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.[1]

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.[2][3]

Gangar
View of the Kattsund-Koster dyke swarm in the Koster Islands, western Sweden.
Mackenzie dike swarm
Map of the Mackenzie dike swarm in Canada
Matachewan and Mistassini dike swarms
Map of the Matachewan and Mistassini dike swarms in Canada

Examples

Africa

Antarctica

  • Vestfold Hills dike swarms (East Antarctica)

Asia

  • North China dike swarm (North China craton, China)
  • Sayan dike swarm (Russia)
  • Shirotori-Hiketa dike swarm (northeastern Shikoku, Japan)

Australia

  • Gairdner dyke swarm (South Australia)
  • Mundine Well dyke swarm (Western Australia)
  • Wood's Point dyke swarm (Victoria, Australia)

Europe

North America

Canada

Greenland

United States

WestSpanishPeakCO
Magmatic dikes radiating from West Spanish Peak, Colorado, U.S.

South America

See also

References

  1. ^ Mackenzie dike swarm (geological feature, Canada) -- Britannica Online Encyclopedia.
  2. ^ Galgana, Gerald A.; Grosfils, Eric B.; McGovern, Patrick J. (2013). "Radial dike formation on Venus: Insights from models of uplift, flexure and magmatism". Icarus. 225 (1): 538–547. Bibcode:2013Icar..225..538G. doi:10.1016/j.icarus.2013.04.020.
  3. ^ Ernst, R.E.; Grosfils, E.B.; Mège, D. (2001). "Giant Dike Swarms: Earth, Venus, and Mars". Annual Review of Earth and Planetary Sciences. 29: 489–534. Bibcode:2001AREPS..29..489E. CiteSeerX 10.1.1.473.1821. doi:10.1146/annurev.earth.29.1.489.
  4. ^ Nkouandou, Oumarou Faarouk; Bardintzeff, Jacques-Marie; Mahamat, Oumar; Fagny Mefire, Aminatou; Ganwa, Alembert Alexandre (2017-05-22). "The dolerite dyke swarm of Mongo, Guéra Massif (Chad, Central Africa): Geological setting, petrography and geochemistry". Open Geosciences. 9 (1): 138–150. Bibcode:2017OGeo....9...12N. doi:10.1515/geo-2017-0012. ISSN 2391-5447.
  5. ^ Puchkov, Victor; Ernst, Richard E.; Hamilton, Michael A.; Söderlund, Ulf; Sergeeva, Nina (2016). "A Devonian >2000-km-long dolerite dyke swarm-belt and associated basalts along the Urals-Novozemelian fold-belt: part of an East-European (Baltica) LIP tracing the Tuzo Superswell". GFF. 138: 6–16. doi:10.1080/11035897.2015.1118406.
  6. ^ Larson, E. E.; Strangway, D. W. (1969-03-01). "Magnetization of the Spanish Peaks Dike Swarm, Colorado, and Shiprock Dike, New Mexico". Journal of Geophysical Research. 74 (6): 1505–1514. Bibcode:1969JGR....74.1505L. doi:10.1029/JB074i006p01505.
  7. ^ Druecker, M.D.; Gay, Jr., S.P., Mafic Dyke Swarms Associated with Mesozoic Rifting in Eastern Paraguay, South America
Barents Sea dike swarm

Barents Sea dike swarm consists of two groups of dolerite dikes across the Svalbard and Franz Josef Land regions. The emplacement of dikes was associated with the Cretaceous High Arctic Large Igneous Province (HALIP).

As revealed by aeromagnetic data, the dolerite dikes in the northern Barents Sea can be grouped in two regional dike swarms running oblique to the northern passive margin of the Barents Sea: the Franz Josef Land and Svalbard dike swarms, respectively. Multichannel seismic data indicate that the dikes fed the dolerite sills, resided in Permian to Early Cretaceous sedimentary strata in the East Barents Sea sedimentary basin. U/Pb dating of dolerites indicate an emplacement age of 121-125 Ma.

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.

Bella Bella and Gale Passage dike swarms

The Bella Bella and Gale Passage dike swarms are two parallel dike swarms on the Central Coast of British Columbia, Canada. They range in age from 14.5 to 12.5 million years old. They are both chemically bimodal, consisting of rocks such as basalt, trachyte and comendite. They form the westernmost extent of the Anahim Volcanic Belt on Athlone Island, Dufferin Island and Denny Island.The Bella Bella and Gale Passage dike swarms are petrographically similar to the shield complexes in the central Anahim Volcanic Belt. As a result, the swarms are thought to represent the roots of a peralkaline magma system in which they are the magma conduits connecting the underlying magma chamber to the volcanic centre at the surface, which has been extensively eroded to remnants of eruptive breccia.

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.

Franklin Large Igneous Province

The Franklin Large Igneous Province is a Neoproterozoic large igneous province in the Canadian Arctic of Northern Canada. It represents one of the largest large igneous provinces in Canada, consisting of the Natkusiak flood basalts on Victoria Island, the Coronation sills on the southern shore of the Coronation Gulf and the large Franklin dike swarm, which extends for more than 1,200 km (750 mi) across the Canadian Arctic Archipelago and northwestern Greenland. The Franklin Large Igneous Province covers an area of more than 1,100,000 km2 (420,000 sq mi).

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).

