Arctica or Arctida
was an ancient
continent
A continent is any of several large landmasses. Generally identified by convention rather than any strict criteria, up to seven geographical regions
In geography, regions, otherwise referred to as zones, lands or territories, are areas t ...
which formed approximately 2.565
billion years ago
bya or b.y.a. is an abbreviation for "billion years ago". It is commonly used as a unit of time to denote length of time before the present in 109 years. This initialism is often used in the sciences of astronomy, geology, and paleontology.
The " ...
in the
Neoarchean
The Neoarchean (; also spelled Neoarchaean) is the last geologic era in the Archean eon that spans from 2800 to 2500 million years ago—the period being defined chronometrically and not referencing a specific level in a rock section on Ear ...
era. It was made of Archaean
craton
A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging an ...
s, including the
Siberian Craton
Siberia, also known as Angaraland (or simply Angara) and Angarida, is an ancient craton in the heart of Siberia. Today forming the Central Siberian Plateau, it was an independent continent before the Permian period. The Verkhoyansk Sea, a passive ...
, with its
Anabar Anabar may refer to:
* Anabar Bay, Laptev Sea
* Anabar Constituency, Nauru
* Anabar District, Nauru
* Anabar District, Russia, Sakha, Russia
* Anabar Highway, Russia
* Anabar Plateau, Russia
* Anabar (river), Sakha, Russia
* Anabar Shield
An ...
/
Aldan shields in
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...
, and the
Slave,
Wyoming
Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the s ...
,
Superior, and
North Atlantic cratons in North America. Arctica was named by because the
Arctic Ocean
The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...
formed by the separation of the
North American
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Ca ...
and
Siberian cratons. Russian geologists writing in English call the continent "Arctida" since it was given that name in 1987,
alternatively the Hyperborean craton, in reference to the
hyperborea
In Greek mythology, the Hyperboreans ( grc, Ὑπερβόρε(ι)οι, ; la, Hyperborei) were a mythical people who lived in the far northern part of the known world. Their name appears to derive from the Greek , "beyond Boreas" (the God of ...
ns in
Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, the lives and activities ...
.
Nikolay Shatsky
Nikolay Sergeyevich Shatsky (Nicholas Shatski, russian: Николай Серге́евич Шатский) ( in Moscow – August 1, 1960 in Moscow) was a Soviet geologist, an expert in tectonics of ancient platforms. () was the first to assume that the crust in the Arctic region was of continental origin. Shatsky, however, was a "fixist" and, erroneously, explained the presence of Precambrian and Paleozoic metamorphic rocks on the New Siberian, Wrangel, and De long Islands with
subduction. "Mobilists", on the other hand, also erroneously, proposed that North America had rifted from Eurasia and that the Arctic basins had opened behind a retreating Alaska.
Precambrian continent
In his reconstruction of the
supercontinent cycle
The supercontinent cycle is the quasi-periodic aggregation and dispersal of Earth's continental crust. There are varying opinions as to whether the amount of continental crust is increasing, decreasing, or staying about the same, but it is agree ...
, Rogers proposed that the continent
Ur formed at about 3
Ga and formed East
Gondwana in the Middle Proterozoic by accretion to
East Antarctica; Arctica formed around 2.5–2 Ga by the amalgamation of the
Canadian
Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...
and Siberian shields plus Greenland; and
Atlantica
Atlantica ( gr, Ατλαντικα; ''Atlantika'') is an ancient continent that formed during the Proterozoic about (two billion years ago, Ga) from various 2 Ga cratons located in what are now West Africa and eastern South America.
The name, ...
formed around 2 Ga by the amalgamation of the
West African Craton
The West African Craton (WAC) is one of the five cratons of the Precambrian basement rock of Africa that make up the African Plate, the others being the Kalahari craton, Congo craton, Saharan Metacraton and Tanzania Craton.Jessell M.W., Liégeo ...
and eastern South America. Arctica then grew around 1.5 Ga by accretion of East Antarctica and
Baltica
Baltica is a paleocontinent that formed in the Paleoproterozoic and now constitutes northwestern Eurasia, or Europe north of the Trans-European Suture Zone and west of the Ural Mountains.
The thick core of Baltica, the East European Craton, ...
to form the supercontinent
Nena
Gabriele Susanne Kerner (born 24 March 1960), better known as Nena, is a German singer and songwriter who rose to international fame in 1983 as the lead vocalist of the band Nena (band), Nena with the Neue Deutsche Welle song "99 Luftballons". I ...
. Around 1 Ga Nena, Ur, and Atlantica collided to form the supercontinent
Rodinia.
argued that most cratons that were around at 2.5 Ga most likely formed in a single region simply because they were located in a single region in Pangaea, which is the reason Rogers argued for the existence of Arctica.
The core of Arctica was the Canadian Shield, which named
Kenorland
Kenorland was one of the earliest known supercontinents on Earth. It is thought to have formed during the Neoarchaean Era c. 2.72 billion years ago (2.72 Ga) by the accretion of Neoarchaean cratons and the formation of new continental crust. ...
