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Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the Indian subcontinent.
Gondwana was formed by the accretion of several (large stable blocks of the Earth's crust), beginning with the East African Orogeny, the collision of India and Madagascar with East Africa, and culminating in with the overlapping Brasiliano and Kuunga orogeny orogenies, the collision of South America with Africa, and the addition of Australia and Antarctica, respectively. Eventually, Gondwana became the largest piece of continental crust of the Paleozoic Era, covering an area of some , about one-fifth of the Earth's surface. It fused with Laurasia during the Carboniferous to form Pangaea.
Gondwana began to separate from northern Pangea (Laurasia) during the Triassic, and started to fragment during the Early Jurassic (around 180 million years ago). The final stages of break-up saw the fragmentation of the Antarctic land bridge (involving the separation of Antarctica from South America and Australia, forming the Drake Passage and Tasmanian Passages), which occurred during the Paleogene (from around (Ma)). Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name (see ), it is also commonly called Gondwanaland.
Regions that were part of Gondwana shared Flora and Fauna elements that persist to the present day.
Some scientists prefer the term "Gondwanaland" for the supercontinent to make a clear distinction between the region and the supercontinent.
The last stages of Gondwanan assembly overlapped with the opening of the Iapetus Ocean between Laurentia and western Gondwana. During this interval, the Cambrian explosion occurred. Laurentia was docked against the western shores of a united Gondwana for a brief period near the Precambrian and Cambrian boundary, forming the short-lived and still disputed supercontinent Pannotia.
The Mozambique Belt separated the Congo craton–Tanzania craton–Bangweulu Block of central Africa from Neoproterozoic India (India, the Antongil Bay Block in far eastern Madagascar, the Seychelles, and the Napier and Rayner Complexes in East Antarctica). The Azania continentDefined but not named in : "Azania" was a Greek name for the East African coast (much of central Madagascar, the Horn of Africa and parts of Yemen and Arabia) was an island in the Mozambique Ocean.
The continents of Australia and East Antarctica were still separated from India, eastern Africa, and Kalahari by , when most of western Gondwana had already been amalgamated. By 550 Ma, India had reached its Gondwanan position, which initiated the Kuunga orogeny (also known as the Pinjarra orogeny). Meanwhile, on the other side of the newly forming Africa, Kalahari collided with Congo and Rio de la Plata which closed the Adamastor Ocean. 540–530 Ma, the closure of the Mozambique Ocean brought India next to Australia–East Antarctica, and both North China and South China were in proximity to Australia.
As the rest of Gondwana formed, a complex series of orogenic events assembled the eastern parts of Gondwana (eastern Africa, Arabian-Nubian Shield, Seychelles, Madagascar, India, Sri Lanka, East Antarctica, Australia) . First, the Arabian-Nubian Shield collided with eastern Africa (in the Kenya-Tanzania region) in the East African Orogeny . Then Australia and East Antarctica were merged with the remaining Gondwana in the Kuunga Orogeny.
The later Malagasy orogeny at about 550–515 Mya affected Madagascar, eastern East Africa and southern India. In it, Neoproterozoic India collided with the already combined Azania and Congo–Tanzania–Bangweulu Block, suturing along the Mozambique Belt.
The Terra Australis Orogen developed along Gondwana's western, southern, and eastern margins. Proto-Gondwanan Cambrian arc belts from this margin have been found in eastern Australia, Tasmania, New Zealand, and Antarctica. Though these belts formed a continuous arc chain, the direction of subduction was different between the Australian-Tasmanian and New Zealand-Antarctica arc segments.
In the Early Paleozoic, the Armorican terrane, which today form large parts of France, was part of Peri-Gondwana; the Rheic Ocean closed in front of it and the Paleo-Tethys Ocean opened behind it. Precambrian rocks from the Iberian Peninsula suggest that it, too, formed part of core Gondwana before its detachment as an orocline in the Variscan orogeny close to the Carboniferous–Permian boundary.
South-east Asia was made of Gondwanan and continental fragments that were assembled during the Mid-Paleozoic and Cenozoic. This process can be divided into three phases of rifting along Gondwana's northern margin: first, in the Devonian, North and South China, together with Tarim Basin and Quidam (north-western China) rifted, opening the Paleo-Tethys behind them. These terranes accreted to Asia during Late Devonian and Permian. Second, in the Late Carboniferous to Early Permian, Cimmerian terranes opened Meso-Tethys Ocean; Sibumasu and Qiangtang were added to south-east Asia during Lopingian and Early Jurassic. Third, in the Late Triassic to Late Jurassic, Lhasa terrane, Burma terrane, Woyla terranes opened the Neo-Tethys Ocean; Lhasa collided with Asia during the Early Cretaceous, and Burma and Woyla during the Late Cretaceous.
