Gondwana

Gondwana

Overview
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinent
Supercontinent
In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...

s (the other being Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...

) that later became parts of the Pangaea
Pangaea
Pangaea, Pangæa, or Pangea is hypothesized as a supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration....

 supercontinent. It existed from approximately 510 to 180 million years ago (Mya). Gondwana is believed to have suture
Suture (geology)
In structural geology, a suture is a major fault zone through an orogen or mountain range. Sutures separate terranes, tectonic units that have different plate tectonic, metamorphic and paleogeographic histories...

d between ca. 570 and 510 Mya, thus joining East Gondwana to West Gondwana. It separated from Laurasia 200-180 Mya (the mid Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

 era) during the breakup of Pangaea, drifting further south after the split.

Gondwana included most of the landmasses in today's Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

, including Antarctica, South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

, Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

 and the Australian continent
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

, as well as the Arabian Peninsula
Arabian Peninsula
The Arabian Peninsula is a land mass situated north-east of Africa. Also known as Arabia or the Arabian subcontinent, it is the world's largest peninsula and covers 3,237,500 km2...

 and the Indian subcontinent
Indian subcontinent
The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...

, which have now moved entirely into the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

.

The continent of Gondwana was named by Austrian scientist, Eduard Suess
Eduard Suess
Eduard Suess was a geologist who was an expert on the geography of the Alps. He is responsible for hypothesising two major former geographical features, the supercontinent Gondwana and the Tethys Ocean.Born in London to a Jewish Saxon merchant, when he was three his family relocated toPrague,...

, after the Gondwana region
Gondwana (India)
Gondwana is a region of India. Named after the Gondi people who live there , the name of the ancient continent of Gondwanaland was derived from Gondwana, because some of the earliest rock formations of this continent were first investigated in part of the region, in modern Orissa.As Gonds are...

 of central northern India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 (from Sanskrit
Sanskrit
Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...

 gondavana "forest of the Gonds
Gondi people
The Gondi, Goindi or Gond people are people in central India, spread over the states of Madhya Pradesh, eastern Maharashtra , Chhattisgarh, northern Andhra Pradesh, and Western Orissa. With over four million people, they are the largest tribe in Central India.The Gondi language is related to...

"), from which the Gondwana sedimentary sequences (Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

-Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

) are also described.

The adjective Gondwanan is in common use in biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...

 when referring to patterns of distribution of living organisms, typically when the organisms are restricted to two or more of the now-discontinuous regions that were once part of Gondwana, including the Antarctic flora
Antarctic flora
The Antarctic flora is a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana, and is now found on several separate areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia and New Caledonia...

.
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Encyclopedia
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinent
Supercontinent
In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...

s (the other being Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...

) that later became parts of the Pangaea
Pangaea
Pangaea, Pangæa, or Pangea is hypothesized as a supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration....

 supercontinent. It existed from approximately 510 to 180 million years ago (Mya). Gondwana is believed to have suture
Suture (geology)
In structural geology, a suture is a major fault zone through an orogen or mountain range. Sutures separate terranes, tectonic units that have different plate tectonic, metamorphic and paleogeographic histories...

d between ca. 570 and 510 Mya, thus joining East Gondwana to West Gondwana. It separated from Laurasia 200-180 Mya (the mid Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

 era) during the breakup of Pangaea, drifting further south after the split.

Gondwana included most of the landmasses in today's Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

, including Antarctica, South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

, Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

 and the Australian continent
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

, as well as the Arabian Peninsula
Arabian Peninsula
The Arabian Peninsula is a land mass situated north-east of Africa. Also known as Arabia or the Arabian subcontinent, it is the world's largest peninsula and covers 3,237,500 km2...

 and the Indian subcontinent
Indian subcontinent
The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...

, which have now moved entirely into the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

.

The continent of Gondwana was named by Austrian scientist, Eduard Suess
Eduard Suess
Eduard Suess was a geologist who was an expert on the geography of the Alps. He is responsible for hypothesising two major former geographical features, the supercontinent Gondwana and the Tethys Ocean.Born in London to a Jewish Saxon merchant, when he was three his family relocated toPrague,...

