The Canadian Shield, also called the Laurentian Plateau, is a large area of exposed Precambrian igneous and high-grade metamorphic rocks that forms the ancient geologic core of the North American continent. Glaciation has left the area with only a thin layer of soil, through which the composition of igneous rock resulting from long volcanic history is frequently visible. As a deep, common, joined bedrock region in eastern and central Canada, the Shield stretches north from the Great Lakes to the Arctic Ocean, covering over half of Canada and most of Greenland; it also extends south into the northern reaches of the United States. Human population is sparse and industrial development is minimal, but mining is prevalent.
Kimberlite is an igneous rock, which sometimes contains diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.70 g) diamond called the Star of South Africa in 1869 spawned a diamond rush and the digging of the open-pit mine called the Big Hole. Previously, the term kimberlite has been applied to olivine lamproites as Kimberlite II, however this has been in error.
A xenolith is a rock fragment that becomes enveloped in a larger rock during the latter's development and solidification. In geology, the term xenolith is almost exclusively used to describe inclusions in igneous rock entrained during magma ascent, emplacement and eruption. Xenoliths may be engulfed along the margins of a magma chamber, torn loose from the walls of an erupting lava conduit or explosive diatreme or picked up along the base of a flowing body of lava on the Earth's surface. A xenocryst is an individual foreign crystal included within an igneous body. Examples of xenocrysts are quartz crystals in a silica-deficient lava and diamonds within kimberlite diatremes. Xenoliths can be non-uniform within individual locations, even in areas which are spatially limited, e.g. rhyolite-dominated lava of Niijima volcano (Japan) contains two types of gabbroic xenoliths which are of different origin - they were formed in different temperature and pressure conditions.
The Ekati Diamond Mine ("Ekati") is Canada's first surface and underground diamond mine. It is located 310 km (190 mi) north-east of Yellowknife, Northwest Territories, and about 200 km (120 mi) south of the Arctic Circle, near Lac de Gras. Until 2014 Ekati was a joint venture between Dominion Diamond Mines (80%), and the two geologists who discovered kimberlite pipes north of Lac de Gras, Chuck Fipke and Stewart Blusson each holding a 10% stake in the mine, until Fipke sold his share to Dominion.
Ultramafic rocks are igneous and meta-igneous rocks with a very low silica content, generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals. The Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks.
Northern Alberta is a geographic region located in the Canadian province of Alberta.
Volcanic activity is a major part of the geology of Canada and is characterized by many types of volcanic landform, including lava flows, volcanic plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, submarine volcanoes, calderas, diatremes, and maars, along with less common volcanic forms such as tuyas and subglacial mounds.
The Valkyrie pipe is a diatreme in northern Alberta, Canada. It is associated with a group of diatremes called the Birch Mountains kimberlite field which is thought to have formed about 75 million years ago when this part of Alberta was volcanically active during the Late Cretaceous period.
The Jericho pipe is a diamondiferous diatreme in the Slave craton of Nunavut, Canada, located 400 km (249 mi) northeast of Yellowknife near the northern end of Contwoyto Lake. It is home to the now closed Jericho Diamond Mine.
The Buffalo Head Hills kimberlite field is a group of kimberlitic volcanic pipes or diatremes in north-central Alberta, Canada. As of 2011, 41 kimberlite pipes, of which 28 are diamondiferous, had been identified in the field. They were emplaced during Late Cretaceous to early Paleocene time.
The Birch Mountains kimberlite field is a cluster of kimberlitic volcanic pipes or diatremes in north-central Alberta, Canada that were emplaced during a period of kimberlitic volcanism in the Late Cretaceous epoch. As of 2011, 8 diatremes had been discovered in the field, and diamonds and microdiamononds had been recovered during sampling programs.
Sleet Cone is a cinder cone in northern British Columbia, Canada. It lies in the Desolation Lava Field and is thought to have last erupted in the Holocene period and is part of the Mount Edziza volcanic complex.
Storm Cone is a cinder cone in northern British Columbia, Canada. It is thought to have last erupted in the Holocene period and lies on the Desolation lava field which is part of the Mount Edziza volcanic complex.
The Drybones Bay kimberlite pipe is a diamondiferous diatreme in the Slave craton of the Northwest Territories, Canada. It is the largest diatreme discovered in the Northwest Territories.
The Northern Alberta Kimberlite Province (NAKP) consists of three groups of diatremes or volcanic pipes in north-central Alberta, Canada, most of which are kimberlites and some of which are diamondiferous. They are called the Birch Mountains (BM), Buffalo Head Hills (BHH), and the Mountain Lake cluster (ML), and they were discovered between about 1990 and 1997. Most of the diatremes were emplaced during the Late Cretaceous Epoch although a few are as young as early Paleocene.
The volcanology of Eastern Canada includes the hundreds of volcanic areas and extensive lava formations in Eastern Canada. The region's different volcano and lava types originate from different tectonic settings and types of volcanic eruptions, ranging from passive lava eruptions to violent explosive eruptions. Eastern Canada has very large volumes of magmatic rock called large igneous provinces. They are represented by deep-level plumbing systems consisting of giant dike swarms, sill provinces and layered intrusions. The most capable large igneous provinces in Eastern Canada are Archean age greenstone belts containing a rare volcanic rock called komatiite.
Volcanism of Western Canada has produced lava flows, lava plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, greenstone belts, submarine volcanoes, calderas, diatremes and maars, along with examples of more less common volcanic forms such as tuyas and subglacial mounds.
Volcanism of Northern Canada has produced hundreds of volcanic areas and extensive lava formations across Northern Canada. The region's different volcano and lava types originate from different tectonic settings and types of volcanic eruptions, ranging from passive lava eruptions to violent explosive eruptions. Northern Canada has a record of very large volumes of magmatic rock called large igneous provinces. They are represented by deep-level plumbing systems consisting of giant dike swarms, sill provinces and layered intrusions.
The Mess Lake Lava Field is a volcanic field associated with the Mount Edziza volcanic complex of the Northern Cordilleran Volcanic Province in northwestern British Columbia, Canada. It lies northwest of the Spectrum Range on the Kitsu Plateau and consists of young basaltic lava flows and tephra. The source for the basaltic lava and tephra was three cinder cones, including Mess Lake Cone and The Ash Pit, which may be the youngest volcanic feature of the Mount Edziza volcanic complex.
The Igwisi Hills are a volcanic field in Tanzania. Three tuff cones are found there, one of which is associated with a lava flow. They are one of the few locations of possibly kimberlitic lava flows on Earth.