Gondwana's long, northern margin remained a mostly passive margin throughout the Paleozoic. The Early Permian opening of the Neo-Tethys Ocean along this margin produced a long series of terranes, many of which were and still are being deformed in the Himalayan orogeny. These terranes are, from Turkey to north-eastern India: the Taurides in southern Turkey; the Lesser Caucasus Terrane in Georgia; the Sanand, Alborz, and Lut terranes in Iran; the Mangysglak Terrane in the Caspian Sea; the Afghan Terrane; the Karakorum Terrane in northern Pakistan; and the Lhasa and Qiangtang terranes in Tibet. The Permian–Triassic widening of the Neo-Tethys pushed all these terranes across the Equator and over to Eurasia.
In the western end of Pangaea, the collision between Gondwana and Laurasia closed the Rheic Ocean and Paleo-Tethys oceans. The obliquity of this closure resulted in the docking of some northern terranes in the Marathon Uplift, Ouachita orogeny, Alleghanian, and Variscan orogeny orogenies, respectively. Southern terranes, such as Chortis Block and Oaxaca, on the other hand, remained largely unaffected by the collision along the southern shores of Laurentia. Some Peri-Gondwanan terranes, such as Maya Block and Florida Platform, were buffered from collisions by major promontories. Other terranes, such as Carolina terrane and Meguma terrane, were directly involved in the collision. The final collision resulted in the Variscan-Appalachian Mountains, stretching from present-day Mexico to southern Europe. Meanwhile, Baltica collided with Siberia and Kazakhstania which resulted in the Uralian orogeny and Laurasia. Pangaea was finally amalgamated in the Late Carboniferous-Early Permian, but the oblique forces continued until Pangaea began to rift in the Triassic.
In the eastern end, collisions occurred slightly later. The North China, South China, and Sunda plate blocks rifted from Gondwana during the middle Paleozoic and opened the Proto-Tethys Ocean. North China docked with Mongolia and Siberia during the Carboniferous–Permian, followed by South China. The Cimmerian blocks then rifted from Gondwana to form the Paleo-Tethys and Tethys Ocean oceans in the Late Carboniferous, and docked with Asia during the Triassic and Jurassic. Western Pangaea began to rift while the eastern end was still being assembled.
The formation of Pangaea and its mountains had a tremendous impact on global climate and sea levels, which resulted in glaciations and continent-wide sedimentation. In North America, the base of the Absaroka sequence coincides with the Alleghanian and Ouachita orogenies and are indicative of a large-scale change in the mode of deposition far away from the Pangaean orogenies. Ultimately, these changes contributed to the Permian–Triassic extinction event and left large deposits of hydrocarbons, coal, evaporite, and metals.
The breakup of Pangaea began with the Central Atlantic magmatic province (CAMP) between South America, Africa, North America, and Europe. CAMP covered more than seven million square kilometres over a few million years, reached its peak at , and coincided with the Triassic–Jurassic extinction event. The reformed Gondwanan continent was not precisely the same as that which had existed before Pangaea formed; for example, most of Florida and southern Georgia and Alabama is underlain by rocks that were originally part of Gondwana, but this region stayed attached to North America when the Central Atlantic opened.
The Madagascar block and the Mascarene Plateau, stretching from the Seychelles to Réunion, were broken off India, causing Madagascar and Insular India to be separate landmass: elements of this break-up nearly coincide with the Cretaceous–Paleogene extinction event. The India–Madagascar–Seychelles separations appear to coincide with the eruption of the Deccan Traps, whose eruption site may survive as the Réunion hotspot. The Seychelles and the Maldives are now separated by the Central Indian Ridge.
During the initial break-up in the Early Jurassic, a marine transgression swept over the Horn of Africa covering Triassic planation surfaces with sandstone, limestone, shale, and . (2025). 9789401780261 ISBN 9789401780261
Separation between Australia and East Antarctica began with seafloor spreading occurring . A shallow seaway developed over the South Tasman Rise during the Early Cenozoic and as oceanic crust started to separate the continents during the Eocene global ocean temperature dropped significantly. A dramatic shift from arc- to rift magmatism separated Zealandia, including New Zealand, the Campbell Plateau, Chatham Rise, Lord Howe Rise, Norfolk Ridge, and New Caledonia, from West Antarctica .
