hypothesis continental drift meaning

Continental Drift: The groundbreaking theory of moving continents

Continental drift theory introduced the idea of moving continents.

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Continental drift was a revolutionary theory explaining that continents shift position on Earth's surface. The theory was proposed by geophysicist and meteorologist Alfred Wegener in 1912, but was rejected by mainstream science at the time. Scientists confirmed some of Wegener's ideas decades later, which are now part of the widely accepted theory of plate tectonics .

Wegener's continental drift theory introduced the idea of moving continents to geoscience. He proposed that Earth must have once been a single supercontinent before breaking up to form several different continents. This explained how similar rock formations and plant and animal fossils could exist on separated continents. Modern science recognizes this ancient supercontinent called Pangaea did exist before breaking up about 200 million years ago, as Wegener theorized. 

Related: Massive supercontinent will form hundreds of millions of years from now  

Why did scientists reject Wegener's continental drift theory?

Geologists roundly denounced Wegener's continental drift theory after he published the details in a 1915 book called " The Origin of Continents and Oceans ." Part of the opposition was because Wegener didn't have a good model to explain how the continents moved, something scientists later explained under the umbrella of plate tectonics — the theory that Earth's crust is fractured into plates that move over a rocky inner layer called the mantle . 

"There's an irony that the key objection to continent drift was that there is no mechanism, and plate tectonics was accepted without a mechanism," to move the continents, Henry Frankel (1944–2019), an emeritus professor at the University of Missouri-Kansas City and author of the four volume " The Continental Drift Controversy " (Cambridge University Press, 2012) previously told Live Science.

Though most of Wegener's observations about fossils and rocks were correct, he was outlandishly wrong on a couple of key points. For instance, Wegener thought the continents might have plowed through the ocean crust like icebreakers smashing through ice. 

When Wegener proposed continental drift, many geologists were contractionists. They thought Earth's incredible mountains were created because our planet had been cooling and shrinking since its formation, Frankel said. And to account for the identical fossils discovered on continents such as South America and Africa, scientists invoked ancient land bridges, now vanished beneath the sea. 

Researchers argued over the land bridges right up until the plate tectonics theory was developed from the 1950s to the 1970s, Frankel said. For instance, as geophysicists began to realize that continental rocks were too light to sink down to the ocean floor, prominent paleontologists instead wrongly suggested that the similarities between fossils had been overestimated, Frankel said.

Plate tectonics is like a modern update to continental drift. In the 1960s, scientists discovered plate edges through magnetic surveys of the ocean floor and through the seismic listening networks built to monitor nuclear testing, according to Encyclopedia Britannica . Alternating patterns of magnetic anomalies on the ocean floor indicated seafloor spreading , where new plate material is born. Magnetic minerals aligned in ancient rocks on continents also showed that the continents have shifted relative to one another. 

Related: Plate tectonics are 3.6 billion years old, oldest minerals on Earth reveal  

What evidence is there for continental drift?

A map of the continents inspired Wegener's quest to explain Earth's geologic history. He was intrigued by the interlocking fit of Africa's and South America's shorelines. Wegener then assembled an impressive amount of continental drift evidence to show that Earth's continents were once connected in a single supercontinent.

Wegener knew that fossil plants and animals such as mesosaurs , a freshwater reptile found only in South America and Africa during the Permian period, could be found on many continents. He also matched up rock formations on either side of the Atlantic Ocean like puzzle pieces. For example, the Appalachian Mountains (United States) and Caledonian Mountains (Scotland) fit together, as do the Karoo strata in South Africa and Santa Catarina rocks in Brazil.

In fact, plates moving together created the highest mountains in the world, the Himalayans, and the mountains are still growing due to the plates pushing together, even now, according to National Geographic . Despite his incredible continental drift evidence, Wegener never lived to see his theory gain wider acceptance. He died in 1930 at age 50 just two days after his birthday while on a scientific expedition in Greenland , according to the University of Berkeley .

• Learn more about the history of continental drift and plate tectonics from the U.S. Geological Survey . 
• Learn more about Alfred Wegener from the NASA Earth Observatory . 
• Watch this short video on YouTube about plate tectonics and continental drift, from National Geographic . 

This article was updated on Dec. 14, 2021, by Live Science Staff Writer Patrick Pester. Additional reporting by Alina Bradford, Live Science contributor.  

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The Continental Drift Theory: Revolutionary and Significant

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Opposition to Continental Drift Theory

Data supporting continental drift theory.

• Wegener's Search for Scientific Truth

Acceptance of Continental Drift Theory

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Continental drift was a revolutionary scientific theory developed in the years 1908-1912 by Alfred Wegener (1880-1930), a German meteorologist, climatologist, and geophysicist, that put forth the hypothesis that the continents had all originally been a part of one enormous landmass or supercontinent about 240 million years ago before breaking apart and drifting to their current locations. Based on the work of previous scientists who had theorized about horizontal movement of the continents over the Earth's surface during different periods of geologic time, and based on his own observations drawing from different fields of science, Wegener postulated that about 200 million years ago, a supercontinent that he called Pangaea (which means "all lands" in Greek) began to break up. Over millions of years the pieces separated, first into two smaller supercontinents, Laurasia and Gondwanaland, during the Jurassic period and then by the end of the Cretaceous period into the continents we know today.

Wegener first presented his ideas in 1912 and then published them in 1915 in his controversial book, "The Origins of Continents and Oceans , " which was received with great skepticism and even hostility. He revised and published subsequent editions of his book in 1920,1922, and 1929. The book (Dover translation of the 1929 fourth German edition) is still available today on Amazon and elsewhere.

Wegener's theory, although not completely correct, and by his own admission, incomplete, sought to explain why similar species of animals and plants, fossil remains, and rock formations exist on disparate lands separated by great distances of sea. It was an important and influential step that ultimately led to the development of the theory of plate tectonics , which is how scientists understand the structure, history, and dynamics of the Earth’s crust.

There was much opposition to Wegener's theory for several reasons. For one, he was not an expert in the field of science in which he was making a hypothesis , and for another, his radical theory threatened conventional and accepted ideas of the time. Furthermore, because he was making observations that were multidisciplinary, there were more scientists to find fault with them.

There were also alternative theories to counter Wegener’s continental drift theory. A commonly held theory to explain the presence of fossils on disparate lands was that there was once a network of land bridges connecting the continents that had sunk into the sea as part of a general cooling and contraction of the earth. Wegener, however, refuted this theory maintaining that continents were made of a less dense rock than that of the deep-sea floor and so would have risen to the surface again once the force weighing them down had been lifted. Since this had not occurred, according to Wegener, the only logical alternative was that the continents themselves had been joined and had since drifted apart.

Another theory was that the fossils of temperate species found in the arctic regions were carried there by warm water currents. Scientists debunked these theories, but at the time they helped stall Wegener’s theory from gaining acceptance.

In addition, many of the geologists who were Wegener's contemporaries were contractionists. They believed that the Earth was in the process of cooling and shrinking, an idea they used to explain the formation of mountains, much like wrinkles on a prune. Wegener, though, pointed out that if this were true, mountains would be scattered evenly all over the Earth's surface rather than lined up in narrow bands, usually at the edge of a continent. He also offered a more plausible explanation for mountain ranges. He said they formed when the edge of a drifting continent crumpled and folded — as when India hit Asia and formed the Himalayas.

