Pangaea

Also called: Pangea · Topic: Continental Drift, Sea-floor Spreading and Plate Tectonics · NCERT: Class 11, Ch 4 "Distribution of Oceans and Continents"

Meaning

Pangaea (also spelt Pangea; Greek for "all earth") was the single supercontinent (a very large landmass made of all or most continents joined together) that Alfred Wegener said once held all the landmasses. It was surrounded by one huge ocean, Panthalassa ("all water"). It began to break up about 200 million years ago, first into Laurasia in the north and Gondwanaland in the south.

• Pangaea is the starting point of Wegener's continental drift theory (1912). Today's continents are its broken pieces.
• It explains why India shares rocks, coal and fossils with Africa, Australia and Antarctica, and why the Himalayas rose.

Explanation

Wegener's idea and its timing

• Alfred Wegener (1880-1930) was a German meteorologist (a scientist who studies weather and climate). He first trained as an astronomer and was also a geophysicist [3][4].
• In 1912 he said that all continents were once one landmass. It broke up, and the pieces slowly drifted to where they are now.
• Continental drift means the slow, sideways movement of continents across the earth's surface over millions of years.

• He explained the theory in detail in his book The Origin of Continents and Oceans (1915) [5].

• When Pangaea existed:

• Wegener thought it existed from about 350 to 245 million years ago [5].
• It was fully put together by the Early Permian period, about 299 to 273 million years ago [5].
• It began to break up about 200 million years ago. USGS gives a range of 225 to 200 million years ago [2].

Parts: Pangaea and Panthalassa

Name	Meaning	What it was	Present-day trace
Pangaea	"all earth"	One supercontinent	Today's continents
Panthalassa	"all water"	One huge ocean (mega-ocean) around Pangaea	The Pacific Ocean is thought to be what is left of it

The break-up, step by step

• Step 1: Pangaea starts to split (about 200 million years ago).
• Step 2: Two large landmasses form.
• Laurasia (north) later became North America, Europe and most of Asia, but not India.
• Gondwanaland (south) later became South America, Africa, Madagascar, India, Australia and Antarctica.

• The South African geologist Alexander Du Toit, a strong supporter of Wegener, developed this two-part model [2].

• Step 3: The Tethys Sea opens between them. It was a long, narrow sea. Sediments (mud, sand and other material laid down in layers) collected in it and were later pushed up to form the Himalayas.

• Step 4: Both landmasses keep breaking up into the continents we know today.
• India broke away from Gondwana, where Africa had been its neighbour, and moved north towards Asia.

Proof that Pangaea existed

• Jigsaw fit: the east coast of South America (the bulge of Brazil) fits the west coast of Africa (the Gulf of Guinea), and the rock layers on both sides match [2][3].
• Glossopteris (an extinct seed plant) is found in India, Australia, South America, Africa and Antarctica. One plant could not have spread across seas and such different climates unless these lands were joined [2][3].
• Mesosaurus (a small freshwater reptile) is found only in southern Africa and South America. A freshwater animal could not swim across the Atlantic [3].
• Coal (made from tropical plants) is found in Antarctica, so Antarctica once lay nearer the equator [2].
• Glacial deposits (material left behind by ice sheets) in the Vaal River valley, South Africa show that these lands were once near the South Pole [2].

Why it was doubted, and the later correction

• No mechanism: Wegener could not explain what force was strong enough to push whole continents [2][3].

• Harold Jeffreys argued that solid continental rock could not plough through the ocean floor without breaking up [2].

• Accepted in the 1960s: by then sea-floor spreading (new ocean floor forming at mid-ocean ridges and moving outwards on both sides) had been shown through the work of Harry Hess and the ocean-floor maps of Marie Tharp [3].

• Pangaea was not the first supercontinent. It was itself made when older continental masses came together.
• Continents join and split again and again. This is called the supercontinent cycle [5].
• Rodinia existed about 1 billion years ago and began to break up more than 700 million years ago [3][5].

