View source for Garibaldi Volcanic Belt

{{Short description|Volcanic chain in southwestern British Columbia, Canada}}
{{Infobox landform
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| name              = Garibaldi Volcanic Belt
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| type              = [[Volcanism|Volcanic area]]
| photo             = Mount Meager massif 1987.jpg
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| photo_caption     = The Mount Meager massif in 1987. Summits left to right are Capricorn Mountain, Mount Meager and Plinth Peak.
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| map_image         = Garibaldi Volcanic Belt-en.svg
| map_caption       = The location and extent of the Garibaldi Volcanic Belt, showing its isolated volcanoes and related volcanic features. 
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| location          = British Columbia, Canada
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  | [[Lava flow]]s<ref>{{cite web|title=Tricouni Southwest|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_tsw_047|archive-url=https://web.archive.org/web/20101211093136/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_tsw_047|url-status=dead|archive-date=2010-12-11|access-date=2010-03-04}}</ref>
  | [[lava dome]]s<ref>{{cite web|title=Columnar Peak|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_cpk_010|archive-url=https://web.archive.org/web/20060219225839/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_cpk_010|url-status=dead|archive-date=2006-02-19|access-date=2010-03-04}}</ref>
  | [[cinder cone]]s<ref>{{cite web|title=Opal Cone|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_ocn_007|archive-url=https://web.archive.org/web/20060219230131/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_ocn_007|url-status=dead|archive-date=2006-02-19|access-date=2010-03-04}}</ref>
  | [[stratovolcano]]es<ref>{{cite web |title=Mount Price |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_mpc_009 |archive-url=https://web.archive.org/web/20090628152522/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_mpc_009 |archive-date=2009-06-28 |access-date=2010-03-04 |url-status=dead }}</ref>
  | [[subglacial volcano]]es<ref name="LD">{{cite web |title=Slag Hill |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_shl_021 |archive-url=https://web.archive.org/web/20101212060850/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_shl_021 |archive-date=2010-12-12 |access-date=2010-03-04 |url-status=dead }}</ref>
  | [[volcanic plug]]s<ref>{{cite web |title=Sham Hill |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_shi_003 |archive-url=https://web.archive.org/web/20101211095015/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_shi_003 |archive-date=2010-12-11 |access-date=2010-03-04 |url-status=dead }}</ref>
  | [[caldera]]s<ref name="NIO">{{cite web |title=Silverthrone Caldera |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_scl_044 |archive-url=https://web.archive.org/web/20101212053650/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_scl_044 |archive-date=2010-12-12 |access-date=2010-03-04 |url-status=dead }}</ref>
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The '''Garibaldi Volcanic Belt''' is a northwest–southeast trending volcanic chain in the [[Pacific Ranges]] of the [[Coast Mountains]] that extends from [[Watts Point]] in the south to the [[Ha-Iltzuk Icefield]] in the north. This chain of volcanoes is located in southwestern [[British Columbia]], Canada. It forms the northernmost segment of the [[Cascade Volcanoes|Cascade Volcanic Arc]], which includes [[Mount St. Helens]] and [[Mount Baker]].<ref name="JP"/><ref name="QQQ">{{cite web|title=Garibaldi volcanic belt |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-04-02 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/belt_garibaldi_e.php |archive-url=https://web.archive.org/web/20110528100742/http://gsc.nrcan.gc.ca/volcanoes/cat/belt_garibaldi_e.php |archive-date=2011-05-28 |access-date=2010-02-20 |url-status=dead }}</ref> Most volcanoes of the Garibaldi chain are dormant [[stratovolcano]]es and [[subglacial volcano]]es that have been eroded by glacial ice. Less common volcanic landforms include [[cinder cone]]s, [[volcanic plug]]s, [[lava dome]]s and [[caldera]]s. These diverse formations were created by different styles of volcanic activity, including [[Peléan eruption|Peléan]] and [[Plinian eruption]]s.

Eruptions along the length of the chain have created at least three major volcanic zones. The first began in the [[Powder Mountain Icefield]] 4.0&nbsp;million years ago. [[Mount Cayley]] began its formation during this period. Multiple eruptions from 2.2&nbsp;million to 2,350&nbsp;years ago created the [[Mount Meager massif]], and eruptions 1.3&nbsp;million to 9,300&nbsp;years ago formed [[Mount Garibaldi]] and other volcanoes in the [[Garibaldi Lake]] area. These major volcanic zones lie in three echelon segments, referred to as the northern, central, and southern segments.<ref name="QM">{{cite book|last=Wood|first=Charles A.|author2=Kienle, Jürgen|pages=112, 113, 140, 141, 142, 143, 144, 145, 136, 137, 138, 148|title=Volcanoes of North America: United States and Canada|date=1990|publisher=[[Cambridge University Press]]|location=[[Cambridge]], [[England]]|isbn=0-521-43811-X}}</ref> Each segment contains one of the three major volcanic zones. Apart from these large volcanic zones, two large poorly studied volcanic complexes lie at the northern end of the Pacific Ranges, namely [[Silverthrone Caldera]] and [[Franklin Glacier Complex]]. They are considered to be part of the Garibaldi Volcanic Belt, but their [[tectonics|tectonic]] relationships to other volcanoes in the Garibaldi chain are unclear because of minimal studies.<ref name="NIO"/><ref name="ZJT">{{cite web |title=Franklin Glacier |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_fgl_006 |archive-url=https://web.archive.org/web/20101211094941/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_fgl_006 |archive-date=2010-12-11 |access-date=2010-02-20 |url-status=dead }}</ref>

==Geology==

===Background===
Prior to Garibaldi Belt formation, a number of older, but related [[volcanic belt]]s were constructed along the Southern Coast of British Columbia. This includes the east–west trending [[Alert Bay Volcanic Belt]] on northern [[Vancouver Island]] and the [[Pemberton Volcanic Belt]] along the coastal mainland. The Pemberton Belt began its formation when the former [[Farallon Plate]] was [[subduction|subducting]] under the [[British Columbia Coast]] 29&nbsp;million years ago during the [[Oligocene]] [[Epoch (geology)|epoch]]. At this time, the north-central portion of the Farallon Plate was just starting to subduct under the U.S. state of California, splitting it into northern and southern sections. Between 18&nbsp;and five million years ago during the [[Miocene]] period, the northern remnant of the Farallon Plate fractured into two tectonic plates, known as the [[Gorda Plate|Gorda]] and [[Juan de Fuca Plate|Juan de Fuca]] plates. After this breakup, subduction of the Juan de Fuca Plate might have been coincident with the northern end of Vancouver Island eight million years ago during the late Miocene period. This is when the Alert Bay Belt became active. A brief interval of plate motion adjustment about 3.5&nbsp;million years ago may have triggered the generation of [[basalt]]ic [[magma]] along the descending plate edge. This eruptive period postdates the formation of the Garibaldi Belt and evidence for more recent [[volcanism]] in the Alert Bay Belt has not been found, indicating that volcanism in the Alert Bay Belt is likely extinct.<ref name="QM"/>

[[Bedrock]] under the Garibaldi chain consists of [[granite|granitic]] and [[diorite|dioritic]] rocks of the [[Coast Plutonic Complex]], which makes up much of the Coast Mountains.<ref>{{cite journal |author1=Lewis, T. J. |author2= Judge, A. S. |author3=Souther, J. G. |author-link3=Jack Souther |title=Possible geothermal resources in the Coast Plutonic Complex of southern British Columbia, Canada|journal=Pure and Applied Geophysics |date=1978 |volume=117 |issue=1–2 |pages=172–179 |bibcode=1978PApGe.117..172L |doi=10.1007/BF00879744|s2cid=186232157 }}</ref><ref>{{cite journal |last1=Mahoney |first1=J. Brian |last2=Gordee |first2=Sarah M. |last3=Haggart |first3=James W. |last4=Friedman |first4=Richard M. |last5=Diakow |first5=Larry J. |last6=Woodsworth |first6=Glenn J. |date=2009 |title=Magmatic evolution of the eastern Coast Plutonic Complex, Bella Coola region, west-central British Columbia |journal=GSA Bulletin |volume=121 |issue=9–10 |pages=1362–80 |doi=10.1130/B26325.1 |bibcode=2009GSAB..121.1362M |url=http://gsabulletin.gsapubs.org/content/121/9-10/1362.abstract |access-date=March 29, 2010 |url-access=subscription }}</ref><ref>{{cite web|last=Girardi|first=James Daniel|title=Evolution of magmas and magma sources to the Coast Mountains Batholith, British Columbia, Canada, {{sic|refel|cted|nolink=y}} by elemental and isotopic geochemistry|publisher=[[University of Arizona]]|url=http://www.geo.arizona.edu/Antevs/Theses/GirardiMS08.pdf|page=5|date=2008|access-date=2010-02-22}}</ref> This is a large [[batholith]] complex that was formed when the Farallon and [[Kula Plate|Kula]] plates were subducting along the western margin of the North American Plate during the [[Jurassic]] and [[Tertiary period]]s. It lies on [[island arc]] remnants, [[oceanic plateau]]s and clustered [[continental margin]]s that were added along the western margin of North America between the [[Triassic]] and [[Cretaceous]] periods.<ref name="XLL">{{cite web|url=http://www.geo.arizona.edu/tectonics/Ducea/Batholiths/Tectonics.htm|title=Tectonic overview of the CPC|publisher=[[University of Arizona]]|access-date=2010-03-04}}</ref>