One of the biggest flaws of Wegener’s continental drift theory was that he did not have a viable explanation for how continental drift could have occurred. He proposed two different mechanisms, but each was weak and could be disproven. One was based on the centrifugal force caused by the rotation of the Earth, and the other was based on the tidal attraction of the sun and the moon.

Though much of what Wegener theorized was correct, the few things that were wrong were held against him and prevented him from seeing his theory accepted by the scientific community during his lifetime. However, what he got right paved the way for plate tectonics theory.

Fossil remains of similar organisms on widely disparate continents support the theories of continental drift and plate tectonics. Similar fossil remains, such as those of the Triassic land reptile Lystrosaurus and the fossil plant Glossopteris , exist in South America, Africa, India, Antarctica, and Australia, which were the continents comprising Gondwanaland, one of the supercontinents that broke off from Pangaea about 200 million years ago. Another fossil type, that of the ancient reptile Mesosaurus , is only found in southern Africa and South America.  Mesosaurus was a freshwater reptile only one meter long that could not have swum the Atlantic Ocean, indicating that there was once a contiguous landmass that provided a habitat for it of freshwater lakes and rivers.

Wegener found evidence of tropical plant fossils and coal deposits in the frigid arctic near the North Pole, as well as evidence of glaciation on the plains of Africa, suggesting a different configuration and placement of the continents than their present one.

Wegener observed that the continents and their rock strata fit together like pieces of a jigsaw puzzle, particularly the east coast of South America and the west coast of Africa, specifically the Karoo strata in South Africa and Santa Catarina rocks in Brazil. South America and Africa were not the only continents with similar geology , though. Wegener discovered that the Appalachian Mountains of the eastern United States, for instance, were geologically related to the Caledonian Mountains of Scotland. 

Wegener's Search for Scientific Truth

According to Wegener, scientists still did not appear to understand sufficiently that all earth sciences must contribute evidence toward unveiling the state of our planet in earlier times, and that the truth of the matter could only be reached by combing all this evidence. Only by combing the information furnished by all the earth sciences would there be hope to determine "truth," that is to say, to find the picture that sets out all the known facts in the best arrangement and that therefore has the highest degree of probability. Further, Wegener believed that scientists always need to be prepared for a possibility that a new discovery, no matter what science furnishes it, may modify the conclusions we draw.

Wegener had faith in his theory and persisted in using an interdisciplinary approach, drawing on the fields of geology, geography, biology, and paleontology, believing that to be the way to strengthen his case and to keep up the discussion about his theory. His book, "The Origins of Continents and Oceans , " also helped when it was published in multiple languages in 1922, which brought it worldwide and ongoing attention within the scientific community. When Wegener gained new information, he added to or revised his theory, and published new editions. He kept the discussion of the plausibility of the continental drift theory going until his untimely death in 1930 during a meteorologic expedition in Greenland.

The story of the continental drift theory and its contribution to scientific truth is a fascinating example of how the scientific process works and how scientific theory evolves. Science is based on hypothesis, theory, testing, and interpretation of data, but the interpretation can be skewed by the perspective of the scientist and his or her own field of specialty, or denial of facts altogether. As with any new theory or discovery, there are those who will resist it and those who embrace it. But through Wegener’s persistence, perseverance, and open-mindedness to the contributions of others, the theory of continental drift evolved into the widely accepted theory today of plate tectonics. With any great discovery it is through the sifting of data and facts contributed by multiple scientific sources, and ongoing refinements of the theory, that scientific truth emerges.

When Wegener died, discussion of continental drift died with him for a while. It was resurrected, however, with the study of seismology and further exploration of the ocean floors in the 1950s and 1960s that showed mid-ocean ridges, evidence in the seafloor of the Earth's changing magnetic field, and proof of seafloor spreading and mantle convection, leading to the theory of plate tectonics. This was the mechanism that was missing in Wegener's original theory of continental drift. By the late 1960s, plate tectonics was commonly accepted by geologists as accurate.

But the discovery of seafloor spreading disproved a part of Wegener's theory, because it wasn't just the continents that were moving through static oceans, as he had originally thought, but rather entire tectonic plates, consisting of the continents, ocean floors, and parts of the upper mantle. In a process similar to that of a conveyor belt, hot rock rises from the mid-ocean ridges and then sinks down as it cools and becomes denser, creating convection currents that cause movement of the tectonic plates.

The theories of continental drift and plate tectonics are the foundation of modern geology. Scientists believe that there were several supercontinents like Pangaea that formed and broke apart over the course of Earth's 4.5-billion year lifespan. Scientists also now recognize that Earth is constantly changing and that even today, the continents are still moving and changing. For example, the Himalayas, formed by the collision of the Indian plate and the Eurasian plate is still growing, because plate tectonics is still pushing the Indian plate into the Eurasian plate. We may even be heading toward the creation of another supercontinent in 75-80 million years due to the continued movement of tectonic plates.

But scientists are also realizing that plate tectonics does not work merely as a mechanical process but as a complex feedback system, with even things such as climate affecting the movement of the plates, creating yet another quiet revolution in the theory of plate tectonics variable in our understanding of our complex planet.

• Learn About the History and Principles of Plate Tectonics
• Biography of Alfred Wegener, German Scientist
• History of the Supercontinent Pangea
• Alfred Wegener's Pangaea Hypothesis
• All About Supercontinents
• Divergent Plate Boundaries
• Map of Tectonic Plates and Their Boundaries
• The Most Influential Geologists of All Time
• The Age of the Ocean Floor
• Measuring Plate Motion in Plate Tectonics
• Orogeny: How Mountains Form Through Plate Tectonics
• Tectonic Plates' Effect on Evolution
• What Is an Ophiolite?
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2.1: Alfred Wegener’s Continental Drift Hypothesis

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Alfred Wegener (1880-1930) was a German scientist who specialized in meteorology and climatology. His knack for questioning accepted ideas started in 1910 when he disagreed with the explanation that the Bering Land Bridge was formed by isostasy and that similar land bridges once connected the continents [ 1 ]. After reviewing the scientific literature, he published a hypothesis stating the continents were originally connected and then drifted apart. While he did not have the precise mechanism worked out, his hypothesis was backed up by a long list of evidence.

Early Evidence for Continental Drift Hypothesis

Wegener’s first piece of evidence was that the coastlines of some continents fit together like pieces of a jigsaw puzzle. People noticed the similarities in the coastlines of South America and Africa on the first world maps, and some suggested the continents had been ripped apart [ 3 ]. Antonio Snider-Pellegrini did preliminary work on continental separation and matching fossils in 1858.

What Wegener did differently was synthesizing a large amount of data in one place. He used the true edges of the continents, based on the shapes of the continental shelves [ 4 ]. This resulted in a better fit than previous efforts that traced the existing coastlines [ 5 ].

Wegener also compiled evidence by comparing similar rocks, mountains, fossils, and glacial formations across oceans. For example, the fossils of the primitive aquatic reptile Mesosaurus were found on the separate coastlines of Africa and South America. Fossils of another reptile, Lystrosaurus, were found in Africa, India, and Antarctica. He pointed out these were land-dwelling creatures could not have swum across an entire ocean.