, after the Gondwana region
Gondwana (India)
Gondwana is a region of India. Named after the Gondi people who live there , the name of the ancient continent of Gondwanaland was derived from Gondwana, because some of the earliest rock formations of this continent were first investigated in part of the region, in modern Orissa.As Gonds are...

 of central northern India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 (from Sanskrit
Sanskrit
Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...

 gondavana "forest of the Gonds
Gondi people
The Gondi, Goindi or Gond people are people in central India, spread over the states of Madhya Pradesh, eastern Maharashtra , Chhattisgarh, northern Andhra Pradesh, and Western Orissa. With over four million people, they are the largest tribe in Central India.The Gondi language is related to...

"), from which the Gondwana sedimentary sequences (Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

-Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

) are also described.

The adjective Gondwanan is in common use in biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...

 when referring to patterns of distribution of living organisms, typically when the organisms are restricted to two or more of the now-discontinuous regions that were once part of Gondwana, including the Antarctic flora
Antarctic flora
The Antarctic flora is a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana, and is now found on several separate areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia and New Caledonia...

. For example, the Proteaceae
Proteaceae
Proteaceae is a family of flowering plants distributed in the Southern Hemisphere. The family comprises about 80 genera with about 1600 species. Together with the Platanaceae and Nelumbonaceae they make up the order Proteales. Well known genera include Protea, Banksia, Embothrium, Grevillea,...

, a family of plants known only from southern South America, South Africa and Australia, are considered to have a "Gondwanan distribution". This pattern is often considered to indicate an archaic, or relict
Relict
A relict is a surviving remnant of a natural phenomenon.* In biology a relict is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas....

, lineage.

Formation



The assembly of Gondwana was a protracted process. Several orogenies
Orogeny
Orogeny refers to forces and events leading to a severe structural deformation of the Earth's crust due to the engagement of tectonic plates. Response to such engagement results in the formation of long tracts of highly deformed rock called orogens or orogenic belts...

 led to its final amalgamation 550–500 Mya at the end of the Ediacaran
Ediacaran
The Ediacaran Period , named after the Ediacara Hills of South Australia, is the last geological period of the Neoproterozoic Era and of the Proterozoic Eon, immediately preceding the Cambrian Period, the first period of the Paleozoic Era and of the Phanerozoic Eon...

, and into the Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...

. These include the Brasiliano Orogeny, the East African Orogeny
East African Orogeny
East African Orogeny is the Neoproterozoic orogeny that affects the East African Orogen. The orogeny evolved from an accretionary orogeny involving the amalgamation of arcs and evolved into a collisional orogeny when the Neoproterozoic continent Azania collided with the Congo-Tanzania-Bangweulu...

, the Malagasy Orogeny
Malagasy Orogeny
Malagasy Orogeny is the name given to the Ediacaran to Cambrian orogeny that resulted as India collided with the already amalgamated African continent that consisted of Azania and the Congo-Tanzania-Bangweulu Block. The orogeny affects the parts of the East African Orogen that are now found in...

, and the Kuunga Orogeny. The final stages of Gondwana assembly overlapped with the opening of the Iapetus Ocean
Iapetus Ocean
The Iapetus Ocean was an ocean that existed in the Neoproterozoic and Paleozoic eras of the geologic timescale . The Iapetus Ocean was situated in the southern hemisphere, between the paleocontinents of Laurentia, Baltica and Avalonia...

 between Laurentia
Laurentia
Laurentia is a large area of continental craton, which forms the ancient geological core of the North American continent...

 and western Gondwana. During this interval the Cambrian explosion
Cambrian explosion
The Cambrian explosion or Cambrian radiation was the relatively rapid appearance, around , of most major phyla, as demonstrated in the fossil record, accompanied by major diversification of other organisms, including animals, phytoplankton, and calcimicrobes...

 occurred.