===Formation===
[[Image:Cascadia subduction zone USGS.png|thumb|right|alt=Map of the Cascadia subduction zone and location of nearby volcanoes along coastal United States and Canada.|Area of the Cascadia subduction zone, including the Cascade Volcanic Arc (red triangles). The Garibaldi Volcanic Belt is shown here as three red triangles at the northernmost end of the arc.]]
{{Main|Cascadia subduction zone}}
The Garibaldi Belt has formed in response to ongoing subduction of the Juan de Fuca Plate under the [[North American Plate]] at the Cascadia subduction zone along the British Columbia Coast.<ref name="QQQ"/> This is a {{Convert|1094|km|mi|abbr=on}} long [[fault (geology)|fault]] zone running {{Convert|80|km|mi|abbr=on}} off the [[Pacific Northwest]] from [[Northern California]] to southwestern British Columbia. The plates move at a relative rate of over {{Convert|10|mm|in|abbr=on}} per year at a somewhat oblique angle to the subduction zone. Because of the very large fault area, the Cascadia subduction zone can produce large [[earthquake]]s of [[Seismic scale|magnitude]] 7.0&nbsp;or greater. The interface between the Juan de Fuca and North American plates remains locked for periods of roughly 500&nbsp;years. During these periods, stress builds up on the interface between the plates and causes uplift of the North American margin. When the plate finally slips, the 500&nbsp;years of stored energy are released in a mega-earthquake.<ref name="ZEQ"/>

Unlike most subduction zones worldwide, there is no deep [[oceanic trench]] present in the bathymetry of the [[continental margin]] in Cascadia.<ref name="CLI">{{cite web|url=http://www.nature.nps.gov/geology/usgsnps/province/cascade2.html|title=Pacific Mountain System – Cascades volcanoes|publisher=[[United States Geological Survey]]|date=2000-10-10|access-date=2010-03-05|archive-date=2011-12-11|archive-url=https://web.archive.org/web/20111211154105/http://www.nature.nps.gov/geology/usgsnps/province/cascade2.html|url-status=dead}}</ref> This is because the mouth of the [[Columbia River]] empties directly into the subduction zone and deposits silt at the bottom of the [[Pacific Ocean]] to bury the oceanic trench. Massive floods from prehistoric [[Glacial Lake Missoula]] during the [[Late Pleistocene]] also deposited massive amounts of [[sediment]] into the trench.<ref name="ZZL">{{cite web|title=Cascade Ranges Volcanoes Compared |url=http://www.uwsp.edu/geo/projects/geoweb/participants/dutch/VTrips/CascadesComp.HTM |publisher=[[University of Wisconsin]] |last=Dutch |first=Steven |date=2003-04-07 |access-date=2010-05-20 |url-status=dead |archive-url=https://web.archive.org/web/20120318021653/http://www4.uwsp.edu/geo/projects/geoweb/participants/dutch/VTrips/CascadesComp.HTM |archive-date=2012-03-18 }}</ref> However, in common with other subduction zones, the outer margin is slowly being compressed, similar to a giant spring.<ref name="ZEQ">{{cite web|url=http://gsc.nrcan.gc.ca/geodyn/cascadia_e.php|title=Cascadia Subduction Zone|work=Geodynamics|publisher=[[Natural Resources Canada]]|date=2008-01-15|access-date=2010-03-06|url-status=dead|archive-url=https://web.archive.org/web/20100122185307/http://gsc.nrcan.gc.ca/geodyn/cascadia_e.php|archive-date=2010-01-22}}</ref> When the stored energy is suddenly released by slippage across the fault at irregular intervals, the Cascadia subduction zone can create very large earthquakes, such as the magnitude 9.0&nbsp;[[1700 Cascadia earthquake|Cascadia earthquake on January 26, 1700]].<ref name="LXI">{{cite web|url=http://earthquakescanada.nrcan.gc.ca/histor/15-19th-eme/1700/1700-eng.php |archive-url=https://archive.today/20130101014120/http://earthquakescanada.nrcan.gc.ca/histor/15-19th-eme/1700/1700-eng.php |url-status=dead |archive-date=2013-01-01 |title=The M9 Cascadia Megathrust Earthquake of January 26, 1700 |publisher=[[Natural Resources Canada]] |date=2010-03-03 |access-date=2010-03-06 }}</ref> However, earthquakes along the Cascadia subduction zone are fewer than expected and there is evidence of a decline in volcanic activity over the past few million years. The probable explanation lies in the rate of convergence between the Juan de Fuca and North American plates. These two tectonic plates currently converge {{Convert|3|cm|in|abbr=on}} to {{Convert|4|cm|in|abbr=on}} per year. This is only about half the rate of convergence of seven million years ago.<ref name="CLI"/>

Scientists have estimated that there have been at least 13&nbsp;significant earthquakes along the Cascadia subduction zone in the past 6,000&nbsp;years. The most recent, the [[1700 Cascadia earthquake]], was recorded in the oral traditions of the First Nations people on Vancouver Island. It caused considerable tremors and a massive [[tsunami]] that traveled across the Pacific Ocean. The significant shaking associated with this earthquake demolished houses of the [[Cowichan Tribes]] on Vancouver Island and caused several landslides. Shaking due to this earthquake made it too difficult for the Cowichan people to stand, and the tremors were so lengthy that they were sickened. The tsunami created by the earthquake ultimately devastated a winter village at [[Pachena Bay]], killing all the people that lived there. The 1700 Cascadia earthquake caused near-shore subsidence, submerging [[marsh]]es and forests on the coast that were later buried under more recent debris.<ref name="LXI"/>

Many thousand years of dormancy are expected between large [[explosive eruption]]s of volcanoes in the Garibaldi Belt. A possible explanation for the lower rates of volcanism in the Garibaldi chain is that the associated [[terrain]] is being compressed in contrast to the more southern portions of the Cascade Arc. In continental [[rift]] zones, magma is able to push its way up through the Earth's crust rapidly along faults, providing less chance for differentiation. This is likely the case south of [[Mount Hood]] to the [[California]] border and east-southeast of the massive [[Newberry Volcano|Newberry shield volcano]] adjacent to the [[Cascade Range]] in central [[Oregon]] because the [[Brothers Fault Zone]] lies in this region. This rift zone might explain the massive amounts of basaltic lava in this part of the central Cascade Arc. A low convergence rate in a compressional setting with massive stationary bodies of magma under the surface could explain the low volume and differentiated magmas throughout the Garibaldi Volcanic Belt. In 1958, Canadian volcanologist [[Bill Mathews]] proposed there could be a connection between regional glaciation of the North American continent during [[glacial period]]s and higher rates of volcanic activity during regional glacial unload of the continent. However, this is hard to predict due to the infrequent geological record in this region. But there is specific data, including the temporal grouping of eruptions synglacially or just postglacial within the Garibaldi Belt, that suggests this could be probable.<ref name="NP"/>

===Glaciovolcanism===
[[File:RockSlide 1200W.jpg|thumb|right|alt=Wall of rock covered with trees and rubble extending down its side.|The edge of The Barrier ice-marginal lava flow. Debris extending down the edge of The Barrier is where historical landslides have occurred.]]
Dominating the Garibaldi chain are volcanoes and other volcanic formations that formed during periods of intense glaciation.  This includes flow-dominated [[tuya]]s, subglacial lava domes and [[ice-marginal lava flow]]s. Flow-dominated tuyas differ from the typical basaltic tuyas throughout British Columbia in that they are composed of piles of flat-lying lava flows and lack [[hyaloclastite]] and [[pillow lava]]. They are interpreted to have formed as a result of magma intruding into and melting a vertical hole through adjacent glacial ice that eventually breached the surface of the glacier.<ref name="JP">{{cite book|last=Smellie|first=J.L.|author2=Chapman, Mary G.|pages=195, 197|title=Volcano-Ice Interaction on Earth and Mars|date=2002|publisher=[[Geological Society of London]]|isbn=1-86239-121-1}}</ref> As this magma ascends, it ponds and spreads into horizontal layers.<ref>{{cite web|title=Types of volcanoes|work=Volcanoes of Canada|url=http://gsc.nrcan.gc.ca/volcanoes/type_e.php#glacier|archive-url=https://web.archive.org/web/20110514012053/http://gsc.nrcan.gc.ca/volcanoes/type_e.php#glacier|archive-date=2011-05-14|publisher=[[Natural Resources Canada]]|date=2009-04-02|access-date=2010-05-27|url-status=dead}}</ref> Lava domes that were formed mainly during subglacial activity comprise steep flanks made of intense columnar joints and [[volcanic glass]]. Ice-marginal lava flows form when lava erupts from a subaerial vent and ponds against glacial ice. [[The Barrier]], a [[volcanic dam|lava dam]] impounding [[Garibaldi Lake]] in the southern segment, is the best represented ice-marginal lava flow in the Garibaldi Belt.<ref name="JP"/><ref>{{BCGNIS|11694|The Barrier}}</ref>

Flow-dominated tuyas and the absence of subglacial fragmental deposits are two uncommon glaciovolcanic features in the Garibaldi chain. This is due to their different lava compositions and decline of direct lava-water contact during volcanic activity. The lava composition of these volcanic edifies changes their structure because eruption temperatures are lower than those associated with basaltic activity and lava containing [[silica]] increases thickness and glass differentiation temperatures. As a result, subglacial volcanoes that erupt silicic content melt less qualities of ice and are not as likely to contain water close to the volcanic vent. This forms volcanoes with structures that display their relationship with the regional glaciation. The surrounding landscape also changes the flow of meltwater, favouring lava to pond within valleys dominated by glacial ice. And if the edifice is eroded, it could change the prominence of fragmental glaciovolcanic deposits as well.<ref name="JP"/>

