Gondwana

For other uses of Gondwana and Gondwanaland, see Gondwana (disambiguation).

Gondwana (IPA: /ɡɒnˈdwɑːnə/^[1], originally Gondwanaland) was a southern supercontinent that existed about 500 to 200 Ma ago. In Geology, a supercontinent is a Landmass comprising more than one Continental core or Craton. Annum is one form of the Latin noun meaning Year, not a form normally used for derivatives in modern languages the accusative singular Gondwana included most of the landmasses in today's southern hemisphere, including Antarctica, South America, Africa, Madagascar, Australia-New Guinea, and New Zealand, as well as Arabia and the Indian subcontinent, which are in the Northern Hemisphere. Southern Hemisphere is the half of a Planet that is South of the Equator —the word hemisphere literally means 'half ball' South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a Madagascar, or Republic of Madagascar (older name Malagasy Republic) is an Island nation in the Indian Ocean off the southeastern New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island The Arabian Peninsula (in Arabic: شبه الجزيرة العربية šibh al-jazīra al-ʻarabīya or جزيرة العرب jazīrat al-ʻarab) This article deals with the geophysical region in Asia For geopolitical treatments see South Asia. Northern Hemisphere is the half of a Planet that is North of the Equator —the word hemisphere literally means 'half ball' The name is derived from the Gondwana region of central northern India (from Sanskrit gondavana "forest of Gond"). Gondwana is a region of India. Named after the Gondi people who live there (though they can also be found in other parts of India the name of the ancient continent India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Sanskrit (sa संस्कृता वाक् saṃskṛtā vāk, for short sa संस्कृतम् saṃskṛtam) is a historical The Gondi (Gōndi are a people in central India. The Gondi or Gond people are spread over the states of Madhya Pradesh, eastern Maharashtra

The adjective "Gondwanan" is in common use in biogeography 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; e. Biogeography is the study of the distribution of Biodiversity over Space and Time. g. , the Proteaceae, a family of plants that is known only from Chile, South Africa, and Australia are considered to have a "Gondwanan distribution". Proteaceae is a family of Flowering plants. Mainly restricted to the Southern Hemisphere, it is a fairly large family with around 80 genera Chile, officially the Republic of Chile ( Spanish:) is a country in South America occupying a long and narrow Coastal strip wedged between the The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa For a topic outline on this subject see List of basic Australia topics. This pattern is often considered to indicate an archaic, or relict lineage. The term relict is used to refer to surviving remnants of natural phenomena

1 Formation
2 Pangaea
3 Climate
4 Breakup
- 4.1 Mesozoic
- 4.2 Cenozoic
5 See also
6 References
7 Further reading
8 External links

Formation

The assembly of Gondwana was a protracted process. Several orogenies led to its final amalgamation 550–500 million years ago in the Cambrian. Orogeny (Greek for "mountain generating" is the process of natural Mountain building and may be studied as a tectonic structural event as a geographical event and The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with ^[2] These include the Brasiliano Orogeny, the East African Orogeny, the Malagasy Orogeny, and the Kuunga Orogeny. The final stages of Gondwana assembly overlapped with the opening of the Iapetus Ocean between Laurentia and western Gondwana. The Iapetus Ocean was an Ocean that existed in the Southern Hemisphere between Laurentia ( Scotland and North America) and Baltica Laurentia (also known as the North American craton) like all Craton land was created as continents moved about the surface of the Earth During this interval the Cambrian Explosion occurred. The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex Animals around, as evidenced by the

Gondwanaland was formed by these earlier continents and microcontinents, and others, colliding in these orogenies:

