View source for Earth:Mammoth Mountain


{{Infobox mountain
| name = Mammoth Mountain 
| photo = Ritter Range and Mammoth Mountain.jpg
| photo_caption = Mammoth Mountain from the south, with Ritter Range behind
| elevation_ft = 11059
| elevation_ref = {{NAVD88}}<ref name="ngs">{{cite ngs |pid=HR2739 |name=706 702 2=Mammoth |accessdate=2014-01-16}}</ref>
| prominence_ft = 1647
| prominence_ref = <ref name="pb">{{cite peakbagger |pid=2648 |name=Mammoth Mountain, California |accessdate=2009-08-03}}</ref>
| location = Inyo National Forest,<br />Madera / Mono counties, {{wipe|California}}
| range = Sierra Nevada
| map = USA California#USA
| coordinates = {{coord|37.630626492|N|119.032625631|W|type:mountain_region:US-CA_scale:100000_source:NGS|format=dms|display=inline,title}}
| range_coordinates = 
| coordinates_ref = <ref name="ngs"/>
| topo = USGS Mammoth Mountain
| type = [[Earth:Lava dome|Lava dome]] complex<ref name="SI"/>
| age = About 50,000 to 200,000 years
| last_eruption = 1260 ± 40 years<ref name="SI"/>
| first_ascent = 
| easiest_route = Gondola<ref name="NYT_SKI"/>
}}
'''Mammoth Mountain''' is a [[Earth:Lava dome|lava dome]] complex partially located within the town of Mammoth Lakes, California, in the Inyo National Forest of Madera and Mono Counties.<ref name="SI"/> It is home to a large ski area primarily on the Mono County side.

Mammoth Mountain was formed in a series of eruptions that ended 57,000 years ago. Mammoth still produces [[Chemistry:Mazuku|hazardous volcanic gases]] that kill trees and caused ski patroller fatalities in 2006.<ref name=latimes2006/>

==Geology==
Mammoth Mountain is a [[Earth:Lava dome|lava dome]] complex in Mono County, California. It lies in the southwestern corner of the [[Earth:Long Valley Caldera|Long Valley Caldera]]<ref name=igarss2000/> and consists of about 12 [[Earth:Rhyodacite|rhyodacite]] and [[Earth:Dacite|dacite]] overlapping domes.<ref name=volcanoworld/> These domes formed in a long series of eruptions from 110,000 to 57,000 years ago, building a [[Earth:Volcano|volcano]] that reaches {{convert|11059|ft|m}} in elevation.<ref name=osti2006/> During this time, massive [[Earth:Dacite|dacite]] eruptions occurred roughly every 5000 years.<ref name=Harris2005/> The volcano is still active with minor eruptions, the largest of which was a minor [[Earth:Phreatic|phreatic]] (steam) eruption 700 years ago.<ref name="SI"/>

Mammoth Mountain also lies on the south end of the Mono-Inyo chain of [[Earth:Volcanic crater|volcanic crater]]s.<ref name=usgs2000/> The magma source for Mammoth Mountain is distinct from those of both the [[Earth:Long Valley Caldera|Long Valley Caldera]] and the Inyo Craters.<ref name="SI"/><ref name="Hildreth2004">{{cite journal | last=Hildreth | first=Wes | title=Volcanological perspectives on Long Valley, Mammoth Mountain, and Mono Craters: several contiguous but discrete systems | journal=Journal of Volcanology and Geothermal Research | volume=136 | issue=3–4 | pages=169–198 | publisher=Elsevier B.V. | date=2004-09-14 | doi=10.1016/j.jvolgeores.2004.05.019|bibcode = 2004JVGR..136..169H }}</ref><ref name="LBL"/>
Mammoth Mountain is composed primarily of [[Earth:Dacite|dacite]] and [[Earth:Rhyolite|rhyolite]],<ref name="USGS_GEO_HIST"/> part of which has been altered by hydrothermal activity from fumaroles (steam vents).<ref>{{cite web| url=http://www.indiana.edu/~sierra/papers/2007/rpease.html|title=Hydrothermal System of the Long Valley Caldera|work=Volcanoes of the Eastern Sierra Nevada: Geology and Natural Heritage of the Long Valley Caldera|first=Robert C.|last=Pease|access-date=2010-05-07}}</ref>

