Slag Hill is a

subglacial volcano A subglacial volcano, also known as a glaciovolcano, is a volcanic form produced by subglacial eruptions or eruptions beneath the surface of a glacier or ice sheet which is then melted into a lake by the rising lava. Today they are most common i ...

associated with the

Mount Cayley volcanic field The Mount Cayley volcanic field (MCVF) is a remote volcanic zone on the South Coast of British Columbia, Canada, stretching from the Pemberton Icefield to the Squamish River. It forms a segment of the Garibaldi Volcanic Belt, the Canadian portio ...

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. It consists of glassy,

augite Augite, also known as Augurite, is a common rock-forming pyroxene mineral with formula . The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees. Characteristics Augite is a solid soluti ...

-phyric

basaltic andesite Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Ameri ...

in steep-sided, glassy, finely jointed domes and one small, flat-topped

bluff Bluff or The Bluff may refer to: Places Australia * Bluff, Queensland, Australia, a town * The Bluff, Queensland (Ipswich), a rural locality in the city of Ipswich * The Bluff, Queensland (Toowoomba Region), a rural locality * Bluff River (New ...

. The finely jointed domes are similar to those of Ember Ridge. There are quench features at Slag Hill, which is suggesting that the volcanic activity was subglacial. Slag Hill was formed throughout the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

period, but its most recent volcanic activity produced a lava flow on its western lobe that shows no evidence of ice-contact volcanism.Catalogue of Canadian Volcanoes
Retrieved on 2007-05-28 This indicates the lava flow was erupted less than 10,000 years ago after the last glacial period.

References

See also