===Southern segment===
[[File:MtGaribaldi-NorthFace-TheTable.jpg|thumb|left|alt=Prominent mountain rising over a smaller steep-sided, flat-topped mountain and a turquoise-coloured alpine lake.|North face of Mount Garibaldi. [[The Table (British Columbia)|The Table]] is the flat-topped steep-sided edifice in the foreground rising above Garibaldi Lake.]]
{{main|Garibaldi Lake volcanic field}}
{{main|Squamish volcanic field}}
On the eastern side of [[Howe Sound]] lies the southernmost zone of volcanic activity in the Garibaldi chain. This zone, known as the [[Watts Point volcanic centre]], is a small [[outcrop]] of [[volcanic rock]] that is a portion of a subglacial volcano.  The outcrop covers an area of about {{Convert|0.2|km2|mi2|abbr=on}} and an eruptive volume of roughly {{Convert|0.02|km3|mi3|abbr=on}}. The location is heavily forested and the [[BC Rail]] mainline passes through the lower portion of the outcrop about {{Convert|40|m|ft|abbr=on}} above sea level.<ref name="NF">{{cite journal|last=Bye|first=A.|author2=Edwards, B. R.|author3=Hickson, C. J.|title=Preliminary field, petrographic and geochemical analysis of possible subglacial, dacitic volcanism at the Watts Point volcanic centre, southwestern British Columbia|journal=Current Research, Part A|volume=2000-A20|pages=1, 2, 3|publisher=[[Natural Resources Canada]]|date=2000|url=http://dsp-psd.communication.gc.ca/Collection-R/GSC-CGC/M44-2000/M44-2000-A20E.pdf|access-date=2010-03-04|url-status=dead|archive-url=https://web.archive.org/web/20110706181514/http://dsp-psd.communication.gc.ca/Collection-R/GSC-CGC/M44-2000/M44-2000-A20E.pdf|archive-date=2011-07-06}}</ref> It represents a feature in the Squamish volcanic field.<ref>{{cite web |title=Watts Point |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_wpt_046 |archive-url=https://web.archive.org/web/20101211095134/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_wpt_046 |archive-date=2010-12-11 |access-date=2010-07-22 |url-status=dead }}</ref>

Mount Garibaldi, one of the larger volcanoes in the southern Garibaldi Belt with a volume of {{Convert|6.5|km3|mi3|abbr=on}}, is composed of [[dacite]] lavas that were erupted in the past 300,000&nbsp;years. It was constructed when volcanic material erupted onto a portion of the [[Cordilleran Ice Sheet]] during the Pleistocene period. This created the unique asymmetrical shape of the mountain. Successive landslides on Garibaldi's flanks occurred after glacial ice of the Cordilleran Ice Sheet retreated.<ref name="QM"/> Subsequent volcanism about 9,300&nbsp;years ago produced a {{Convert|15|km|mi|abbr=on}} long dacite lava flow from [[Opal Cone]] on Garibaldi's southeastern flank. This is unusually long for a dacite flow,<ref name=":0">{{Cite journal |last1=Morison |first1=Conner A. G. |last2=Hickson |first2=Catherine J. |date=May 2023 |title=Mount Garibaldi: hazard potential from a long-dormant volcanic system in the Pacific Northwest |journal=Canadian Journal of Earth Sciences |volume=60 |issue=5 |pages=464–484 |doi=10.1139/cjes-2022-0067 |bibcode=2023CaJES..60..464M |issn=0008-4077|doi-access=free }}</ref> which commonly travel only short distances from a volcanic vent due to their high viscosity.<ref name="AVN">{{cite web|last=Edwards |first=Ben |title=Mt. Garibaldi, SW British Columbia, Canada |publisher=VolcanoWorld |date=November 2000 |url=http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/canada/Final-Gar.html |access-date=2010-03-18 |url-status=dead |archive-url=https://web.archive.org/web/20100731224109/http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/canada/Final-Gar.html |archive-date=2010-07-31 }}</ref><ref>{{cite web|title=Lava Domes, Volcanic Domes, Composite Domes|work=Volcanic Lava Domes|url=https://vulcan.wr.usgs.gov/Glossary/Domes/description_lava_dome.html|publisher=[[United States Geological Survey]]|date=2009-06-25|access-date=2010-03-18|archive-date=2013-02-24|archive-url=https://web.archive.org/web/20130224230918/http://vulcan.wr.usgs.gov/Glossary/Domes/description_lava_dome.html|url-status=dead}}</ref> The Opal Cone lava flow represents one of the most recent volcanic features at Mount Garibaldi.<ref name="AVN"/><ref name=":0" />

On the western shore of Garibaldi Lake, [[Mount Price (British Columbia)|Mount Price]] represents a stratovolcano with an elevation of {{Convert|2050|m|ft|abbr=on}}. It was constructed during three periods of activity. The first phase 1.2&nbsp;million years ago formed a [[hornblende]] [[andesite]] stratovolcano on the drift-covered floor of a circular basin. After this stratovolcano was constructed, volcanism moved to the west where a series of andesite-dacite lava flows and pyroclastic flows were extruded during a period of Peléan activity 300,000&nbsp;years ago. This created the {{Convert|2050|m|ft|abbr=on}} high cone of Mount Price, which was later buried under glacial ice. Before Mount Price was overridden by glacial ice, volcanic activity took place on its northern flank where a satellite vent is present. Renewed activity took place at [[Clinker Peak]] on the western flank of Mount Price around 13,000&nbsp;years ago. This produced the Rubble Creek and [[Clinker Ridge]] andesite lava flows that extend {{Convert|6|km|mi|abbr=on}} to the northwest and southwest.<ref name="QM"/><ref name="XBF"/><ref name=":0" /> After these flows traveled {{Convert|6|km|mi|abbr=on}}, they were dammed against glacial ice to form an ice-marginal lava flow more than {{Convert|250|m|ft|abbr=on}} thick known as The Barrier.<ref name="QM"/>

[[File:Garibaldi black tusk.jpg|thumb|left|alt=Craggy mountain with its main summit surrounded by a ridge to its right and its left flank covered with rubble.|The Black Tusk viewed from the southeast. Its craggy edifice is the result of prolonged erosion.]]
[[Cinder Cone (British Columbia)|Cinder Cone]] on the north shore of Garibaldi Lake is a cinder cone partly engulfed by the Helmet Glacier. It consists of volcanic ash, [[lapilli]] and dispersed ropy and [[lava bomb]] segments that bring the cone's prominence to {{Convert|500|m|ft|abbr=on}}. Its minimal degree of erosion indicates that it might have erupted in the past 1,000&nbsp;years.<ref name="AVJ">{{BCGNIS|670|Cinder Cone}}</ref> A series of [[basaltic andesite]] flows were erupted from Cinder Cone about 11,000&nbsp;years ago that traveled into a deep north trending U-shaped valley on the eastern flank of [[The Black Tusk]]. Subsequent volcanism produced another sequence of basaltic lava flows 4,000&nbsp;years ago that flowed in the same glacial valley.<ref name="QM"/>

The Black Tusk, a black pinnacle of volcanic rock on the northwestern shore of Garibaldi Lake, is the glacially eroded remnant of a much larger volcano that formed during two periods of volcanic activity. The first between 1.1&nbsp;and 1.3&nbsp;million years ago erupted hornblende andesite lava flows and tuffs. These volcanics compose mountain ridges southwest, southeast and northwest of the prime volcanic structure. Subsequent erosion demolished the newly formed volcano. This ultimately exposed the roots of the cone, which currently form the rugged edifice of The Black Tusk. After the cone was eroded, a series of hypersthene andesite lava flows were erupted between 0.17&nbsp;and 0.21&nbsp;million years ago. These end at adjacent ice-marginal lava flows that form {{Convert|100|m|ft|abbr=on}} cliffs. This eruptive phase also produced a lava dome that comprises the current {{Convert|2316|m|ft|abbr=on}} high pinnacle. Consequently, the regional [[Late Pleistocene]] ice sheet carved a deep north-trending U-shaped valley into the eastern flank of the second-stage cone. Here, subsequent lava flows from Cinder Cone filled the valley.<ref name="QM"/>

===Central segment===
[[File:Mount Fee2 crop.jpg|thumb|right|alt=A dark rugged mountain rising over glacial ice in the foreground and glaciated mountains in the background.|Mount Fee and its jagged ridge]]
{{main|Mount Cayley volcanic field}}
Immediately southeast of Mount Cayley lies [[Mount Fee]], an extensively eroded volcano containing a north–south trending ridge. It is one of the older volcanic features in the central Garibaldi chain. Its volcanics are undated, but its large amount of dissection and evidence of glacial ice overriding the volcano indicates that it formed more than 75,000&nbsp;years ago before the [[Wisconsinan Glaciation]]. Therefore, volcanism at Mount Fee does not display evidence of interaction with glacial ice. The remaining product from Fee's earliest volcanic activity is a minor portion of [[pyroclastic rock]]. This is evidence of explosive volcanism from Fee's eruptive history, as well as its first volcanic event. The second volcanic event produced a sequence of lavas and breccias on the eastern flank of the main ridge. These volcanics were likely placed when a sequence of lava flows and broken lava fragments erupted from a volcanic vent and moved down the flanks during the construction of a large volcano. Following extensive dissection, renewed volcanism produced a viscous series of lava flows forming its narrow, flat-topped, steep-sided northern limit and the northern end of the main ridge. The conduit for which these lava flows originated from was likely vertical in structure and intruded through older volcanics deposited during Fee's earlier volcanic events. This volcanic event was also followed by a period of erosion, and likely one or more glacial periods. Extensive erosion following the last volcanic event at Mount Fee has created the rugged north–south trending ridge that currently forms a prominent landmark.<ref name="LE">{{cite web|title=Mount Fee|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_mfe_026|archive-url=https://web.archive.org/web/20060219230043/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_mfe_026|url-status=dead|archive-date=2006-02-19|access-date=2010-03-03}}</ref>