==Volcanic gas discharge==
Mammoth is [[Physics:Outgassing|outgassing]] large amounts of [[Chemistry:Carbon dioxide|carbon dioxide]] out of its south flank, near Horseshoe Lake, causing [[Chemistry:Mazuku|mazuku]] in that area. The concentration of carbon dioxide in the ground ranges from 20 to 90 percent CO<sub>2</sub>. Measurements of the total discharge of carbon dioxide gas at the Horseshoe Lake tree-kill area range from {{convert|50|to|150|ST|MT|sigfig=2|lk=on}} per day. This high concentration causes trees to die in six regions that total about {{convert|170|acre|km2|2}} in size (see photo).<ref name="usgsco2"/>

The tree-kills originally were attributed to a severe drought that affected California in the late 1980s and early 1990s. Another idea was that the kills were the result of a [[Biology:Pathogen|pathogen]] or other biological infestation. However, neither idea explained why all trees in the affected areas were killed regardless of age or health. Then, in March 1990, a U.S. Forest Service Ranger became ill with suffocation symptoms after being in a snow-covered cabin near Horseshoe Lake.<ref name="magmatic"/>
[[File:TreeKill.jpg|thumb|left|Carbon dioxide has killed a large area of trees]]

Measurements around the lake found that restrooms and [[Engineering:Tent|tent]]s had a greater than 1% CO<sub>2</sub> concentration (toxic) and a deadly 25% concentration of CO<sub>2</sub> in a small cabin.  CO<sub>2</sub> concentrations of less than 1% are typical and healthy in most [[Chemistry:Soil|soil]]s; however, soil concentrations of CO<sub>2</sub> in the tree-kill areas ranged from 20% to 90%. This overabundance of CO<sub>2</sub> was found to be the cause of the tree-kills because tree roots need to absorb O<sub>2</sub> directly and the high CO<sub>2</sub> level reduced available O<sub>2</sub>. Researchers also determined that Mammoth releases about {{convert|1300|ST|MT|sigfig=2}} of CO<sub>2</sub> every day. As of 2003, the concentration of carbon dioxide in [[Chemistry:Soil gas|soil gas]] at Mammoth Mountain is being monitored on a continuous, year-round basis at four sites—three at Horseshoe Lake and one near the base of Chair 19 at the ski area.<ref name="usgsco2"/>

The most likely sources of the CO<sub>2</sub> are degassing of intruded [[Biology:Magma|magma]] and gas release from [[Earth:Limestone|limestone]]-rich metasedimentary rocks that are heated by magmatic intrusions. The remarkable uniformity in chemical and [[Physics:Isotope|isotopic]] composition of the CO<sub>2</sub> and accompanying gases at different locations around Mammoth Mountain indicates that there may actually be a large reservoir of gas deep below the mountain from which gas escapes along faults to the surface.<ref name="usgsco2"/> Measurements of helium emissions support the theory that the gases emitted in the tree kill area have the same source as those discharged from Mammoth Mountain Fumarole.<ref name="LBL"/><ref>{{cite web | title=Helium Discharge at Mammoth Mountain Fumarole (MMF) | publisher=United States Geological Survey | date=2003-07-30 | url=http://volcanoes.usgs.gov/lvo/activity/monitoring/helium.php | access-date=2008-08-19 | archive-url=https://web.archive.org/web/20100602221532/http://volcanoes.usgs.gov/lvo/activity/monitoring/helium.php | archive-date=2010-06-02}}</ref> There is evidence that the rate of CO<sub>2</sub> discharge has been declining,<ref>{{cite conference | first=C.D. | last=Farrar |author2=Bergfeld, D. | title=Magmatic Carbon Dioxide Emissions From Mammoth Mountain, California —- A Decreasing Trend From 1996 to 2007 | conference=American Geophysical Union, Fall Meeting 2007 | publisher=[[Organization:American Geophysical Union|American Geophysical Union]] | date=December 2007 | bibcode=2007AGUFM.V21C0722F }}</ref> with emissions peaking in 1991.<ref name="usgs172-96"/>

In April 2006, three members of the Mammoth Mountain Ski Area ski patrol died while on duty. All three died from suffocation by [[Chemistry:Carbon dioxide|carbon dioxide]] when they fell into a fumarole on the slopes of the mountain.<ref>{{cite web | last = Covarrubias | first = Amanda |author2=Doug Smith | title = 3 Die in Mammoth Ski Patrol Accident | work = {{wipe|Los Angeles Times}} | date = 2006-06-07 | url = http://articles.latimes.com/2006/apr/07/local/me-mammoth7 | access-date = 2013-01-08}}</ref>

