Mackenzie dike swarm

The Mackenzie dike swarm, also called the Mackenzie dikes, form a large igneous province in the western Canadian Shield of Canada. It is part of the larger Mackenzie Large Igneous Province and is one of more than three dozen dike swarms in various parts of the Canadian Shield.

The Mackenzie dike swarm is the largest dike swarm known on Earth,[1] more than 500 km (310 mi) wide and 3,000 km (1,900 mi) long, extending in a northwesterly direction across the whole of Canada from the Arctic to the Great Lakes. The mafic dikes cut Archean and Proterozoic rocks, including those in the Athabasca Basin in Saskatchewan, Thelon Basin in Nunavut and the Baker Lake Basin in the Northwest Territories.

The source for the Mackenzie dike swarm is considered to have been a mantle plume center called the Mackenzie hotspot. About 1,268 million years ago, the Slave craton was partly uplifted and intruded by the giant Mackenzie dike swarm. This was the last major event to affect the core of the Slave craton, although later on some younger mafic magmatism registered along its edges.

Mackenzie dike swarm
Map of the Mackenzie dike swarm

See also

References

  1. ^ Suppressing Varying Directional Trends Archived 2007-07-08 at the Wayback Machine Retrieved on 2007-07-28

External links

Athabasca Basin

This article is about the uranium mining region near Lake Athabasca. Not to be confused with the drainage basin of the Athabasca River.

The Athabasca Basin is a region in the Canadian Shield of northern Saskatchewan and Alberta Canada. It is best known as the world's leading source of high-grade uranium and currently supplies about 20% of the world's uranium.The basin is located just to the south of Lake Athabasca, west of Wollaston Lake and encloses almost all of Cree Lake. It covers about 100,000 square kilometres in Saskatchewan and a small portion of Alberta. The surface of the basin consists of main sandstone sediment varying from 100 to 1000 metres in depth. The uranium ore is mostly found at the base of this sandstone, at the point where it meets the basement.

On the northern and eastern edges are the communities of Fort Chipewyan in Alberta and Camsell Portage, Stony Rapids, Fond du Lac, Black Lake and Wollaston Lake in Saskatchewan. Much of the Athabasca Basin is within the migratory range of the Beverly caribou herd a major source of sustenance for the Denesuline communities.

Within the basin are the Athabasca Sand Dunes Provincial Park on the south shore of Lake Athabasca and the Carswell crater. The Cluff Lake mine site is located in the crater area.

Points North Landing a permanent supply depot and camp serves the eastern area of the basin.

Road access to the area is provided by Saskatchewan Highway 955 from the village of La Loche on the west side and Saskatchewan Highway 914 and Saskatchewan Highway 905 north of the town of La Ronge on the east side.

Bear River dikes

The Bear River dikes are a 1,265 to 1,269 million year old group of dikes in northern Yukon, Canada. They represent a feature related to magmatism of the extensive Mackenzie Large Igneous Province and are considered to be the western extension of the northwest-southeast trending Mackenzie dike swarm.

Canadian Shield

The Canadian Shield, also called the Laurentian Plateau, or Bouclier canadien (French), is a large area of exposed Precambrian igneous and high-grade metamorphic rocks (geological shield) that forms the ancient geological core of the North American continent (the North American Craton or Laurentia). Composed of igneous rock resulting from its long volcanic history, the area is covered by a thin layer of soil. With a deep, common, joined bedrock region in eastern and central Canada, it stretches north from the Great Lakes to the Arctic Ocean, covering over half of Canada; it also extends south into the northern reaches of the United States. Human population is sparse, and industrial development is minimal, while mining is prevalent.

Coppermine River Group

The Coppermine River Group is a sequence of Mesoproterozoic continental flood basalts forming part of the Mackenzie Large Igneous Province in the Northwest Territories and Nunavut, Canada. It is among the largest flood basalt province on Earth, covering the area with a volume of approximately 650,000 km3 (155,943 cu mi).

Dike (geology)

A dike or dyke, in geological usage, is a sheet of rock that is formed in a fracture in a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.

Dike swarm

A dike swarm or dyke swarm is a large geological structure consisting of a major group of parallel, linear, or radially oriented dikes intruded within continental crust. They consist of several to hundreds of dikes emplaced more or less contemporaneously during a single intrusive event, and are magmatic and stratigraphic. Such dike swarms may form a large igneous province and are the roots of a volcanic province.

The occurrence of mafic dike swarms in Archean and Paleoproterozoic terrains is often cited as evidence for mantle plume activity associated with abnormally high mantle potential temperatures.

Dike swarms may extend over 400 km (250 mi) in width and length. The largest dike swarm known on Earth is the Mackenzie dike swarm in the western half of the Canadian Shield in Canada, which is more than 500 km (310 mi) wide and 3,000 km (1,900 mi) long.The number of known giant dike swarms on Earth is small, only about 25. However, the primary geometry of most giant dike swarms is poorly known due to their age and subsequent tectonic activity.

Dike swarms have also been found on Venus and Mars.

