HOME
The Info List - Gondwana



--- Advertisement ---


(i) (i) (i) (i)

In paleogeography , GONDWANA ( /ɡɒndˈwɑːnə/ ), also GONDWANALAND, is the name given to an ancient supercontinent . It is believed to have sutured about 600 to 530 million years ago , joining East Gondwana
Gondwana
to West Gondwana. Gondwana
Gondwana
formed prior to Pangaea
Pangaea
, and later became part of it.

Around 335 to 250 million years ago , Gondwana
Gondwana
and Laurasia
Laurasia
joined together to form the supercontinent Pangaea, which existed until approximately 215 to 175 million years ago . Gondwana
Gondwana
then separated from Laurasia
Laurasia
(the mid- Mesozoic era ) in the breakup of Pangaea, drifting farther south after the split. Gondwana
Gondwana
itself then also broke apart.

Gondwana
Gondwana
included most of the landmasses in today's Southern Hemisphere , including Antarctica
Antarctica
, South America
South America
, Africa
Africa
, Madagascar
Madagascar
, and the Australian continent , as well as the Arabian Peninsula and the Indian subcontinent
Indian subcontinent
, which have now moved entirely into the Northern Hemisphere
Northern Hemisphere
.

The continent of Gondwana
Gondwana
was named by Austrian scientist Eduard Suess , after the Gondwana
Gondwana
region of central northern India
India
which is derived from Sanskrit
Sanskrit
for "forest of the Gonds ". The name had been previously used in a geological context, first by H.B. Medlicott in 1872, from which the Gondwana
Gondwana
sedimentary sequences (Permian - Triassic
Triassic
) are also described.

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, including the Antarctic flora . For example, the plant family Proteaceae , known only from southern South America, South Africa, Australia, and New Zealand, is considered to have a "Gondwanan distribution". This pattern is often considered to indicate an archaic, or relict , lineage.

CONTENTS

* 1 Formation * 2 Pangaea
Pangaea
* 3 Weather

* 4 Breakup

* 4.1 Mesozoic * 4.2 Cenozoic
Cenozoic

* 5 See also * 6 References * 7 Further reading * 8 External links

FORMATION

Life timeline view • discuss • edit -4500 — – -4000 — – -3500 — – -3000 — – -2500 — – -2000 — – -1500 — – -1000 — – -500 — – 0 — WATER Single-celled life PHOTOSYNTHESIS EUKARYOTES Multicellular life LAND LIFE DINOSAURS MAMMALS FLOWERS ← Earliest Earth
Earth
(−4540 ) ← Earliest water ← Earliest life ← LHB meteorites ← Earliest oxygen ← Atmospheric oxygen ← Oxygen crisis ← Earliest sexual reproduction ← Ediacara biota ← Cambrian explosion
Cambrian explosion
← Earliest humans P h a n e r o z o i c

P r o t e r o z o i c

A r c h e a n H a d e a n Pongola Huronian Cryogenian Andean Karoo Quaternary Axis scale : millions of years . Orange labels: known ICE AGES. Also see: Human
Human
timeline and Nature timeline Eastern Gondwana Orogens and Kuungan Orogens

The assembly of Gondwana
Gondwana
was a protracted process. Several orogenies led to its final amalgamation 550 to 500 million years ago at the end of the Ediacaran
Ediacaran
, and into the Cambrian
Cambrian
. These include the Brasiliano Orogeny , the East African Orogeny , the Malagasy Orogeny , and the Kuunga Orogeny . The final stages of Gondwanan assembly overlapped with the opening of the Iapetus Ocean
Iapetus Ocean
between Laurentia and western Gondwana. During this interval, the Cambrian
Cambrian
explosion occurred.

Gondwana
Gondwana
was formed from the following earlier continents and microcontinents , among others, colliding in the following orogenies:

* Azania : much of central Madagascar
Madagascar
, the Horn of Africa
Africa
and parts of Yemen
Yemen
and Arabia
Arabia
(Named by Collins and Pisarevsky (2005): "Azania" was a Greek name for the East African coast.) * The Congo – Tanzania
Tanzania
Bangweulu Block of central Africa; * Neoproterozoic India: India, the Antongil Block in far eastern Madagascar, the Seychelles
Seychelles
, and the Napier and Rayner Complexes in East Antarctica
Antarctica
* The Australia/Mawson continent: Australia west of Adelaide and a large extension into East Antarctica
Antarctica
* Other blocks which helped to form Argentina
Argentina
and some surrounding regions, including a piece transferred from Laurentia when the west edge of Gondwana
Gondwana
scraped against southeast Laurentia in the Ordovician . This is the Famatinian block (named after Famatina in northwest Argentina) and it formerly continued the line of the Appalachians southwards.