==Recreational use==
[[File:Mammoth Mtn ski area (16126219736).jpg|thumb|right|Ski runs]]
Mammoth Mountain is home to the Mammoth Mountain Ski Area, founded by Dave McCoy in 1953. Mammoth is a ski, snowboard, and snowmobile mountain during the winter months. Mammoth is the highest ski resort in California and is notable for the unusually large amount of snowfall it receives compared to other Eastern Sierra peaks—about 400" annually and about 300 out of 365 days of sunshine—due to its location in a low gap in the Sierra crest.<ref name=wsc2001/> In the summer months the ski [[Engineering:Gondola lift|gondola]]s are used by mountain bikers and  tourists who wish to get a summit view of [[Earth:Long Valley Caldera|Long Valley Caldera]] directly to the east and Sierra peaks to the west, south and north.<ref name="NYT_SKI"/> To the south of the mountain, there are a number of lakes that serve as tourist attractions in the summer.

==References==
{{clear right}}
{{Reflist|colwidth=33em|refs=
<!-- In alphabetical order -->
<ref name=Harris2005>
  {{cite book | last=Harris|first=Stephen L.
  | title=Fire Mountains of the West | year=2005 | edition=3rd
  | publisher=Mountain Press Publishing Company | location=Missoula, Montana|isbn=978-0-87842-511-2}}</ref>
<ref name=igarss2000>
  {{cite conference | author1=Martini, B.A. | author2=Silver, E.A.|author3=Potts, D.C. |author4= Pickles, W.L.
  | title=Geological and geobotanical studies of Long Valley Caldera, CA, USA utilizing new 5m hyperspectral imagery
  | conference=Geoscience and Remote Sensing Symposium, 2000. Proceedings. IGARSS 2000. IEEE 2000 International
  | pages=1376–1378 | volume=4 | publisher=[[Organization:Institute of Electrical and Electronics Engineers|Institute of Electrical and Electronics Engineers]] | date=July 2000 
  | doi=10.1109/IGARSS.2000.857212 | url=https://digital.library.unt.edu/ark:/67531/metadc736229/m2/1/high_res_d/792730.pdf }}</ref>
<ref name=latimes2006>
  {{cite news | url=http://articles.latimes.com/2006/apr/09/local/me-mammoth9
  | title=How Routine Turned to Tragedy at Mammoth | date=2006-04-09 
  | first1=Steve|last1=Hymon|first2=Amanda|last2=Covarrubias|access-date=2011-05-09|newspaper=Los Angeles Times}}</ref>
<ref name="LBL">
  {{cite web|author1=DePaolo, Don |author2=Sorey, Mike |author3=Evans, Bill |author4=Farrar, Chris |author5=Cook, Andrea |author6=Hainsworth, Laura |author7=Rogie, John |title=Volcanic Hazards and CO<sub>2</sub> Emissions: Mammoth Mountain Long Valley Caldera, California |work=Center for Isotope Geochemistry – Nobel Gas Isotope Geochemistry |publisher=[[Organization:Lawrence Berkeley National Laboratory|Lawrence Berkeley National Laboratory]] |url=http://www-esd.lbl.gov/CIG/noblegas/volcanic.html |access-date=2008-08-19 |url-status=dead |archive-url=https://web.archive.org/web/20080921225441/http://www-esd.lbl.gov/CIG/noblegas/volcanic.html |archive-date=September 21, 2008 }}</ref>
<ref name="magmatic">
  {{cite web|url=http://pubs.usgs.gov/wri/wri98-4217/|title=Magmatic Carbon Dioxide Emissions at Mammoth Mountain, California
  | author1=Farrar, C.D.|author2=Neil, J. M.  |author3=Howle, J. F.
  | publisher=USGS|work=Water-Resources Investigations report 98-4217|year=1999}}</ref>
<ref name="NYT_SKI">
  {{cite news | last=Jones | first=Finn-Olaf | title=Mammoth Mountain Ski Area | work=Ski Guide
  | publisher=The New York Times | date=2008-02-29
  | url=http://travel.nytimes.com/2008/02/29/travel/escapes/29MAMMOTH.html | access-date=2008-08-18}}</ref>
<ref name=osti2006>
  {{cite journal | first=Jennifer L. | last=Lewicki | author2= Birkholzer, Jens |author3 = Tsang, Chin-Fu
  | title=Natural and Industrial Analogues for Release of {{CO2}} from Storage Reservoirs: Identification of Features, Events, and Processes and Lessons Learned
  | publisher=United States Department of Energy/Office of Scientific and Technical Information | date=February 2006
