Laurasia is defined at Dictionary.com as "an ancient supercontinent." What was the LauraSIA Supercontinent?

Laurasia was the more northern of the two large landmasses that formed the Pangaea supercontinent from 335 to 175 million.After the split of Pangaea, it was separated from Gondwana 215 to 175 Mya and then broke apart with the opening of the North Atlantic Ocean.

Laurussia, also known as the Old Red Sandstone Continent, was formed after a series of smaller terranes collided in the Caledonian orogeny.Pangaea was formed after Laurussia and Gondwana collided.Laurasia was formed when Siberia and Kazakhstania were added to Pangaea.Laurasia became an independent continental mass when Pangaea broke up.[4]

The core of North America and continental fragments collided with Baltica and Avalonia in the Caledonian orogeny to form Laurussia.Pangaea was formed in the Late Carboniferous Laurussia and Gondwana.Laurasia was formed after Siberia and Kazakhstania collided with Baltica.East and Southeast Asia were later added to Laurasia.

The continents in the Southern Hemisphere were once merged into a larger continent called Gondwana.Alfred Wegener proposed a supercontinent called Pangaea in 1915.Alexander du Toit proposed in 1937 that Pangaea should be divided into two landmasses, Laurasia in the Northern Hemisphere and Gondwana in Southern Hemisphere, separated by the Tethys Ocean.[5]

The merger between Laurentia and Baltica was defined in 1988 as "Laurussia".The Silurian-Carboniferous deposits in the central landmass of Laurussia are often referred to as the "Old Red Continent".[6]

In the 1990s and later, several earlier supercontinents proposed and debated.There were earlier connections between Laurentia, Baltica, and Siberia.The intermittent duration and recurrent fit of these original connections is debated.[7]

The continental mass known as Proto-Laurasia was formed as part of the supercontinent Columbia which was assembled over two thousand years ago.The Trans- Hudson orogen in Laurentia is one of the surviving sutures from this assembly.[9]

There was an additional Proterozoic crust of 1,300 Mya along the Laurentia-Greenland-Baltica margin.Laurentia and Baltica formed a continental mass with southern Greenland and Labrador.There was a magmatic arcs from southern Greenland to northern Baltica.The break-up of Columbia began 1,600 Mya, including along the western margin of Laurentia and the northern Margin of Baltica.[8]

Evidence for continental mergers can be found in the trace left by large igneous provinces.Those related to Proto-Laurasia include:

The core of the supercontinent Rodinia was formed in the majority of plate tectonic reconstructions, but the exact fit of various continents is debated.Amazonia was docked along Baltica's Tornquist margin in some reconstructions.Australia and East Antarctica were located on the western margin.It was [13].

Siberia was close to the north in most reconstructions.The southern margin (modern coordinates) of Siberia merged with the northern margin of Laurentia, forming the Central Asian Foldbelt.[15]

The Proto-Pacific opened and Rodinia began to break apart.Both Laurentia and Baltica were located south of 30S.[16]

The Central Iapetus Magmatic Province caused Laurentia and Baltica to separate.The Iapetus Ocean and Mya opened between them.Laurentia was stuck over a cold spot in the Proto-pacific when it began to move north.In the southern latitudes, Baltica remained near Gondwana.[16]

Within the supercontinent Pannotia or Greater Gondwana, Siberia and Baltica were connected to each other.There are a number of continental blocks that form part of Asia at this time.Blocks that now form part of southwestern Europe and North America from New England to Florida were still attached to the African-South American margin of Gondwana.The Hunic terranes are now spread from Europe to China.[18]

Pannotia broke apart in the late Precambrian.The Cadomian–Avalonian, Cathaysian and Cimmerian terranes broke away from Gondwana and began to drift north.[19]

Laurentia was separated from Baltica by the up to 3,000 km Iapetus Ocean during the early Palaeozoic.The opening of a series of large back-arc basins was caused by the mid-ocean ridge in the Iapetus Ocean subduct.The basins evolved into a new ocean, the Rheic Ocean, which separated the terranes of Avalonia, Carolinia, and Armorica from Gondwana.[21]

Baltica and Avalonia collided near the Ordovician–Silurian boundary.Baltica-Avalonia was pushed to the north.The Old Red Continent, also known as Laurussia, was formed after the collision between these continents.[20][21]

The landmass of Baltica and Avalonia remained static near the Equator during the Devonian.The largest trilobites were greater than 3 ft and were found in the warm, shallow seas.The Old Red Sandstone Continent stretched across northern Laurentia and into Baltica but a narrow seaway kept the North Atlantic from opening.The oldest known fossils are from Greenland.Natural barriers produced by low sea-levels resulted in provincialism within the benthic fauna.The Transcontinental Arch divided brachiopods into two provinces, with one of them confined to a large embayment west of the Appalachians.The two provinces had been united into one by the Middle Devonian.The basins of Laurentia were left black by anoxic events caused by high plankton productivity.[23]

The first contact between Laurussia and Gondwana occurred after the subduction of the Iapetus Ocean and ended in a collision.The supercontinent Pangaea was formed after the orogeny closed the Rheic Ocean between Avalonia and Armorica.The exact timing and order of the collision between the involved microcontinent has been debated for decades.[25]

