Garibaldi Volcanic Belt
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[[Image:Garibaldi Volcanic Belt-en.svg|thumb|right|400px|Map of the Garibaldi Volcanic Belt centers]]
The '''Garibaldi Volcanic Belt''' is a north-south range of [[volcano]]es in southwestern [[British Columbia]], [[Canada]]. It is the northern extension of the [[Cascade Volcanoes|Cascade Volcanic Arc]], a chain of volcanoes of major [[andesite|andesitic]] to [[dacitic]] [[stratovolcano]]es extending northward from [[northern California]] to British Columbia and contains the most explosive young volcanoes in Canada. The Garibaldi Volcanic Belt includes the [[Bridge River Cones]], [[Mount Cayley]], [[Mount Fee]], [[Mount Garibaldi]], [[Mount Price]], [[Mount Meager]] and the Squamish Volcanic Field.
==Geology==
Eruption styles in the Garibaldi Volcanic Belt range from [[effusive eruption|effusive]] to [[explosive eruption|explosive]], with compositions from [[basalt]] to [[rhyolite]]. Morphologically, centers include [[caldera]]s, [[cinder cone]]s, [[stratovolcano]]es and small isolated [[lava]] masses. Due to repeated continental and alpine glaciations, many of the volcanic deposits in the belt reflect complex interactions between [[magma]] composition, topography, and changing ice configurations.
Mount Meager is the most unstable volcanic massif in Canada. It has dumped [[clay]] and [[Rock (geology)|rock]] several meters deep into the [[Pemberton Valley]] at least three times during the past 7,300 years. Recent drilling into the Pemberton Valley bed encountered remnants of a [[debris flow]] that had travelled 50 kilometers from the volcano shortly before it last erupted 2350 years ago. About 1,000,000,000 m³ of rock and sand extended over the width of the valley. Two previous debris flows, about 4,450 and 7,300 years ago, sent [[debris]] at least 32 kilometers from the volcano. Recently, the volcano has created smaller landslides about every ten years, including one in [[1975]] that killed four [[geologist]]s near [[Meager Creek]]. The possibility of Mount Meager covering stable sections of the Pemberton Valley in a debris flow is estimated at about one in 2400 years. There is no sign of volcanic activity with these events. However [[scientist]]s warn the volcano could release another massive debris flow over populated areas anytime without warning.
Volcanoes of the Garibaldi Volcanic Belt have been sporadically active over a time span of several millions of years. The most recenty documented eruption was the 2350 BP eruption of Mount Meager. This eruption may have been close in size to that of the [[May 18]], [[1980 eruption of Mount St. Helens]]. Ash from this eruption can be traced eastward to western [[Alberta]]. Hot springs in the vicinity of [[Mount Cayley]] and Mount Meager suggest that magmatic heat is still present. The long history of volcanism in the region, coupled with continued subduction off the coast, suggests that volcanism has not yet ended in the Garibaldi Volcanic Belt. Long repose periods, up to several thousand years, between major explosive events at the major volcanoes (Mounts [[Mount Meager|Meager]], [[Mount Cayley|Cayley]] and [[Mount Garibaldi|Garibaldi]]), appears to typify the Garibaldi Volcanic Belt.
Young [[dike (geology)|dikes]] in the Squamish-Garibaldi area show a strong north-northwest to north-northeast trend. Ages of these dikes are not well constrained but they are probably mainly [[Miocene]] and younger; at least some are related to Garibaldi volcanism.
The Garibaldi Volcanic Belt contains two extra volcanic fields, the [[Franklin Glacier Volcano]] and the [[Silverthrone Caldera]], which lie 140 and 190 [[kilometre]]s northwest of the main volcanic belt. These volcanoes are originally part of the [[erosion|eroded]] [[Miocene]] [[Pemberton Volcanic Belt]].
The [[Chilcotin Plateau Basalts]] east of the Garibaldi Volcanic Belt, is thought to have formed as a result of extension of the [[crust (geology)|crust]] behind the [[Cascadia subduction zone]].
==Cascadia subduction zone==
{{main|Cascadia subduction zone}}
[[Image:Cascadia subduction zone USGS.png|thumb|right|Area of the [[Cascadia subduction zone]], including the Garibaldi Volcanic Belt (three northernmost red triangles) ]]
The Garibaldi Volcanic Belt was formed by [[subduction]] of the [[Juan de Fuca Plate]] and the [[Explorer Plate|Explorer]] plates (remnants of the much larger [[Farallon Plate]]) under the [[North American Plate]] along the [[Cascadia subduction zone]]. This is a 680 mi (1,094 km) long [[geologic fault|fault]], running 50 mi (80 km) off the west-coast of the [[Pacific Northwest]] from [[northern California]] to [[Vancouver Island]], [[British Columbia]]. The plates move at a relative rate of over 0.4 inches (10 mm) per year at a somewhat oblique angle to the subduction zone.