Later, South America was connected to North America via the Isthmus of Panama, cutting off a circulation of warm water and thereby making the Arctic colder, as well as allowing the Great American Interchange.
The break-up of Gondwana can be said to continue in eastern Africa at the Afar triple junction, which separates the Arabian plate, African plate, and Somali plate plates, resulting in rifting in the Red Sea and East African Rift.
Australia was warm and wet during the Paleocene and dominated by rainforests. The opening of the Tasman Gateway at the Eocene-Oligocene boundary () resulted in abrupt cooling but the Oligocene became a period of high rainfall with swamps in southeastern Australia. During the Miocene, a warm and humid climate developed with pockets of rainforests in central Australia, but before the end of the period, colder and drier climate severely reduced this rainforest. A brief period of increased rainfall in the Pliocene was followed by drier climate which favoured grassland. Since then, the fluctuation between wet interglacial periods and dry glacial periods has developed into the present arid regime. Australia has thus experienced various over a 15-million-year period with a gradual decrease in precipitation.
The Tasman Gateway between Australia and Antarctica began to open . Palaeontological evidence indicates the Antarctic Circumpolar Current (ACC) was established in the Late Oligocene with the full opening of the Drake Passage and the deepening of the Tasman Gateway. The oldest oceanic crust in the Drake Passage, however, is -old which indicates that the spreading between the Antarctic and South American plates began near the Eocene-Oligocene boundary. Deep sea environments in Tierra del Fuego and the Scotia plate during the Eocene and Oligocene indicate a "Proto-ACC" opened during this period. Later, , a series of events severally restricted the Proto-ACC: change to shallow marine conditions along the North Scotia Ridge; closure of the Fuegan Seaway, the deep sea that existed in Tierra del Fuego; and uplift of the Patagonian Cordillera. This, together with the reactivated Iceland hotspot, contributed to global warming. During the Miocene, the Drake Passage began to widen, and as water flow between South America and the Antarctic Peninsula increased, the renewed ACC resulted in cooler global climate.
Since the Eocene, the northward movement of the Australian Plate has resulted in an Continental arc collision with the Philippine and Caroline plate plates and the uplift of the New Guinea Highlands. From the Oligocene to the late Miocene, the climate in Australia, dominated by warm and humid rainforests before this collision, began to alternate between open forest and rainforest before the continent became the arid or semiarid landscape it is today.
By the end of the Ordovician, Cooksonia, a slender, ground-covering plant, became the first known vascular plant to establish itself on land. This first colonisation occurred exclusively around the Equator on landmasses then limited to Laurasia and, in Gondwana, to Australia. In the late Silurian, two distinctive lineages, and Rhyniophyte, had colonised the tropics. The former evolved into the Lycopodiopsida that were to dominate the Gondwanan vegetation over a long period, whilst the latter evolved into Equisetum and . Most of Gondwana was located far from the Equator during this period and remained a lifeless and barren landscape.
West Gondwana drifted north during the Devonian, bringing Gondwana and Laurasia close together. Global cooling contributed to the Late Devonian extinction (19% of marine families and 50% of genera went extinct) and glaciation occurred in South America. Before Pangaea had formed, terrestrial plants, such as , began to diversify rapidly resulting in the colonisation of Gondwana. The Baragwanathia Flora, found only in the Yea Beds of Victoria, Australia, occurs in two strata separated by or 30 Ma; the upper assemblage is more diverse and includes Baragwanathia, the first primitive Herbaceous plant lycopod to evolve from the zosterophylls. During the Devonian, Lepidodendron replaced the Baragwanathia Flora, introducing the first trees, and by the Late Devonian this first forest was accompanied by the , including the first large trees Archaeopteris. The Late Devonian extinction probably also resulted in Osteolepiformes fishes evolving into the amphibian tetrapods, the earliest land vertebrates, in Greenland and Russia. The only traces of this evolution in Gondwana are amphibian footprints and a single jaw from Australia.