Azania: much of central Madagascar, the Horn of Africa and parts of Yemen and Arabia. For a topic outline on this subject see List of basic Australia topics. Azania is the name that has been applied to various parts of sub-Saharan Africa. The Horn of Africa (alternatively Northeast Africa, and sometimes Somali Peninsula; shortened to HOA) is a Peninsula in East Africa Yemen ( Arabic: اليَمَن al-Yaman officially the Republic of Yemen ( Arabic: الجمهورية اليمنية al-Jumhuuriyya The Arabian Peninsula (in Arabic: شبه الجزيرة العربية šibh al-jazīra al-ʻarabīya or جزيرة العرب jazīrat al-ʻarab) (Named by Collins and Pisarevsky (2005): "Azania" was a Greek name for the East African coast. )
The Congo–Tanzania–Bangweulu Block of central Africa. The Congo River (for a time known as the Zaire River) is the largest River in Western Central Africa. Tanzania ˌtænzəˈniːə officially the United Republic of Tanzania (Jamhuri ya Muungano wa Tanzania is a country in East Africa bordered by Kenya Bangweulu — 'where the water sky meets the sky' — is one of the world's great wetland systems comprising Lake Bangweulu, the Bangweulu Swamps
Neoproterozoic India: India, the Antongil Block in far eastern Madagascar, the Seychelles, and the Napier and Rayner Complexes in East Antarctica. Helodranon' Antongila (Bay of Antongila more commonly called Antongil Bay in English is the largest bay in Madagascar. Seychelles (seɪˈʃɛl or /seɪˈʃɛlz/ in English and seʃɛl in French) officially the Republic of Seychelles (République des Seychelles Creole East Antarctica, also called Greater Antarctica, is one of the two major regions of the Antarctic Continent, lying on the Indian Ocean side of
The Australia/Mawson continent: Australia west of Adelaide and a large extension into East Antarctica. East Antarctica, also called Greater Antarctica, is one of the two major regions of the Antarctic Continent, lying on the Indian Ocean side of
Other blocks which helped to form Argentina and around, including a piece transferred from Laurentia when the west edge of Gondwana scraped against southeast Laurentia in the Ordovician^[3]^[4]. For a topic outline on this subject see List of basic Argentina topics. Laurentia (also known as the North American craton) like all Craton land was created as continents moved about the surface of the Earth The Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488

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 Ma ago affected a large part of Arabia, north-eastern Africa, East Africa and Madagascar. Madagascar, or Republic of Madagascar (older name Malagasy Republic) is an Island nation in the Indian Ocean off the southeastern Collins and Windley (2002) propose that in this orogeny Azania collided with the Congo–Tanzania–Bangweulu Block. The Congo River (for a time known as the Zaire River) is the largest River in Western Central Africa. Tanzania ˌtænzəˈniːə officially the United Republic of Tanzania (Jamhuri ya Muungano wa Tanzania is a country in East Africa bordered by Kenya Bangweulu — 'where the water sky meets the sky' — is one of the world's great wetland systems comprising Lake Bangweulu, the Bangweulu Swamps

The later Malagasy orogeny at ~550–515 Ma ago 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

Orogens and Kuungan Orogens.

Other large continental masses, including the cores of North America (Canadian Shield or Laurentia), Europe (Baltica), and Siberia were added over time to form the supercontinent Pangaea by Permian time. The Canadian Shield &mdash also called the Laurentian Plateau, or Bouclier Canadien (French &mdash is a large geological shield covered by Baltica redirects here For the Russian beer, see Baltika Breweries Baltica is a name applied by geologists to a late- Proterozoic, Siberia (Сиби́рь Sibir) is the name given to the vast region constituting almost all of Northern Asia and for the most part currently serving Pangaea, Pangæa or Pangea (pænˈdʒiːə from παν pan, meaning entire, and Γαῖα Gaea, meaning Earth in The Permian is a geologic period and system that extends from 299 When Pangaea broke up (mostly during the Jurassic), two large masses, Gondwana and Laurasia, were formed. The Jurassic is a geologic period and system that extends from about Ma (million years ago to Ma that is from the end of the Triassic to the beginning Laurasia (lɔˈreɪʃiə lɔˈreɪʒə was a Supercontinent that most recently existed as a part of the split of the Pangaean supercontinent in the late Mesozoic

When Pangaea broke up, the re-formed Gondwana continent was not precisely the same as before Pangaea formed; for example, most of Florida and southern Georgia and Alabama are underlain by rocks that were originally part of Gondwana but that were left attached to North America when Pangaea broke apart. Florida ( is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the The State of Georgia ( is a state in the United States and was one of the original Thirteen Colonies that revolted against British rule Alabama (formally the State of Alabama;) is a State located in the southern region of the United States of America.

