PANGAEA or PANGEA ( /pænˈdʒiːə/ ) was a supercontinent that
existed during the late
Paleozoic and early
Mesozoic eras. It
assembled from earlier continental units approximately 335 million
years ago, and it began to break apart about 175 million years ago.
In contrast to the present
Earth and its distribution of continental
mass, much of
Pangaea was in the southern hemisphere and surrounded by
Pangaea was the most recent supercontinent
to have existed and the first to be reconstructed by geologists.
* 1 Origin of the concept
* 2 Formation
* 3 Evidence of existence
* 4 Rifting and break-up
* 5 Tectonic plate shift
* 6 Life
* 7 Climate change after
* 8 Implications of extinction
* 9 See also
* 10 References
* 11 External links
ORIGIN OF THE CONCEPT
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 ←
Earth (−4540 ) ← Earliest water ← Earliest
life ← LHB meteorites ← Earliest oxygen ←
Atmospheric oxygen ← Oxygen crisis ← Earliest sexual
reproduction ← Ediacara biota ←
← Earliest humans P
n Pongola Huronian
Cryogenian Andean Karoo Quaternary
Axis scale : millions of years .
Orange labels: known _ICE AGES_.
Also see: _
Human timeline _ and _Nature timeline _
The name "Pangaea/Pangea" is derived from
Ancient Greek _pan_
(πᾶν, "all, entire, whole") and _Gaia _ (Γαῖα, "Mother Earth
, land"). The concept that the continents once formed a continuous
land mass was first proposed by
Alfred Wegener , the originator of the
theory of continental drift , in his 1912 publication _The Origin of
Continents_ (_Die Entstehung der Kontinente_). He expanded upon his
hypothesis in his 1915 book _The Origin of Continents and Oceans_
(_Die Entstehung der Kontinente und Ozeane_), in which he postulated
that, before breaking up and drifting to their present locations, all
the continents had formed a single supercontinent that he called the
The name "Pangea" occurs in the 1920 edition of _Die Entstehung der
Kontinente und Ozeane_, but only once, when Wegener refers to the
ancient supercontinent as "the
Pangaea of the Carboniferous". Wegener
used the Germanized form "Pangäa", but the name entered German and
English scientific literature (in 1922 and 1926, respectively) in the
Latinized form "Pangaea" (of the Greek "Pangaia"), especially due to a
symposium of the American Association of Petroleum Geologists in
The forming of supercontinents and their breaking up appears to have
been cyclical through Earth's history. There may have been many others
before Pangaea. The fourth-last supercontinent, called Columbia or
Nuna, appears to have assembled in the period 2.0–1.8 Ga.
Columbia/Nuna broke up and the next supercontinent,
Rodinia , formed
from the accretion and assembly of its fragments.
Rodinia lasted from
about 1.1 billion years ago (Ga) until about 750 million years ago,
but its exact configuration and geodynamic history are not nearly as
well understood as those of the later supercontinents,
Rodinia broke up, it split into three pieces: the supercontinent
Proto-Laurasia , the supercontinent of
Proto-Gondwana , and the
Congo craton .
separated by the
Proto-Tethys Ocean . Next
Proto-Laurasia itself split
apart to form the continents of
Baltica moved to the east of Laurentia, and
Siberia moved northeast of
Laurentia. The splitting also created two new oceans, the Iapetus
Ocean and Paleoasian Ocean . Most of the above masses coalesced again
to form the relatively short-lived supercontinent of
Pannotia . This
supercontinent included large amounts of land near the poles and, near
the equator, only a relatively small strip connecting the polar
Pannotia lasted until 540 Ma, near the beginning of the
Cambrian period and then broke up, giving rise to the continents of
Baltica , and the southern supercontinent of
Cambrian period, the continent of
Laurentia , which would
North America , sat on the equator , with three bordering
Panthalassic Ocean to the north and west, the Iapetus
Ocean to the south and the
Khanty Ocean to the east. In the Earliest
Ordovician , around 480 Ma, the microcontinent of
Avalonia – a
landmass incorporating fragments of what would become eastern
Newfoundland , the southern
British Isles , and parts of
Nova Scotia ,
New England , South Iberia and
Africa – broke free from
Gondwana and began its journey to
Laurentia . Baltica, Laurentia, and
Avalonia all came together by the
end of the
Ordovician to form a minor supercontinent called Euramerica
or Laurussia, closing the Iapetus Ocean. The collision also resulted
in the formation of the northern
Siberia sat near
Euramerica, with the
Khanty Ocean between the two continents. While
all this was happening,
Gondwana drifted slowly towards the South
Pole. This was the first step of the formation of Pangaea.
The second step in the formation of
Pangaea was the collision of
Euramerica . By
Silurian time, 440 Ma,
already collided with Laurentia, forming Euramerica.