Ember Ridge, a volcanic mountain ridge between [[Tricouni Peak]] and Mount Fee, consists of at least eight lava domes composed of andesite.  They were likely formed between 25,000&nbsp;and 10,000&nbsp;years ago when lava erupted beneath glacial ice of the [[Fraser glaciation|Fraser Glaciation]]. Their current structures are comparable to their original forms due to the minimal degree of erosion. As a result, the domes display the shaps and columnar joints typical of subglacial volcanoes. The random shaps of the Ember Ridge domes are the result of erupted lava taking advantage of former ice pockets, eruptions taking place on uneven surfaces, subsidence of the domes during volcanic activity to create rubble and separation of older columnar units during more recent eruptions. The northern dome, known as Ember Ridge North, covers the summit and eastern flank of a mountain ridge. It comprises at least one lava flow that reaches a thickness of {{Convert|100|m|ft|abbr=on}}, as well as the thinnest columnar units in the Mount Cayley volcanic field. The small size of the columnar joints indicates that the erupted lava was cooled immediately and are mainly located on the dome's summit.<ref name="XMG">{{cite web |title=Ember Ridge North |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_ern_028 |archive-url=https://web.archive.org/web/20101211094924/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_ern_028 |archive-date=2010-12-11 |access-date=2010-03-28 |url-status=dead }}</ref> Ember Ridge Northeast, the smallest subglacial dome of Ember Ridge, comprises one lava flow that has a thickness no more than {{Convert|40|m|ft|abbr=on}}.<ref>{{cite web |title=Ember Ridge Northeast |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_ene_029 |archive-url=https://web.archive.org/web/20101211092856/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_ene_029 |archive-date=2010-12-11 |access-date=2010-03-28 |url-status=dead }}</ref> Ember Ridge Northwest, the most roughly circular subglacial dome, comprises at least one lava flow.<ref>{{cite web|title=Ember Ridge Northwest|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_enw_030|archive-url=https://web.archive.org/web/20101211094908/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_enw_030|url-status=dead|archive-date=2010-12-11|access-date=2010-03-28}}</ref> Ember Ridge Southeast is the most complex of the Ember Ridge domes, consisting of a series of lava flows with a thickness of {{Convert|60|m|ft|abbr=on}}.  It is also the only Ember Ridge dome that contains large amounts of rubble.<ref name="CMM">{{cite web |title=Ember Ridge Southeast |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-03-10 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_ese_031 |archive-url=https://web.archive.org/web/20101212060837/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_ese_031 |archive-date=2010-12-12 |access-date=2010-03-28 |url-status=dead }}</ref> Ember Ridge Southwest comprises at least one lava flow that reaches a thickness of {{Convert|80|m|ft|abbr=on}}. It is the only subglacial dome of Ember Ridge that contains hyaloclastite.<ref name="AAAV">{{cite web|title=Ember Ridge Southwest|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_esw_032|archive-url=https://web.archive.org/web/20101211092913/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_esw_032|url-status=dead|archive-date=2010-12-11|access-date=2010-03-28}}</ref> Ember Ridge West comprises only one lava flow that reaches a thickness of {{Convert|60|m|ft|abbr=on}}.<ref>{{cite web|title=Ember Ridge West|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_erw_033|archive-url=https://web.archive.org/web/20101211075959/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_erw_033|url-status=dead|archive-date=2010-12-11|access-date=2010-03-28}}</ref>

[[File:South Face of Pyroclastic Peak.jpg|thumb|right|alt=Jagged mountain with its summit hidden in clouds.|South face of [[Pyroclastic Peak]], the second highest peak of the Mount Cayley massif.]]
To the northwest, Mount Cayley constitutes the largest and most persistent volcano in the central Garibaldi Belt. It is a highly eroded stratovolcano composed of dacite and [[rhyodacite]] lava that was deposited during three phases of volcanic activity.<ref name="QM"/><ref name="ANE"/> The first eruptive phase started about four million years ago with the eruption of dacite lava flows and pyroclastic rock.<ref name="QM"/> This resulted in the creation of Mount Cayley itself.<ref name="ANE"/> Subsequent volcanism during this volcanic phase constructed a significant lava dome. This acts like a volcanic plug and composes the [[lava spine]]s that currently form pinnacles on Cayley's rugged summit.<ref name="QM"/> After Mount Cayley was constructed, lava flows, [[tephra]] and welded dacite rubble were erupted.<ref name="ANE"/> This second phase of activity {{nowrap|2.7 ± 0.7}} million years ago resulted in the creation of the [[Vulcan's Thumb]], a craggy volcanic ridge on the southern flank of Mount Cayley.<ref name="QM"/><ref name="ANE"/> Lengthy dissection from an extended period of erosion demolished much of the original stratovolcano.<ref name="QM"/> Volcanic activity after this prolonged period of erosion produced thick dacite lava flows from [[parasitic vents]] 300,000&nbsp;years ago that extended into the [[Turbid Creek (British Columbia)|Turbid]] and [[Shovelnose Creek]] valleys near the Squamish River.<ref name="QM"/><ref name="ANE"/> This subsequently created two minor parasitic lava domes 200,000&nbsp;years ago.<ref name="QM"/> These three volcanic events are in contrast to several others around Cayley in that they do not show signs of interaction with glacial ice.<ref name="ANE"/>

[[Pali Dome]], an eroded volcano north of Mount Cayley, consists of two [[geological unit]]s. Pail Dome East is composed of a mass of andesite lava flows and small amounts of pyroclastic material. It lies on the eastern portion of the large glacial icefield that covers much of the Mount Cayley volcanic field. Much of the lava flows form gentle topography at high elevations but terminate in finely jointed vertical cliffs at low elevations. The first volcanic activity likely occurred about 25,000&nbsp;years ago, but it could also be significantly older. The most recent volcanic activity produced a series of lava flows that were erupted when the vent area was not covered by glacial ice. However, the flows show evidence of interaction with glacial ice in their lower units. This indicates that the lavas were erupted about 10,000&nbsp;years ago during the waning stages of the Fraser Glaciation.  The ice-marginal lava flows reach thicknesses of up to {{Convert|100|m|ft|abbr=on}}.<ref name="SFW">{{cite web|url=http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_pde_022|title=Pali Dome East|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|access-date=2010-03-07}}{{dead link|date=February 2017|bot=medic}}{{cbignore|bot=medic}}</ref> Pali Dome West consists of at least three andesite lava flows and small amounts of pyroclastic material; its vent is presently buried under glacial ice.  At least three eruptions have occurred at Pali Dome East. The age of the first volcanic eruption is unknown, but it could have occurred in the past 10,000&nbsp;years. The second eruption produced a lava flow that was erupted when the vent area was not buried under glacial ice. However, the flow does show evidence of interaction with glacial ice at its lower unit. This indicates that the lavas were erupted during the waning stages of the Fraser Glaciation. The third and most recent eruption produced another lava flow that was largely erupted above glacial ice, but was probably constrained on its northern margin by a small glacier. Unlike the lava flow that was erupted during the second eruption, this lava flow was not impounded by glacial ice at its lower unit. This suggests that it erupted less than 10,000&nbsp;years ago when the regional Fraser Glaciation retreated.<ref name="CVY">{{cite web|url=http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_pdw_022|archive-url=https://archive.today/20240525080934/https://www.webcitation.org/5yTgFoM8M?url=http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php%3Fid=gvb_pdw_022|archive-date=2024-05-25|title=Pali Dome West|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|access-date=2010-03-07|url-status=dead}}</ref>

[[Cauldron Dome]], a subglacial volcano north of Mount Cayley, lies west of the massive glacier covering much the region. Like Pali Dome, it is composed of two geological units. Upper Cauldron Dome is a flat-topped, oval-shaped pile of at least five andesite lava flows that resembles a tuya. The five andesite flows are [[joint (geology)|columnar jointed]] and were likely extruded through glacial ice. The latest volcanic activity might have occurred between 10,000&nbsp;and 25,000&nbsp;years ago when this area was still influenced by glacial ice of the Fraser Glaciation. Lower Cauldron Dome, the youngest unit comprising the entire Cauldron Dome subglacial volcano, consists of a flat-topped, steep-sided pile of andesite lava flows {{Convert|1800|m|ft|abbr=on}} long and a maximum thickness of {{Convert|220|m|ft|abbr=on}}. These volcanics were extruded about 10,000&nbsp;years ago during the waning stages of the Fraser Glaciation from a vent adjacent to upper Cauldron Dome that is currently buried under glacial ice.<ref name="ZZZ">{{cite web|url=http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_cdm_023|archive-url=https://archive.today/20071109111439/http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_cdm_023|archive-date=2007-11-09|title=Cauldron Dome|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|access-date=2010-03-07|url-status=dead}}</ref>

