Catalogue of Canadian volcanoes |
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Catalogue of Canadian volcanoes Stikine volcanic belt: Volcano Mountain
Volcano Mountain is located immediately north of the junction of the
Pelly and Yukon rivers, half way between Whitehorse and Dawson
City, central Yukon Territory. The volcano comprises a cinder
cone and a series of lava flows that issued through breaks in
the cone wall both to the northeast and the southwest (Figure A28, Figure A29).
The northeastern lava flow travelled about 5.5 km and the southwestern
flows, only about 3 km. The lavas at Volcano Mountain represent
a unique type of lava, called 'olivine nephelinite', that is
very uncommon in the geological record. These lavas are generally
thought to have come from much deeper in the Earth than the
basalt magmas common to most of the other young volcanoes in
northwestern British Columbia and the Yukon Territory. They
are also unusual because they contain small, angular to rounded
fragments (nodules) of rock that come from the mantle, below
the Earth's crust. These green nodules are called 'peridotites'
because they are composed predominantly of the mineral olivine
or, in gem form, 'peridot'. These lavas and the nodules they
contain are similar to those erupted in the Wells Gray area
of British Columbia.
Figure A28. Volcano MountainVolcano Mountain is a small, asymmetrical cinder cone approximately 300 m high. Lava flows issued through breaks in the cone wall to the northeast and to the southwest.
(Photograph by L. Jackson)
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Figure A29. Volcano Mountain lava flowThe surface of this basaltic lava flow from Volcano Mountain broke into chunks as the lava flowed. These chunks have been tossed about and upended creating a clinkery surface typical of some basaltic lava flows.
(Photograph by L. Jackson)
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The fluid nature of the lavas and the lack of significant fragmental material
erupted from Volcano Mountain suggest that any future eruptions
would probably be dominated by lava flows, with little to no
explosive activity. Thus, the main hazards posed by any renewed
activity include forest fires started by the hot lavas. However,
evidence from older volcanic deposits immediately south of Volcano
Mountain, in the Fort Selkirk area, indicates that lava flows
may have once partly blocked or at least altered the course
of the Yukon and Pelly rivers. Renewed activity in this area
could disrupt the course of one or both of these major rivers
and have a serious impacts on people living or working downstream.
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