. They argued that this continent formed around 2.5 Ga then rifted before reassembling along the 1.8 Ga
Trans-Hudson and
Taltson-Thelon orogenies. These two orogenies are derived from continental crust (not oceanic crust) and were probably intracontinental, leaving Kenorland intact from 2.5 Ga to present. Correlations between orogenies in Canada and Siberia remain more controversial.
Laurentia
Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, althoug ...
and Baltica were connected during the Late Palaeoproterzoic (1.7–1.74 Ga) and Siberia later joined them. Paleomagnetic reconstructions indicate that they formed a single supercontinent during the Mesoproterozoic (1.5–1.45 Ga) but paleomagnetic data and geological evidences also suggest a considerable spatial gap between Siberia and Laurentia and Arctica is thought to be the missing link.
Phanerozoic microcontinent
The current geological structure of the Arctic Region is the result of tectonic processes during the Mesozoic and Cenozoic (250
Ma to present) when the
Amerasian and
Eurasian
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern Hemisphere, Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Ja ...
basins formed, but the presence of Precambrian metamorphic complexes discovered in the 1980s indicated a continent once existed between
Laurentia
Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, althoug ...
,
Baltica
Baltica is a paleocontinent that formed in the Paleoproterozoic and now constitutes northwestern Eurasia, or Europe north of the Trans-European Suture Zone and west of the Ural Mountains.
The thick core of Baltica, the East European Craton, ...
, and
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...
.
In the reconstruction of , Arctica originally formed as a continent during the
Tonian
The Tonian (from grc, τόνος, tónos, meaning "stretch") is the first geologic period of the Neoproterozoic Era. It lasted from to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by the ICS based ...
950 Ma and became part of the supercontinent
Rodinia. It reformed during the Permian-Triassic 255 Ma and became part of
Pangaea
Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...
. During this period the configuration of Arctica changed and the continent moved from near the Equator to near the North Pole while keeping its position between three major cratons: Laurentia, Baltica, and Siberia.
An extended magmatic event, the
High Arctic Large Igneous Province
The High Arctic Large Igneous Province (HALIP) is a Cretaceous large igneous province in the Arctic. The region is divided into several smaller magmatic provinces. Svalbard, Franz Josef Land, Sverdrup Basin, Amerasian Basin, and northern Greenlan ...
, broke Arctica in part 130–90 Ma, opened the
Arctic Ocean
The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...
, and left radiating
dyke swarm
A dike swarm (American spelling) or dyke swarm (British spelling) is a large geological structure consisting of a major group of parallel, linear, or radially oriented magmatic dikes intruded within continental crust or central volcanoes ...
s across the Arctic.
Fragments of this continent include the
Kara Shelf,
New Siberian Islands
The New Siberian Islands ( rus, Новосиби́рские Oстрова, r=Novosibirskiye Ostrova; sah, Саҥа Сибиир Aрыылара, translit=Saña Sibiir Arıılara) are an archipelago in the Extreme North of Russia, to the north o ...
, northern
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...
,
Chukotka Peninsula
The Chukchi Peninsula (also Chukotka Peninsula or Chukotski Peninsula; russian: Чуко́тский полуо́стров, ''Chukotskiy poluostrov'', short form russian: Чуко́тка, ''Chukotka''), at about 66° N 172° W, is the eastern ...
, Inuit Fold Belt in northern Greenland, and two Arctic underwater ridges, the
Lomonosov and
Alpha-
Mendeleev Ridge
The Mendeleev Ridge (or Mendeleev Rise, russian: Хребет Менделеева) is a broad ridge in the Arctic Ocean from the East Siberian Sea area of the Siberian Shelf to the central areas of the ocean. It is attached to the Alpha Ridge o ...
s. More recent reconstructions also include Barentsia (including
Svalbard and Timan-Pechora Plates).
Remains of the last continent are now located on the
Kara Sea
The Kara Sea (russian: Ка́рское мо́ре, ''Karskoye more'') is a marginal sea, separated from the Barents Sea to the west by the Kara Strait and Novaya Zemlya, and from the Laptev Sea to the east by the Severnaya Zemlya archipelago. ...
Shelf,
New Siberian Islands
The New Siberian Islands ( rus, Новосиби́рские Oстрова, r=Novosibirskiye Ostrova; sah, Саҥа Сибиир Aрыылара, translit=Saña Sibiir Arıılara) are an archipelago in the Extreme North of Russia, to the north o ...
and adjacent shelf,
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...
north of
Brooks Ridge,
Chukchi Peninsula
The Chukchi Peninsula (also Chukotka Peninsula or Chukotski Peninsula; russian: Чуко́тский полуо́стров, ''Chukotskiy poluostrov'', short form russian: Чуко́тка, ''Chukotka''), at about 66° N 172° W, is the eastern ...
in easternmost Siberia, and fragments in northern
Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland i ...
and
Northern Canada and in the submerged
Lomonosov Ridge.
See also
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References
Notes
Sources
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{{Continents of the world
Historical continents
Archean
Proterozoic
Natural history of Asia
Natural history of North America
Prehistory of the Arctic
Former supercontinents