[[File:Volcanic cinder.jpg|thumb|left|alt=Rugged landscape of rubble covered with snow on a cloudy day.|Volcanic rubble in the Mount Cayley area. Its ridge-like structure provides easy travel to the north towards Mount Fee.]]
Lying at the northern portion of the Mount Cayley volcanic field is a subglacial volcano named [[Slag Hill]]. At least two geologic units compose the edifice. Slag Hill proper consists of andesite lava flows and small amounts of pyroclastic rock. Lying on the western portion of Slag Hill is a lava flow that likely erupted less than 10,000&nbsp;years ago due to the lack of features indicating volcano-ice interactions.<ref name="LD"/> The Slag Hill flow-dominated tuya {{Convert|900|m|ft|abbr=on}} northeast of Slag Hill proper consists of a flat-topped, steep-sided pile of andesite. It protrudes through remnants of volcanic material erupted from the Slag Hill proper, but it represents a separate volcanic vent due to its geographical appearance. This small subglacial volcano possibly formed between 25,000&nbsp;and 10,000&nbsp;years ago throughout the waning stages of the Fraser Glaciation.<ref name="ABI">{{cite web|url=http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_sht_022|archive-url=https://www.webcitation.org/5yTg2xLkr?url=http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_sht_022|archive-date=2011-05-06|title=Slag Hill tuya|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|access-date=2010-03-08|url-status=dead}}</ref>

[[Ring Mountain (British Columbia)|Ring Mountain]], a flow-dominated tuya lying at the northern portion of the Mount Cayley volcanic field, consists of a pile of at least five andesite lava flows lying on a mountain ridge. Its steep-sided flanks reach heights of {{Convert|500|m|ft|abbr=on}} and are composed of volcanic rubble. This makes it impossible to measure its exact base elevation or how many lava flows constitute the edifice. With a summit elevation of {{Convert|2192|m|ft|abbr=on}}, Ring Mountain had its last volcanic activity between 25,000&nbsp;and 10,000&nbsp;years ago when the Fraser Glaciation was close to its maximum. Northwest of Ring Mountain lies a minor andesite lava flow. Its chemistry is somewhat unlike other andesite flows comprising Ring Mountain, but it probably erupted from a volcanic vent adjacent to or at Ring Mountain. The part of it that lies higher in elevation contains some features that indicate lava-ice interactions, while the lower-elevation portion of it does not. Therefore, this minor lava flow was likely extruded after Ring Mountain formed but when glacial ice covered a broader area than it does currently, and that the lava flow extends beyond the region in which glacial ice existed at that time.<ref name="CVB">{{cite web|url=http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_cdm_024|archive-url=https://web.archive.org/web/20070320135411/http://cgc.rncan.gc.ca/volcanoes/cat/volcano_e.php?id=gvb_cdm_024|url-status=dead|archive-date=2007-03-20|title=Ring Mountain (Crucible Dome)|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-03-10|access-date=2010-03-07}}</ref>

===Northern segment===
[[File:Bridge River Vent ice and debris.jpg|thumb|right|alt=Glacially covered mountain with vegetation on its lower flanks.|Northern flank of the Mount Meager massif. The volcanic vent that produced its latest eruption 2,350&nbsp;years ago is the bowl-shaped depression in the middle of this image.]]
The Mount Meager massif is the most voluminous [[complex volcano|composite volcano]] in the Garibaldi chain and British Columbia, as well as the most recent to erupt.<ref name="ACER">{{cite web|title=3 Volcanism|url=http://web.viu.ca/earle/geol312/unit3.pdf|last=Earle|first=Steven|publisher=[[Malaspina University-College]]|pages=21, 24|date=2005|access-date=2010-03-19}}</ref> It has a volume of {{Convert|20|km3|mi3|abbr=on}} and consists of an eroded stratovolcano, ranging in composition from andesite to rhyodacite.<ref name="NP">{{cite book|last=Monger|first=J.W.H.|chapter=Character of volcanism, volcanic hazards, and risk, northern end of the Cascade magmatic arc, British Columbia and Washington State|pages=232, 235, 236, 241, 243, 247, 248|title=Geology and Geological Hazards of the Vancouver Region, Southwestern British Columbia|date=1994|publisher=[[Natural Resources Canada]]|isbn=0-660-15784-5}}</ref><ref name="QL">{{cite gvp|vn=320180|name=Meager|accessdate=2010-02-24}}</ref> Several dissected lava domes and volcanic plugs are present on its glaciated summit, as well as a clearly defined [[volcanic crater]] with a lava dome placed within it.<ref name="ACER"/><ref name="QL"/> At least eight volcanic vents compose the complex and have been the sources for volcanic activity throughout massif's 2.2&nbsp;million year history.<ref name="QM"/><ref name="ABGY"/>  A well-documented history of volcanism is present at the Mount Meager massif, with its most recent eruption about 2,350&nbsp;years ago that was similar in character to the [[1980 eruption of Mount St. Helens]] and the continuous eruption of [[Soufrière Hills]] on the island of [[Montserrat]].<ref name="QL"/><ref name="ZNR">{{cite journal |last1=Friele |first1=Pierre |last2=Jakob |first2=Matthias |last3=Clague |first3=John |date=March 16, 2008 |title=Haz ard and risk from large landslides from Mount Meager volcano, British Columbia, Canada |journal=Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards |volume=2 |issue=1 |page=61 |doi=10.1080/17499510801958711|bibcode=2008GAMRE...2...48F |s2cid=15157361 |issn=1749-9518 }}</ref><ref>{{cite web|title=Canada Volcanoes and Volcanics|url=https://vulcan.wr.usgs.gov/Volcanoes/Canada/description_canadian_volcanics.html|publisher=[[United States Geological Survey]]|date=2009-11-06|access-date=2010-03-29|archive-date=2013-02-25|archive-url=https://web.archive.org/web/20130225070259/http://vulcan.wr.usgs.gov/Volcanoes/Canada/description_canadian_volcanics.html|url-status=dead}}</ref> This is the largest recorded Holocene explosive eruption in Canada, originating from a volcanic vent on the northeastern flank of [[Plinth Peak]].<ref name="QL"/> It was Plinian in nature, sending an eruption column at least {{Convert|20|km|mi|abbr=on}} high into the [[stratosphere]].<ref name="ABGY"/> As prevailing winds carried ash of the column eastwards, it deposited across British Columbia and [[Alberta]].<ref>{{cite web|title=Distribution of tephra deposits in Western North America |work=Volcanoes of Canada |publisher=[[Natural Resources Canada]] |date=2008-02-12 |url=http://gsc.nrcan.gc.ca/volcanoes/fig08_e.php |archive-url=https://web.archive.org/web/20110604153752/http://gsc.nrcan.gc.ca/volcanoes/fig08_e.php |archive-date=2011-06-04 |access-date=2010-03-29 |url-status=dead }}</ref> Subsequent pyroclastic flows were sent down the flanks of Plinth Peak for {{Convert|7|km|mi|abbr=on}} and were later succeeded by the eruption of a lava flow that demolished many times. This created thick agglutinated rubble that successfully blocked the adjacent Lillooet River to form a lake. Subsequently, the breccia dam collapsed to produce a catastrophic flood that deposited house-sized boulders more than {{Convert|1|km|mi|abbr=on}} downstream. After the flood took place, a small dacite lava flow was erupted that later solidified to form a series of well-preserved columnar joints. This is the last phase of the 2350 BP eruption, and subsequent stream erosion has cut through this lava flow to form a waterfall.<ref name="ABGY"/>

A group of small volcanoes on the upper [[Bridge River]], known as the [[Bridge River Cones]], includes stratovolcanoes, volcanic plugs and lava flows. These volcanoes are unlike others throughout the Garibaldi Volcanic Belt in that they are mainly composed of volcanic rocks with mafic compositions, including alkaline basalt and [[hawaiite]]. The different magma compositions might be related to a smaller degree of [[partial melting]] in the Earth's mantle or a descending plate edge effect. The oldest volcano in the group, known as [[Sham Hill]], is a {{Convert|60|m|ft|abbr=on}} high volcanic plug with a potassium-argon date of one million years. It is about {{Convert|300|m|ft|abbr=on}} wide and its uncovered glaciated surface is strewn with glacial erratics. Its massive level rock columns were constructed inside the main volcanic vent of a stratovolcano that has since been reduced by erosion. To the southeast, the [[Salal Glacier volcanic complex]] was constructed between 970,000&nbsp;and 590,000&nbsp;years ago. It consists of subaerial tephra and thin lava flow deposits that are surrounded by {{Convert|100|m|ft|abbr=on}} thick ice-ponded lava flows. These ice-marginal lava flows were created when lava ponded against glacial ice in the nearby valleys before the [[Wisconsin Glaciation]]. North of the Salal Glacier complex lies a small basaltic stratovolcano named [[Tuber Hill]]. It began to form about 600,000&nbsp;years ago when adjacent valleys were filled by glacial ice. When lava flows were erupted from Tuber Hill, they interacted with the valley-filling glaciers on its southern flank and produced a glacial meltwater lake. Here, more than {{Convert|150|m|ft|abbr=on}} of stacked hyaloclastite, lahars and lacustrine tuff were deposited. A series of pillow lavas were also deposited during this eruptive period. The most recent volcanic activity in the Bridge River volcanic field produced a series of basaltic lava flows in the regional valleys that overlie till of the last glacial period. The age of these valley-filling lava flows is unknown but the presence of unconsolidated glacial till under the flows suggests that they are less than 1,500&nbsp;years old.<ref name="QM"/>

