Catalogue of Canadian volcanoes |
Proactive disclosure Print version | | Natural Resources Canada > Earth Sciences Sector > Priorities > Strong and safe communities > Volcanoes of Canada
Catalogue of Canadian volcanoes Nazko Cone Nazko cone is a small, tree-covered volcano in central British Columbia,
approximately 75 km west of Quesnel. It is believed to be the
easternmost expression of the Anahim hot spot that stretches
across central British Columbia from Nazko to the Pacific Ocean.
The volcano comprises lava flows, a composite cinder cone, and
air-fall tephra. The sequence of eruption at Nazko started with
the eruption of two distinct series of fluid lava flows, an
older, grey basalt overlain by a younger, darker black basalt.
The passive lava eruptions were followed by a period of explosive,
pyroclastic eruptions of volcanic bombs and ash. This explosive
activity built three overlapping cinder cones that were breached
by the eruption of two lava flows near the end stages of the
explosive eruptions. Finally, explosive volcanic activity scattered
tephra to the north and east of the cones. The tephra deposits
are deepest near the cones (>3 m) and thin to less than a
few centimetres only a few kilometres away, suggesting that
the explosive eruptions were relatively small. However, scientists
at the Geological Survey of Canada surmise that this last eruption
at Nazko cone may have started forest fires because charcoal
is found within the tephra layer.
Figure A14. Nazko ConeNazko cone is easily reached by road by travelling west from the main highway running through the town of Quesnel, British Columbia. The fire-fountaining eruptions that built the cone produced thick accumulations of scoriaceous tephra, which covered the surrounding landscape. The accumulations of tephra from Nazko cone are over several metres thick in some places. The material is unweathered and unconsolidated, making it a prime target for commercial exploitation.
(Photograph by C.J. Hickson (Geological Survey of Canada))
|
The lowermost (hence oldest) lava flows at Nazko volcano have been dated at
approximately 340 000 years using the K-Ar method. The youngest
deposits of air-fall tephra were dated indirectly by analyzing
burned wood within the tephra; the burned wood ranges from 10
000 to 7000 radiocarbon years old. The ages for the tephra can
be confirmed geologically because the air-fall material is found
on top of glacial till deposited during the Fraser Glaciation,
which ended about 10 000 years ago. The cinder cones at Nazko
are currently mined for their valuable resources of scoria,
which is used for light-weight aggregate, landscaping and groundcover,
and in agricultural and horticultural applications as a soil
additive (Figure A14).
The most immediate hazard relating to future eruptions from Nazko cone
is of local concern only and includes the possibility of forest
fires and the disruption of local air traffic should an ash
cloud be produced.
List all List by type Map Nazko Cone |
---|
Type of volcanic feature: | Polygenetic cinder cone | Additional volcanic features: | | Region: | British Columbia | Volcanic belt: | Anahim volcanic belt | Area: | Nazko Cone | Latitude: | 52.93 N | Longitude: | 123.73 W | Age of last eruption: | Holocene (0-0.01 Ma) | Oldest known eruption: | 340,000 years ago | Most recent known eruption: | 7200 radiocarbon years ago | Summit elevation: | 1200 m | Base elevation: | 1066 m | Estimated volume erupted: | < 0.1 km3 |
|