Avalonia had not
yet collided with
Laurentia , but as
Avalonia inched towards
Laurentia, the seaway between them, a remnant of the
Iapetus Ocean ,
was slowly shrinking. Meanwhile, southern
Europe broke off from
Gondwana and began to move towards
Euramerica across the newly formed
Rheic Ocean . It collided with southern
Baltica in the
though this microcontinent was an underwater plate. The Iapetus
Ocean's sister ocean, the Khanty Ocean, shrank as an island arc from
Siberia collided with eastern
Baltica (now part of Euramerica). Behind
this island arc was a new ocean, the
Ural Ocean .
Silurian time, North and South China split from
started to head northward, shrinking the
Proto-Tethys Ocean in their
path and opening the new
Paleo-Tethys Ocean to their south. In the
Gondwana itself headed towards Euramerica, causing
Rheic Ocean to shrink. In the Early
Carboniferous , northwest
Africa had touched the southeastern coast of
Euramerica , creating the
southern portion of the
Appalachian Mountains , the Meseta Mountains
and the Mauritanide Mountains .
South America moved northward to
southern Euramerica, while the eastern portion of
Australia ) headed toward the South Pole from the
equator . North and South China were on independent continents. The
Kazakhstania microcontinent had collided with
Siberia . (
been a separate continent for millions of years since the deformation
of the supercontinent
Pannotia in the Middle Carboniferous.)
Kazakhstania collided with
Baltica in the Late Carboniferous,
Ural Ocean between them and the western Proto-Tethys in
Uralian orogeny ), causing the formation of not only the Ural
Mountains but also the supercontinent of Laurasia. This was the last
step of the formation of Pangaea. Meanwhile,
South America had
collided with southern
Laurentia , closing the
Rheic Ocean and forming
the southernmost part of the
Ouachita Mountains . By
Gondwana was positioned near the South Pole and glaciers
were forming in Antarctica, India, Australia, southern
South America. The
North China block collided with
Siberia by Late
Carboniferous time, completely closing the Proto-Tethys Ocean.
Permian time, the
Cimmerian plate split from
headed towards Laurasia, thus closing the
Paleo-Tethys Ocean , but
forming a new ocean, the
Tethys Ocean , in its southern end. Most of
the landmasses were all in one. By the
Triassic Period, Pangaea
rotated a little and the
Cimmerian plate was still travelling across
the shrinking Paleo-Tethys, until the
Middle Jurassic time. The
Paleo-Tethys had closed from west to east, creating the Cimmerian
Orogeny . Pangaea, which looked like a _C_, with the new Tethys Ocean
inside the _C_, had rifted by the Middle Jurassic, and its deformation
is explained below.
EVIDENCE OF EXISTENCE
The distribution of fossils across the continents is one line of
evidence pointing to the existence of Pangaea.
Fossil evidence for
Pangaea includes the presence of similar and
identical species on continents that are now great distances apart.
For example, fossils of the therapsid _
Lystrosaurus _ have been found
Antarctica , alongside members of the
Glossopteris _ flora, whose distribution would have ranged from the
polar circle to the equator if the continents had been in their
present position; similarly, the freshwater reptile _
Mesosaurus _ has
been found in only localized regions of the coasts of
Brazil and West
Additional evidence for
Pangaea is found in the geology of adjacent
continents, including matching geological trends between the eastern
South America and the western coast of
Africa . The polar ice
cap of the
Carboniferous Period covered the southern end of Pangaea.
Glacial deposits, specifically till , of the same age and structure
are found on many separate continents which would have been together
in the continent of Pangaea.
Paleomagnetic study of apparent polar wandering paths also support
the theory of a supercontinent. Geologists can determine the movement
of continental plates by examining the orientation of magnetic
minerals in rocks; when rocks are formed, they take on the magnetic
properties of the
Earth and indicate in which direction the poles lie
relative to the rock. Since the magnetic poles drift about the
rotational pole with a period of only a few thousand years,
measurements from numerous lavas spanning several thousand years are
averaged to give an apparent mean polar position. Samples of
sedimentary rock and intrusive igneous rock have magnetic orientations
that are typically an average of the "secular variation" in the
orientation of magnetic north because their remanent magnetizations
are not acquired instantaneously. Magnetic differences between sample
groups whose age varies by millions of years is due to a combination
of true polar wander and the drifting of continents. The true polar
wander component is identical for all samples, and can be removed,
leaving geologists with the portion of this motion that shows
continental drift and can be used to help reconstruct earlier
The continuity of mountain chains provides further evidence for
Pangaea. One example of this is the
Appalachian Mountains chain which
extends from the southeastern
United States to the
Ireland, Britain, Greenland, and Scandinavia.
