Salton Buttes: Difference between revisions

Salton Buttes
Salton Buttes
Niland Field
	Salton Buttes
Highest point
Elevation	−40 m (−130 ft)
Coordinates	33°11′49″N 115°36′58″W / 33.197°N 115.616°W

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Salton Buttes (also known as Niland Field^[2]) is a group of volcanoes in California. Located on the Salton Sea, they consist of a 7 kilometres (4.3 mi) long row of five lava domes named Mullet Island, North Red Hill, Obsidian Butte, Rock Hill and South Red Hill. They are closely associated with a fumarolic and a geothermal field, and there is evidence of buried volcanoes underground.

The Salton Buttes lie within the Salton Trough, a tectonic depression formed by the San Andreas Fault and the San Jacinto Faults that forms the northward extension of the Gulf of California and is separated from it by the Colorado River Delta. A number of geothermal and volcanic features are located in the general region, which is a region of active seafloor spreading.

While the Salton Buttes were formerly considered to be of late Pleistocene age, more recent dating efforts have determined that all of them formed during the Holocene through mostly effusive eruptions.

Geomorphology and geography

The Salton Buttes lie on the southeastern shores of the Salton Sea, at an elevation of −40 metres (−130 ft),^[1] in Imperial County,^[3] California.^[4] The towns of Niland and Calipatria lie northeast and southeast of the Salton Buttes, respectively, and the Alamo River enters the Salton Sea between the Salton Buttes.^[5]

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The Salton Buttes form a 7 kilometres (4.3 mi) long row^[6] of five lava domes^[1] that rise 30–40 metres (98–131 ft) above the surrounding terrain.^[6] They are named Mullet Island (33°13′32″N 115°36′30″W / 33.22556°N 115.60833°W / 33.22556; -115.60833), North Red Hill (33°12′0″N 115°36′43″W / 33.20000°N 115.61194°W / 33.20000; -115.61194), Obsidian Butte (33°10′17″N 115°38′16″W / 33.17139°N 115.63778°W / 33.17139; -115.63778), Rock Hill (33°11′1″N 115°37′24″W / 33.18361°N 115.62333°W / 33.18361; -115.62333) and South Red Hill (33°11′46″N 115°36′42″W / 33.19611°N 115.61167°W / 33.19611; -115.61167).^[2] The Red Hills form a paired volcano^[7]^[8] which is also known as Red Island;^[9] Red Island and Mullet Island were islands in 2005,^[10] the latter is now a peninsula.^[9]

Lava domes such as the Salton Buttes are formed from congealed lava that has risen within a volcanic vent.^[11] Obsidian Butte is surrounded by a lava flow and Mullet Island has a characteristic "onion-skin" foliation.^[7] A quarry is situated in Red Hill.^[12]

A fumarole field characterized by gryphons^[a] and salses^[b] is found close to Mullet Island,^[3] and exhale carbon dioxide and steam as well as ammonia and hydrogen sulfide. Some of these fumarolic vents reach heights of 2 metres (6 ft 7 in) and resemble these of actual igneous volcanoes. Mud pots are also found.^[14] Parts of the field has recently emerged from the Salton Sea owing to dropping water levels,^[15] leading to noticeable development and growth of fumarolic vents.^[16]

A geothermal field is associated with the Salton Buttes^[1] and is one of the largest and warmest on Earth,^[17] with temperatures of 360 °C (680 °F) at 1.5–2.5 kilometres (0.93–1.55 mi) depth.^[7] Various volcanic rocks such as andesite, basalt, dacite, diabase, gabbro and rhyolite, some bearing traces of hydrothermal alteration have been found in drill cores at the Salton Buttes and sometimes reach thicknesses of 100 metres (330 ft).^[18] There may be other volcanoes buried in the sediment pile.^[19]

Mullet Island
Obsidian Butte
Red Island and Rock Hill
Mud volcanoes close to the Salton Buttes

Geology

Since the Pliocene,^[20] the Salton Trough and the Gulf of California form an active rift zone south of the San Andreas Fault where seafloor spreading is underway, accompanied by volcanic and geothermal activity, active faulting^[c] and fast sedimentation. Since 5 million years ago, the formation of the Colorado River Delta has separated the Salton Trough from the actual Gulf of California, forming a large depression that reaches a depth of 40 metres (130 ft) below sea level.^[21] This depression is a pull-apart basin that opened up between various branches of the San Andreas Fault^[5] and the San Jacinto Fault,^[22] and is still actively subsiding at rates of 3 millimetres per year (0.12 in/year), increasing to 4–8 millimetres per year (0.16–0.31 in/year) in the central area of the Trough.^[23]