Gondwana was formed by these earlier continent
Continent
A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...

s and microcontinents, and others, colliding in these orogenies:
  • Azania
    Azania
    Azania is the name that has been applied to various parts of sub-Saharan Africa. In Roman times—and perhaps earlier—the name referred to a portion of the Southeast African coast south of the Horn of Africa, extending south perhaps as far as modern Tanzania....

    : much of central Madagascar
    Madagascar
    The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

    , the Horn of Africa
    Horn of Africa
    The Horn of Africa is a peninsula in East Africa that juts hundreds of kilometers into the Arabian Sea and lies along the southern side of the Gulf of Aden. It is the easternmost projection of the African continent...

     and parts of Yemen
    Yemen
    The Republic of Yemen , commonly known as Yemen , is a country located in the Middle East, occupying the southwestern to southern end of the Arabian Peninsula. It is bordered by Saudi Arabia to the north, the Red Sea to the west, and Oman to the east....

     and Arabia. (Named by Collins and Pisarevsky (2005): "Azania" was a Greek name for the East African coast.)
  • The Congo
    Congo Basin
    The Congo Basin is the sedimentary basin that is the drainage of the Congo River of west equatorial Africa. The basin begins in the highlands of the East African Rift system with input from the Chambeshi River, the Uele and Ubangi Rivers in the upper reaches and the Lualaba River draining wetlands...

    Tanzania
    Tanzania
    The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

    –Bangweulu Block of central Africa.
  • Neoproterozoic India: India, the Antongil Block in far eastern Madagascar, the Seychelles
    Seychelles
    Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....

    , and the Napier and Rayner Complexes in East Antarctica
    East Antarctica
    East Antarctica, also called Greater Antarctica, constitutes the majority of the Antarctic continent, lying on the Indian Ocean side of the Transantarctic Mountains...

    .
  • The Australia/Mawson
    Mawson Sea
    Mawson Sea is an area of the sea along the Queen Mary Land coast of East Antarctica between the Shackleton Ice Shelf in the west and Vincennes Bay in the east. West of it, on the western side of Shackleton Ice Shelf, is the Davis Sea. To the east is Bowman Island and Vincennes Bay.Two important...

     continent: Australia west of Adelaide and a large extension into East Antarctica
    East Antarctica
    East Antarctica, also called Greater Antarctica, constitutes the majority of the Antarctic continent, lying on the Indian Ocean side of the Transantarctic Mountains...

    .
  • Other blocks which helped to form Argentina
    Argentina
    Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

     and around, including a piece transferred from Laurentia
    Laurentia
    Laurentia is a large area of continental craton, which forms the ancient geological core of the North American continent...

     when the west edge of Gondwana scraped against southeast Laurentia in the Ordovician
    Ordovician
    The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...

    . This is the Famatinian block (named after Famatina
    Famatina
    Famatina is a town in the province of La Rioja, Argentina. It has 6,371 inhabitants as per the , and is the only municipality in the Famatina Department...

     in northwest Argentina) and it formerly continued the line of the Appalachians southwards.


One of the major sites of Gondwana amalgamation was the East African Orogen (Stern, 1994), where these two major orogenies are superimposed on each other:
The East African Orogeny (as later defined) at ~650–630 Mya affected a large part of Arabia, north-eastern Africa, East Africa and Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

. Collins and Windley (2002) propose that in this orogeny Azania collided with the Congo
Congo Basin
The Congo Basin is the sedimentary basin that is the drainage of the Congo River of west equatorial Africa. The basin begins in the highlands of the East African Rift system with input from the Chambeshi River, the Uele and Ubangi Rivers in the upper reaches and the Lualaba River draining wetlands...

Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

–Bangweulu Block.

The later Malagasy orogeny at ~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.

At the same time, in the Kuunga Orogeny Neoproterozoic India collided with the Australia/Mawson continent.