Reconstruction showing final stages of assembly of Gondwana, 550 Mya

One of the major sites of Gondwanan amalgamation was the East African Orogeny (Stern, 1994), where these two major orogenies are superimposed. The East African Orogeny at about 650–630 Mya affected a large part of Arabia, north-eastern Africa, East Africa, and Madagascar
Madagascar
. Collins and Windley (2002) propose that in this orogeny, Azania collided with the Congo – Tanzania
Tanzania
–Bangweulu Block.

The later Malagasy orogeny at about 550–515 Mya affected Madagascar, eastern East Africa
Africa
and southern India. In it, Neoproterozoic India
India
collided with the already combined Azania and Congo–Tanzania–Bangweulu Block, suturing along the Mozambique Belt .

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

PANGAEA

Other large continental masses, including the core cratons of North America (the Canadian Shield
Canadian Shield
or Laurentia), Europe
Europe
( Baltica
Baltica
), and Siberia
Siberia
, were added over time to form the supercontinent Pangaea
Pangaea
by Permian
Permian
time. When Pangaea
Pangaea
broke up (mostly during the Jurassic
Jurassic
), two large masses, Gondwana
Gondwana
and Laurasia, were formed.

The reformed Gondwanan continent was not precisely the same as that which had existed before Pangaea
Pangaea
formed; for example, most of Florida and southern Georgia and Alabama
Alabama
is underlain by rocks that were originally part of Gondwana, but this region stayed attached to North America when Pangaea
Pangaea
broke apart.

WEATHER

During the late Paleozoic , Gondwana
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 , the world was on average considerably warmer than it is today. Gondwana
Gondwana
was then host to a huge variety of flora and fauna for many millions of years. The laurel forest of Australia, New Caledonia
New Caledonia
, and New Zealand
New Zealand
have a number of other related species of the laurissilva de Valdivia, through the connection of the Antarctic flora as gymnosperms and deciduous angiosperm Nothofagus. Corynocarpus laevigatus is called the bay of New Zealand, Laurelia novae-zelandiae belongs to the same genus Laurelia . The sempervirens tree niaouli grows in Australia, New Caledonia, and New Zealand.

New Caledonia
New Caledonia
and New Zealand
New Zealand
ecoregions became separated from Australia by continental drift 85 million years ago. The islands still retain plants that originated in Gondwana
Gondwana
and spread to the Southern Hemisphere continents later. However, strong evidence exists of glaciation during the Carboniferous
Carboniferous
to Permian
Permian
time, especially in South Africa.

BREAKUP

MESOZOIC

The Nothofagus plant genus illustrates Gondwanan distribution, having descended from the supercontinent and existing in present-day Australia, New Zealand, New Caledonia, and the Southern Cone . Fossils have also recently been found in Antarctica.

Gondwana
Gondwana
began to break up in the early Jurassic
Jurassic
and the early Cretaceous
Cretaceous
(about 184 to 132 million years ago ) accompanied by massive eruptions of basalt lava, as East Gondwana, comprising Antarctica, Madagascar, India, and Australia, began to separate from Africa. South America
South America
began to drift slowly westward from Africa
Africa
as the South Atlantic Ocean opened, beginning about 130 Mya during the Early Cretaceous , and resulting in open marine conditions by 110 Mya. East Gondwana
Gondwana
then began to separate about 120 Mya when India
India
began to move northward.

The Madagascar
Madagascar
block, and a narrow remnant microcontinent presently occupied by the Seychelles
Seychelles
Islands, were broken off India; elements of this breakup nearly coincide with the Cretaceous–Paleogene extinction event . The India–Madagascar– Seychelles
Seychelles
separations appear to coincide with the eruption of the Deccan basalts , whose eruption site may survive as the Réunion hotspot .