A number of volcanic centres have formed during Quaternary time in the region, including Cerro Prieto, Consag Rock, Isla San Luis, Isla Tortuga, the Salton Buttes and Sierra Pinacate which is the largest of these volcanoes.^[12] Strong geothermal activity has been observed as well, with the Salton Trough alone hosting five geothermal fields (Brawley-Mesquite, Cerro Prieto, East Mesa, Heber and Salton Sea) with a total heat output of 1,000–10,000 megawatts (1,300,000–13,400,000 hp).^[24] This heat output is in part harnessed to obtain geothermal power, with annual production of 1–3 terawatt-hours per year (110–340 MW).^[17]^[20]

The Salton Buttes volcanoes were formed on Quaternary sediments^[10] of the Colorado River Delta^[1] and the basement is formed by sediments deposited in lakes and by rivers, such as mudstones, sandstones and siltstones.^[25] This 5 kilometres (3.1 mi) thick upper layer is underlain by metamorphic greenschist rocks formed by hydrothermal alteration and thermal metamorphism of sediments, and finally by gabbroic rocks at 18–10 kilometres (11.2–6.2 mi) of depth. Diabasic rocks and intruded rhyolites have been identified in the sediments as well.^[22]

All of the Salton Buttes except for Mullet Island are developed on a lineament that is characterized by a magnetic anomaly.^[12] The volcanoes seem to share a common feeder dyke that may be connected to deep seated extensional processes^[26] along a transform fault that links the San Andreas Fault to the Gulf of California.^[7] The source of heat for the volcanoes and geothermal field is controversial, with deep mafic and shallow felsic sources both proposed.^[22] Seismic tomography of the area of the Salton Buttes has identified low-velocity anomalies in the mantle, consistent with higher temperatures there.^[27]

Composition

The domes are formed by rhyolite,^[1] which has an alkaline and calcium-poor composition^[12] and defines a potassium-rich suite. Scarce phenocrysts include amphibole, anorthoclase, apatite, clinopyroxene, ilmenite, magnetite, orthopyroxene, quartz and zircon.^[28] The isotopic composition of these volcanic rocks differs from that of the Salton Trough sediments. The total volume of the domes is about 0.5 cubic kilometres (0.12 cu mi).^[6]

The genesis of the magmas has been explained with several different processes, including assimilation of hydrothermally altered rocks, fractional crystallization and partial melting.^[22] One model presumes the existence of a continuously active deep magmatic reservoir that generates precursor magmas and episodically delivers them to a shallower magmatic reservoir where the rhyolites are formed.^[29]

Xenoliths encountered in the volcanic rocks include granite, granophyre, metasediments and tholeiite,^[28] often heavily altered by interaction with the volcanic system. Some of these basalts resemble these from the active rift zones in the Gulf of California and the East Pacific Rise.^[18]

Eruption history

Most of the Buttes formed between 1,800 and 2,300 years ago, although Mullet Island may be 5,000 years older.^[1] According to the Global Volcanism Program, Mullet Island formed 290 BCE ± 100 years, Obsidian Butte 10 AD ± 100 years and the other Buttes 210 AD ± 100 years.^[30] If Mullet Island formed at the same time as the other Buttes, the eruption episode that formed the Salton Buttes lasted probably no more than 500 years.^[31]

Research history

Various ages have been inferred for the Salton Buttes with various dating techniques.^[1] Early potassium-argon dating at Obsidian Butte yielded an age of 55,000 - 16,000 years before present^[12] as well as ages of 33,000 ± 18,000 and less than 10,000 years ago,^[18] and archeomagnetic methods concluded that the Salton Buttes were not simultaneously active with Cerro Prieto or Crater Elegante in the Sierra Pinacate.^[32] Subsurface volcanic rocks at the Salton Buttes have been dated to 3.8 ± 0.4 million years ago, 960,000 ± 190,000 years ago^[18] and 479,000 - 420,000 years ago,^[22] but some of the granites formed much more recently and are among the youngest known granites on Earth.^[33]