Pangaea


Other large continental masses, including the cores of North America (Canadian Shield
Canadian Shield
The Canadian Shield, also called the Laurentian Plateau, or Bouclier Canadien , is a vast geological shield covered by a thin layer of soil that forms the nucleus of the North American or Laurentia craton. It is an area mostly composed of igneous rock which relates to its long volcanic history...

 or Laurentia), Europe (Baltica
Baltica
Baltica is a name applied by geologists to a late-Proterozoic, early-Palaeozoic continent that now includes the East European craton of northwestern Eurasia. Baltica was created as an entity not earlier than 1.8 billion years ago. Before this time, the three segments/continents that now comprise...

), and Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

 were added over time to form the supercontinent Pangaea
Pangaea
Pangaea, Pangæa, or Pangea is hypothesized as a supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration....

 by Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 time. When Pangea broke up (mostly during the Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

), two large masses, Gondwana and Laurasia, were formed.

When Pangea broke up, the re-formed Gondwana continent was not precisely the same as before Pangaea formed; for example, most of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

 and southern Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...

 and Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...

 are underlain by rocks that were originally part of Gondwana but that were left attached to North America when Pangea broke apart.

Climate


During the late Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...

, Gondwana extended from a point at or near the south pole to near the equator. Across much of Gondwana, the climate was mild. During the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

, the world was on average considerably warmer than today. Gondwana was then host to a huge variety of flora and fauna for many millions of years. The laurel forest
Laurel forest
Laurel forest is a subtropical or mild temperate forest, found in areas with high humidity and relatively stable and mild temperatures. They are characterized by tree species with evergreen, glossy, enlongated leaves, known as laurophyll or lauroide...

 of Australia, New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...

 and New Zealand have a number of other related species of the laurissilva de Valdivia, through the connection of the Antarctic flora
Antarctic flora
The Antarctic flora is a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana, and is now found on several separate areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia and New Caledonia...

 as gymnosperms and deciduous angiosperm Nothofagus. Corynocarpus laevigatus is called the bay of New Zealand, Laurelia novae-zelandiae
Laurelia novae-zelandiae
Laurelia novae-zelandiae, also called Pukatea, is a large laurifolia evergreen tree, endemic to the forests of New Zealand . with so-called 'toothed' leaves and producing small flowers...

belongs to the same genus Laurelia
Laurelia
Laurelia is a genus of flowering plants included in the order Laurales, in the family Atherospermataceae. They are Evergreen fragrant laurifolia trees formerly in the Monimiaceae family....

. The sempervirens tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

 niaouli, it grows in Australia, New Caledonia and New Zealand. New Caledonia and New Zealand ecoregion are separated by continental drift
Continental drift
Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912...

 from Australia 85 million years ago. The islands still retain plants and animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

 that originated in Gondwana and spread to the southern hemisphere continents later.
But there is strong evidence of glaciation during Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 to Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 time, especially in South Africa.

Mesozoic



Gondwana began to break up in the early-Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

 (about 184 Mya) accompanied by massive eruptions of basalt lava, as East Gondwana, comprising Antarctica, Madagascar, India and Australia, began to separate from Africa. South America began to drift slowly westward from Africa as the South Atlantic Ocean opened, beginning about 130 Mya during the Early
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...

 Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

, and resulting in open marine conditions by 110 Mya. East Gondwana then began to separate about 120 Mya when India began to move northward.

The Madagascar block, and a narrow remnant microcontinent presently occupied by the Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....

 Islands, were broken off India; elements of this breakup nearly coincide with the Cretaceous-Tertiary extinction event
Cretaceous-Tertiary extinction event
The Cretaceous–Paleogene extinction event, formerly named and still commonly referred to as the Cretaceous-Tertiary extinction event, occurred approximately 65.5 million years ago at the end of the Maastrichtian age of the Cretaceous period. It was a large-scale mass extinction of animal and plant...

. The India–Madagascar–Seychelles separations appear to coincide with the eruption of the Deccan basalts
Deccan Traps
The Deccan Traps are a large igneous province located on the Deccan Plateau of west-central India and one of the largest volcanic features on Earth. They consist of multiple layers of solidified flood basalt that together are more than thick and cover an area of and a volume of...

