Why was continental drift rejected?
According to the theory, the continents of Earth were originally joined into a single supercontinent before they gradually drifted apart over millions of years.
Several scientists refused to accept continental drift as a valid theory for most of the twentieth century.
So, why did people cast doubt on the continental drift for so long? And why was Wegener’s theory of continental drift rejected?
Initially, the theory was rejected because of insufficient empirical evidence, lack of any clear mechanism, and skepticism among experts.
A Bit More about Wegener’s Theory of Continental Drift
Long before Alfred Wegener developed his theory of continental drift, increasingly accurate mapping sparked speculation about the fit of the continents.
For the second time, Wegener offered his continental drift hypothesis to the scientific community in 1930.
In 1916, his idea of continental displacement was ridiculed under peer review.
This time, Wegener posited that the continents had drifted apart after once fitting together as one supercontinent he named Pangaea meaning All Earth.
Fact: As per Wegener's continental drift theory, the supercontinent Pangaea existed around 300 million years ago.
What Wegener Claimed in His Theory of Continental Drift?
Wegener claimed that because of movement, Pangaea split, forming two landmasses, including:
- Laurasia
- Gondwanaland
Laurasia would split to form the northern continents, Europe, North America and Asia.
And Gondwanaland split to form those in the south, South America, Antarctica, Australia and India.
He had expanded on his ideas in a book written in German, The Origin of Continents and Oceans in 1915.
But, it was only after it was published in English in 1922 that the scientific community took notice.
And the community accused Wegener of distorting the continents to fit and failing to come up with a mechanism for drifting.
Fact: Plate tectonics is an advanced scientific field that grew out of the earlier hypothesis of continental drift.
Why was Continental Drift Rejected?
The original rejection of the continental drift idea was due to a number of issues.
The lack of a simple mechanism explaining the migration of continents across the Earth’s surface was a major factor.
The lack of robust empirical evidence for the theory’s claims also contributed to widespread criticism among specialists.
Yet, renewed attention was paid to continental drift after the 1960s thanks to technological breakthroughs and the revolutionary discovery of plate tectonics.
Let’s talk about some of these major issues playing a role in why continental drift was rejected:
Insufficient Evidence and Skepticism
Although Wegener offered some evidence for continental drifting, how it happened eluded him.
He was ridiculed for being an amateur geologist at best.
Although the theory captured the public imagination, it was not taken seriously and considered pseudoscience, that is until the 1960s, when modern technology made researching his ideas possible.
Skepticism from Other Scientists
Wegener and his contemporaries had little meaningful geographical data and nothing suggested entire continents could move.
To them, the continents and oceans were static fixtures created by volcanic forces and erosion.
It was the dominant theory put forward by a true geologist, Thomas C. Chamberlin, whose colleagues put him on par with Newton or Galileo for original thinking.
He believed in letting theories compete but was described as in love with his own.
In his support, his son, Rollin T. declared that if science listened to Wegner it would have to ‘forget all it had learned in the last 70 years’.
Inadequate Knowledge of So-Called Experts
Comparatively speaking, what the geologists of the inter-war years knew about land formation was very little.
Coming up with a theory was easy, collecting evidence to test any hypothesis on something as massive as drifting continents was not.
Despite mounting great expeditions of discovery, geologists had only been capable of scratching at the earth.
It was difficult to support or deny claims either way, and although Wegener’s countryman eventually turned on him too, the anti-German sentiment around at the time hadn’t helped.
Although walking on the moon was only decades away, no one really knew what went on under our feet.
Early Evidence for Continental Drift
Wegener had offered evidence in the form of his map of Pangaea with all the continents accounted for, and a small collection of fossils and rocks found on separate continents.
Evidence of a supercontinent perhaps, but not of how enormous landmasses can drift about a globe thousands of miles apart.
Without evidence either supporting or denying continent drift, Wegener’s entire theory was written off as worthless.
The findings were considered the ravings of a lunatic but they did spark new interest.
Although it never lived to see it, over the coming years Wegener’s Theory of Continental Drift steadily gained credibility.
Fact: The concept of continental drift was born when 16th-century explorers and cartographers noticed that the continents fit together like a jigsaw puzzle.
Mechanisms of Drift: The Missing Puzzle Piece
Being unable to account for how the continents drifted was the Achilles heel of Wegener’s work but it triggered speculation.
Geologists knew that under the Earth’s crust was the molten turmoil of the mantle.
They had studied volcanoes so the logical conclusion was that land was created when they erupted.
Identifying the Missing Piece
With continental drift theory, came the idea that the continents somehow sailed like ships through the magma’s surface but exactly what drove them remained a mystery.
With no one coming up with a convincing explanation, the scientific community was torn.
They liked the idea of a Pangaea but many clung to the idea of landmasses being static.
The fit of the continents was a coincidence or god’s design.
Although the paleontological evidence was mounting, there was only so much 200 million-year-old rock around.
It supported a split Pangaea, but offered no explanation as to how continents ended up where they did.
Finding Additional Evidence to Solve the Mystery
The mechanism driving continent drift remained the missing piece of a geological puzzle.
And by the 1960s the other pieces supporting Wegener’s controversial hypothesis were firmly in place.
Species of identical fossilized animals and plants were found oceans apart. But, they collectively occupied clear banded zones of Pangaea.
Also, glacial grooves on separate continents matched up perfectly across the continental boundaries of the supercontinent.
Even volcanic activity had a role.
Evidence of a drift mechanism wasn’t found until we had the technology to visit the ocean’s depths and witness seafloor spreading for ourselves and they weren’t even looking for it.
Prevailing Scientific Theories on Continental Drift
Perhaps Wegener should be considered more akin to Newton and Galileo than his contemporary Chapman, although his idea was not entirely original.
People had noticed how the continents seemed to fit long ago.
But Wegener stood by his work and now Continental Drift Theory is hailed as the precursor of modern plate tectonics.
Continental Drift and Tectonic Plates
With new materials and super technology, humans can now explore the world below.
What was witnessed at the bottom of the ocean was the geological process of seafloor spread.
It happens at the edges of tectonic plates that float on the mantle surface like water lilies pads on a pond.
The edges dump and rub, melt and buckle and are drawn under each other in subduction pushing up magnetic rock ridges.
Magma rises, sometimes forming volcanoes and producing earthquakes.
It fills in the gaps around and through the melting crust edge, spreading the ridges and pushing the continents apart as it cools.
Answer to the Missing Puzzle Piece
The new findings were Wegener’s missing puzzle piece and the mechanism by which continents moved.
The continents are not static fixtures, neither do they sail like ships through the magma.
With the best Wegener had available, he would never have been able to prove seafloor spread.
He had to have faith that given time, his theory would stand up to investigation.
He was laughed at by his contemporaries but Darwin was ridiculed just a few years before.
But Wegener was a German and an amateur in the science of geology, introducing an old idea and lacking proof, not once but twice, pre and post war years.
Fact: To support his hypothesis, Wegener noted similarities between the Appalachian Mountains in North America and the Scottish Highlands in Europe.
Takeaway
Why was continental drift rejected?
Many issues, including insufficient empirical data, the absence of a clear mechanism, and mistrust among scientific specialists, contributed to continental drift’s early rejection.
Although initially disregarded, the theory of moving tectonic plates and Earth’s dynamic surface gave new life to Wegener’s theory in the 1960s.
