Continental Drift Theory (Alfred Wegener, 1912): Pangea, Panthalassa, Laurasia, Gondwanaland
Geography › Plate Tectonics and Distribution of Continents and Oceans · Topic 4.1
The continental drift theory was put forward by the German scientist Alfred Wegener in 1912. It says that all the continents were once joined in a single huge supercontinent, Pangaea, surrounded by one ocean, Panthalassa, and that Pangaea began to break up about 200 million years ago. It split first into Laurasia in the north and Gondwanaland in the south, and the pieces then drifted to their present positions. The theory was rejected at first because Wegener could not explain the force that moved the continents.
5 min read · UPSC Prelims · Geography · Plate Tectonics and Distribution of Continents and Oceans
At a Glance
- Proposed by Alfred Wegener, 1912
- Supercontinent Pangaea, with the ocean Panthalassa
- First split Laurasia (north) and Gondwanaland (south)
- Breakup began About 200 million years ago
- Weak point No convincing driving force
- Exam link UPSC Prelims, Geography: Plate Tectonics and Distribution of Continents and Oceans
Where Does It Fit?
This is the first topic of the macro on plate tectonics. It begins with the older idea of drifting continents, which was later explained by sea-floor spreading and plate tectonics. The topics that follow give the evidence, the proposed forces and the modern theory. Previous topic: Plateaus: Formation, Types (Dissected, Volcanic), Economic Significance, Major Plateaus of the World. Next topic: Evidence for Continental Drift: Jigsaw Fit, Matching Rock Ages, Tillite, Placer Deposits, Fossil Distribution.
What Is the Continental Drift Theory?
In short: Wegener argued that the continents were once one landmass that broke apart and drifted to their present positions.
The idea that the continents fit together like a jigsaw had been noticed by earlier thinkers, but the German meteorologist Alfred Wegener put it forward as a full theory in 1912 and published it in his book on the origin of continents and oceans in 1915. According to him, all the continents formed a single huge landmass called Pangaea, meaning all earth, which was surrounded by a vast ocean called Panthalassa, meaning all water. About 200 million years ago Pangaea began to split. It first broke into two large landmasses: Laurasia in the north, which included North America, Europe and most of Asia, and Gondwanaland in the south, which included South America, Africa, India, Australia and Antarctica. The Tethys Sea lay between them. These then fragmented and drifted into their present positions. The ocean floor and the continents therefore were not fixed, which was a radical idea at the time.
How Did Pangaea Break Up?
| Time (approximate) | Event |
|---|---|
| About 300 million years ago | Nearly all land joined as Pangaea, surrounded by the Panthalassa ocean; the Tethys Sea cut into it from the east |
| About 200 million years ago | Pangaea began to split into Laurasia (North America, Europe and Asia) in the north and Gondwanaland in the south |
| About 130 to 120 million years ago | Gondwanaland breaks: South America separates from Africa, and the South Atlantic opens; India separates from Antarctica and Australia |
| About 66 million years ago | India moves north across the Tethys; the North Atlantic widens |
| About 50 million years ago | India collides with Asia and the Himalaya begin to rise; Australia separates from Antarctica |
The southern supercontinent was named Gondwanaland after the Gondwana region of central India, where the rocks and fossils that point to the former union were first studied. The Tethys Sea, which once lay between Laurasia and Gondwanaland, closed as Africa and India moved north, and the Mediterranean is a remnant of it.
Who Was Alfred Wegener and What Did He Say?
Alfred Wegener (1880-1930) was a German meteorologist and geophysicist. He first presented his ideas in 1912 and published them in the work The Origin of Continents and Oceans in 1915; the English edition of 1922 spread them widely. His main points were these.
- One land mass: all continents were once joined in a single supercontinent, Pangaea, which means ‘all earth’.
- Drift: continents are lighter blocks of sial that plough through the heavier sima of the ocean floor, and have moved apart over geological time.
- Proof: the fit of coastlines, rocks, fossils and ancient climates across the oceans, as in Evidence for Continental Drift: Jigsaw Fit, Matching Rock Ages, Tillite, Placer Deposits, Fossil Distribution.
- Forces: he proposed the pole-fleeing force and the tidal force, which were too weak, as in Forces of Drifting: Pole-Fleeing Force, Tidal Force.