Opponents of continental drift insisted trans-oceanic land bridges allowed animals and plants to move between continents [ 6 ]. The land bridges eventually eroded away, leaving the continents permanently separated. The problem with this hypothesis is the improbability of a land bridge being tall and long enough to stretch across a broad, deep ocean.

More support for continental drift came from the puzzling evidence that glaciers once existed in normally very warm areas in southern Africa, India, Australia, and Arabia. These climate anomalies could not be explained by land bridges. Wegener found similar evidence when he discovered tropical plant fossils in the frozen region of the Arctic Circle. As Wegener collected more data, he realized the explanation that best fit all the climate, rock, and fossil observations involved moving continents.

Proposed Mechanism for Continental Drift

Figure \(\PageIndex{5}\): [Click to Animate] Animation of the basic idea of convection: an uneven heat source in a fluid causes rising material next to the heat and sinking material far from the heat.

Wegener’s work was considered a fringe science theory for his entire life. One of the biggest flaws in his hypothesis was the inability to provide a mechanism for how the continents moved. Obviously, the continents did not appear to move, and changing the conservative minds of the scientific community would require exceptional evidence that supported a credible mechanism. Other pro-continental drift followers used expansion, contraction, or even the moon’s origin to explain how the continents moved. Wegener used centrifugal forces and precession, but this model was proven wrong [ 7 ]. He also speculated about seafloor spreading, with hints of convection, but could not substantiate these proposals [ 8 ]. As it turns out, current scientific knowledge reveals convection is the major force in driving plate movements.

Development of Plate Tectonic Theory

Wegener died in 1930 on an expedition in Greenland. Poorly respected in his lifetime, Wegener and his ideas about moving continents seemed destined to be lost in history as fringe science. However, in the 1950s, evidence started to trickle in that made continental drift a more viable idea. By the 1960s, scientists had amassed enough evidence to support the missing mechanism—namely, seafloor spreading—for Wegener’s hypothesis of continental drift to be accepted as the theory of plate tectonics. Ongoing GPS and earthquake data analyses continue to support this theory. The next section provides the pieces of evidence that helped transform one man’s wild notion into a scientific theory.

Mapping of the Ocean Floors

In 1947 researchers started using an adaptation of SONAR to map a region in the middle of the Atlantic Ocean with poorly-understood topographic and thermal properties [ 9 ]. Using this information, Bruce Heezen and Marie Tharp created the first detailed map of the ocean floor to reveal the Mid-Atlantic Ridge [ 10 ], a basaltic mountain range that spanned the length of the Atlantic Ocean, with rock chemistry and dimensions unlike the mountains found on the continents. Initially, scientists thought the ridge was part of a mechanism that explained the expanding Earth or ocean-basin growth hypotheses [ 11 ; 12 ]. In 1959, Harry Hess proposed the hypothesis of seafloor spreading – that the mid-ocean ridges represented tectonic plate factories, where a new oceanic plate was issuing from these long volcanic ridges. Scientists later included transform faults perpendicular to the ridges to better account for varying rates of movement between the newly formed plates [ 13 ]. When earthquake epicenters were discovered along the ridges, the idea that earthquakes were linked to plate movement took hold [ 14 ].

Seafloor sediment, measured by dredging and drilling, provided another clue. Scientists once believed sediment accumulated on the ocean floors over a very long time in a static environment. When some studies showed less sediment than expected, these results were initially used to argue against the continental movement [ 15 ; 16 ]. With more time, researchers discovered these thinner sediment layers were located close to mid-ocean ridges, indicating the ridges were younger than the surrounding ocean floor. This finding supported the idea that the seafloor was not fixed in one place [ 17 ].

Paleomagnetism

The seafloor was also mapped magnetically. Scientists had long known of strange magnetic anomalies that formed a striped pattern of symmetrical rows on both sides of mid-oceanic ridges. What made these features unusual was the north and south magnetic poles within each stripe was reversed in alternating rows [ 18 ]. By 1963, Harry Hess and other scientists used these magnetic reversal patterns to support their model for seafloor spreading [ 19 ] (see also Lawrence W. Morley [ 20 ]).

Paleomagnetism is the study of magnetic fields frozen within rocks, basically a fossilized compass. In fact, the first hard evidence to support plate motion came from paleomagnetism.

Igneous rocks containing magnetic minerals like magnetite typically provide the most useful data. In their liquid state as magma or lava, the magnetic poles of the minerals align themselves with the Earth’s magnetic field. When the rock cools and solidifies, this alignment is frozen into place, creating a permanent paleomagnetic record that includes magnetic inclination related to global latitude, and declination related to magnetic north.

Scientists had noticed for some time the alignment of magnetic north in many rocks was nowhere close to the earth’s current magnetic north. Some explained this as part of the normal movement of earth magnetic north pole. Eventually, scientists realized adding the idea of continental movement explained the data better than the pole movement alone [ 21 ].

Wadati-Benioff Zones

Around the same time mid-ocean ridges were being investigated, other scientists linked the creation of ocean trenches and island arcs to seismic activity and tectonic plate movement [ 22 ]. Several independent research groups recognized earthquake epicenters traced the shapes of oceanic plates sinking into the mantle. These deep earthquake zones congregated in planes that started near the surface around ocean trenches and angled beneath the continents and island arcs [ 23 ]. Today these earthquake zones called Wadati-Benioff zones.

Based on the mounting evidence, the theory plate tectonics continued to take shape. J. Tuzo Wilson was the first scientist to put the entire picture together by proposing that the opening and closing of the ocean basins [ 24 ]. Before long, scientists proposed other models showing plates moving with respect to each other, with clear boundaries between them [ 25 ]. Others started piecing together complicated histories of tectonic plate movement [ 26 ]. The plate tectonic revolution had taken hold.