Unlike most subduction zones worldwide, there is no [[oceanic trench]] present along the [[continental margin]] in [[Cascadia]]. Instead, [[terrane]]s and the accretionary wedge have been uplifted to form a series of coast ranges and exotic mountains. A high rate of sedimentation from the outflow of the three major rivers ([[Fraser River]], [[Columbia River]], and [[Klamath River]]) which cross the Cascade Range contributes to further obscuring the presence of a trench. However, in common with most other subduction zones, the outer margin is slowly being compressed, similar to a giant [[spring (device)|spring]]. When the stored energy is suddenly released by slippage across the fault at irregular intervals, the Cascadia subduction zone can create very large [[earthquake]]s such as the [[Richter Magnitude Scale|magnitude]] 9 [[1700 Cascadia earthquake|Cascadia earthquake of 1700]].
==History==
First Nations people have inhabited the area for thousands of years and developed their own [[myth]]s and [[legend]]s concerning the Cascade volcanoes. According to some of these tales, [[Mount Garibaldi]] was used as refuge from a great [[flood]].
[[Hot spring]]s in the Canadian side of the arc, were originally used and revered by [[First Nations]] people. The springs located on [[Meager Creek]] are called ''Teiq''<ref>[http://www.bivouac.com/MtnPg.asp?MtnId=953 Mount Meager] in the Canadaian Mountain Encyclopedia. Retrieved on [[2007-10-16]]</ref> in the language of the [[Lillooet River]] and were the farthest up the [[Lillooet River]] the spirit-beings/wizards known as "the Transformers" reached during their journey into the [[Lillooet Country]], and a "training" place for young First Nations men who would privite themselves at the at the springs to acquire power and knowledge. In this area, also, was found the blackstone chief's head pipe that is famous of Lillooet artifacts; found buried in [[volcanic ash]], one supposes from the 2350 BP eruption of Mount Meager.
Volcanics of the Garibaldi Volcanic Belt were first discovered and [[map]]ped in [[1911]].
==Volcanoes==
The volcanoes within the belt include (in approximately south-north order):
[[Image:Mount Garibaldi.jpg|thumb|right|200px|[[Mount Garibaldi]] as seen from [[Squamish]] ]]
[[Image:Mount_Cayley.jpg|thumb|right|200px|[[Mount Cayley]] as seen from its southeast slopes]]
[[Image:MountMeagerPlinthCapricorn.jpg|thumb|right|200px|The [[Mount Meager]] volcanic complex as seen from the east near Pemberton, BC. Summits left to right are [[Capricorn Mountain]], Mount Meager, and [[Plinth Peak]].]]
*[[Watts Point volcanic centre]]
*[[The Castle (volcano)|The Castle]]
*[[Mount Garibaldi]]
**[[Opal Cone]]
**[[Atwell Peak]]
*[[Garibaldi Lake Volcanic Field]]
**[[The Table]]
**[[Mount Price]]
**[[Clinker Peak]]
**[[Black Tusk]]
**[[Cinder Cone (British Columbia)|Cinder Cone]]
*[[Mount Cayley]]
**[[Mount Fee]]
**[[Brandywine Mountain]]
<!--Brandywine Mountain is a volcanic plug isn't it?-->
**[[Pyroclastic Peak]]
**[[Vulcan's Thumb]]
**[[Powder Mountain (volcano)|Powder Mountain]]
**[[Mount Brew (Cheakamus River)|Mount Brew]]
**[[Little Ring Peak]]
**[[Pali Dome]]
**[[Cauldron Dome]]
**[[Crucible Dome]]
**[[Ring Mountain]]
**[[Ember Ridge]]
**[[Slag Hill]]
**[[Cheakamus Valley Vent]]
*[[Mount Meager]]
**[[Plinth Peak]]
**[[Pylon Peak]]
**[[Mount Job]]
**[[Devastator Peak]]
**[[Capricorn Mountain]]
***[[Perkin's Pillar]]
*[[Bridge River Cones]]
**[[Nichols Valley Flows]]
**[[Sham Hill]]
**[[Tuber Hill]]
**[[Tuber Hill East]]
**[[Salal Glacier]]
*[[Franklin Glacier Volcano]]
*[[Silverthrone Caldera]]
**[[Mount Silverthrone]]
**[[Machmel River Cone]]
**[[Charnaud Creek]]
**[[Trudel Creek]]
==See also==
*[[Cascade Volcanoes]]
*[[Anahim Volcanic Belt]]
*[[Northern Cordilleran Volcanic Province]]
*[[Wrangell Volcanic Field]]
*[[Chilcotin Plateau Basalts]]
*[[Wells Gray-Clearwater Volcanic Field]]
*[[Garibaldi Lake Volcanic Field]]
*[[Volcanism in Canada]]
*[[List of volcanoes in Canada]]
*[[Geology of the Pacific Northwest]]
==References==
{{reflist}}
==External links==
* [http://gsc.nrcan.gc.ca/volcanoes/map/map_e.php?id=gvb National Resources Canada]
{{Cascade volcanoes}}
[[Category:Volcanic areas of Canada]]
[[Category:Subduction volcanoes]]
[[Category:Cascade Volcanoes]]
[[Category:Volcanic belts]]
[[Category:Pacific Ranges]]
[[simple:Garibaldi Volcanic Belt]]