Grenville dike swarm

The Grenville dike swarm is a large Proterozoic dike swarm in the Canadian provinces of Ontario and Quebec. It is one of the several major magmatic events in the Canadian Shield and it possibly formed 590 million years ago along a triple junction that might have been related to a mantle plume. The maximum length of the Grenville dike swarm is 700 km (435 mi).The Ottawa-Bonnechere Graben is associated with the Grenville dike swarm, as some of its features date from that time.

Independence dike swarm

The Independence Dike Swarm is a major Late Jurassic dike swarm extending over 373 miles (600 km) from the eastern Transverse Ranges northward to the east-central Sierra Nevada in southeastern California, United States.

The swarm consists of hundreds of dikes, filled with mafic to felsic rocks and are individually about 10 feet (3 m) in width. These dikes may be the roots of linear-fissure-array supervolcanoes.

Kangaamiut dike swarm

The Kangaamiut dike swarm (old spelling: Kangâmiut) is a 2.04 billion year old dike swarm located in the Kangerlussuaq region of western Greenland. The dikes cut Archean orthogneisses and are exposed along approximately 150 km (93 mi) of the coast and a similar distance up to the inland ice to the east, covering an area of about 18,000 km2 (6,900 sq mi). To the north it is bounded by the paleoproterozoic Ikertooq shear zone (old spelling: Ikertôq) while to the south the boundary is gradational with a gradual reduction in the density of dikes.

Long Range dikes

The Long Range dikes are a Neoproterozoic mafic dike swarm of Newfoundland and Labrador, Canada. It consists of a large igneous province with an area of 105,000 km2 (41,000 sq mi) that was constructed about 620 million years ago when Laurentia broke-up from Baltica. Its formation might have occurred when the ancient Iapetus Ocean began to open.Long Range is the oldest of a series of magmatic events that occurred along the eastern margin of Laurentia 620–560 Ma, before the opening of the Iapetus Ocean. It can be linked to magmatism in Baltica, the basaltic dike swarm in Egersund, Norway, and Baltoscandian swarms. It was followed by the 590 Ma Grenville-Adirondack swarm, Upstate New York, associated with separation from Amazonia and the 563 Ma Sept Îles, Quebec, layered intrusions (coeval with the Catoctin large igneous province) associated with the break-up of the Dashwoods microcontinent of West Newfoundland.

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.

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, 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.

Marathon Large Igneous Province

The Marathon Large Igneous Province is a Paleoproterozoic large igneous province along the southern Superior craton of Ontario, Canada, located around the northern margin of Lake Superior. It consists of three diabase dike swarms known as Marathon, Kapuskasing and Fort Frances. The Kapuskasing and Marathon dike swarms range in age from about 2,126 to 2,101 million years old while the Fort Frances dike swarm is between 2,076 and 2,067 million years old.A single, periodically active mantle plume was responsible for the creation of the Marathon Large Igneous Province due to the lack of apparent polar wander during the formation of the igneous province. The large magmatic event covers an area of at least 400,000 km2 (150,000 sq mi) and the entire large igneous province was constructed in 60 million years.

Matachewan dike swarm

The Matachewan dike swarm is a large 2,500 to 2,450 million year old Paleoproterozoic dike swarm of Northern Ontario, Canada. It consists of basaltic dikes that were intruded in greenschist, granite-greenstone, and metamorphosed sedimentary terrains of the Superior craton of the Canadian Shield. With an area of 360,000 km2 (140,000 sq mi), the Mistassini dike swarm stands as a large igneous province.

Matachewan hotspot

The Matachewan hotspot was a volcanic hotspot responsible for the creation of the large 2,500 to 2,450 million year old Matachewan dike swarm, as well as continental rifting of the Superior and Hearne cratons during the Paleoproterozoic period.

Mistassini dike swarm

The Mistassini dike swarm is a 2.5 billion year old Paleoproterozoic dike swarm of western Quebec, Canada. It consists of mafic dikes that were intruded in the Superior craton of the Canadian Shield. With an area of 100,000 km2 (39,000 sq mi), the Mistassini dike swarm stands as a large igneous province.

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.

Nipissing sills

The Nipissing sills, also called the Nipissing diabase, is a large 2217– to 2210–million year old group of sills in the Superior craton of the Canadian Shield in Ontario, Canada, which intrude the Huronian Supergroup. Nipissing sills intrude all the Huronian sediments and older basement rocks in the northern margin of the Sudbury Basin; they were emplaced after the faulting and folding of Huronian rocks, and are hornblende gabbro of tholeiitic basalt composition. In the Sudbury–Elliot Lake area the Nipissing diabase is deformed; outcrops are parallel to the fold axes of the Huronian sedimentary rocks. Nipissing diabase intrusions are east-northeast trending and are no wider than 460 m (1,510 ft).The Nipissing sills in the Southern Province of the Superior craton are thought to originate from a radiating dike swarm area 1,300 km (810 mi) to the northeast. The mantle source for the Nipissing sills did not come from the mantle beneath the Southern Province that had generated the 2500– to 2450–million year old Matachewan dike swarm. The 2217– to 2210–million year old Ungava magmatic event – located under the Labrador Trough – fed the Nipissing sills; evidence shows the sills were laterally fed from a mantle plume center 1,500 km (930 mi) away via the 2216–million year old Senneterre dikes which form part of the radiating dike swarm.

Sudbury dike swarm

The Sudbury dike swarm, also called the Sudbury dikes, is a Mesoproterozoic dike swarm in northeastern Ontario, Canada. With an age of 1,238 million years, it is younger than the Sudbury Basin impact event and predates the impact event that formed Lake Wanapitei.

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