• 1. Fluegel, von H. W. Wegener-Ampferer-Schwinner. Ein Beitrag zur Geschichte der Geologie in Österreich. Mitt. Oesterr. Geol. Ges. 73 , 237–254 (1980).
• 3. Bacon, F. & Montagu, B. The Works of Francis Bacon, Lord Chancellor of England: With a Life of the Author . (Parry & McMillan, 1848).
• 4. Drake, E. T. Alfred Wegener’s reconstruction of Pangea. Geology 4 , 41–44 (1976).
• 5. Mantovani, R. Les fractures de l’écorce terrestre et la théorie de Laplace. Bull. Soc. Sc. et Arts Réunion 41–53 (1889).
• 6. Wells, H. G., Huxley, J. & Wells, G. P. The Science of Life. Philosophy 6 , 506–507 (1931).
• 7. Scheidegger, A. E. Examination of the physics of theories of orogenesis. Geol. Soc. Am. Bull. 64 , 127–150 (1953).
• 8. Jacoby, W. R. Modern concepts of Earth dynamics anticipated by Alfred Wegener in 1912. Geology 9 , 25–27 (1981).
• 9. Tolstoy, I. & Ewing, M. North Atlantic hydrography and the Mid-Atlantic Ridge. Geol. Soc. Am. Bull. 60 , 1527–1540 (1949).
• 10. Heezen, B. C., Tharp, M. & Ewing, M. The Floors of the Oceans I. The North Atlantic. Geological Society of America Special Papers 65 , 1–126 (1959).
• 11. Heezen, B. C. The Rift in the Ocean Floor. Sci. Am. 203 , 98–110 (1960).
• 12. Dietz, R. S. Continent and ocean basin evolution by spreading of the seafloor. Nature 190 , 854–857 (1961).
• 13. Wilson, J. T. A new class of faults and their bearing on continental drift. Nature (1965).
• 14. Heezen, B. C. & Tharp, M. Tectonic Fabric of the Atlantic and Indian Oceans and Continental Drift. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences 258 , 90–106 (1965).
• 15. Ewing, M., Ewing, J. I. & Talwani, M. Sediment distribution in the oceans: The Mid-Atlantic Ridge. Geol. Soc. Am. Bull. 75 , 17–36 (1964).
• 16. Saito, T., Ewing, M. & Burckle, L. H. Tertiary sediment from the mid-atlantic ridge. Science 151 , 1075–1079 (1966).
• 17. Ewing, M., Houtz, R. & Ewing, J. South Pacific sediment distribution. J. Geophys. Res. 74 , 2477–2493 (1969).
• 18. Mason, R. G. A magnetic survey off the west coast of the United-States between latitudes 32-degrees-N and 36-degrees-N longitudes 121-degrees-W and 128-degrees-W. Geophysical Journal of the Royal Astronomical Society 1 , 320 (1958).
• 19. Vine, F. J. & Matthews, D. H. Magnetic anomalies over oceanic ridges. Nature 199 , 947–949 (1963).
• 20. Frankel, H. The Development, Reception, and Acceptance of the Vine-Matthews-Morley Hypothesis. Hist. Stud. Phys. Biol. Sci. 13 , 1–39 (1982).
• 21. Irving, E. Palaeomagnetic and palaeoclimatological aspects of polar wandering. Geofis. pura appl. 33 , 23–41 (1956).
• 22. Coats, R. R. Magma type and crustal structure in the Aleutian Arc. in The Crust of the Pacific Basin 92–109 (American Geophysical Union, 1962). doi:10.1029/GM006p0092
• 23. Wadati, K. On the activity of deep-focus earthquakes in the Japan Islands and neighbourhoods. Geophys. Mag. 8 , 305–325 (1935).
• 24. Wilson, J. T. Did the Atlantic close and then re-open? (Nature, 1966).
• 25. McKenzie, D. P. & Parker, R. L. The North Pacific: an Example of Tectonics on a Sphere. Nature 216 , 1276–1280 (1967).
• 26. Atwater, T. Implications of Plate Tectonics for the Cenozoic Tectonic Evolution of Western North America. Geol. Soc. Am. Bull. 81 , 3513–3536 (1970).

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What is Continental Drift?

In 1912, Alfred Wegener published a theory to explain why the Earth looked like a huge jigsaw. He believed the continents were once joined, forming a supercontinent he called Pangaea. Over 180 million years ago, this supercontinent began to “break up” due to continental drift.

Continental drift

During the 20th Century, scientists developed the theory of Plate Tectonics. The theory suggests that the crust of the Earth is split up into seven large plates (see map below) and a few smaller ones, all of which can slowly move around on the Earth’s surface. They lie on the ductile mantle that allows them to move. There are several explanations for the movement of the Earth’s plates, and these are explored in the Why do plates move? page.

The Earth’s main tectonic plates

What is the evidence for continental drift?

Wegener’s evidence for continental drift was that:

• the same types of fossilised plants and animals are found in South America and Africa;
• the west coast of South America fits the east coast of Africa like a jigsaw puzzle;
• rock formations and mountain chains match in South America and Africa;
• similar mineral deposits and natural resources, such as coal, exist along the east coast of Africa and the west coast of South America.

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5.2: Wegener and the Continental Drift Hypothesis

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What is continental drift?

Wegener put together a tremendous amount of evidence that the continents had been joined. He advanced a great idea. But other scientists didn't accept it.

Wegener’s Continental Drift Hypothesis

Wegener put his idea and his evidence together in his book, The Origin of Continents and Oceans . The book was first published in 1915. He included evidence that the continents had been joined. New editions of the book containing additional evidence were published later.

In his book he said that around 300 million years ago, the continents had all been joined. They created a single landmass he called Pangaea, meaning “all earth” in ancient Greek. The super-continent later broke apart. Since then the continents have been moving into their current positions. He called his hypothesis continental drift .

The Problem With The Hypothesis

Wegener had a lot of evidence to support his hypothesis. But he had a problem. The problem was that he could not explain how the continents could move through the oceans. He suggested that continental drift occurred like an icebreaker plows through sea ice ( Figure below). He thought the continents could cut through the ocean floor.

An icebreaking ship.

Other scientists didn't buy his idea. They thought that the continents would be much more deformed than they are.

Wegener believed that Africa and South America had once been joined. He had the evidence. But very few scientists accepted his idea. He needed a mechanism that they would accept.

Alfred Wegener died in 1930 on an expedition on the Greenland icecap. The continental drift hypothesis was put to rest for a few decades. Only when technology could provide even more evidence for continental drift did scientists look into the idea again. Technology also helped scientists to develop a mechanism for how continents could drift.

Further Reading

Magnetic Polarity Evidence for Continental Drift

Bathymetric Evidence for Seafloor Spreading

Magnetic Evidence for Seafloor Spreading

Seafloor Spreading Hypothesis

• Alfred Wegener said that the continents had been joined as a single landmass, which he called Pangaea.
• Wegener thought that Pangaea was together about 300 million years ago.
• Wegener could not develop a mechanism for continents moving through oceanic crust that other scientists would accept.
• Describe the continental drift hypothesis.
• Why did scientists reject Wegener’s idea? What was needed for them to accept it?
• What was Wegener's mechanism for drifting continents?

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36 Continental Drift: founding block of the Plate Tectonics Theory

The continental drift hypothesis, the foundation of Plate Tectonics theory was developed in the early part of the twentieth century, mostly by Alfred Wegener who proposed that continents move around on Earth’s surface and that they were once joined together as a single supercontinent called Pangaea. His hypothesis did not stand a trial at that time because nobody could explain the mechanism of the movement of continental plates.

Only with discoveries of ocean structure in 1960-1970s scientists understood the mechanism of plate movement.

See below a short documentary about the discovery of Plate Tectonics theory.

The Continental Drift Idea

Figure 1. The continents fit together like pieces of a puzzle. This is how they looked 250 million years ago.

Alfred Wegener, a German climatologist, proposed that the continents were once united into a single supercontinent named Pangaea, meaning all earth  in ancient Greek . He suggested that Pangaea broke up long ago and that the continents then moved to their current positions. He called his hypothesis  continental drift.

Evidence for Continental Drift

Besides the way the continents fit together, Wegener and his supporters collected a great deal of evidence for the continental drift hypothesis.

• Identical rocks, of the same type and age, are found on both sides of the Atlantic Ocean. Wegener said the rocks had formed side-by-side and that the land had since moved apart.
• Mountain ranges with the same rock types, structures, and ages are now on opposite sides of the Atlantic Ocean. The Appalachians of the eastern United States and Canada, for example, are just like mountain ranges in eastern Greenland, Ireland, Great Britain, and Norway (figure 2). Wegener concluded that they formed as a single mountain range that was separated as the continents drifted.

Figure 2. The similarities between the Appalachian and the eastern Greenland mountain ranges are evidences for the continental drift hypothesis.