To the northwest, the Franklin Glacier Complex is a set of volcanic bedrock that encompasses an area {{Convert|20|km|mi|abbr=on}} long and {{Convert|6|km|mi|abbr=on}} wide. It has an elevation of over {{Convert|2000|m|ft|abbr=on}} and is largely destroyed by erosion. A series of dikes and [[subvolcanic rock|subvolcanic]] [[intrusion]]s compose the complex, a few of which seem to represent vents for the overlying sequence of volcanic deposits. Volcanics include dacite breccia and small remnants of hornblende andesite lava flows associated with tuffs that reach {{Convert|450|m|ft|abbr=on}} thick. The complex is poorly known due to minimal studies, but [[potassium-argon dating|potassium-argon dates]] obtained from some of the subvolcanic intrusions indicate that Franklin formed during two volcanic events, each separated by about five million years of dormancy.<ref name="ZJT"/> The first event occurred between six and eight million years ago when volcanic activity in the Garibaldi Belt had not moved to its current location, but was becoming more aerially restricted within a large band to the east and west.<ref name="ZJT"/><ref name="NP"/> During this period, volcanic activity in the Garibaldi Belt and other portions of the northern Cascade Arc took place mainly at the Franklin Glacier Complex and in the [[Intermontane Belt]] further east.<ref name="NP"/> When the Garibaldi Belt moved to its current location five million years ago, another volcanic event occurred at the Franklin complex.<ref name="ZJT"/><ref name="NP"/> This final and most recent volcanic event occurred between two and three million years ago, about a million years after Mount Cayley to the south began its formation.<ref name="ZJT"/><ref name="NP"/>

[[File:Silverthrone Caldera.png|thumb|left|250px|alt=Map of glacial ice, rivers and volcanic deposits in an area of volcanic activity.|Geologic map of the Silverthrone volcanic field and nearby rivers. The white circular feature is the inferred boundary of the Silverthrone Caldera.]]
Silverthrone Caldera is the largest and best-preserved of the two caldera complexes in the northern Garibaldi chain, the other being the Franklin Glacier Complex {{Convert|55|km|mi|abbr=on}} to the east-southeast.<ref name="NIO"/><ref name="NP"/> The caldera has a diameter of {{Convert|20|km|mi|abbr=on}} and contains breccia, lava flows and lava domes. Like Franklin to the east-southeast, the geology of Silverthrone is poorly known due to minimal studies. The region surrounding the Silverthrone complex is significantly jagged due to the mountainous terrain of the Coast Mountains. Near vertical flanks extend from near sea level to more than {{Convert|3000|m|ft|abbr=on}} in elevation. Silverthrone is significantly younger than the Franklin Glacier Complex to the east-southeast and its volcanics likely have ages comparable to other volcanics throughout the Garibaldi chain. The oldest volcanics at the Silverthrone Caldera complex are composed of volcanic breccias, some of which became fused together by intense volcanic heat from when the deposits were first erupted. After these volcanics were deposited, a series of dacite, andesite and rhyolite lava flows were erupted upon volcanic breccia from the first volcanic phase. These eroded lava flows in total are {{Convert|900|m|ft|abbr=on}} thick. Volcanics in the lower portion of this series of lava flows give a potassium-argon date of 750,000&nbsp;years while volcanics slightly above the lava flows are 400,000&nbsp;years old. The most recent volcanic activity produced a series of andesite and basaltic andesite lava flows down Pashleth Creek and the [[Machmell River|Machmell]] and [[Kingcome River|Kingcome]] river valleys. The lava flow extending from near Pashleth Creek to down the Machmell River valley is over {{Convert|25|km|mi|abbr=on}} in length. Its small amount of erosion indicates that it could be 1,000&nbsp;years old or younger.<ref name="NIO"/>

===Geothermal and seismic activity===
At least four volcanoes have had seismic activity since 1985, including Mount Garibaldi (three events), Mount Cayley (four events), Mount Meager massif (seventeen events) and the Silverthrone Caldera (two events).<ref name="ZBR">{{cite book|last=Etkin|first=David|author2=Haque, C.E.|author3=Brooks, Gregory R.|title=An Assessment of Natural Hazards and Disasters in Canada|publisher=Springer|date=2003-04-30|pages=569, 582, 583|isbn=978-1-4020-1179-5}}</ref> Seismic data suggest that these volcanoes still contain active magma chambers, indicating that some Garibaldi Belt volcanoes are likely active, with significant potential hazards.<ref name="ZBR"/><ref>{{cite web|publisher=[[Natural Resources Canada]]|url=http://gsc.nrcan.gc.ca/volcanoes/gscvol_e.php|archive-url=https://web.archive.org/web/20061008200258/http://gsc.nrcan.gc.ca/volcanoes/gscvol_e.php|url-status=dead|archive-date=2006-10-08|title=Volcanology in the Geological Survey of Canada|work=Volcanoes of Canada|access-date=2008-05-09}}</ref> The seismic activity corresponds with some of Canada's recently formed volcanoes and with persistent volcanoes that have had major explosive activity throughout their history, such as Mount Garibaldi and the Mount Cayley and Mount Meager massifs.<ref name="ZBR"/>

[[Image:Meager hot spring.jpg|thumb|right|alt=Steaming pool of water surrounded by a group of rocks.|A volcanic hot spring near [[Meager Creek]] related to volcanism at the Mount Meager massif. This hot spring lies in one of the few hot spring clusters near Meager.]]
A series of [[hot spring]]s adjacent to the Lillooet River valley, such as the [[Harrison Hot Springs, British Columbia|Harrison]], Sloquet, Clear Creek and Skookumchuck springs, are not known to occur near areas with recent volcanic activity. Instead, many are located close to 16–26&nbsp;million year old intrusions that are interpreted to be the roots of heavily eroded volcanoes. These volcanoes formed part of the Cascade Volcanic Arc during the Miocene period and their intrusive roots extend from the [[Fraser Valley]] in the south to Salal Creek in the north. The relationship of these hot springs to the Garibaldi Belt is not clear. However, a few hot springs are known to exist in areas that have experienced relatively recent volcanic activity.<ref name="SCL"/> About five hot springs exist in valleys near Mount Cayley and two small groups of hot springs are present at the Mount Meager massif.<ref name="ANE"/><ref name="ABGY"/> The springs at Meager massif might be evidence of a shallow magma chamber beneath the surface. No hot springs are known to exist at Mount Garibaldi like those found at Mount Meager and Mount Cayley, although there is evidence of abnormal high heat flow at the adjacent Table Meadows and other locations. Abnormal warm water adjacent to [[Britannia Beach]] could be geothermal activity linked to the Watts Point volcanic zone.<ref name="SCL">{{cite web|last=Woodsworth|first=Glenn J.|publisher=Gold Commissioner's Office|location=[[Vancouver]], [[British Columbia]]|title=Geology and Geothermal Potential of the AWA Claim Group, Squamish, British Columbia|pages=9, 10|date=April 2003|url=https://aris.empr.gov.bc.ca/ArisReports/27299.PDF|access-date=2021-01-31|archive-date=2022-01-09|archive-url=https://web.archive.org/web/20220109101020/https://aris.empr.gov.bc.ca/ArisReports/27299.PDF|url-status=dead}}</ref>

==History==

===Human occupation===
People have used resources in and around the Garibaldi Volcanic Belt for centuries. [[Obsidian]] was collected by the [[Squamish Nation]] for making knives, chisels, [[adze]]s and other sharp tools in pre-contact times. This material appears in sites dated 10,000&nbsp;years old up to [[protohistory|protohistoric]] time periods. The source for this material is found in upper parts of the mountainous terrain that surround Mount Garibaldi. At Opal Cone, lava of the Ring Creek flow was normally heated to cook food because its [[pumice]]-like texture is able to maintain heat. It also did not break after it was used for a long period of time.<ref name="SNCL">{{cite web|first=Rudy |last=Reimer/Yumks |title=Squamish Nation Cognitive Landscapes |pages=5, 6 |publisher=[[McMaster University]] |url=http://archaeologywithoutreserve.com/Reimer%20CAA%202006%20Paper.pdf |archive-url=https://web.archive.org/web/20081219153603/http://archaeologywithoutreserve.com/Reimer%20CAA%202006%20Paper.pdf |archive-date=2008-12-19 |access-date=2008-05-19 |url-status=dead }}</ref>

A large pumice outcrop adjacent to the Mount Meager massif has been mined several times in the past, and extends more than {{Convert|2000|m|ft|abbr=on}} in length and {{Convert|1000|m|ft|abbr=on}} in width with a thickness of about {{Convert|300|m|ft|abbr=on}}. The deposit was first hired by J. MacIsaac, who died in the late 1970s. In the mid-1970s the second hirer, W.H. Willes, investigated and mined the pumice. It was crushed, removed then stored close to the village of [[Pemberton, British Columbia|Pemberton]]. Later, the bridge that was used to access the pumice deposit was washed out. Mining operations resumed in 1988 when the deposit was staked by L.B. Bustin. In 1990, the pumice outcrop was bought by D.R. Carefoot from the owners B. Chore and M. Beaupre. In a program from 1991 to 1992, workers evaluated the deposit for its properties as a construction material, absorber of oil and [[stone washing|stonewash]]. About {{Convert|7500|m3|ft3|abbr=on}} of pumice was mined in 1998 by the Great Pacific Pumice Incorporation.<ref name="ZNDA">{{cite web|url=http://minfile.gov.bc.ca/Summary.aspx?minfilno=092JW+040|publisher=[[Government of British Columbia]]|work=MINFILE Mineral Inventory|title=Mount Meager, Lillooet River Pumice, Pum, Great Pacific, Mt. Meager Pumice|date=1998-12-04|access-date=2010-03-16}}</ref>

The hot springs associated with Meager and Cayley have made these two volcanoes targets for geothermal explorations. At Mount Cayley, temperatures of {{Convert|50|C}} to more than {{Convert|100|C}} have been measured in shallow boreholes on its southwestern flank.<ref name="QM"/> Further north, geothermal exploration at the Mount Meager massif has been undertaken by BC Hydro since the late 1970s. Bottom hole temperatures have been calculated at an average of {{Convert|220|C}} to {{Convert|240|C}}, with {{Convert|275|C}} being the highest recorded temperature. This indicates that the area around Meager is a major geothermal site. The geothermal power is expected to run throughout [[Western Canada]] and the likelihood of it extending into the western United States is probable.<ref>{{cite web|publisher=Western GeoPower Corp|title=South Meager Geothermal Project|url=http://www.geothermalmagazine.eu/english/south-meager-geothermal-project/index.html|access-date=2011-05-09}}</ref>