  | url=http://www.osti.gov/bridge/servlets/purl/891824-4U1cp4/891824.pdf | access-date=2008-08-18}}</ref>
<ref name="SI">
  {{cite gvp | vn=323150 | name = Mammoth Mountain | accessdate = 2008-12-18 }}</ref>
<ref name="usgs172-96">
  {{cite journal | author1=Sorey, Michael L.| author2=Farrar, Christopher D. | author3=Gerlach, Terrance M. |author4=McGee, Kenneth A.
  | author5=Evans, William C. | author6=Colvard, Elizabeth M. |author7=Hill, David P. | author8=Bailey, Roy A. 
  | author9=Rogie, John D. | author10=Hendley II, James W. | author11=Stauffer, Peter H. 
  | title=Invisible {{CO2}} Gas Killing Trees at Mammoth Mountain, California – U.S. Geological Survey Fact Sheet 172-96
  | version=Online Version 2.0 | publisher=USGS | date=2007-07-09
  | url=http://pubs.usgs.gov/fs/fs172-96/| access-date=2008-08-19}}</ref>
<ref name=usgs2000>
  {{cite journal | author1= Hill, David P. | author2=Bailey, Roy A. |author3=Sorey, Michael L.
  | author4=Hendley II, James W. |author5= Stauffer, Peter H.
  | title=Living With a Restless Caldera—Long Valley, California – U.S. Geological Survey Fact Sheet 108-96 | version= Online Version 2.1
  | publisher=United States Geological Survey | date=May 2000 | url=http://pubs.usgs.gov/fs/fs108-96/ |  access-date=2008-08-18}}</ref>
<ref name="USGS_GEO_HIST">
  {{cite web | title=Geologic History of Long Valley Caldera and the Mono-Inyo Craters volcanic chain, California 
  | publisher=United States Geological Survey | url=http://pubs.usgs.gov/dds/dds-81/Intro/GeologicMaps/GeologicHistory.html
  | access-date=2008-08-18}}</ref>
<ref name="usgsco2">
  {{cite web | url=http://volcanoes.usgs.gov/lvo/activity/monitoring/co2.php
  | title=Carbon Dioxide and Helium Discharge from Mammoth Mountain|date=2001-12-27
  | work=USGS Volcano Hazards Program Long Valley Observatory
  | access-date=2008-08-18 | publisher=USGS
  | archive-url=https://web.archive.org/web/20100528023418/http://volcanoes.usgs.gov/lvo/activity/monitoring/co2.php
  | archive-date=2010-05-28}}</ref>
<ref name=volcanoworld>
  {{cite web | title=Long Valley Caldera and Mono-Inyo Craters Volcanic Field, California|work=Volcano World
  | url=http://volcano.und.nodak.edu/vwdocs/volc_images/north_america/california/long_valley.html
  | archive-url=https://web.archive.org/web/20080114043639/http://volcano.und.nodak.edu/vwdocs/volc_images/north_america/california/long_valley.html
  | archive-date=2008-01-14}}</ref>
<ref name=wsc2001>
  {{cite conference | last=Burak | first=S.A. |author2=R.E. Davis
  | title=Preliminary evaluation of snow accumulation patterns based on storm type, Mammoth Mountain, California, 1996–2001
  | conference=Proc. Western Snow Conference | year=2001
  | url=http://www.westernsnowconference.org/2001/PDF/WSC2001BurakDavis.PDF
  | archive-url=https://web.archive.org/web/20070930191250/http://www.westernsnowconference.org/2001/PDF/WSC2001BurakDavis.PDF
  | archive-date=2007-09-30}}</ref>
}}

;Further reading
* {{cite book|title=Roadside Geology of Northern and Central California|last=Alt|first=David|author2=Hyndman, Donald
  | publisher=Mountain Press Publishing Company|location=Missoula, Montana|year=2000|isbn=978-0-87842-409-2}}

==External links==
{{Commons and category|Mammoth Mountain}}
* [http://www.mammothmountain.com/winter/mountain-information/mountain-information/trail-map/ Mammoth Mountain Ski Area trail map]
* [http://volcanoes.usgs.gov/lvo/ USGS Volcano Hazards Program, Long Valley Observatory]
* [http://www.virtualguidebooks.com/SouthCalif/EastOfTheSierra/MammothLakes/CO2HazardAreaMammoth_S.php QTVR of tree kill area]
* [https://web.archive.org/web/20091110133923/https://earthquake.usgs.gov/earthquakes/states/events/1980_05_25.php Mammoth Earthquake 1980 May 25 16:33, 16:49, 19:44 UTC  Magnitude 6.2, 5.9, 5.9]


[[Category:Lava domes]]

{{Sourceattribution|Mammoth Mountain|1}}