Franklin dike swarm

The Franklin dike swarm, also called the Franklin dikes, is a Proterozoic dike swarm of the Franklin Large Igneous Province in Northern Canada. It is one of the several major magmatic events in the Canadian Shield and it was formed 723 million years ago. Areas in the Franklin have been prospected for nickel, copper, and platinum group metals.The Franklin dike swarm occupies a major part of the Franklin Large Igneous Province, which covers an area of more than 2,000,000 km2 (770,000 sq mi).

Geography of Northwest Territories

The Northwest Territories is a territory in Northern Canada, specifically in Northwestern Canada between Yukon Territory and Nunavut including part of Victoria Island, Melville Island, and other islands on the western Arctic Archipelago. Originally a much wider territory enclosing most of central and northern Canada, the Northwest Territories was created in 1870 from the Hudson's Bay Company's holdings that were sold to Canada from 1869-1870. In addition, Alberta and Saskatchewan were formed from the territory in 1905. In 1999, it was divided again: the eastern portion became the new territory of Nunavut. Yellowknife stands as its largest city and capital. It has a population of 42,800 and has an area of 532,643 sq mi (1,379,540 km2). The current territory lies west of Nunavut, north of latitude 60° north, and east of Yukon.

It stretches across the top of the North American continent, reaching into the Arctic Circle. The region consists of the following: many islands, such as Victoria Island, the Mackenzie River, and Great Bear and Great Slave lakes. Over half the people are Inuit and First Nations peoples. In the 18th century, the main land was explored by Samuel Hearne for the Hudson's Bay Company and by Alexander Mackenzie. European settlers were mainly whalers, fur traders, and missionaries until the 1920s, when oil was discovered and the territorial administration had formed. The principal industry is now mining, and centers of the petroleum and Natural Gas fields in the western Arctic coastal regions.

Geology of Ontario

The geology of Ontario consists of the study of the rock formations in the most populated province of Canada. Ontario has some of the oldest rocks on Earth. It is made up of ancient Precambrian igneous and metamorphic rock and overlain by younger sedimentary rocks and soils.

About 61% of the province is covered by the Canadian Shield. The shield can further be divided into three sections or provinces. The northwestern parts of the Shield, located roughly north and west of Sudbury, are known as the Superior province is the largest of the three sections, covering about 70% of the Shield portion in Ontario. The Southern province is a narrow region from Sault Ste. Marie to Kirkland Lake. The South central part is dominated by the Grenville Province but flanked by two basins of Phanerozoic materials.

World-class mineral deposits can be found here and are mined extensively.

Hotspot (geology)

In geology, the places known as hotspots or hot spots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Their position on the Earth's surface is independent of tectonic plate boundaries. There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. The other hypothesis is that lithospheric extension permits the passive rising of melt from shallow depths. This hypothesis considers the term "hotspot" to be a misnomer, asserting that the mantle source beneath them is, in fact, not anomalously hot at all. Well-known examples include the Hawaii, Iceland and Yellowstone hotspots.

Large igneous province

A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive (sills, dikes) and extrusive (lava flows, tephra deposits), arising when magma travels through the crust towards the surface. The formation of LIPs is variously attributed to mantle plumes or to processes associated with divergent plate tectonics. The formation of some of the LIPs the past 500 million years coincide in time with mass extinctions and rapid climatic changes, which has led to numerous hypotheses about the causal relationships. LIPs are fundamentally different from any other currently active volcanoes or volcanic systems.

List of Scottish place names in Canada

This is a list of placenames in Scotland that have been applied to parts of Canada by Scottish emigrants or explorers.

For Nova Scotian names in Scottish Gaelic (not necessarily the same as the English versions) see Canadian communities with Scottish Gaelic speakers and Scottish Gaelic placenames in Canada

Note that, unless otherwise stated, province names are not Scottish.

Mackenzie Large Igneous Province

The Mackenzie Large Igneous Province (MLIP) is a major Mesoproterozoic large igneous province of the southwestern, western and northwestern Canadian Shield in Canada. It consists of a group of related igneous rocks that were formed during a massive igneous event starting about 1,270 million years ago. The large igneous province extends from the Arctic in Nunavut to near the Great Lakes in Northwestern Ontario where it meets with the smaller Matachewan dike swarm. Included in the Mackenzie Large Igneous Province are the large Muskox layered intrusion, the Coppermine River flood basalt sequence and the massive northwesterly trending Mackenzie dike swarm.

As a large igneous province, it is an extremely large area of related igneous rocks that were emplaced over an extremely short geological time span. The igneous rocks comprising the Mackenzie Large Igneous Province originated from processes not associated with normal plate tectonics and seafloor spreading. It is one of the several large igneous provinces scattered throughout the Canadian landscape, which can be thousands of kilometres in volume and area. The Mackenzie Large Igneous Province is one of the world's largest Proterozoic magmatic provinces, as well as one of the most well-preserved continental flood basalt terrains on Earth. Igneous rocks of the Mackenzie Large Igneous Province are generally mafic in composition, including basalt and gabbro.