The closure of the Rheic Ocean and the formation of Pangaea in the Carboniferous resulted in the rerouting of ocean currents that initiated an Ice House period. As Gondwana began to rotate clockwise, Australia shifted south to more temperate latitudes. An ice cap initially covered most of southern Africa and South America but spread to eventually cover most of the supercontinent, except northernmost Africa-South America. Giant lycopod and horsetail forests continued to evolve in tropical Laurasia together with a diversified assemblage of true insects. In Gondwana, in contrast, ice and, in Australia, volcanism decimated the Devonian flora to a low-diversity seed fern flora – the pteridophytes were increasingly replaced by the gymnosperms which were to dominate until the Mid-Cretaceous. Australia, however, was still located near the Equator during the Early Carboniferous, and during this period, Temnospondyli and Lepospondyli amphibians and the first amniote reptilians evolved, all closely related to the Laurasian fauna, but spreading ice eventually drove these animals away from Gondwana entirely.
The Gondwana ice sheet melted, and sea levels dropped during the Permian and Triassic global warming. During this period, the extinct Glossopteridales colonised Gondwana and reached peak diversity in the Late Permian when coal-forming forests covered all of Gondwana. The period also saw the evolution of Voltziales, one of the few plant orders to survive the Permian–Triassic extinction (57% of marine families and 83% of genera went extinct) and which came to dominate in the Late Permian and from whom true evolved. Tall lycopods and Equisetidae dominated the wetlands of Gondwana in the Early Permian. Insects co-evolved with glossopterids across Gondwana and diversified with more than 200 species in 21 orders by the Late Permian, many known from South Africa and Australia. Beetles and cockroaches remained minor elements in this fauna. Tetrapod fossils from the Early Permian have only been found in Laurasia but they became common in Gondwana later during the Permian. The arrival of the Therapsida resulted in the first plant-vertebrate-insect ecosystem.
The brief period of icehouse conditions during the Triassic–Jurassic extinction event had a dramatic impact on dinosaurs but left plants largely unaffected. The Jurassic was mostly one of hot-house conditions and, while vertebrates managed to diversify in this environment, plants have left little evidence of such development, apart from Cheiroleidiacean conifers and Caytoniales and other groups of seed ferns. In terms of biomass, the Jurassic flora was dominated by conifer families and other gymnosperms that had evolved during the Triassic. The that had dominated during the Paleozoic were now marginalised, except for ferns. In contrast to Laurentia, very few insect fossils have been found in Gondwana, to a considerable extent because of widespread deserts and volcanism. While plants had a cosmopolitan distribution, dinosaurs evolved and diversified in a pattern that reflects the Jurassic break-up of Pangaea.
The Cretaceous saw the arrival of the Flowering plant, or flowering plants, a group that probably evolved in western Gondwana (South America–Africa). From there the angiosperms diversified in two stages: the Monocotyledon and magnoliids evolved in the Early Cretaceous, followed by the Hamamelidaceae Dicotyledon. By the Mid-Cretaceous, angiosperms constituted half of the flora in northeastern Australia. There is, however, no obvious connection between this spectacular angiosperm radiation and any known extinction event nor with vertebrate/insect evolution. Insect orders associated with pollination, such as , Fly, Lepidoptera, Hymenoptera, radiated continuously from the Permian-Triassic, long before the arrival of the angiosperms. Well-preserved insect fossils have been found in the lake deposits of the Santana Group in Brazil, the Koonwarra Lake fauna in Australia, and the Orapa diamond mine in Botswana.
Dinosaurs continued to prosper but, as the angiosperm diversified, conifers, bennettitaleans and pentoxylaleans disappeared from Gondwana 115 Ma together with the specialised herbivorous , whilst generalist browsers, such as several families of Sauropodomorpha Saurischia, prevailed. The Cretaceous–Paleogene extinction event killed off all dinosaurs except birds, but plant evolution in Gondwana was hardly affected. Gondwanatheria is an extinct group of non- mammals with a Gondwanan distribution (South America, Africa, Madagascar, India, Zealandia and Antarctica) during the Late Cretaceous and Palaeogene. Xenarthra and Afrotheria, two placental clades, are of Gondwanan origin and probably began to evolve separately when Africa and South America separated.
The of Australia, New Caledonia, and New Zealand have a number of species related to those of the Laurel forest of Valdivia, through the connection of the Antarctic flora. These include gymnosperms and the deciduous species of Nothofagus, as well as the New Zealand laurel, Corynocarpus laevigatus, and Laurelia novae-zelandiae. New Caledonia and New Zealand became separated from Australia by continental drift 85 million years ago. The islands still retain plants that originated in Gondwana and spread to the Southern Hemisphere continents later.
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