Radiometric dating of zircons found in the volcanic rocks and xenoliths as well as other methods however indicated that volcanic activity was much more recent, latest Pleistocene-Holocene.^[34] This recent conclusion was also supported by the fact that the small domes are located in a high sedimentation rate setting and would have been buried if they were too old.^[9] Obsidian hydration dating on the Salton Buttes yielded ages of 8,400 - 2,500 years ago,^[18] while thermoluminescence dating at Obsidian Butte has yielded an age of 3,300 ± 500 years ago,^[8] both implying recent ages.^[35]

Sequence of eruptive activity

The domes were formed by effusive eruptions, but at least Obsidian Butte and South Red Hill also experienced explosive eruptions that deposited pumice and tephra that were encountered in drill cores in the area and also quarried.^[8] Tuffs found farther south at Cerro Prieto have been linked to the Salton Buttes, but the large distance makes such a link questionable.^[36]

After their emplacement, the Salton Buttes were at times submerged in Lake Cahuilla^[d], causing the formation of wave cut terraces;^[7]^[12] however only South Red Hill appears to have been erupted underwater.^[35] Pumice rafts formed on the lake and are now preserved on its shorelines.^[6]

Hazards

The Salton Buttes are monitored by the California Volcano Observatory for possible future volcanic activity. Geophysical evidence shows that liquid magma is still present underneath the Salton Buttes and in light of nearby population density, present-day unrest and past eruptions are considered a high hazard volcano.^[37]

Notes

^ Gryphons are less than 3 metres (9.8 ft) high mud volcanoes.^[13]
^ Salses are water filled pools that seep gas, a variant of a mud volcano.^[13]
^ Such as the Imperial Fault, the San Andreas Fault and the San Jacinto Fault^[9]
^ A lake that existed in the region before the present-day Salton Sea,^[6] covering much of the Salton Trough.^[9] This lake was formed by periodic diversions of the Colorado River into the Salton Trough,^[25] and the present-day Salton Sea formed between 1905-1907 from water spilling through a broken canal.^[3]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h "Salton Buttes". Global Volcanism Program. Smithsonian Institution.
^ ^a ^b "Salton Buttes". Global Volcanism Program. Smithsonian Institution., Synonyms & Subfeatures
^ ^a ^b ^c Lynch, Hudnut & Adams 2013, p. 28.
^ Wright et al. 2015, p. 1198.
^ ^a ^b Schmitt & Hulen 2008, p. 709.
^ ^a ^b ^c ^d ^e Schmitt & Vazquez 2006, p. 262.
^ ^a ^b ^c ^d ^e Wood, Charles A.; Kienle, Jurgen (1992). Volcanoes of North America: United States and Canada. Cambridge University Press. p. 245. ISBN 9780521438117.
^ ^a ^b ^c Wright et al. 2015, p. 1200.
^ ^a ^b ^c ^d ^e Wright et al. 2015, p. 1199.
^ ^a ^b "Salton Buttes". Global Volcanism Program. Smithsonian Institution., Photo Gallery
^ Stovall, Marcaida & Mangan 2014, p. 2.
^ ^a ^b ^c ^d ^e ^f de Boer 1980, p. 1.
^ ^a ^b Planke, S.; Svensen, H.; Hovland, M.; Banks, D. A.; Jamtveit, B. (1 December 2003). "Mud and fluid migration in active mud volcanoes in Azerbaijan". Geo-Marine Letters. 23 (3–4): 159. doi:10.1007/s00367-003-0152-z. ISSN 0276-0460.
^ Lynch, Hudnut & Adams 2013, p. 31.
^ Lynch, Hudnut & Adams 2013, p. 29.
^ Lynch, Hudnut & Adams 2013, p. 34.
^ ^a ^b Karakas et al. 2017, p. 10.
^ ^a ^b ^c ^d ^e Schmitt & Vazquez 2006, p. 263.
^ "Quaternary volcanism in the United States". Developments in Quaternary Sciences. 1: 361. 2003-01-01. doi:10.1016/S1571-0866(03)01016-9. ISSN 1571-0866.
^ ^a ^b Schmitt & Hulen 2008, p. 708.
^ Schmitt & Vazquez 2006, pp. 260–261.
^ ^a ^b ^c ^d ^e Karakas et al. 2017, p. 11.
^ Schmitt & Hulen 2008, p. 716.
^ Schmitt & Vazquez 2006, p. 261.
^ ^a ^b Schmitt & Hulen 2008, p. 710.
^ Karakas et al. 2017, p. 12.
^ Barak, S.; Klemperer, L.S.; Lawrence, J.F. (December 2014). "Ambient Noise Tomography of Southern California Images Dipping San Andreas-Parallel Structure and Low-Velocity Salton Trough Mantle". AGU Fall Meeting Abstracts.
^ ^a ^b Wright et al. 2015, p. 1201.
^ Karakas et al. 2017, p. 15.
^ "Salton Buttes". Global Volcanism Program. Smithsonian Institution., Eruption History
^ Wright et al. 2015, p. 1206.
^ de Boer 1980, p. 6.
^ Schmitt & Vazquez 2006, p. 272.
^ Schmitt & Vazquez 2006, p. 269.
^ ^a ^b Wright et al. 2015, p. 1209.
^ de Boer 1980, p. 2.
^ Stovall, Marcaida & Mangan 2014, p. 1.