• Fossils of the seed fern  Glossopteris  were too heavy to be carried so far by wind.
• Mesosaurus  was a swimming reptile but could only swim in fresh water.
• Cynognathus  and  Lystrosaurus  were land reptiles and were unable to swim.

• Grooves and rock deposits left by ancient glaciers are found today on different continents very close to the equator. This would indicate that the glaciers either formed in the middle of the ocean and/or covered most of the Earth. Today glaciers only form on land and nearer the poles. Wegener thought that the glaciers were centered over the southern land mass close to the South Pole and the continents moved to their present positions later on.
• Coral reefs and coal-forming swamps are found in tropical and subtropical environments, but ancient coal seams and coral reefs are found in locations where it is much too cold today. Wegener suggested that these creatures were alive in warm climate zones and that the fossils and coal later had drifted to new locations on the continents.

Although Wegener’s evidence was sound, but most geologists at the time rejected his hypothesis of continental drift. Why do you think they did not accept continental drift?

Scientists argued that there was no way to explain how solid continents could plow through solid oceanic crust. Wegener’s idea was nearly forgotten until technological advances presented even more evidence that the continents moved and gave scientists the tools to develop a mechanism for Wegener’s drifting continents.

Magnetic Polarity Evidence

Figure 4. Earth’s magnetic field is like a magnet with its north pole near the geographic North Pole and the south pole near the geographic South Pole.

Puzzling new evidence came in the 1950s from studies on the Earth’s magnetic history (figure 4).

Scientists used  magnetometers , devices capable of measuring the magnetic field intensity, to look at the magnetic properties of rocks in many locations .

Magnetic Pole Moving?

Geologic Approach to Magnetic Pole Wandering

All igneous rocks have magnetite, a mineral consisting mainly of iron. Igneous rocks can be found in many parts of the world.

Magnetite  crystals are like tiny magnets that point to the north magnetic pole as they crystallize from magma. The crystals record both the direction and strength of the  magnetic field  at the time. The direction is known as the field’s  magnetic polarity.

Geologists noted important things about the magnetic polarity of different aged rocks on the same continent:

• Magnetite crystals in fresh volcanic rocks point to the current magnetic north pole  (figure 5) no matter what continent or where on the continent the rocks are located.

• Older rocks that are the same age and are located on the same continent point to the same location, different from the current north magnetic pole.
• Older rock that are of different ages do not point to the same locations or to the current magnetic north pole.

In other words, although the magnetite crystals were pointing to the magnetic north pole, the location of the pole seemed to wander.  Scientists were amazed to find that the north magnetic pole changed location through time (figure 6).

Figure 6. The location of the north magnetic north pole 80 million years before present (mybp), then 60, 40, 20, and now.

There are three possible explanations for this:

1. The continents remained fixed and the north magnetic pole moved.

2. The north magnetic pole stood still and the continents moved.

3. Both the continents and the north pole moved.

During studies of magnetism in various countries geologists noted that for rocks of the same age on different continents , the  magnets pointed to different magnetic north poles .

• 400-million-year-old magnetite in Europe pointed to a different north magnetic pole than the same-aged magnetite in North America.
• 250 million years ago, the north poles were also different for the two continents.

The scientists looked again at the three possible explanations. Only one can be correct.

If the continents had remained fixed while the north magnetic pole moved, there must have been two separate north poles.

Since there is only one north pole,   the only reasonable explanation is that the north magnetic pole has remained fixed but that the continents have moved.

To test this, geologists fitted the continents together as Wegener had done. It worked!

There has only been one magnetic north pole and the continents have drifted (see figure below). The view on this map is from the north down (polar projection).

The maps above show the polar wandering curve through Pangaea as well as through the present day configuration, which provides further evidence for moving tectonic plates.

This evidence for continental drift gave geologists renewed interest in understanding how continents could move about on the planet’s surface.

Lesson Summary

• In the early part of the 20th century, scientists began to put together evidence that the continents could move around on Earth’s surface.
• The evidence for continental drift included the fit of the continents; the distribution of ancient fossils, rocks, and mountain ranges; and the locations of ancient climatic zones.
• Although the evidence for continental drift was extremely strong, scientists rejected the idea because no mechanism for how solid continents could move around on the solid earth was developed.
• The discovery of apparent polar wander renewed scientists interest in continental drift.

Geology 101 for Lehman College (CUNY) Copyright © by Yuri Gorokhovich and Lumen Learning is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

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What is Continental Drift?

The theory of continental drift was presented by a German geologist, Alfred Wegener in 1910. He suggested that at the beginning of the Mesozoic era (200 million years ago), all the continents of the earth were united together. These continents were united to form a single supercontinent, which he called “Pangaea” . The huge ocean, that surrounded it, he called “Panthalassa” . Wegener proposed that this vast continent began to break up into smaller continents at the beginning of the Mesozoic era, which then steadily drifted to their current positions, just like pieces of wood floating on water. What is Continental Drift?

The continents drifted westward, and equator-ward under the differential gravitational forces. The term “Gondwana Land”  was used for the southern huge landmass, which included Africa, South America, Antarctica, and India, while the term “Laurasia”  was used for the northern landmass, which included North America, Greenland, and Eurasia. What is continental drift?

To support his theory, Wegener gave much geological evidence, such as similarities in geological structure, distribution of rock types and fossils, and similar shape of coastlines on either side of the Atlantic Ocean.

The theory of continental drift was not accepted for 40 years. It received support only in the 1950s and 60s when geomagnetic pieces of evidence were discovered in its favor. What is Continental Drift?

Evidence for Continental Drift

Alfred Wegener’s hypothesis was continuously rejected by most scientists for 40 years. To prove his theory he persisted to keep on studying Earth’s features, visited libraries, and explored evidence until his death. Wegener never lived to see his theory accepted—he died at the age of 50 while on an expedition in Greenland. Only decades later, in the 1960s, did the idea of continental drift resurface. The most prominent pieces of evidence he found at different locations are as under. What is Continental Drift?

Evidence for Gondwanaland

Similarities in shapes of coastlines: The Atlantic coast of South America and Africa have roughly similar shapes. They would fit in nicely if they were brought in contact with each other. However, the coastlines are not reliable geological features because their shapes change with the rise and fall of the sea level relative to the land. The real edge of the continent occurs at the continental slope, where the sea bottom falls rapidly down to the deep ocean floor. The mapping of the continental slopes of eastern South America and West Africa has indicated that their contours match excellently. This evidence strongly suggests that these two continents were once joined together. What is Continental Drift?

Similar Orogenic Belts: If the eastern coast of South America and the western coast of Africa are fitted together, the orogenic belts of the two continents which have the same range of ages and similar structural trends are found to align themselves across the join. For example, in Ghana near Accra (West Africa), there is a clear boundary between 2000 million years old rocks and the much younger (about 400 million years old) rocks. The same boundary occurs in Brazil (Eastern South America) at Sao Luis. These data provide some of the best evidence supporting their original continuity.

Permo-Carboniferous Glaciation: In the Parana basin in Eastern Brazil (South Africa) glacial deposits of Permo-Carboniferous age are widespread. Their average thickness is about 600 meters. The direction of ice movement that the source area of these glacial deposits lies to the southwest of the present Brazilian coast. In southwest Africa, though the glacial deposits are meager, there is abundant evidence for ice erosion . The direction of ice flow recorded is from east to west. This suggests that South West Africa was covered by an actively eroding ice sheet, which dumped its load further west in Brazil (South America). This evidence proves the original continuity between Africa and South America.