The Asian blocks were assembled by the Permian.The emergence of the Pangaean megamonsoon took place during the period when the supercontinent was centred on the Equator.Peat formation and extensive coal deposits were caused by heavy rain.[28]

When the oceans separated, only pelagic marine organisms, such as plankton, could move across the open ocean and therefore the oceanic gaps between continents were easily detected in the fossil records of marine bottom dwellers and non-marine species.When the continents were pushed closer together, benthos (brachiopods and trilobites) could spread between continents while ostracods and fishes remained isolated.The fish species in both Laurussia and Gondwana began to migrate between continents after the end of the Devonian and Pangaea formed.[28]

The Gilboa forest in central Laurussia is the location of the oldest tree fossils.The coal forest was covered by tropical rainforests in the late Carboniferous.The rainforests collapsed as the climate became arid and the lycopsids were replaced by treeferns.In the dry climate, a detritivorous fauna, including ringed worms, molluscs and arthropods, evolved and diversified.30

Laurasia was formed during the Carboniferous–Permian Siberia, Kazakhstan, and Baltica collision.[31]

The Palaezoic-Mesozoic transition was marked by the reorganisation of Earth's tectonic plates which resulted in the assembly of Pangaea.When the subducted mantle slabs were removed, there was a reorganisation that resulted in the creation of large igneous provinces.The extinction event was caused by the tectonic activity.Floodbasalts in the West Siberia Basin, the Pechora Basin and South China are caused by tentional stresses.[32]

Laurasia and Gondwana had different geological histories.The assembly of Laurasia occurred after the formation of the supercontinent, while Gondwana was assembled before Pangaea.There were different patterns of basin formation and transport.The highest ground within Pangaea was East Antarctica and it was the location of the first evidence of Laurasia.Between 30 and 40% of Laurasia were covered by shallow marine water.[33]

The assembly of Pangaea Laurasia grew as continental blocks broke off Gondwana's northern margin and were pulled by new opening oceans behind them.The Proto-Tethys Ocean split the Asian blocks from the northern shores of Gondwana during the break-up of Rodinia.[21]

The opening of the Paleo-Asian Ocean between Baltica and Siberia in the north and Tarim and North China on the south was caused by the break-up of Rodinia.The Central Asian Orogenic Belt is the largest orogen on Earth.[35]

Gondwana was broken off by North China, South China and other countries during the Silurian-Devonian.The Cimmerian continental fragments broke off in the Early Permian.Southwest Sumatra, West Sulawesi, and parts of Borneo broke off during the Late Triassic- Late Jurassic period.36

During the Carboniferous and Permian period, Baltica first collided with Siberia.South China had been in contact with North China long enough to allow floral exchange between the two continents.The rift from Gondwana was blocked by the Cimmerian.[31]

The Neo-Tethys Ocean opened behind the Cimmerian terranes and closed in front in the late Carboniferous.While Siberia was added to Laurussia and Gondwana collided with Laurasia, the eastern branch of the Palaeo- Tethys Ocean remained open.[34]

A series of Asian blocks formed a separate southern Asian continent when the eastern Palaeo-Tethys closed.North China, Qilian, Alex, and Tarim were along with the Central China orogen to form a combined East Asian continent.The formation of the East Asian continent was marked by the collision of Baltica and Siberia.The rifting of western Pangaea began by this time.[31]

The Tethys Seaway opened between Gondwana and Laurasia as Pangaea split in two.There are two groups of mammals that evolved separately on the newly formed landmasses.The location and duration of a land bridge that is intermittent is suggested by the fossil record.[37]

Pine trees originated in Laurasia in competition with faster growing plants.The evolution limited the pine range to between 31 and 50 north and resulted in a split into two subgeneras: one for stress and the other for fire-prone landscapes.From North America to East Asia, pines were established by the end of the Cretaceous.[38]

Before the break-up of Pangaea, archosaurs had a global distribution.Laurasia was assembled as cosmopolitanism ended.The distribution of terosaurs wasn't affected by plate tectonics in the Late Jurassic.The Laurasian and Gondwanan populations of crocodiles evolved from the former.The distribution of the dinosaurs was similar to that of crocodiles.East Asia has a number of endemic species, including horned dinosaurs and club-tailed dinosaurs.[39]

A peak in global warming led to a pan-Arctic fauna with salamanders and alligators.Land animals were able to migrate between continents in the early Palaeogene.Europe and Asia were separated from each other by the Turgai Sea and as this sea or strait dried out, a massive faunal interchange took place and the extinction event in Europe is known as the Grande Coupure.40

The Coraciiformes are an order of birds.The group started in the north and spread south across Laurasia and across the Equator.[41]

The opening of the Central Atlantic Ocean was preceded by the formation of a series of large rift basins, such as the Newark Basin, between eastern North America and the Gulf of Mexico.[42]

The spreading of mya began in the North Atlantic between the Rockall Plateau and North America.By 56 Mya was separated from North America by the Labrador Sea-Baffin Bay Rift.The spreading of mya ceased in the Labrador Sea by 33.Laurasia was broken in two by the opening of the North Atlantic Ocean.