Where it occurs

• Atlantic coasts: South America–Africa and North America–Europe face each other like two halves of a jigsaw.
• India – Gond region of central India: Gondwanaland is named after it. Its rocks and fossils match those of Africa, South America, Australia and Antarctica.
• Gondwana Supergroup of India: a thick group of rock layers that holds India's main coal, refractory clays (clays that can stand very high heat) and coal bed methane (natural gas trapped in coal seams) [6].

• These rocks lie unconformably on much older Proterozoic rocks. This means there is a time gap between the two layers [6].

• Marine Gondwana Fossil Park, Manendragarh (district Sarguja, Chhattisgarh): sea fossils from the Permian period (280-240 million years ago) in the Talchir Formation [6].

• Jharkhand coal mines: fossils of at least 14 species of Glossopteris and its close relatives. The first-ever juvenile male cone of Glossopteris was found in the Damodar Basin [7].
• Vaal River valley, South Africa: glacial deposits in what is now a warm, dry area [2].
• Antarctica: coal deposits [2].
• Pacific Ocean: regarded as what is left of Panthalassa.

Don't confuse with

• Panthalassa: the single ocean ("all water") around Pangaea. Pangaea was the land ("all earth").
• Gondwanaland: the southern part that formed when Pangaea split. It included India. As a southern supercontinent, it also existed before Pangaea, from about 600-550 million years ago to 180 million years ago [3].
• Laurasia: the northern part (North America, Europe, most of Asia). It did not include India, even though India is in Asia today.
• Rodinia: an older supercontinent from about 1 billion years ago [3][5]. Pangaea came much later, in the Early Permian.

Prelims Hooks

• Pangaea = "all earth"; Panthalassa = "all water". The Pacific is regarded as what is left of Panthalassa.
• Pangaea began to break up about 200 million years ago (USGS: 225-200 million years ago) [2]. It split into Laurasia (north) and Gondwanaland (south), with the Tethys Sea between them.
• Trap: Wegener was a meteorologist, not a geologist by training. He gave his theory in 1912, wrote his book in 1915 and died in Greenland in 1930 [2][3]. The jigsaw idea was first suggested by Abraham Ortelius in 1596, not Wegener [2].
• Trap: India belonged to Gondwanaland, not Laurasia. Gondwanaland is named after the Gond region of central India.
• Fossil proof: Glossopteris (plant) is found across India, Australia, South America, Africa and Antarctica. Mesosaurus (freshwater reptile) is found only in southern Africa and South America [2][3].
• Order (oldest → youngest): Rodinia → Gondwana → Pangaea → Laurasia and Gondwanaland → today's continents.

Mains Points

• How the idea grew (GS-I): it started as a guess from maps (Ortelius, 1596).
• Wegener (1912) backed it with proof: the coastline fit, matching rocks, fossils (Glossopteris, Mesosaurus) and signs of old climates (coal in Antarctica, glacial deposits in South Africa).

• He failed only on the mechanism. Sea-floor spreading (Hess, 1960s) and plate tectonics later supplied it [3]. This shows how science corrects itself.

• Why it matters for India (GS-I / GS-III): India was part of Gondwanaland.

• India's main coal lies in Gondwana rocks in old river basins such as the Damodar [6][7].
• India shares rocks and fossils with Africa, Antarctica and Australia.

• India moved north and hit Asia. This closed the Tethys Sea and raised the Himalayas.

• Continents are not fixed: Pangaea was built from older blocks such as Rodinia, and continents are still moving today [5].

• The shapes of oceans, mountain belts, where earthquakes happen and where minerals are found all come from this long cycle of joining and splitting.

Related concepts

• Abraham Ortelius
• Alfred Wegener
• Continental drift theory
• Panthalassa
• Laurasia
• Gondwanaland

Read more

• Continental drift: Wegener, Pangaea and the break-up