Wegener died on an expedition to the Greenland ice sheet in 1930, before his idea was accepted.
What Was the Lasting Contribution?
New data from the ocean floor in the 1950s and 1960s, including mapping of mid-ocean ridges and the study of paleomagnetism, revived the idea in a stronger form. The seafloor spreading theory, covered in Convectional Current Theory and Mapping of the Ocean Floor, showed that the ocean floor, and not just the continents, is in motion. This led to the unifying theory of plate tectonics, in Plate Tectonics: Major and Minor Lithospheric Plates. Wegener’s central idea, that continents have moved, was proved correct, but the explanation is now that continents are carried along on plates, rather than ploughing through the ocean floor on their own.
Why Is This Topic Important?
- Foundation Precursor to plate tectonics
- Evidences Frequent Prelims theme
- India Gondwana link
What Came Next?
The next topic sets out the evidence that Wegener and later scientists gave in support of continental drift. Next topic: Evidence for Continental Drift: Jigsaw Fit, Matching Rock Ages, Tillite, Placer Deposits, Fossil Distribution.
Key People and Terms
- Pangaea Single supercontinent
- Panthalassa Ocean around Pangaea
- Laurasia Northern landmass
- Gondwanaland Southern landmass
- Tillite Rock formed from glacial deposits
- Glossopteris Fossil seed fern of Gondwana
Exam Corner
Points to Remember
- Proposed by Alfred Wegener in 1912.
- Pangaea began to split about 200 million years ago.
- Laurasia in the north, Gondwanaland in the south.
- Forces: pole-fleeing and tidal.
- Evidence included Glossopteris and tillite.
Do Not Confuse With
- Pangaea and Panthalassa Land versus ocean
- Laurasia and Gondwanaland North versus south
- Continental drift and plate tectonics Continents moving alone versus carried on plates
Memory Hook
One land, one sea; two pieces, many parts; fit, fossils, ice and rock, but no force to push.
Mains Angle
Questions ask for evidence and limitations. These points add depth.
- Evidence Fit, fossils, glaciation
- Limitation No adequate mechanism
- Legacy Led to seafloor spreading
A Question You May Face
An original practice question, not a past paper question.
“Critically examine Wegener’s theory of continental drift and the evidence for it.”
How to Answer
- Theory Pangaea and its breakup.
- Evidence Fit, fossils, rocks.
- Criticism Forces too weak.
- Legacy Plate tectonics.
GS Relevance
Frequently Asked Questions
Who proposed the continental drift theory?
The continental drift theory was proposed by the German meteorologist Alfred Wegener in 1912 and described in his 1915 book. It states that the continents were once a single landmass, Pangaea, that split and drifted to their present positions.
What are Pangaea and Panthalassa?
Pangaea was the single supercontinent that included all the landmasses of the Earth, and Panthalassa was the vast ocean that surrounded it. Pangaea began to break up about 200 million years ago into Laurasia in the north and Gondwanaland in the south.
What is the evidence for continental drift?
The evidence includes the jigsaw fit of the coasts of South America and Africa, matching rock belts across the Atlantic, the same fossils such as Mesosaurus and Glossopteris on separated continents, tillite deposits of a common ice age, and coal in Antarctica.
What forces did Wegener suggest for drift?
Wegener suggested two forces: the pole-fleeing force, arising from the Earth's rotation and the equatorial bulge, and the tidal force, the pull of the Moon and the Sun. Scientists later found that both were far too weak to move the continents.
Why was the continental drift theory not accepted?
The theory was not accepted because Wegener could not give a force strong enough to move continents through the ocean floor. The lack of a convincing mechanism overshadowed the evidence, and acceptance came only after seafloor spreading and plate tectonics were developed.
PYQ Practice — Statement Analysis
1 Wegener proposed that the continents were once joined as a single mass called Pangaea.
He proposed it in 1912.
2 Gondwanaland included North America and Europe.
It included the southern continents and India.
3 Glossopteris fossils support the idea of continental drift.
They occur on separated southern continents.
4 Wegener's forces were considered more than enough to move continents.
They were far too weak.
Past Mains Questions on This Topic
This topic comes under Plate Tectonics and Distribution of Continents and Oceans. UPSC Mains questions asked on the matching syllabus topic, year-wise with marks:
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