Even though the Mackenzie Large Igneous Province is classified as a large igneous province like other extremely large accumulations of igneous rocks on Earth, it is much larger than large igneous province standards. The standard size classification for large igneous provinces is a minimum areal extent of 100,000 km2 (39,000 sq mi). However, the Mackenzie dike swarm itself occupies an area of at least 2,700,000 km2 (1,000,000 sq mi), making the Mackenzie Large Igneous Province larger than the Ontong Java Plateau (in the southwestern Pacific Ocean) and the U.S. state of Alaska.

Muskox intrusion

The Muskox intrusion is a layered intrusion in Nunavut, Canada. It is located 144 km (89 mi) northeast of Great Bear Lake and 90 km (56 mi) south of Kugluktuk on Coronation Gulf. It was formed during a large magmatic event during the Proterozoic by hotspot or mantle plume volcanism that emplaced the widespread Coppermine River Group flood basalts.

The intrusion is a tilted trough shaped body with an exposed length of 120 km (75 mi) and a thickness or original vertical dimension of over 6 km (3.7 mi). Rock types include picrite, peridotite, dunite, pyroxenite, gabbro and granophyre. A feeder dike of olivine gabbro is exposed "below" the now tilted sequence.Potassium argon dating in the region provides an age of 1095 - 1155 Ma for the Muskox intrusion, 1100 - 1200 Ma for the Mackenzie dike swarm and 740 - 1200 Ma for the Coppermine basalt flows (younger dates are interpreted as having been reset by later intrusion of gabbro sills at 604 - 718 Ma). Further stratigraphic and structural evidence provides further support that the Muskox, the MacKenzie dikes and the Coppermine flows are of the same magmatic event that formed the Mackenzie Large Igneous Province and the Muskox is interpreted as occupying the magma chamber which fed the volcanism.

Siberian Traps

The Siberian Traps (Russian: Сибирские траппы, Sibirskiye trappy) is a large region of volcanic rock, known as a large igneous province, in Siberia, Russia. The massive eruptive event that formed the traps is one of the largest known volcanic events in the last 500 million years.

The eruptions continued for roughly two million years and spanned the P–T boundary, or the Permian–Triassic boundary, which occurred between 251 to 250 million years ago.Large volumes of basaltic lava covered a large expanse of Siberia in a flood basalt event. Today, the area is covered by about 7 million km2 (3 million sq mi) of basaltic rock, with a volume of around 4 million km3 (1 million cu mi).

Timeline of volcanism on Earth

This timeline of volcanism on Earth is a list of major volcanic eruptions of approximately at least magnitude 6 on the Volcanic Explosivity Index (VEI) or equivalent sulfur dioxide emission around the Quaternary period (from 2.58 Mya to the present).

Some eruptions cooled the global climate—inducing a volcanic winter—depending on the amount of sulfur dioxide emitted and the magnitude of the eruption. Before the present Holocene epoch, the criteria are less strict because of scarce data availability, partly since later eruptions have destroyed the evidence. Only some eruptions before the Neogene period (from 23 Mya to 2.58 Mya) are listed. Known large eruptions after the Paleogene period (from 66 Mya to 23 Mya) are listed, especially those relating to the Yellowstone hotspot, the Santorini caldera, and the Taupo Volcanic Zone.

Active volcanoes such as Stromboli, Mount Etna and Kilauea do not appear on this list, but some back-arc basin volcanoes that generated calderas do appear. Some dangerous volcanoes in "populated areas" appear many times: so Santorini, six times and Yellowstone hotspot, twenty-one times. The Bismarck volcanic arc, New Britain, and the Taupo Volcanic Zone, New Zealand, appear often too.

In addition to the events listed below, are many examples of eruptions in the Holocene on the Kamchatka Peninsula, which are described in a supplemental table by Peter Ward.

Volcanology of Canada

Volcanology of Canada includes lava flows, lava plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, submarine volcanoes, calderas, diatremes, and maars, along with examples of more less common volcanic forms such as tuyas and subglacial mounds. It has a very complex volcanological history spanning from the Precambrian eon at least 3.11 billion years ago when this part of the North American continent began to form.Although the country's volcanic activity dates back to the Precambrian eon, volcanism continues to occur in Western and Northern Canada where it forms part of an encircling chain of volcanoes and frequent earthquakes around the Pacific Ocean called the Pacific Ring of Fire. But because volcanoes in Western and Northern Canada are in remote rugged areas and the level of volcanic activity is less frequent than with other volcanoes around the Pacific Ocean, Canada is commonly thought to occupy a gap in the Pacific Ring of Fire between the volcanoes of western United States to the south and the Aleutian volcanoes of Alaska to the north. However, the mountainous landscape of Western and Northern Canada includes more than 100 volcanoes that have been active during the past two million years and whose eruptions have claimed many lives. Volcanic activity has been responsible for many of Canada's geological and geographical features and mineralization, including the nucleus of North America called the Canadian Shield.

Volcanism has led to the formation of hundreds of volcanic areas and extensive lava formations across Canada, indicating volcanism played a major role in shaping its surface. The country'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. Canada has a rich 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 most capable large igneous provinces in Canada are Archean (3,800–2,500 million years ago) age greenstone belts containing a rare volcanic rock called komatiite.

Volcanology of Northern Canada

Volcanology of Northern Canada includes 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.

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