Australia began to separate from Antarctica
Antarctica
perhaps 80 Mya (Late Cretaceous), but sea-floor spreading between them became most active about 40 Mya during the Eocene
Eocene
epoch of the Paleogene
Paleogene
Period.

New Zealand
New Zealand
probably separated from Antarctica
Antarctica
between 130 and 85 Mya.

CENOZOIC

As the age of mammals commenced, 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
Gondwana
for about 10 million years.

About 45 Mya, the Indian Plate
Indian Plate
collided with Asia, buckling the crust and forming the Himalayas
Himalayas
. At about the same time, the southernmost part of Australia (modern Tasmania
Tasmania
) finally separated from Antarctica, letting ocean currents flow between the two continents for the first time. Antarctica
Antarctica
became cooler and Australia became drier because ocean currents circling Antarctica
Antarctica
were no longer directed around northern Australia into the subtropics .

The separation of South America
South America
from West Antarctica
Antarctica
some time during the Oligocene
Oligocene
, perhaps 30 Mya, also caused climate changes . Immediately before this separation, South America
South America
and East Antarctica were not connected directly. However, the many microplates of the Antarctic Peninsula
Antarctic Peninsula
remained near southern South America, acting as "stepping stones " and allowing continued biological interchange and stopped oceanic current circulation. When the Drake Passage opened, a barrier was no longer present to force the cold waters of the Southern Ocean to be exchanged with warmer tropical water. Instead, a cold circumpolar current developed and Antarctica
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 effect which drastically changed weather patterns in Australia, drying it out.

Later, South America
South America
was connected to North America
North America
via the Isthmus of Panama , cutting off a circulation of warm water and thereby making the Arctic
Arctic
colder , as well as allowing the Great American Interchange .

The Red Sea
Red Sea
and East African Rift are modern examples of continental rifting.

SEE ALSO

* Continental drift , the movement of the Earth's continents relative to each other * Geology
Geology
of the Australasian ecozone * Gondwana Rainforests of Australia * The Great Escarpment of Southern Africa * Plate tectonics
Plate tectonics
, a theory which describes the large-scale motions of Earth's lithosphere * South Polar dinosaurs , which proliferated during the Early Cretaceous
Cretaceous
(145–100 Mya) while Australia was still linked to Antarctica
Antarctica
to form East Gondwana * Tarkine wilderness

REFERENCES

* ^ "gondwana". Dictionary.com . Lexico Publishing Group. Retrieved 2010-01-18. * ^ "Gondwanaland". Merriam-Webster Online Dictionary . Retrieved 2010-01-18. * ^ A B Buchan, Craig (November 7–10, 2004). Paper No. 207-8 - Linking Subduction Initiation, Accretionary Orogenesis And Supercontinent Assembly. 2004 Denver Annual Meeting. Geological Society of America . Retrieved 2010-01-18. * ^ Houseman, Greg. "Dispersal of Gondwanaland". University of Leeds . Retrieved 21 Oct 2008. * ^ Eduard Suess, Das Antlitz der Erde (The Face of the Earth), vol. 1 (Leipzig, Germany: G. Freytag, 1885), page 768. From p. 768: "Wir nennen es Gondwána-Land, nach der gemeinsamen alten Gondwána-Flora, … " (We name it Gondwána-Land, after the common ancient flora of Gondwána … ) * ^ Rapalini, AE (2001). The Assembly of Southern South America
South America
in the Late Proterozoic and Paleozoic: Some Paleomagnetic Clues. Spring Meeting 2001. American Geophysical Union
American Geophysical Union
. Retrieved 2010-01-18. * ^ Rapalini, AE (1998). "Syntectonic magnetization of the mid-Palaeozoic Sierra Grande Formation: further constraints on the tectonic evolution of Patagonia". Journal of the Geological Society . 155 (1): 105–114. doi :10.1144/gsjgs.155.1.0105 . * ^ http://sp.lyellcollection.org/content/142/1/219.abstract Laurentia- Gondwana
Gondwana
collision: the origin of the Famatinian-Appalachian Orogenic Belt (a review) * ^ Collins, Alan S; Windley, Brian F (May 2002). "The Tectonic Evolution of Central and Northern Madagascar
Madagascar
and Its Place in the Final Assembly of Gondwana". The Journal of Geology
Geology
. 110 (3): 325–339. Bibcode :2002JG....110..325C. doi :10.1086/339535 . * ^ Grantham, G.H.; Maboko, M.; Eglington, B.M. (2003). "A review of the evolution of the Mozambique Belt and implications for the amalgamation and dispersal of Rodinia and Gondwana". Proterozoic East Gondwana: supercontinent assembly and breakup. Geological Society. pp. 417–418. ISBN 1-86239-125-4 . * ^ " Gondwana
Gondwana
Remnants In Alabama
Alabama
And Georgia: Uchee Is An \'Exotic\' Peri-Gondwanan Arc Terrane, Not Part Of Laurentia". ScienceDaily. February 4, 2008. Retrieved 2011-10-22. * ^ H.M. Li and Z.K. Zhou (2007) Fossil nothofagaceous leaves from the Eocene
Eocene
of western Antarctica
Antarctica
and their bearing on the origin, dispersal and systematics of Nothofagus. Science in China. 50(10): 1525-1535. * ^ Encarnación, John; Fleming, Thomas H.; Elliot, David H.; Eales, Hugh V. (1996-06-01). "Synchronous emplacement of Ferrar and Karoo dolerites and the early breakup of Gondwana". Geology. 24 (6): 535–538. ISSN 0091-7613 . doi :10.1130/0091-7613(1996)0242.3.CO;2 . * ^ Luyendyk, B. P., D. Forsyth, and J. D. Phillips (1972). "An experimental approach to the paleocirculation of the oceanic surface waters". Bulletin of the Geological Society of America. 83: 2649–2664. CS1 maint: Multiple names: authors list (link )

