = E.| title = Tunable diode laser measurements of hydrothermal/volcanic CO2 and implications for the global CO2 budget| journal = Solid Earth | date = 2014| volume = 5 | issue = 2 | pages = 1209–1221| doi = 10.5194/se-5-1209-2014| bibcode = 2014SolE....5.1209P | doi-access = free }}</ref> and [[sulfur dioxide]]. Other principal magmatic gases include [[hydrogen sulfide]], [[hydrogen chloride]], and [[hydrogen fluoride]].{{sfn|Schmincke|2003|p=42}}

The solubility of magmatic gases in magma depends on pressure, magma composition, and temperature. Magma that is extruded as lava is extremely dry, but magma at depth and under great pressure can contain a dissolved water content in excess of 10%. Water is somewhat less soluble in low-silica magma than high-silica magma, so that at 1,100&nbsp;°C and 0.5 [[GPa]], a basaltic magma can dissolve 8% {{chem2|H2O}} while a granite pegmatite magma can dissolve 11% {{chem2|H2O}}.{{sfn|Philpotts|Ague|2009|pp=244-250}} However, magmas are not necessarily saturated under typical conditions.

{| style="border:0px solid black; text-align: left;"
|+
!valign="top" |
{| class="wikitable"
|+Water concentrations in magmas (wt%){{sfn|Schmincke|2003|p=44}}
! Magma composition
! {{chem2|H2O}} concentration<br/>wt %
|-
| [[MORB]] ([[tholeiite]]s)
| style="text-align: center;" |  0.1 &ndash; 0.2
|-
| Island tholeiite
|style="text-align: center;" |   0.3 &ndash; 0.6
|-
| Alkali basalts
|style="text-align: center;" |   0.8 &ndash; 1.5
|- 
| Volcanic arc basalts
| style="text-align: center;" |  2&ndash;4
|- 
| [[Basanite]]s and [[nephelinite]]s
|style="text-align: center;" |   1.5&ndash;2
|- 
| Island arc andesites and dacites
|style="text-align: center;" |   1&ndash;3
|- 
| Continental margin andesites and dacites
|style="text-align: center;" |   2&ndash;5
|- 
| Rhyolites
| style="text-align: center;" |  up to 7
|}
|}

Carbon dioxide is much less soluble in magmas than water, and frequently separates into a distinct fluid phase even at great depth. This explains the presence of carbon dioxide fluid inclusions in crystals formed in magmas at great depth.{{sfn|Schmincke|2003|p=44}}