RIFTING AND BREAK-UP
Animation of the rifting of
There were three major phases in the break-up of Pangaea. The first
phase began in the Early -
Middle Jurassic (about 175 Ma), when Pangaea
began to rift from the
Tethys Ocean in the east to the
Pacific in the
west. The rifting that took place between
North America and Africa
produced multiple failed rifts . One rift resulted in a new ocean, the
Atlantic Ocean .
Atlantic Ocean did not open uniformly; rifting began in the
north-central Atlantic. The
South Atlantic did not open until the
Laurasia started to rotate clockwise and moved
North America to the north, and
Eurasia to the south.
The clockwise motion of
Laurasia led much later to the closing of the
Tethys Ocean . Meanwhile, on the other side of
Africa and along the
adjacent margins of east Africa,
Madagascar , new rifts
were forming that would lead to the formation of the southwestern
Indian Ocean that would open up in the Cretaceous.
The second major phase in the break-up of
Pangaea began in the Early
Cretaceous (150–140 Ma), when the minor supercontinent of Gondwana
separated into multiple continents (Africa, South America, India,
Antarctica, and Australia). The subduction at
Tethyan Trench probably
Australia to move northward, causing the
opening of a "South Indian Ocean". In the Early Cretaceous, Atlantica
South America and Africa, finally separated from eastern
India and Australia). Then in the Middle
Gondwana fragmented to open up the South
Atlantic Ocean as
South America started to move westward away from Africa. The South
Atlantic did not develop uniformly; rather, it rifted from south to
Also, at the same time,
India began to separate from
Antarctica and moved northward, opening up the Indian Ocean.
India separated from each other 100–90 Ma in the Late
India continued to move northward toward
Eurasia at 15
centimeters (6 in) a year (a plate tectonic record), closing the
eastern Tethys Ocean, while
Madagascar stopped and became locked to
African Plate .
New Zealand ,
New Caledonia and the rest of
Zealandia began to separate from Australia, moving eastward toward the
Pacific and opening the
Coral Sea and
Tasman Sea .
The third major and final phase of the break-up of
in the early
Laurasia split when
North America/Greenland (also called
Laurentia ) broke free from
Eurasia, opening the
Norwegian Sea about 60–55 Ma. The Atlantic and
Indian Oceans continued to expand, closing the Tethys Ocean.
Australia split from
Antarctica and moved quickly
northward, just as
India had done more than 40 million years before.
Australia is currently on a collision course with eastern
Asia . Both
India are currently moving northeast at 5–6
centimeters (2–3 in) a year.
Antarctica has been near or at the
South Pole since the formation of
Pangaea about 280 Ma.
to collide with
Asia beginning about 35 Ma, forming the Himalayan
orogeny , and also finally closing the Tethys Seaway ; this collision
continues today. The
African Plate started to change directions, from
west to northwest toward
Europe , and
South America began to move in a
northward direction, separating it from
Antarctica and allowing
complete oceanic circulation around
Antarctica for the first time.
This motion, together with decreasing atmospheric carbon dioxide
concentrations, caused a rapid cooling of
Antarctica and allowed
glaciers to form. This glaciation eventually coalesced into the
kilometers-thick ice sheets seen today. Other major events took place
Cenozoic , including the opening of the Gulf of California
, the uplift of the
Alps , and the opening of the
Sea of Japan . The
Pangaea continues today in the
Red Sea Rift and East
African Rift .
TECTONIC PLATE SHIFT
The breakup of
Pangaea over time
Pangaea's formation is now commonly explained in terms of plate
tectonics . The involvement of plate tectonics in Pangaea's
separation helps to show how it did not separate all at once, but at
different times, in sequences. Additionally, after these separations,
it has also been discovered that the separated land masses may have
also continued to break apart multiple times. The formation of each
environment and climate on
Pangaea is due to plate tectonics, and
thus, it is as a result of these shifts and changes different climatic
pressures were placed on the life on Pangaea. Although plate tectonics
was paramount in the formation of later land masses, it was also
essential in the placement, climate, environments, habitats, and
overall structure of Pangaea.
What can also be observed in relation to tectonic plates and Pangaea,
is the formations to such plates. Mountains and valleys form due to
tectonic collisions as well as earthquakes and chasms.
Consequentially, this shaped
Pangaea and animal adaptations .
Furthermore, plate tectonics can contribute to volcanic activity ,
which is responsible for extinctions and adaptations which have
evidently affected life over time, and without doubt on Pangaea.
Example of an ammonite
For the approximately 160 million years
Pangaea existed, many species
had fruitful times whereas others struggled. The
an example of such prospering animals, eating a diet of only plants.