, whose eruption site may survive as the Réunion hotspot
Réunion hotspot
The Réunion hotspot is a volcanic hotspot which currently lies under the Island of Réunion in the Indian Ocean. The Chagos-Laccadive Ridge and the southern part of the Mascarene Plateau are volcanic traces of the Réunion hotspot....

.

Australia began to separate from Antarctica perhaps 80 Mya (Late Cretaceous), but sea-floor spreading between them became most active about 40 Mya during the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 epoch of the Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...

 Period.

New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 probably separated from Antarctica between 130 and 85 Mya.

Cenozoic


As the age of mammals
Cenozoic
The Cenozoic era is the current and most recent of the three Phanerozoic geological eras and covers the period from 65.5 mya to the present. The era began in the wake of the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and...

 got underway, the continent of Australia-New Guinea began gradually to separate and move north (55 Mya), rotating about its axis to begin with, and thus retaining some connection with the remainder of Gondwana for about 10 million years.

About 45 Mya, the Indian Plate collided with Asia, buckling the crust and forming the Himalayas
Himalayas
The Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...

. At about the same time, the southernmost part of Australia (modern Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

) finally separated from Antarctica, letting ocean currents flow between the two continents for the first time. Antarctica became cooler and Australia became drier because ocean currents circling Antarctica were no longer directed around northern Australia into the subtropics.

The separation of South America from West Antarctica
West Antarctica
West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of the continent that lies within the Western Hemisphere including the Antarctic Peninsula.-Location and description:...

 some time during the Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

, perhaps 30 Mya also caused climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

s. Immediately before this, South America and East Antarctica were not connected directly, but the many microplates of the Antarctic Peninsula
Antarctic Peninsula
The Antarctic Peninsula is the northernmost part of the mainland of Antarctica. It extends from a line between Cape Adams and a point on the mainland south of Eklund Islands....

 remained near southern South America acting as "stepping stones" allowing continued biological interchange and stopped oceanic current circulation. But when Drake Passage
Drake Passage
The Drake Passage or Mar de Hoces—Sea of Hoces—is the body of water between the southern tip of South America at Cape Horn, Chile and the South Shetland Islands of Antarctica...

 opened, there was now no barrier to force the cold waters of the Southern Ocean
Southern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...

 north, to be exchanged with warmer tropical water. Instead, a cold circumpolar current developed and Antarctica became what it is today: a frigid continent that locks up much of the world's fresh water as ice. Sea temperatures dropped by almost 10°C, and the global climate became much colder.

By about 15 Mya, the collision between New Guinea (on the leading edge of the Australian Plate) and the southwestern part of the Pacific Plate pushed up the New Guinea highlands, causing a rain shadow
Rain shadow
A rain shadow is a dry area on the lee side of a mountainous area. The mountains block the passage of rain-producing weather systems, casting a "shadow" of dryness behind them. As shown by the diagram to the right, the warm moist air is "pulled" by the prevailing winds over a mountain...

 effect which drastically changed weather patterns in Australia, drying it out.

Later, South America was connected to North America via the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...

, cutting off a circulation of warm water and thereby creating the Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...

 , as well as allowing the Great American Faunal Interchange
Great American Interchange
The Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents...

.

The Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...

 and East African Rift
East African Rift
The East African Rift is an active continental rift zone in eastern Africa that appears to be a developing divergent tectonic plate boundary. It is part of the larger Great Rift Valley. The rift is a narrow zone in which the African Plate is in the process of splitting into two new tectonic plates...

 are modern examples of the continuing dismemberment of Gondwana.

See also

  • Continental drift
    Continental drift
    Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912...

    , the movement of the Earth's continents relative to each other
  • Plate tectonics
    Plate tectonics
    Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

    , a theory which describes the large scale motions of Earth's lithosphere
  • South Polar dinosaurs, which proliferated during the Early Cretaceous (145-100 Ma) while Australia was still linked to Antarctica to form East Gondwana
  • Geology of the Australasian ecozone

External links