Climate

During the late Paleozoic, Gondwana extended from a point at or near the south pole to near the equator. The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life" Across much of Gondwana, the climate was mild. India contains about 3% of the world's coal reserves and much of the mined coal is derived from the late Paleozoic Gondwana sedimentary sequence. The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life" During the Mesozoic, the world was on average considerably warmer than today. The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. Gondwana was then host to a huge variety of flora and fauna for many millions of years. But there is strong evidence of glaciation during Carboniferous to Permian time, especially in South Africa. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 The Permian is a geologic period and system that extends from 299

Breakup

Mesozoic

Reconstruction showing final stages of assembly of Gondwana, 550 Ma ago.

Gondwana began to break up in the mid-Jurassic (about 167 million years ago), when East Gondwana, comprising Antarctica, Madagascar, India and Australia, began to separate from Africa. The Jurassic is a geologic period and system that extends from about Ma (million years ago to Ma that is from the end of the Triassic to the beginning South America began to drift slowly westward from Africa as the South Atlantic Ocean opened, beginning about 130 million years ago during the Early Cretaceous, and resulting in open marine conditions by 110 million years ago. The Early Cretaceous ( timestratigraphic name or the Lower Cretaceous ( logstratigraphic name is the earlier of the two major divisions of the Cretaceous The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of East Gondwana itself began to be dismembered about 120 million years ago as India began to move northward.

The Madagascar block, and a narrow remnant microcontinent presently occupied by the Seychelles Islands, were broken off India; elements of this breakup nearly coincide with the Cretaceous-Tertiary extinction event. Seychelles (seɪˈʃɛl or /seɪˈʃɛlz/ in English and seʃɛl in French) officially the Republic of Seychelles (République des Seychelles Creole The Cretaceous–Tertiary extinction event, which occurred approximately ( Ma) was a large-scale mass extinction of animal and plant species in a geologically The India–Madagascar–Seychelles separations appear to coincide with the eruption of the Deccan basalts, whose eruption site may survive as the Réunion hotspot. The Deccan Traps are a Large igneous province located on the Deccan Plateau of west-central India (between 17-24N 73-74E and one of the largest Volcanic The Réunion hotspot is a Volcanic hotspot which currently lies under the Island of Réunion in the Indian Ocean.

Australia began to separate from Antarctica perhaps 80 million years ago (Late Cretaceous), but sea-floor spreading between them became most active about 40 million years ago during the Eocene epoch of the Tertiary Period. The Eocene epoch (558 ± 02 - 339 ± 01 Ma) is a major division of the Geologic timescale and the second epoch of the Palaeogene period in The chuprichondira geological time interval covers roughly the time span between the demise of the non- avian Dinosaurs and beginning of the most recent Ice Age, approximately

New Zealand probably separated from Antarctica between 130 and 85 million years ago. New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island

Cenozoic

As the age of mammals got underway, the continent of Australia-New Guinea began gradually to separate and move north (55 million years ago), rotating about its axis to begin with, and thus retaining some connection with the remainder of Gondwana for about 10 million years. The Cenozoic (also Caenozoic or Cainozoic) Era (ˌsiːnəˈzoʊɪk/ /ˌsɛn- (meaning "new life" ( Greek ( kainos) "new"

About 45 million years ago, the Indian Plate collided with Asia, buckling the crust and forming the Himalayas. The India or Indian Plate is a Tectonic plate that was originally a part of the ancient continent of Gondwanaland from which it split off eventually At about the same time, the southernmost part of Australia (modern Tasmania) finally separated from Antarctica, letting ocean currents flow between the two continents for the first time. Tasmania is an Australian island and state of the same name It is located south of the eastern side of the Continent, being separated from it by Bass Cooler and drier climates developed on both continents because ocean currents enveloping Antarctica were no longer directed into the subtropics, where they would have flowed around northern Australia. The subtropics are the zones of the Earth immediately north and south of the tropic zone which is bounded by the Tropic of Cancer and the Tropic of