Plants dependent on spore reproduction had been taken out of the
ecosystems , and replaced by the gymnosperm plant, which reproduces
through the use of seeds instead. Later on, insects (beetles,
dragonflies, mosquitos) also thrived during the
Permian period 299 to
252 million years ago. However, the
Permian extinction at 252 Mya
greatly impacted these insects in mass extinction, being the only mass
extinction to affect insects. When the
Triassic Period came, many
reptiles were able to also thrive, including Archosaurs, which were an
ancestor to modern-day crocodiles and birds.
Little is known about marine life during the existence of Pangaea.
Scientists are unable to find substantial evidence or fossilized
remains in order to assist them in answering such questions. However,
a couple of marine animals have been determined to have existed at the
time- the Ammonites and Brachiopods . Additionally, evidence pointing
towards massive reefs with varied ecosystems, especially in the
species of sponges and coral, have also been discovered.
CLIMATE CHANGE AFTER PANGAEA
Pangaea has tremendously affected the setup of the world now. We live
in a post
Pangaea time period where the reconfiguration of continents
and oceans has changed the climate of many areas. There is scientific
evidence that proves that climate was drastically altered. When the
continents separated and reformed themselves, it changed the flow of
the oceanic currents and winds. The scientific reasoning behind all of
the changes is Continental Drift . The theory of Continental Drift,
Alfred Wegener , explained how the continents shifted
Earth’s surface and how that affected many aspects such as climate,
rock formations found on different continents and plant and animal
fossils. Wegener studied plant fossils from the frigid Arctic of
Norway . He determined that such plants were not meant to
adapt to a glacial climate. The fossils he found were from tropical
plants that were meant to adapt and thrive in warmer and tropical
climate. Because we would not assume that the plant fossils were
capable of traveling to a different place we suspect that Svalbard
possibly had a warmer, less frigid climate in the past.
Pangaea separated, the reorganization of the continents changed
the function of the oceans and seaways. The restructuring of the
continents, changed and altered the distribution of warmth and
coolness of the oceans. When
North America and South America
connected, it stopped equatorial currents from passing from the
Atlantic Ocean to the
Pacific Ocean. Researchers have found evidence
by using computer hydrological models to show that this strengthened
the Gulf Stream by diverting more warm currents towards Europe. Warm
waters at high latitudes led to an increased evaporation and
eventually atmospheric moisture. Increased evaporation and atmospheric
moisture resulted in increased precipitation. Evidence of increased
precipitation is the development of snow and ice that covers
Greenland, which led to an accumulation of the icecap. Greenland’s
growing ice cap led to further global cooling . Scientists also found
evidence of global cooling through the separation of
Antarctica and the formation of the Antarctic Ocean. Ocean currents in
the newly formed Antarctic or Southern Ocean created a circumpolar
current. The creation of the new ocean that caused a circumpolar
current eventually led to atmospheric currents that rotated from west
to east. Atmospheric and oceanic currents stopped the transfer of
warm, tropical air and water to the higher latitudes. As a result of
the warm air and currents moving northward,
Antarctica cooled down so
much that it became frigid.
Although many of Alfred Wegener’s theories and conclusions were
valid, scientists are constantly coming up with new innovative ideas
or reasoning behind why certain things happen. Wegener’s theory of
Continental Drift was later replaced by the theory of tectonic plates
IMPLICATIONS OF EXTINCTION
There is evidence to suggest that the deterioration of northern
Pangaea contributed to the
Permian Extinction , one of Earth’s five
major mass extinction events, which resulted in the loss of over 90%
of marine and 70% of terrestrial species. There were three main
sources of environmental deterioration which are believed to have had
a hand in the extinction event.
The first of these sources is a loss of oxygen concentration in the
ocean which caused deep water regions called the lysocline to grow
shallower. With the lysocline shrinking, there were fewer places for
calcite to dissolve in the ocean, considering calcite only dissolves
at deep ocean depths. This led to the extinction of carbonate
producers such as brachiopods and corals that relied on dissolved
calcite to survive. The second source is the eruption of the Siberian
Traps , a large volcanic event which is argued to be the result of
Pangaean tectonic movement. This had several negative repercussions
on the environment, including metal loading and excess atmospheric
carbon. Metal loading, the release of toxic metals from volcanic
eruptions into the environment, led to acid rain and general stress on
the environment. These toxic metals are known to infringe on vascular
plants ’ ability to photosynthesize , which may have resulted in the
loss of Permian-era flora. Excess carbon dioxide in the atmosphere is
believed to be the main cause of the shrinking of lysocline areas.
The third cause of this extinction event that can be attributed to
Pangaea is the beginnings of anoxic ocean environments, or
oceans with very low oxygen concentrations. The mix of anoxic oceans
and ocean acidification due to metal loading led to increasingly
acidic oceans, which ultimately led to the extinction of benthic
North America portal
South America portal
* History of the
List of supercontinents
* Potential future supercontinents:
Pangaea Ultima ,
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