===Early impressions===
The belt of volcanoes has been the subject of myths and legends by [[First Nations in Canada|First Nations]]. To the Squamish Nation, Mount Garibaldi is called ''Nch'kay''. In their language it means "Dirty Place". This name of the mountain refers to the volcanic rubble in the area. This mountain, like others located in the area, is considered sacred as it plays an important part of their [[History of the Squamish people|history]]. In their [[Oral tradition|oral history]], they passed down a story of the [[Deluge myth|flood]] covering the land. During this time, only two mountains peaked over the water, and Garibaldi was one of them. It was here that the remaining survivors of the flood latched their canoes to the peak and waited for the waters to subside. The Black Tusk on the northwestern end of Garibaldi Lake and Mount Cayley northwest of Mount Garibaldi are called ''ta<u>k</u>'ta<u>k</u>mu'yin tl'a in7in'axa7en'' in the [[Squamish language]], which means "Landing Place of the Thunderbird".<ref name="STUS"/> The [[Thunderbird (mythology)|Thunderbird]] is a [[legendary creature]] in [[Indigenous peoples of the Americas|North American indigenous peoples']] history and culture. The rocks that make up The Black Tusk and Mount Cayley were said to have been burnt black by the Thunderbird's lightning.<ref name="STUS">{{cite report|author=Yumks|author2=Reimer, Rudy|title=Squamish Traditional Use Study: Squamish Traditional Use of Nch'kay Or the Mount Garibaldi and Brohm Ridge Area|version=Draft|publisher=First Heritage Archaeological Consulting|date=April 2003|pages=8, 11, 17|url=http://www.llbc.leg.bc.ca/public/pubdocs/bcdocs/414673/d24044/1181338763782_401d3802844e42babeb6eb41577ab95b.pdf|access-date=2010-03-30}}</ref>

===Protection and monitoring===
[[File:The Table1.jpg|thumb|left|alt=Flat-topped, steep-sided mountain rising above the surrounding mountainous landscape.|[[The Table (British Columbia)|The Table]], a flow-dominated tuya rising above the southwestern side of Garibaldi Lake.]]
A number of volcanic features in the Garibaldi Belt are protected by [[provincial park]]s. [[Garibaldi Provincial Park]] at the southern end of the chain was established in 1927 to protect the abundant geological history, glaciated mountains and other natural resources in the region.<ref name="ZKY">{{cite web|url=http://www.env.gov.bc.ca/bcparks/explore/parkpgs/garibaldi/|title=Garibaldi Provincial Park|publisher=BCParks|access-date=2010-03-06}}</ref> It was named after the {{Convert|2678|m|ft|abbr=on}} stratovolcano Mount Garibaldi, which in turn was named after the Italian military and political leader [[Giuseppe Garibaldi]] in 1860.<ref name="ZKY"/><ref>{{BCGNIS|5329|Mount Garibaldi}}</ref> To the northwest, [[Brandywine Falls Provincial Park]] protects Brandywine Falls, a {{Convert|70|m|ft|abbr=on}} high waterfall composed of at least four basaltic lava flows with columnar joints.<ref name="CNT">{{cite journal|last=Stelling|first=Peter L.|author2=Tucker, David Samuel|title=Floods, Faults, and Fire: Geological Field Trips in Washington State and Southwest British Columbia|journal=Current Research, Part A|pages=2, 14|publisher=[[Geological Society of America]]|date=2007|url=https://books.google.com/books?id=F1Sx3i2CZyUC&q=Miocene+Garibaldi+Volcanic+Belt&pg=PA2|isbn=978-0-8137-0009-0|access-date=2010-03-04}}</ref><ref name="KLY">{{cite web|url=http://www.env.gov.bc.ca/bcparks/explore/parkpgs/brandywine_falls/|title=Brandywine Falls Provincial Park|publisher=BCParks|access-date=2010-03-06}}</ref> Its name origin is unclear, but it may have originated from two surveyors named Jack Nelson and Bob Mollison.<ref name="KLY"/>

Like other volcanic zones in Canada, the Garibaldi Volcanic Belt  is not monitored closely enough by the Geological Survey of Canada to ascertain how active its magma system is. This is partly because several volcanoes in the chain are located in remote regions and no major eruptions have occurred in Canada in the past few hundred years.<ref name="AKB">{{cite web|url=http://gsc.nrcan.gc.ca/volcanoes/mon_e.php |archive-url=https://web.archive.org/web/20110514011941/http://gsc.nrcan.gc.ca/volcanoes/mon_e.php |archive-date=2011-05-14 |title=Monitoring volcanoes |work=Volcanoes of Canada |publisher=[[Natural Resources Canada]] |date=2009-02-26 |access-date=2010-03-24 |url-status=dead }}</ref> As a result, volcano monitoring is less important than dealing with other natural processes, including [[tsunami]]s, earthquakes and landslides.<ref name="AKB"/> However, with the existence of earthquakes, further volcanism is expected and would probably have considerable effects, particularly in a region like southwestern British Columbia where the Garibaldi volcanoes are located in a highly populated area.<ref name="QQQ"/><ref name="AKB"/><ref name=":0" />

==Volcanic hazards==
The volcanoes comprising the Garibaldi chain are adjacent to the highly populated southwest portion of British Columbia.<ref name="QQQ"/> Unlike the central Cascade Arc, renewed volcanic activity in the Garibaldi Belt at a single feeder to create stratovolcanoes is not typical. Instead, volcanic activity results in the formation of volcanic fields. Of the entire Cascade Arc, the Garibaldi chain has the lowest rate of volcanic activity.<ref name="NP"/> In the past two million years, the volume of erupted material in the Garibaldi Belt has been less than 10% of that in the [[U.S. state]]s of California and Oregon and about 20% of that within the U.S. state of Washington.<ref name="ACER"/> As a result, the risk of eruptions throughout this part of the Cascade Arc is minor. Individual volcanoes and volcanic fields remain quiet for a long period of time and certain vents may never erupt again. However, considerable volcanic activity has taken place in the geologically recent past, most notably the explosive eruption that occurred at the Mount Meager massif 2,350&nbsp;years ago.<ref name="NP"/>

[[Jack Souther]], a leading authority on geothermal resources and volcanism in the Canadian Cordillera has stated, "at present the volcanoes of the Garibaldi Belt are quiet, presumed dead but still not completely cold. But the flare-up of Meager Mountain 2,500 years ago raises the question, 'Could it happen again?' Was the explosive eruption of Meager Mountain the last gasp of the Garibaldi Volcanic Belt or only the most recent event in its on-going life? The short answer is nobody really knows for sure&nbsp;...&nbsp;So just in case I sometimes do a quick check of the old hot-spots when I get off the Peak Chair&nbsp;..."<ref>{{cite web|url=http://www.cangea.ca/images/uploads/Jack_Souther_Biography.pdf |archive-url=https://www.webcitation.org/5tfQWFYBa?url=http://www.cangea.ca/images/uploads/Jack_Souther_Biography.pdf |archive-date=2010-10-22 |title=CanGEA {{Sic|?|nolink=y|Honou|rary|expected=Honorary}} Member 2008 Dr. Jack Souther |publisher=Canadian Geothermal Energy Association |access-date=2010-03-04 |url-status=dead }}</ref> Recent seismic imaging from Geological Survey of Canada employees supported lithoprobe studies in the region of Mount Cayley in which scientists found a large reflector interpreted to be a pool of molten rock roughly {{Convert|15|km|mi|abbr=on}} below the surface. The existence of hot springs at the Mount Meager massif and Mount Cayley indicates that magmatic heat is still present beneath or near these volcanoes. This long history of volcanic activity along a still active plate boundary indicates that volcanic eruptions in the Garibaldi Belt have not ended and risks for future eruptions remain.<ref name="NP"/>

===Tephra===
[[File:Keyhole Falls.jpg|thumb|right|alt=View of a waterfall dropping from a cliff in a basin-like depression in a mountainous landscape.|[[Keyhole Falls]], the largest waterfall along the Lillooet River. The solid-looking rock cliffs formed when a lava flow front repeatedly collapsed and collected downslope from the vent associated with the eruption of Plinth Peak 2,350 years ago.]]
The largest threat from volcanoes in the Garibaldi chain would likely be due to tephra released during explosive eruptions.<ref name="NP"/> Mount Meager massif in particular poses a major long-distance threat to communities throughout southern British Columbia and Alberta because of its explosive history.<ref name="ABGY">{{cite web|title=Garibaldi volcano belt: Mount Meager volcanic field|work=Catalogue of Canadian volcanoes|publisher=[[Natural Resources Canada]]|date=2009-04-01|url=http://gsc.nrcan.gc.ca/volcanoes/cat/feature_meager_e.php|archive-url=https://web.archive.org/web/20051228155047/http://gsc.nrcan.gc.ca/volcanoes/cat/feature_meager_e.php|url-status=dead|archive-date=2005-12-28|access-date=2010-03-04}}</ref> It is estimated that over 200&nbsp;eruptions have occurred throughout the entire Cascade Volcanic Arc in the past 12,000&nbsp;years, many of them in the United States. Many eruptions in the western United States have sent large amounts of tephra in southern British Columbia. However, all major cities in southwestern British Columbia with populations more than 100,000&nbsp;are located west of the Garibaldi Volcanic Belt and prevailing winds travel eastwards. Therefore, these communities are less likely to have large amounts of tephra. In the [[Lower Mainland]], a {{Convert|10|cm|in|abbr=on}} thick layer of volcanic ash can deposit once every 10,000&nbsp;years and {{Convert|1|cm|in|abbr=on}} once every 1,000&nbsp;years. More minor amounts of volcanic ash can be expected more commonly. During Mount St. Helens' eruption in 1980, {{Convert|1|mm|in|abbr=on}} of tephra was deposited from southeastern British Columbia to [[Manitoba]].<ref name="NP"/>