Evidence of Permo-Carboniferous Glaciation has been found in all the continents of the southern hemisphere, such as South America, Africa, India, Antarctica, Madagascar, and Australia. The till deposits and fossil plants found on these continents have been examined and correlated. If these landmasses had always been in the tropical latitude, as they are today. It would mean that glaciation extended from the polar regions to the equator. This idea is apparently, unreasonable. The only explanation for this puzzle is that all these continents were joined together to form a single landmass, Gondwanaland, which was located over the South Pole.

Glossopteris Flora: The remains of the “glossopteris flora”  occur in rock beds of the Gondwana Series in South America, South Africa, India, Australia, and Antarctica. These flora reached their maximum development in the Permo-carboniferous period. The nature of their species distribution can only be explained if all the southern continents were joined together. What is Continental Drift?

Land Bridges:  To account for the distribution of some plants and animals in the fossil record, land bridges were postulated between the continents. It was assumed that these land bridges disappeared by subsidence. The detailed study of ocean floors in recent years has ruled out this idea. If the existence of Gondwanaland is accepted the distribution of many animals and plants can easily be explained. For example, remains of the reptile “mesosaurus”, which could not have swum on the ocean, have been found in western South Africa and Brazil.

Palaeomagnetic Evidence:  Igneous rocks record the earth’s magnetic field present at the time of their formation. A study of fossil magnetism in a region where several volcanic eruptions had occurred on widely separated occasions, has led to an interesting discovery. The orientation of the earth’s magnetic field in each of the separate lava flows is found to be different. This suggests that between volcanic eruptions, the magnetic poles have moved to a new location. Thus palaeomagnetic techniques, which locate the magnetic pole of any stage in the past, give consistent results on each continent only when they are placed in the proposed framework of “Gondwanaland”.

Evidence of Laurasia

Laurasia was the northern landmass, which consisted of North America, Greenland, and Eurasia. The geometrical fit of these continents is quite good. To confirm the existence of Laurasia, geologists have shown the now widely separated Norwegian, Caledonian, Appalachian, and East Greenland mountains were originally formed as a single chain. This match suggests that the northern continents were a single unit sometime in the interval 260 to 70 million years ago.

Position of India

To fit Australia, Antarctica, and India together, geology is used as a guide. The paleozoic mountain belts in Antarctica and Australia indicate how they were joined together. The same pattern of belts also continues into Africa and South America. Further, the edges of Antarctica and Australia at 500 fathoms (1000 meters) line also match nicely. However, there is doubt about the proper position of India. Ahmad, an Indian geologist, has suggested that close links exist between the geology of South East India, and Northwest Australia. He reached this conclusion when he studied the sedimentary basins of the Permian age in these two continents and found them very similar. The main objections for fitting India against northwest Australia are as follows.

• The Upper Carboniferous tillites pattern does not match across the join. What is Continental Drift?
• A recently published fit based entirely on palaeomagnetic data does not support the placing of Inida against northwest Australia.

Thus except for the link between India and Antarctica, there is positive evidence that Gondwanaland existed as a supercontinent until Jurassic time (190 million years ago). If the evidence of seafloor spreading and plate tectonic are added to the argument, continental drift may be regarded as a fact.

Breakup of Pangaea

The chief event of the break up of the supercontinent Pangaea, are as follows;

• Pangaea that existed in Permian times, a little more than 200 million years ago. It was surrounded by a huge ocean called “Panthalassa”. The Tethys Sea existed between Africa and Eurasia.
• The North Atlantic Ocean was formed as North America was separated from the African Continent. Due to this, the Tethys Sea contracted.
• The Laurasia was separated from the Gondwanaland.
• A Y-shaped rift was formed in the southern Pangaea, which separated Antarctica-Australia from Africa-South America, and sent India on its northward journey.
• By the end of the Jurassic period (about 135 million years ago), South America broke from Africa, thereby forming the “South Atlantic Ocean”. The North Atlantic and Indian Oceans were enlarged but the Tethys Sea continued to close. India moved further northward.
• At the close of the Cretaceous period (65 million years ago), Madagascar was separated from Africa and the South Atlantic Ocean widened. The Tethys closed further to form an inland sea, the Mediterranean.
• About 40 million years ago, India collided with Asia and produced the Himalayan Mountains.
• Greenland has separated quite recently from North America.

You may like to study:

• What is Isostasy
• Mantle Convection 
• Interior Structure and Composition of the Earth

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Theory of Plate Tectonics

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Continental Drift versus Plate Tectonics

A scientific idea that was initially ridiculed paved the way for the theory of plate tectonics, which explains how Earth’s continents move.

Earth Science, Geology, Geography, Physical Geography

Alfred Wegener in Greenland

Plate tectonics is the theory that Earth's land masses are in constant motion. The realization that Earth's land masses move was first proposed by Alfred Wegener, which he called continental drift. He is shown here in Greenland.

Photograph from Pictoral Press

We don’t perceive that the continents we live on are moving. After all, it’s not as if an airplane flight between Europe and Africa takes five hours one year but only three hours the next. But the continents actually are shifting, very slowly, relative to one another. In the early 20th century, a scientific theory called continental drift was proposed about this migration of the continents . That theory was initially ridiculed, but it paved the way for another theory called plate tectonics that scientists have now accepted to explain how Earth’s continents move. The story begins with Alfred Wegener (1880–1930), a German meteorologist and geophysicist who noticed something curious when he looked at a map of the world. Wegener observed that the continents of South America and Africa looked like they would fit together remarkably well—take away the Atlantic Ocean and these two massive landforms would lock neatly together. He also noted that similar fossils were found on continents separated by oceans, additional evidence that perhaps the landforms had once been joined. He hypothesized that all of the modern-day continents had previously been clumped together in a super continent he called Pangaea (from ancient Greek, meaning “all lands” or “all the Earth”). Over millions of years, Wegener suggested, the continents had drifted apart. He did not know what drove this movement, however. Wegener first presented his idea of continental drift in 1912, but it was widely ridiculed and soon, mostly, forgotten. Wegener never lived to see his theory accepted—he died at the age of 50 while on an expedition in Greenland. Only decades later, in the 1960s, did the idea of continental drift resurface. That’s when technologies adapted from warfare made it possible to more thoroughly study Earth. Those advances included seismometers used to monitor ground shaking caused by nuclear testing and magnetometers to detect submarines. With seismometers , researchers discovered that earthquakes tended to occur in specific places rather than equally all over Earth. And scientists studying the seafloor with magnetometers found evidence of surprising magnetic variations near undersea ridges: alternating stripes of rock recorded a flip-flopping of Earth’s magnetic field . Together, these observations were consistent with a new theory proposed by researchers who built on Wegener’s original idea of continental drift —the theory of plate tectonics . According to this theory , Earth’s crust is broken into roughly 20 sections called tectonic plates on which the continents ride. When these plates press together and then move suddenly, energy is released in the form of earthquakes. That is why earthquakes do not occur everywhere on Earth—they’re clustered around the boundaries of tectonic plates. Plate tectonics also explains the stripes of rock on the seafloor with alternating magnetic properties: As buoyant, molten rock rises up from deep within Earth, it emerges from the space between spreading tectonic plates and hardens, creating a ridge. Because some minerals within rocks record the orientation of Earth’s magnetic poles and this orientation flips every 100,000 years or so, rocks near ocean ridges exhibit alternating magnetic stripes. Plate tectonics explains why Earth’s continents are moving; the theory of continental drift did not provide an explanation. Therefore, the theory of plate tectonics is more complete. It has gained widespread acceptance among scientists. This shift from one theory to another is an example of the scientific process: As more observations are made and measurements are collected, scientists revise their theories to be more accurate and consistent with the natural world. By running computer simulations of how Earth’s tectonic plates are moving, researchers can estimate where the planet's continents will likely be in the future. Because tectonic plates move very slowly—only a few centimeters per year, on average—it takes a long time to observe changes. Scientists have found that the planet’s continents will likely again be joined together in about 250 million years. Researchers have dubbed this future continental configuration “ Pangaea Proxima.” One intriguing aspect of Pangaea Proxima is that it will likely contain a new mountain range with some of the world’s highest mountains. That is because as Africa continues to migrate north it will collide with Europe, a collision that will probably create a Himalaya-scale mountain range. However, Christopher Scotese, one of the scientists who developed these simulations , cautions that it is difficult to predict exactly how the continents will be arranged in millions of years. “We don’t really know the future, obviously,” Scotese told NASA. “All we can do is make predictions of how plate motions will continue, what new things might happen, and where it will all end up.”

