Bennett Lake Volcanic Complex

Infobox Mountain
Name=Bennett Lake Volcanic Complex
Photo=
Caption=
Elevation=1500 m (4900 ft)
Location=British Columbia/Yukon, Canada
Range=Boundary Ranges, Coast Mountains
Prominence =
Coordinates =
Topographic

Type=Caldera
Volcanic_Arc/Belt=
Age=50 million years
Last eruption=Eocene
First ascent=
Easiest route=

The Bennett Lake Volcanic Complex (BLVC) is a huge 50 million year old extinct caldera complex that spans across the BC-Yukon border in Canada. The caldera complex is surrounded by granitic rocks containing pendants.

Geographic extent

It is located near the eastern contact of the Coast Plutonic Complex and the Whitehorse Trough. There are thick series of pyroclastic and epiclastic rocks at the caldera. Remnants of this huge caldera complex are preserved near Lake Bennett in the Coast Mountains. The complex compose the Skukum Group.

Formation

The Bennett Lake Volcanic Complex was formed when the ancient Kula Plate was subducting under North America during the early Eocene period. [http://article.pubs.nrc-cnrc.gc.ca/ppv/RPViewDoc?_handler_=HandleInitialGet&journal=cjes&volume=40&calyLang=eng&articleFile=e03-063.pdf Crustal recycling during subduction at the Eocene Cordilleran margin of North America] Retrieved on 2007-06-26 ]

Eruptive history

Cataclysmic eruptions from the Bennett Lake Volcanic Complex were from vents along arcuate fracture systems that spewed out about 850 km³ (200 cu mi) of glowing avalanches.

Evacuation of the underlying magma chamber was followed by several stages of collapse to form two calderas, one nested inside the other, that produced an elliptical depression 19 km (12 mi) by 30 km (19 mi) across. The calderas were from 200 m (650 ft) to 2700 m (8800 ft) deep.

Volcanism continued for some time after the caldera collapse. High level andesite and rhyolite dykes and intrusive bodies crosscut volcanic flows and tuffs at all levels dyke swarms are emplaced along ring fractures and fault zones at the southwest edge of the caldera.

Near the dying stages of the volcano, magma surged upward and arched the roof of the magma chamber into a broad dome with relief of about 1500 m (4900 ft).

ee also

*List of volcanoes in Canada
*Volcanism in Canada

References