Sources

de Boer, J. (February 1980). "Paleomagnetism of the Quaternary Cerro Prieto, Crater Elegante, and Salton Buttes volcanic domes in the northern part of the Gulf of California rhombochasm" (PDF). University of North Texas Digital Library. Proceedings of the Second Symposium on the Cerro Prieto Geothermal Field. Retrieved 26 August 2018. {{cite web}}: Invalid |ref=harv (help)
Karakas, Ozge; Dufek, Josef; Mangan, Margaret T.; Wright, Heather M.; Bachmann, Olivier (June 2017). "Thermal and petrologic constraints on lower crustal melt accumulation under the Salton Sea Geothermal Field". Earth and Planetary Science Letters. 467: 10–17. doi:10.1016/j.epsl.2017.02.027. ISSN 0012-821X. {{cite journal}}: Invalid |ref=harv (help)
Lynch, David K.; Hudnut, Kenneth W.; Adams, Paul M. (August 2013). "Development and growth of recently-exposed fumarole fields near Mullet Island, Imperial County, California". Geomorphology. 195: 27–44. doi:10.1016/j.geomorph.2013.04.022. ISSN 0169-555X. {{cite journal}}: Invalid |ref=harv (help)
Schmitt, Axel K.; Hulen, Jeffrey B. (December 2008). "Buried rhyolites within the active, high-temperature Salton Sea geothermal system". Journal of Volcanology and Geothermal Research. 178 (4): 708–718. doi:10.1016/j.jvolgeores.2008.09.001. ISSN 0377-0273. {{cite journal}}: Invalid |ref=harv (help)
Schmitt, A.K.; Vazquez, J.A. (December 2006). "Alteration and remelting of nascent oceanic crust during continental rupture: Evidence from zircon geochemistry of rhyolites and xenoliths from the Salton Trough, California". Earth and Planetary Science Letters. 252 (3–4): 260–274. doi:10.1016/j.epsl.2006.09.041. ISSN 0012-821X. {{cite journal}}: Invalid |ref=harv (help)
Stovall, Wendy K.; Marcaida, Mae; Mangan, Margaret T. (2014). "The California Volcano Observatory: Monitoring the state's restless volcanoes". Fact Sheet. doi:10.3133/fs20143120. ISSN 2327-6932. {{cite journal}}: Invalid |ref=harv (help)
Wright, Heather M.; Vazquez, Jorge A.; Champion, Duane E.; Calvert, Andrew T.; Mangan, Margaret T.; Stelten, Mark; Cooper, Kari M.; Herzig, Charles; Schriener, Alexander (April 2015). "Episodic Holocene eruption of the Salton Buttes rhyolites, California, from paleomagnetic, U-Th, and Ar/Ar dating". Geochemistry, Geophysics, Geosystems. 16 (4): 1198–1210. doi:10.1002/2015GC005714. {{cite journal}}: Invalid |ref=harv (help)

[14] Gryphons are less than 3 metres (9.8 ft) high mud volcanoes.^[13]

[15] Salses are water filled pools that seep gas, a variant of a mud volcano.^[13]

[23] Such as the Imperial Fault, the San Andreas Fault and the San Jacinto Fault^[9]

[40] A lake that existed in the region before the present-day Salton Sea,^[6] covering much of the Salton Trough.^[9] This lake was formed by periodic diversions of the Colorado River into the Salton Trough,^[25] and the present-day Salton Sea formed between 1905-1907 from water spilling through a broken canal.^[3]

[GVP-1] ^ ^a ^b ^c ^d ^e ^f ^g ^h "Salton Buttes". Global Volcanism Program. Smithsonian Institution.

