Age of rock Miocene Elevation 2,252 m Last eruption Pliocene Parent range Pacific Ranges | Mountain type Caldera Province British Columbia Mountain range Pacific Ranges | |
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Location British Columbia, Canada Volcanic arc/belt Canadian Cascade Arc
Pemberton/Garibaldi Belt Similar Mount Silverthrone, Slag Hill, Bridge River Vent, Watts Point volcanic centre, Monmouth Creek complex | ||
Franklin Glacier Volcano is a deeply eroded and huge 20 km (12 mi) long and 6 km (4 mi) wide caldera complex in southwestern British Columbia, Canada, located east-southeast of the Silverthrone Caldera in the Hoodoo Creek and Franklin Glacier area on the northwest flank of the Waddington Massif of the Pacific Ranges of the Coast Mountains. Franklin Glacier Volcano consists of a series of dikes and high-level magma intrusions.
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Map of Franklin Glacier Volcano, Mount Waddington A, BC, Canada
Origins
The still largely unexplained tectonic causes of the volcanism that has produced Franklin Glacier Volcano are a matter of ongoing research. Franklin is not above a hotspot as are Nazko or Hawaii. However, with the existence of andesite, basalt, and rhyodacite, it may be a product of the Cascadia subduction zone because such volcanic rocks are products of subduction volcanism. At issue are the current plate configuration and rate of subduction but Franklin's chemistry indicates that Franklin is subduction related.
Eruptive history
The eruptive history of Franklin Glacier Volcano is poorly known and poorly understood. Franklin Glacier Volcano is considerably older than Silverthrone Caldera, its nearest prominent neighbour. Potassium-argon dates from some of the high-level intrusions indicate Franklin Glacier Volcano has had at least two distinct eruptive events. The first event began between six and eight million years ago, and the other between two and three million years ago, indicating Franklin Glacier Volcano has long periods of inactivity and has a period of activity about every three million years. At least some intrusions of Franklin Glacier Volcano were sources for the two distinct volcanic events. Volcanics include dacite breccia, minor lava flows, tuffs, and scarce remnants of hornblende andesite lava flows that reach thicknesses of 450 m (1,476 ft).