fld009-01 29 pages
1
Russell, J.K., Hickson, C.J., and Andrews, G., 2007, Canadian Cascade volcanism: Subglacial to explosive eruptions along the Sea to Sky Corridor, British
Columbia, in Stelling, P., and Tucker, D.S., eds., Floods, Faults, and Fire: Geological Field Trips in Washington State and Southwest British Columbia: Geological
Society of America Field Guide 9, p. 1–29, doi: 10.1130/2007.fld009(01). For permission to copy, contact editing@geosociety.org. ©2007 The Geological Society
of America. All rights reserved.
INTRODUCTION
This field guide was prepared in support of a two-day field
trip to examine Quaternary volcanism in the Canadian Cascade
arc informally named the Garibaldi volcanic belt. The field trip
has two somewhat diverse goals. The first day of the trip pro-
ceeds along the Whistler corridor from Squamish to Pemberton
and focuses on Quaternary glaciovolcanic deposits. Interactions
between volcanoes and ice in the Garibaldi volcanic belt have
been common during the past two million years. This style of vol-
canism has created a diverse array of landforms, including sub-
glacial domes, tuyas, impounded lava masses, and esker-shaped
The Geological Society of America
Field Guide 9
2007
Canadian Cascade volcanism: Subglacial to explosive eruptions
along the Sea to Sky Corridor, British Columbia
J.K. Russell
Earth and Ocean Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
C.J. Hickson
Geological Survey of Canada, Vancouver, British Columbia, Canada
Graham Andrews
Earth and Ocean Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
ABSTRACT
Here we describe a two-day field trip to examine Quaternary volcanism in the
Canadian Cascade arc, named the Garibaldi volcanic belt. Day 1 of the trip proceeds
along the Whistler corridor from Squamish to Pemberton and focuses on Quaternary
glaciovolcanic deposits. Interactions between volcanoes and ice in the Garibaldi vol-
canic belt have been common during the past two million years and this has resulted
in a diverse array of landforms, including subglacial domes, tuyas, impounded lava
masses, and sinuous lavas that exploited within-ice drainage systems. On Day 2, the
trip heads northwest of Pemberton, British Columbia, along logging roads to see
deposits from the 2360 yr B.P. eruption of the Mount Meager volcanic complex. This
eruption began Plinian-style, generating pyroclastic fall and flow deposits and ended
with the production of block and ash pyroclastic flows by explosive (Vulcanian) col-
lapse of lava domes (e.g., Soufriére Hills). Many of the traits of the deposits seen on
this two day trip are a reflection of, both, the style of eruption and the nature of the
surrounding landscape. In this regard, the trip provides a spectacular window into
the nature and hazards of effusive and explosive volcanism occurring in mountainous
terrains and the role of water and ice.
Keywords: Cascades, Garibaldi volcanic belt, glaciovolcanism, Mount Meager,
explosive, topography.