[GVPN-2] "Salton Buttes". Global Volcanism Program. Smithsonian Institution., Synonyms & Subfeatures

[FOOTNOTELynchHudnutAdams201328-3] Lynch, Hudnut & Adams 2013, p. 28.

[FOOTNOTEWrightVazquezChampionCalvert20151198-4] Wright et al. 2015, p. 1198.

[FOOTNOTESchmittHulen2008709-5] Schmitt & Hulen 2008, p. 709.

[FOOTNOTESchmittVazquez2006262-6] Schmitt & Vazquez 2006, p. 262.

[WoodKienle1992-7] Wood, Charles A.; Kienle, Jurgen (1992). Volcanoes of North America: United States and Canada. Cambridge University Press. p. 245. ISBN 9780521438117.

[FOOTNOTEWrightVazquezChampionCalvert20151200-8] Wright et al. 2015, p. 1200.

[FOOTNOTEWrightVazquezChampionCalvert20151199-9] Wright et al. 2015, p. 1199.

[GVPP-10] "Salton Buttes". Global Volcanism Program. Smithsonian Institution., Photo Gallery

[FOOTNOTEStovallMarcaidaMangan20142-11] Stovall, Marcaida & Mangan 2014, p. 2.

[FOOTNOTEde_Boer19801-12] ^ ^a ^b ^c ^d ^e ^f de Boer 1980, p. 1.

[PlankeSvensen2003-13] Planke, S.; Svensen, H.; Hovland, M.; Banks, D. A.; Jamtveit, B. (1 December 2003). "Mud and fluid migration in active mud volcanoes in Azerbaijan". Geo-Marine Letters. 23 (3–4): 159. doi:10.1007/s00367-003-0152-z. ISSN 0276-0460.

[FOOTNOTELynchHudnutAdams201331-16] Lynch, Hudnut & Adams 2013, p. 31.

[FOOTNOTELynchHudnutAdams201329-17] Lynch, Hudnut & Adams 2013, p. 29.

[FOOTNOTELynchHudnutAdams201334-18] Lynch, Hudnut & Adams 2013, p. 34.

[FOOTNOTEKarakasDufekManganWright201710-19] Karakas et al. 2017, p. 10.

[FOOTNOTESchmittVazquez2006263-20] Schmitt & Vazquez 2006, p. 263.

[Quaternary-21] "Quaternary volcanism in the United States". Developments in Quaternary Sciences. 1: 361. 2003-01-01. doi:10.1016/S1571-0866(03)01016-9. ISSN 1571-0866.

[FOOTNOTESchmittHulen2008708-22] Schmitt & Hulen 2008, p. 708.

[FOOTNOTESchmittVazquez2006260–261-24] Schmitt & Vazquez 2006, pp. 260–261.

[FOOTNOTEKarakasDufekManganWright201711-25] Karakas et al. 2017, p. 11.

[FOOTNOTESchmittHulen2008716-26] Schmitt & Hulen 2008, p. 716.

[FOOTNOTESchmittVazquez2006261-27] Schmitt & Vazquez 2006, p. 261.

[FOOTNOTESchmittHulen2008710-28] Schmitt & Hulen 2008, p. 710.

[FOOTNOTEKarakasDufekManganWright201712-29] Karakas et al. 2017, p. 12.

[Barak2014-30] Barak, S.; Klemperer, L.S.; Lawrence, J.F. (December 2014). "Ambient Noise Tomography of Southern California Images Dipping San Andreas-Parallel Structure and Low-Velocity Salton Trough Mantle". AGU Fall Meeting Abstracts.

[FOOTNOTEWrightVazquezChampionCalvert20151201-31] Wright et al. 2015, p. 1201.

[FOOTNOTEKarakasDufekManganWright201715-32] Karakas et al. 2017, p. 15.

[GVPE-33] "Salton Buttes". Global Volcanism Program. Smithsonian Institution., Eruption History

[FOOTNOTEWrightVazquezChampionCalvert20151206-34] Wright et al. 2015, p. 1206.