Another significant world climatic event was South America separating from West Antarctica some time during the Oligocene, perhaps 30 million years ago. South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a West Antarctica, or Lesser Antarctica is one of the two major regions of Antarctica, lying on the Pacific Ocean side of the Transantarctic Mountains The Oligocene is a geologic epoch of the Paleogene period and extends from about 33 Immediately before this, South America and East Antarctica were not connected directly, but the many microplates of the Antarctic Peninsula remained near southern South America acting as "stepping stones" allowing continued biological interchange and stopped oceanic current circulation. The Antarctic Peninsula is the northernmost part of the mainland of Antarctica, and almost the only part of that continent that extends outside the Antarctic Circle Stepping stone(s can refer to Stones placed across a shallow river to form a Step-stone bridge so people can step from each to the next and so cross the river without But when Drake Passage opened, there was now no barrier to force the cold waters of the Southern Ocean north, to be exchanged with warmer tropical water. 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, The Southern Ocean, also known as the Great Southern Ocean, the Antarctic Ocean and the South Polar Ocean, comprises the southernmost waters of 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 million years ago, 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 effect which drastically changed weather patterns in Australia, drying it out. For the Australian television series see Rain Shadow (TV series.

Later, South America was connected to North America via the Isthmus of Panama, cutting off a circulation of warm water and thereby creating the Arctic. 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 The Arctic is the Region around the Earth 's North Pole, opposite the Antarctic region around the South Pole.

The Red Sea and East African Rift are modern examples of the continuing dismemberment of Gondwana. The Red Sea is a Salt water Inlet of the Indian Ocean between Africa and Asia. The East African Rift is part of the larger Great Rift Valley.

The continent of Gondwana was named by Eduard Suess after an area of India called Gondwana (meaning "Land of the Gonds"), from which the Gondwana sedimentary sequences (Permian-Triassic) are also described. Eduard Suess ( August 20, 1831 London &ndash April 26, 1914 Vienna) was a Geologist who was an expert on the Gondwana is a region of India. Named after the Gondi people who live there (though they can also be found in other parts of India the name of the ancient continent The Gondi (Gōndi are a people in central India. The Gondi or Gond people are spread over the states of Madhya Pradesh, eastern Maharashtra

References

Cattermole, Peter John. Alexander Logie du Toit ("DOO-TOY" ( 14 March 1878 &ndash 25 February 1948) was a Geologist from South Africa Alfred Lothar Wegener ( November 1, 1880 – November 2 or 3 1930 was a German Scientist and Meteorologist. Continental drift is the movement of the Earth 's Continents relative to each other Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere The Australasian zone is an ecological region that is coincident but not synonymous (by some definitions with the geographic Region of Australasia Building Planet Earth: Five Billion Years of Earth History. Cambridge, Cambridge University Press, 2000.
Collins A. S. and Pisarevsky, S. A. 2005 Amalgamating Eastern Gondwana: The evolution of the circum-Indian orogens. Earth Science Reviews, 71, 229–270.
Cowen, Richard. History of Life. London, Blackwell Publishing, 2000.
Lowrie, William. Fundamentals of Geophysics. Cambridge, Cambridge University Press, 1997.
Meert, J. G. , 2003, A synopsis of events related to the assembly of eastern Gondwana, Tectonphysics, 362, 1-40.
Stern, R. J. 1994 Arc Assembly and continental collision in the Neoproterozoic East African orogeny—implications for the consolidation of Gondwana. Annual Reviews of Earth and Planetary Sciences, 22, 319–351.

External links

Dictionary

-proper noun

Southern supercontinent, formed after the break up of Pangaea before the Triassic Period, including most of the landmasses which make up today's continents of the southern hemisphere

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