Monmouth Creek complex
Encyclopedia
The Monmouth Creek complex is a volcanic complex in southwestern British Columbia
, Canada
, located 4 km (2.5 mi) southwest of the community of Squamish
on the west side of the Squamish River
mouth. It lies in the southern Pacific Ranges
of the Coast Mountains
and is part of the Squamish volcanic field
in the southern Garibaldi Volcanic Belt
, which represents the northernmost extension of the Cascade Volcanic Arc
.
Its prominent and enigmatic edifice is composed of basaltic andesite
to dacite
of unknown age and may represent a group of dikes
and lava dome
s that formed subglacially. At least four dikes protrude its summit. These form the ribs of 60 m (196.9 ft) to 180 m (590.6 ft) high lava spine
s, the tallest being The Castle
, which contains horizontal and radiating columnar joints. The spines are covered by welded breccia close to their bases and columnar jointing extends into the welded sequence. The most elevated lava flows and spines and composed of dacite.
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, located 4 km (2.5 mi) southwest of the community of Squamish
Squamish, British Columbia
Squamish is a community and a district municipality in the Canadian province of British Columbia, located at the north end of Howe Sound on the Sea to Sky Highway...
on the west side of the Squamish River
Squamish River
The Squamish River is a short but very large river in the Canadian province of British Columbia. Its drainage basin is in size. The total length of the Squamish River is approximately .-Course:...
mouth. It lies in the southern Pacific Ranges
Pacific Ranges
The Pacific Ranges are the southernmost subdivision of the Coast Mountains portion of the Pacific Cordillera. Located entirely within British Columbia, Canada, they run northwest from the lower stretches of the Fraser River to Bella Coola, north of which are the Kitimat Ranges.The Pacific Ranges...
of the Coast Mountains
Coast Mountains
The Coast Mountains are a major mountain range, in the Pacific Coast Ranges, of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbia. They are so-named because of their proximity to the sea coast, and are often...
and is part of the Squamish volcanic field
Squamish volcanic field
The Squamish volcanic field is a small north-south trending volcanic field on the South Coast of British Columbia, Canada. It extends for only about from the eastern side of Howe Sound northeast of Britannia Beach to the heavily forested slope on the western side of the Squamish River mouth...
in the southern Garibaldi Volcanic Belt
Garibaldi Volcanic Belt
The Garibaldi Volcanic Belt, also called the Canadian Cascade Arc, is a northwest-southeast trending volcanic chain in the Pacific Ranges of the Coast Mountains that extends from Watts Point in the south to the Ha-Iltzuk Icefield in the north. This chain of volcanoes is located in southwestern...
, which represents the northernmost extension of the Cascade Volcanic Arc
Cascade Volcanoes
The Cascade Volcanoes are a number of volcanoes in a volcanic arc in western North America, extending from southwestern British Columbia through Washington and Oregon to Northern California, a distance of well over 700 mi ...
.
Its prominent and enigmatic edifice is composed of basaltic andesite
Basaltic andesite
Basaltic andesite is a black volcanic rock containing about 55% silica. Minerals in basaltic andesite include olivine, augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central America and the Andes of South America. Basaltic andesite is common in...
to dacite
Dacite
Dacite is an igneous, volcanic rock. It has an aphanitic to porphyritic texture and is intermediate in composition between andesite and rhyolite. The relative proportions of feldspars and quartz in dacite, and in many other volcanic rocks, are illustrated in the QAPF diagram...
of unknown age and may represent a group of dikes
Dike (geology)
A dike or dyke in geology is a type of sheet intrusion referring to any geologic body that cuts discordantly across* planar wall rock structures, such as bedding or foliation...
and lava dome
Lava dome
|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...
s that formed subglacially. At least four dikes protrude its summit. These form the ribs of 60 m (196.9 ft) to 180 m (590.6 ft) high lava spine
Lava spine
A lava spine is a vertically growing monolith of viscous lava that is slowly forced from a volcanic vent, such as those growing on a lava dome . It may also be considered a kind of dome called a spiny dome . In February of 1983, the dome activity of Mount St...
s, the tallest being The Castle
The Castle (volcano)
The Castle is a lava spine located west of Squamish in southwestern British Columbia, Canada. Volcanism at The Castle is controlled by north-south structures and there are no hot springs known in the area...
, which contains horizontal and radiating columnar joints. The spines are covered by welded breccia close to their bases and columnar jointing extends into the welded sequence. The most elevated lava flows and spines and composed of dacite.
External links
- Catelogue of Canadian volcanoes: The Castle
- The Castle in the Canadian Mountain Encyclopedia