[FOOTNOTEde_Boer19806-35] Boer 1980, p. 6.

[FOOTNOTESchmittVazquez2006272-36] Schmitt & Vazquez 2006, p. 272.

[FOOTNOTESchmittVazquez2006269-37] Schmitt & Vazquez 2006, p. 269.

[FOOTNOTEWrightVazquezChampionCalvert20151209-38] Wright et al. 2015, p. 1209.

[FOOTNOTEde_Boer19802-39] Boer 1980, p. 2.

[FOOTNOTEStovallMarcaidaMangan20141-41] Stovall, Marcaida & Mangan 2014, p. 1.

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@@ Line 20: / Line 20: @@
 {{GeoGroup}}
-The Salton Buttes form a {{convert|7|km}} long row{{sfn|Schmitt|Vazquez|2006|p=262}} of five [[lava dome]]s<ref name="GVP" /> that rise {{convert|30|-|40|m}} above the surrounding terrain.{{sfn|Schmitt|Vazquez|2006|p=262}} They are named Mullet Island ({{coord|33|13|32|N|115|36|30|W}}), North Red Hill ({{coord|33|12|0|N|115|36|43|W}}), Obsidian Butte ({{coord|33|10|17|N|115|38|16|W}}), Rock Hill ({{coord|33|11|1|N|115|37|24|W}}) and South Red Hill ({{coord|33|11|46|N|115|36|42|W}}).<ref name="GVPN" /> The Red Hills form a paired volcano<ref name="WoodKienle1992" />{{sfn|Wright|Vazquez|Champion|Calvert|2015|p=1200}} which is also known as Red Island;{{sfn|Wright|Vazquez|Champion|Calvert|2015|p=1199}} Red Island and Mullet Island were [[island]]s in 2005,<ref name="GVPP" /> the latter is now a [[peninsula]].{{sfn|Wright|Vazquez|Champion|Calvert|2015|p=1199}} Obsidian Butte is surrounded by a [[lava flow]] and Mullet Island has a characteristic "onion-skin" foliation.<ref name="WoodKienle1992" /> A [[quarry]] is situated in Red Hill.{{sfn|de Boer|1980|p=1}}
+The Salton Buttes form a {{convert|7|km}} long row{{sfn|Schmitt|Vazquez|2006|p=262}} of five [[lava dome]]s<ref name="GVP" /> that rise {{convert|30|-|40|m}} above the surrounding terrain.{{sfn|Schmitt|Vazquez|2006|p=262}} They are named Mullet Island ({{coord|33|13|32|N|115|36|30|W}}), North Red Hill ({{coord|33|12|0|N|115|36|43|W}}), Obsidian Butte ({{coord|33|10|17|N|115|38|16|W}}), Rock Hill ({{coord|33|11|1|N|115|37|24|W}}) and South Red Hill ({{coord|33|11|46|N|115|36|42|W}}).<ref name="GVPN" /> The Red Hills form a paired volcano<ref name="WoodKienle1992" />{{sfn|Wright|Vazquez|Champion|Calvert|2015|p=1200}} which is also known as Red Island;{{sfn|Wright|Vazquez|Champion|Calvert|2015|p=1199}} Red Island and Mullet Island were [[island]]s in 2005,<ref name="GVPP" /> the latter is now a [[peninsula]].{{sfn|Wright|Vazquez|Champion|Calvert|2015|p=1199}}
+Lava domes such as the Salton Buttes are formed from congealed [[lava]] that has risen within a volcanic vent.{{sfn|Stovall|Marcaida|Mangan|2014|p=2}} Obsidian Butte is surrounded by a [[lava flow]] and Mullet Island has a characteristic "onion-skin" foliation.<ref name="WoodKienle1992" /> A [[quarry]] is situated in Red Hill.{{sfn|de Boer|1980|p=1}}
 A [[fumarole]] field characterized by [[Gryphon (geology)|gryphons]]{{efn|Gryphons are less than {{convert|3|m}} high [[mud volcano]]es.<ref name="PlankeSvensen2003" />}} and [[salsa|salses]]{{efn|Salses are water filled pools that seep gas, a variant of a [[mud volcano]].<ref name="PlankeSvensen2003" />}} is found close to Mullet Island,{{sfn|Lynch|Hudnut|Adams|2013|p=28}} and exhale [[carbon dioxide]] and [[steam]] as well as [[ammonia]] and [[hydrogen sulfide]]. Some of these fumarolic vents reach heights of {{convert|2|m}} and resemble these of actual igneous volcanoes. [[Mud pot]]s are also found.{{sfn|Lynch|Hudnut|Adams|2013|p=31}} Parts of the field has recently emerged from the Salton Sea owing to dropping water levels,{{sfn|Lynch|Hudnut|Adams|2013|p=29}} leading to noticeable development and growth of fumarolic vents.{{sfn|Lynch|Hudnut|Adams|2013|p=34}}