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Module 5: Plate Tectonics

Reading: wegener and the continental drift hypothesis.

Scientists still do not appear to understand sufficiently that all earth sciences must contribute evidence toward unveiling the state of our planet in earlier times, and that the truth of the matter can only be reached by combining all this evidence. . . . It is only by combining the information furnished by all the earth sciences that we can hope to determine ‘truth’ here, that is to say, to find the picture that sets out all the known facts in the best arrangement and that therefore has the highest degree of probability. Further, we have to be prepared always for the possibility that each new discovery, no matter what science furnishes it, may modify the conclusions we draw. — Alfred L. Wegener, The Origins of Continents and Oceans , first published in 1915.

Wegener put together a tremendous amount of evidence that the continents had been joined. He advocated using scientific evidence to find the “truth.” As his colleague, are you convinced? Let’s explore.

Wegener’s Continental Drift Hypothesis

Figure 1. Alfred Wegener suggested that continental drift occurred as continents cut through the ocean floor, in the same way as this icebreaker plows through sea ice.

Wegener put his idea and his evidence together in his book The Origin of Continents and Oceans , first published in 1915. New editions with additional evidence were published later in the decade. In his book he said that around 300 million years ago the continents had all been joined into a single landmass he called Pangaea, meaning “all earth” in ancient Greek. The supercontinent later broke apart and the continents having been moving into their current positions ever since. He called his hypothesis continental drift .

The Problem with the Hypothesis

Wegener’s idea seemed so outlandish at the time that he was ridiculed by other scientists. What do you think the problem was? To his colleagues, his greatest problem was that he had no plausible mechanism for how the continents could move through the oceans. Based on his polar experiences, Wegener suggested that the continents were like icebreaking ships plowing through ice sheets. The continents moved by centrifugal and tidal forces. As Wegener’s colleague, how would you go about showing whether these forces could move continents? What observations would you expect to see on these continents?

Figure 2. Early hypotheses proposed that centrifugal forces moved continents. This is the same force that moves the swings outward on a spinning carnival ride.

Scientists at the time calculated that centrifugal and tidal forces were too weak to move continents. When one scientist did calculations that assumed that these forces were strong enough to move continents, his result was that if Earth had such strong forces the planet would stop rotating in less than one year. In addition, scientists also thought that the continents that had been plowing through the ocean basins should be much more deformed than they are.

Wegener answered his question of whether Africa and South America had once been joined. But a hypothesis is rarely accepted without a mechanism to drive it. Are you going to support Wegener? A very few scientists did, since his hypothesis elegantly explained the similar fossils and rocks on opposite sides of the ocean, but most did not.

Mantle Convection

Figure 3. Thermal convection occurs as hot rock in the deep mantle rises towards the Earth’s surface. This rock then spreads out and cools, sinking back towards the core, where it can be heated again. This circulation of rock through the mantle creates convection cells.

Wegener had many thoughts regarding what could be the driving force behind continental drift. Another of Wegener’s colleagues, Arthur Holmes, elaborated on Wegener’s idea that there is thermal convection in the mantle.

In a convection cell , material deep beneath the surface is heated so that its density is lowered and it rises. Near the surface it becomes cooler and denser, so it sinks. Holmes thought this could be like a conveyor belt. Where two adjacent convection cells rise to the surface, a continent could break apart with pieces moving in opposite directions. Although this sounds like a great idea, there was no real evidence for it, either.

Alfred Wegener died in 1930 on an expedition on the Greenland icecap. For the most part the continental drift idea was put to rest for a few decades, until technological advances presented even more evidence that the continents moved and gave scientists the tools to develop a mechanism for Wegener’s drifting continents. Since you’re on a virtual field trip, you get to go along with them as well.

• Alfred Wegener published his idea that the continents had been joined as a single landmass, which he called Pangaea, about 300 million years ago.
• Wegener’s idea was mostly ridiculed, in part because Wegener could not develop a plausible mechanism for continents moving through oceanic crust.
• Calculations showed that his idea about centrifugal and tidal forces powering the continents could not be right.
• Wegener also thought about mantle convection, an idea expanded on by Arthur Holmes as the driving force for continental drift. There was no evidence available to support the idea at the time.

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• Wegener and the Continental Drift Hypothesis. Provided by : CK-12. Located at : http://www.ck12.org/earth-science/Wegener-and-the-Continental-Drift-Hypothesis/lesson/Wegener-and-the-Continental-Drift-Hypothesis-HS-ES/ . License : CC BY-NC: Attribution-NonCommercial

Alfred Wegener: Building a Case for Continental Drift

Continental Drift

The Theory of Continental Drift is defined as the movement of the Earth’s continents relative to each other, thereby appearing to drift together across the oceanic bed. Although Alfred Wegener was able to produce a viable hypothesis with evidence and specifically state the theory, it should be noted there were previous geologists and scientists who thought similar to Wegener. For example, between 1889 and 1909 Roberto Mantovani speculated that all continents had once been conjoined in a “supercontinent,” and even developed an expanding Earth hypothesis.

A depiction of the continents joined together as the “supercontinent,” Pangea, and the path that led them to the positions they reside in today.

Alfred Wegener’s curiosity toward the possibility of continental drift came in 1910 after he noticed how Earth’s continents resembled pieces of a jigsaw puzzle. For example, he noted how South America coast correctly lined up with the coast of Northwest Africa. It wasn’t until 1911, when Wegener came across several scientific documents listing fossils of identical plants and animals found on opposite sides of the Atlantic that his passion for the subject truly showed. Reflecting on this monumental moment in his life, he wrote, “A conviction of the fundamental soundness of the idea took root in my mind.” Alfred Wegener knew massive amounts of evidence needed to be collected in order to justify such a fantastic idea—because with no practical driving force behind it the theory loses most of its credit. In order to maximize evidence for his theory and overlook the absence of a mechanism, he decided to draw from a variety of scientific fields including geology, geography, biology, and paleontology.