FURTHER READING

* Cattermole, Peter John (2000). Building Planet Earth: Five Billion Years of Earth
Earth
History. London: Cambridge University Press
Cambridge University Press
. ISBN 978-0-521-58278-0 . OCLC
OCLC
317422973 . * Collins, Alan S; Pisarevsky, Sergei A (August 2005). "Amalgamating eastern Gondwana: The evolution of the Circum-Indian Orogens". Earth-Science Reviews. 71 (3–4): 229–270. Bibcode :2005ESRv...71..229.. doi :10.1016/j.earscirev.2005.02.004 . * Cowen, Richard (2000). History of Life (3rd ed.). Malden, MA : Blackwell Science . ISBN 978-0-632-04444-3 . OCLC
OCLC
41572551 . * Encarnacion, J; Fleming, Thomas H.; Elliot, David H.; Eales, Hugh V. (1996). "Synchronous emplacement of Ferrar and Karoo dolerites and the early break-up of Gondwana". Geology. 24 (6): 535–538. Bibcode :1996Geo....24..535E. doi :10.1130/0091-7613(1996)0242.3.CO;2 . * Lowrie, William (1997). Fundamentals of Geophysics. Cambridge ; New York: Cambridge University Press. ISBN 978-0-521-46164-1 . OCLC 35651121 . Also ISBN 978-0-521-46728-5 . * Meert, JG (2003-02-06). "A synopsis of events related to the assembly of eastern Gondwana". Tectonophysics. 363 (1): 1–40. Bibcode :2003Tectp.362....1M. doi :10.1016/S0040-1951(02)00629-7 . * Scheffler, K; Hoernes, S; Schwark, L (July 2003). "Global changes during Carboniferous– Permian
Permian
glaciation of Gondwana: Linking polar and equatorial climate evolution by geochemical proxies". Geology
Geology
. 33 (7): 605–608. Bibcode :2003Geo....31..605S. doi :10.1130/0091-7613(2003)0312.0.CO;2 . * Stern, RJ (May 1994). "ARC Assembly and Continental Collision in the Neoproterozoic East African Orogen: Implications for the Consolidation of Gondwanaland". Annual Review of Earth
Earth
and Planetary Sciences . 22: 319–351. Bibcode :1994AREPS..22..319S. doi :10.1146/annurev.ea.22.050194.001535 .

EXTERNAL LINKS

* Animation showing the dispersal of Gondwanaland * Graphical subjects dealing with Tectonics and Paleontology

.