@@ Line 67: / Line 69: @@
 After their emplacement, the Salton Buttes were at times submerged in [[Lake Cahuilla]]{{efn|A lake that existed in the region before the present-day [[Salton Sea]],{{sfn|Schmitt|Vazquez|2006|p=262}} covering much of the Salton Trough.{{sfn|Wright|Vazquez|Champion|Calvert|2015|p=1199}} This lake was formed by periodic diversions of the [[Colorado River]] into the Salton Trough,{{sfn|Schmitt|Hulen|2008|p=710}} and the present-day [[Salton Sea]] formed between 1905-1907 from water spilling through a broken canal.{{sfn|Lynch|Hudnut|Adams|2013|p=28}}}}, causing the formation of [[Wave-cut platform|wave cut terraces]];<ref name="WoodKienle1992" />{{sfn|de Boer|1980|p=1}} however only South Red Hill appears to have been erupted underwater.{{sfn|Wright|Vazquez|Champion|Calvert|2015|p=1209}} [[Pumice raft]]s formed on the lake and are now preserved on its shorelines.{{sfn|Schmitt|Vazquez|2006|p=262}}
+=== Hazards ===
+The Salton Buttes are monitored by the [[California Volcano Observatory]] for possible future volcanic activity. Geophysical evidence shows that liquid [[magma]] is still present underneath the Salton Buttes and in light of nearby population density, present-day unrest and past eruptions are considered a high hazard volcano.{{sfn|Stovall|Marcaida|Mangan|2014|p=1}}
 == Notes ==
@@ Line 91: / Line 97: @@
 * {{cite journal |last1=Schmitt |first1=Axel K. |last2=Hulen |first2=Jeffrey B. |title=Buried rhyolites within the active, high-temperature Salton Sea geothermal system |journal=Journal of Volcanology and Geothermal Research |date=December 2008 |volume=178 |issue=4 |pages=708–718 |doi=10.1016/j.jvolgeores.2008.09.001 |url=https://www.sciencedirect.com/science/article/pii/S0377027308004708 |ref=harv |language=en |issn=0377-0273}}
 * {{cite journal |last1=Schmitt |first1=A.K. |last2=Vazquez |first2=J.A. |title=Alteration and remelting of nascent oceanic crust during continental rupture: Evidence from zircon geochemistry of rhyolites and xenoliths from the Salton Trough, California |journal=Earth and Planetary Science Letters |date=December 2006 |volume=252 |issue=3-4 |pages=260–274 |doi=10.1016/j.epsl.2006.09.041 |url=https://www.sciencedirect.com/science/article/pii/S0012821X06006984 |ref=harv |language=en |issn=0012-821X}}
+* {{Cite journal|last=Stovall|first=Wendy K.|last2=Marcaida|first2=Mae|last3=Mangan|first3=Margaret T.|date=2014|title=The California Volcano Observatory: Monitoring the state's restless volcanoes|url=http://pubs.er.usgs.gov/publication/fs20143120|journal=Fact Sheet|doi=10.3133/fs20143120|issn=2327-6932|ref=harv}}
 * {{cite journal |last1=Wright |first1=Heather M. |last2=Vazquez |first2=Jorge A. |last3=Champion |first3=Duane E. |last4=Calvert |first4=Andrew T. |last5=Mangan |first5=Margaret T. |last6=Stelten |first6=Mark |last7=Cooper |first7=Kari M. |last8=Herzig |first8=Charles |last9=Schriener |first9=Alexander |title=Episodic Holocene eruption of the Salton Buttes rhyolites, California, from paleomagnetic, U-Th, and Ar/Ar dating |journal=Geochemistry, Geophysics, Geosystems |date=April 2015 |volume=16 |issue=4 |pages=1198–1210 |doi=10.1002/2015GC005714 |ref=harv}}
 {{refend}}