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Continental Drift Theory: Definition, Evidence, Limitations

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The Continental Drift Theory proposes that Earth’s continents were once part of a single supercontinent called Pangaea, which later fragmented and drifted to their current positions over millions of years. This theory, initially proposed by Alfred Wegener, is supported by evidence such as matching coastlines, geological similarities, and fossil distribution across continents. The concept laid the foundation for the modern understanding of plate tectonics.

In this article, We have discussed the Continental Drift Theory and supporting evidence for the Drift Theory, and limitations of the theory, and many more.

Let’s dive right in.

Continental Drift Theory

Continental Drift Theory explains that all the continents once were merged in a single landform called PANGEA and the large water body surrounding it was called PANTHELASA. With time the land was further divided into parts and today’s world was formed.

The following is a Complete overview of Continental Drift Theory:

• Alfred Wegener, a German meteorologist and geophysicist, proposed the Continental Drift Theory.
• Suggests that continents were once part of a single supercontinent called Pangaea.
• Hypothetical supercontinent that existed about 200 million years ago.
• Noted the remarkable fit of coastlines, especially between South America and Africa.
• Observed similar geological formations and rock layers on continents that are now separated by oceans.
• Pointed out the presence of identical fossils on continents that are currently distant.
• Used evidence from paleoclimatology, such as glacial deposits, to support his theory.
• Faced skepticism due to the lack of a convincing mechanism for the movement of continents.
• The theory gained acceptance with the development of plate tectonics in the 1960s.
• Explains that the Earth’s lithosphere is divided into plates that move on the semi-fluid asthenosphere.
• Plates can move apart at mid-ocean ridges, collide at convergent boundaries, or slide past each other at transform boundaries.
• The Continental Drift Theory, coupled with plate tectonics, is now widely accepted in the scientific community.
• Revolutionized the understanding of the Earth’s dynamic processes and the constantly changing configuration of its surface.
• Integral to explaining phenomena like earthquakes, volcanic activity, and the formation of ocean basins.
• Ongoing research continues to refine our understanding of plate tectonics and continental drift.

Evidence for Continental Drift Theory

The following is the list of Evidence for Continental Drift Theory:

Continental Drift Theory – Groundbreaking Theory

Continental Drift theory is also called the Groundbreaking Theory of Moving Continents, as according to this theory the major landmass of earth moved with a very slow rate and with time it broke down into smaller landmass that we see in the present day. Earthquake – Definition, Causes, Effects, Protection

• The major land mass Pangea broke into lauresia and gondwana land and futher boke into the present day continents.
• Due to the drift and movement we observe a lot of similarities in the structure and biological creatures in different continents.
• After observing we can see that there are jig-saw attachment in the shapes of different contents.
• India was previously a part of African continent with time it moved towards Asia and merged with it.

Various Stages of Continental Drift Theory

The Continental Drift Theory is a continuous process and it takes a lot of time ( in billion years). The period of continental Drift theory is divided into 5 stages .

• First Stage : During the Carboniferous epoch, Panthalassa, a mega-ocean, encircled Pangea, a supercontinent, in the first stage.
• Second Stage : Around 200 million years ago, the supercontinent Pangaea began to break apart in the second stage of the Jurassic epoch. The northern and southern components of Pangaea, Laurasia, and Gondwanaland were the first large continental masses to break apart.
• Third Stage : In the third stage of the Mesozoic epoch, the Tethys Sea steadily filled and broadened the territory between Laurasia and Gondwanaland.
• Fourth stage : It began at 100 million years ago, when North and South America pushed westward, forming the Atlantic Ocean. The Rockies and Andes were formed by North and South America’s westward migration.
• Fifth Stage : Mountain-building activity occurred during the fifth Orogenetic Stage.

Forces Responsible for Continental Drift

Many forces were responsible for the occurrence of continental drift theory. few of the major are given below and to note is that these forces are still active and responsible for the structural formation of the world landmasses in future.

• Towards the equator due to the interaction of forces of gravity , pole-fleeing force (due to centrifugal force caused by earth’s rotation), and buoyancy (ship floats in water due to buoyant force offered by water).
• Westwards due to tidal currents because of the earth’s motion (the earth rotates from west to east, so tidal currents act from east to west, according to Wegener).
• Wegener proposed that tidal forces , primarily influenced by the gravitational pull of the moon and, to a lesser extent, the sun, played a significant role in his continental drift theory.
• The polar-fleeing force is associated with the Earth’s rotation. Earth’s shape deviates from a perfect sphere, exhibiting a bulge at the equator induced by the planet’s rotation, which results in a greater centrifugal force at the equator.
• According to Wegener, the phenomenon of pole fleeing is attributed to the escalating centrifugal force experienced as one moves from the poles toward the equator. This increase in centrifugal force is a key element in Wegener’s explanation of continental drift.
• However, most of the scholars considered these forces to be insufficient.

Limitations Of Continental Drift Theory

The Continental Drift Theory had some limitations they are mentioned below:

• Wegener was unable to clarify why the drift started during the Mesozoic epoch.
• According to Wegner, the forces that propelled the movement of continents were buoyancy, tidal currents, and gravity, but these forces were too weak to move continents.
• Pangaea is acknowledged by contemporary ideas (Plate Tectonics), although the explanation disproves Wegner’s theory of drifting.
• His explanation of how the SIAL (Silica-Aluminum)-based continental crust, which is floating over the SIMA (Silica-Magnesium)-based ocean floor, formed island arcs that, according to him, were formed during the drifting of continents as a result of friction, fell short.
• Later Plate Tectonic Theory demonstrated that the entirety of SIAL and SIMA is floating over the asthenosphere

RELATED LINKS Major Landforms of Earth Volcanic Landforms Tectonic Plates movement Evolution of Landforms

FAQs on Continental Drift Theory

1. what is continental drift theory.

Continental drift theory is a hypothesis that states that the major landmass of the earth moves and the form different structural differnece with a long span of time.

2. What was Taylor’s theory of continental drift?

The arcuate (bow-shaped) mountain belts of Asia and Europe resulted from the creep of the continents toward the Equator.

3. Who is the father of the continental drift theory?

Alfred Wegener, a German meteorologist, is credited as the progenitor of the Continental Drift Theory, presenting a comprehensive argument in 1912 about the arrangement of continents and oceans. His theory marked a groundbreaking exploration into the dynamic history of Earth’s landmasses.

4. Who first discovered continental drift?

In 1912, German meteorologist Alfred Wegener revolutionized geoscience by introducing the Continental Drift Theory. His comprehensive argument delved into the distribution of continents and oceans, reshaping our understanding of Earth’s geological evolution.

5. Who discovered Pangea?

The concept of Pangaea, the ancient supercontinent, was developed by the German meteorologist and geophysicist Alfred Wegener. He proposed the idea as part of his Continental Drift Theory in the early 20th century, suggesting that continents were once connected in a single landmass before drifting apart over geological time.

7. What was the first supercontinent?

Pangea is known as the first supercontinent.

8. When was the continental drift theory proposed?

The Continental Drift Theory was proposed by Alfred Wegener in 1912.

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continental drift

Definition of continental drift

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Word History

1926, in the meaning defined above

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“Continental drift.” Merriam-Webster.com Dictionary , Merriam-Webster, https://www.merriam-webster.com/dictionary/continental%20drift. Accessed 29 Apr. 2024.

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