Even though all major cities in southwestern British Columbia are located west of the Garibaldi chain, future eruptions are expected to have significant impacts on the adjacent townships of [[Squamish, British Columbia|Squamish]] and [[Whistler, British Columbia|Whistler]].<ref name=":0" /><ref>{{Cite journal |last1=Stasiuk |first1=Mark V. |last2=Hickson |first2=Catherine J. |author-link2=Catherine Hickson |last3=Mulder |first3=Taimi |date=2003-03-01 |title=The Vulnerability of Canada to Volcanic Hazards |url=https://link.springer.com/article/10.1023/A:1022954829974 |journal=Natural Hazards |language=en |volume=28 |issue=2 |pages=563–589 |doi=10.1023/A:1022954829974 |bibcode=2003NatHa..28..563S |issn=1573-0840|url-access=subscription }}</ref> An eruption column released during Peléan activity would discharge large amounts of tephra that would endanger aircraft. Tephra may also melt the large sheets of glacial ice east of Garibaldi and cause floods. This could later endanger water supplies from [[Pitt Lake]] and fisheries on the [[Pitt River]]. An explosive eruption and the associated tephra may also create temporary or longer-term water supply difficulties for Vancouver and most of southern British Columbia. The water reservoir for the [[Greater Vancouver]] drainage area is south of Mount Garibaldi.<ref name="XBF">{{cite web|url=http://gsc.nrcan.gc.ca/volcanoes/cat/feature_garibaldi_e.php|archive-url=https://web.archive.org/web/20060219225103/http://gsc.nrcan.gc.ca/volcanoes/cat/feature_garibaldi_e.php|url-status=dead|archive-date=2006-02-19|title=Garibaldi volcanic belt: Garibaldi Lake volcanic field|work=Catalogue of Canadian volcanoes|date=2009-04-01|access-date=2010-03-12}}</ref>

===Landslides and lahars===
Several landslides and lahars have occurred throughout the Garibaldi Belt. At the Mount Meager massif, considerable landslides have occurred from [[Pylon Peak (Canada)|Pylon Peak]] and [[Devastator Peak]] in the past 10,000&nbsp;years that have reached more than {{Convert|10|km|mi|abbr=on}} downstream in the Lillooet River valley. At least two significant landslides from the southern flank of Pylon Peak 8,700&nbsp;and 4,400&nbsp;years ago dumped volcanic debris into the adjacent valley of [[Meager Creek]].<ref name="NE">{{cite journal|url=http://article.pubs.nrc-cnrc.gc.ca/ppv/RPViewDoc?issn=1480-3313&volume=41&issue=2&start| page=165|title=Large Holocene landslides from Pylon Peak, southwestern British Columbia|last=Clague|first=Friele|author2=Clague, John J.|date=2004|publisher=[[Natural Resources Canada]]|access-date=2010-03-03|bibcode=2004CaJES..41..165F|volume=41|journal=Canadian Journal of Earth Sciences|doi=10.1139/e03-089|issue=2|url-access=subscription}}{{dead link|date=February 2017|bot=medic}}{{cbignore|bot=medic}}</ref> More recently, a [[1975 Devastation Glacier landslide|large landslide from Devastation Glacier]] buried and killed a group of four geologists on July 22, 1975.<ref>{{cite web|url=http://www.publicsafety.gc.ca/prg/em/cdd/dtls-eng.aspx?disno=+1975.006|archive-url=https://web.archive.org/web/20110721151614/http://www.publicsafety.gc.ca/prg/em/cdd/dtls-eng.aspx?disno=+1975.006|url-status=dead|archive-date=2011-07-21|title=Landslide: Devastator Glacier BC, Jul 22 1975|publisher=[[Natural Resources Canada]]|date=2009-12-01|access-date=2010-03-03}}</ref> The estimated volume of this landslide is {{Convert|13000000|m3|ft3|abbr=on}}.<ref>{{cite web |title=Where do landslides occur? |url=http://www.empr.gov.bc.ca/MINING/GEOSCIENCE/SURFICIALGEOLOGYANDHAZARDS/LANDSLIDES/Pages/Wheredolandslidesoccur.aspx |publisher=[[Government of British Columbia]] |access-date=2010-03-03 |url-status=dead |archive-url=https://web.archive.org/web/20100818050404/http://www.empr.gov.bc.ca/Mining/Geoscience/SurficialGeologyandHazards/Landslides/Pages/Wheredolandslidesoccur.aspx |archive-date=2010-08-18 }}</ref> A considerable landslide as large as Meager's largest throughout the Holocene would likely produce a lahar that would devastate most of the growth in the Lillooet River valley. If such an event would occur without it being identified by authorities who would send out a public warning, it would kill hundreds or even thousands of residents. Because of this, computer programs would be able to identify the approaching information and activate an automatic notice when a large lahar is identified. A similar system for identifying such lahars exists at [[Mount Rainier]] in the U.S. state of Washington.<ref name="ZNR"/>

Large landslides from Mount Cayley have occurred on its western flank, including a major debris avalanche about 4,800&nbsp;years ago that dumped an areal extent of {{Convert|8|km2|mi2|abbr=on}} of volcanic material into the adjacent valley bottom. This blocked the [[Squamish River]] for a long period of time.<ref name="LG">{{cite journal|title=Prehistoric debris avalanches from Mount Cayley volcano, British Columbia:<sup>1</sup> Reply|last=G. Evans|first=S.|author2=Brooks, G. R.|date=1992|publisher=[[Natural Resources Canada]]|doi=10.1139/e92-109|journal=Canadian Journal of Earth Sciences|volume=29|issue=6| page=1346|bibcode = 1992CaJES..29.1343E }}</ref> Although there are no known eruptions from the massif in the past 10,000&nbsp;years, it is associated with a group of hot springs.<ref name="NP"/><ref name="ANE">{{cite web|title=Garibaldi Volcanic Belt: Mount Cayley volcanic field |work=Catalogue of Canadian volcanoes |publisher=[[Natural Resources Canada]] |date=2009-04-07 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/feature_cayley_e.php |archive-url=https://web.archive.org/web/20110604190433/http://gsc.nrcan.gc.ca/volcanoes/cat/feature_cayley_e.php |archive-date=2011-06-04 |access-date=2010-03-03 |url-status=dead }}</ref> Evans (1990) has indicated that a number of landslides and debris flows at Mount Cayley in the past 10,000&nbsp;years might have been caused by volcanic activity.<ref name="NP"/> Since the 4,800 BP&nbsp;landslide, a number of more minor landslides have occurred at it.<ref name="LG"/> In 1968 and 1983, a series of landslides took place that caused considerable damage to logging roads and forest stands, but did not result in any casualties.<ref>{{cite web|title=Photo Collection|work=Landslides|publisher=[[Natural Resources Canada]]|date=2007-02-05|url=http://cgc.rncan.gc.ca/landslides/photo_library_details_e.php?ID=71|archive-url=https://archive.today/20240525080813/https://www.webcitation.org/5yTfqEDgk?url=http://cgc.rncan.gc.ca/landslides/photo_library_details_e.php%3FID=71|archive-date=2024-05-25|access-date=2010-03-03|url-status=dead}}</ref>

===Lava flows===
The threat from lava flows in the Garibaldi Belt is minor unless an eruption takes place in winter or under or adjacent to areas of glacial ice, such as [[ice field]]s. When lava flows over large areas of snow, it creates meltwater. This can produce lahars that could flow further than the associated lavas. If water were to enter a volcanic vent that is erupting basaltic lava, it may create a massive explosive eruption. These explosions are generally more extreme than those during normal basaltic eruptions. Therefore, the existence of water, snow, or glacial ice at a volcanic vent would increase the risk of an eruption having a large impact on the surrounding region. Subglacial eruptions have also caused catastrophic glacial outburst floods.<ref name="NP"/>

==See also==
*[[Anahim Volcanic Belt]]
*[[Geology of British Columbia]]
*[[Geology of the Pacific Northwest]]
*[[List of Cascade volcanoes]]
*[[List of volcanoes in Canada]]
*[[Milbanke Sound Group]]
*[[Northern Cordilleran Volcanic Province]]
*[[Volcanism of Canada]]
*[[Volcanism of Western Canada]]
*[[Wells Gray-Clearwater volcanic field]]

==References==
{{USGS}}
{{Reflist|2}}

==External links==
{{commons and category}}
*[https://web.archive.org/web/20060427235634/http://gsc.nrcan.gc.ca/volcanoes/map/map_e.php?id=gvb Map of the Garibaldi Volcanic Belt]

{{Garibaldi Volcanic Belt}}
{{Cascade volcanoes}}

[[Category:Garibaldi Volcanic Belt| ]]
[[Category:Pliocene volcanism]]
[[Category:Pleistocene volcanism]]
[[Category:Holocene volcanism]]
[[Category:Landslides in Canada]]
[[Category:Belt regions]]
[[Category:Giuseppe Garibaldi]]