Have you ever looked at the various continents on Earth and thought: “They look like they could be put together like a jigsaw puzzle?”
That idea was something that Alfred Wegener wanted to pursue. This single large landmass, referred to as “Pangaea,” intrigued Wegener. His primary interest in life was meterology, but then he realized a flooded land bridge would contradict the balance between the mantle and crust of the planet. This caused him to pursue ideas about how Pangaea could have produced how the continents exist today.
By 1912, Wegener was ready to present his continental drift theory. By analyzing fossilized plants, geological structures, and rock types on both sides of the Atlantic Ocean, he realized that there were significant similarities to what he was seeing.
What Are the Mechanisms of Wegener’s Continental Drift Theory?
The idea of Pangaea is essentially the beginning of Wegener’s continental drift theory. His argument was one of the first from a scientific foundation that there was once a single landmass on Earth. These land masses were now in their current position because of a drifting mechanism that had occurred.
There were several different ideas that Wegener suggested that could be responsible for the continental drifting process.
- Polflucht. In this idea, the mechanisms that caused the drift could have been the centrifugal forces that are generated by the rotation of the planet.
- Sea Floor Spreading. The Mid-Atlantic Ridge is a zone of floor for the Atlantic Ocean which replicates a mountain range, tearing apart to make room for rising magma, and this could encourage the continents to continue moving.
- Astronomical Precession. The continents could have been encouraged to drive because of slow and continuous changes that were induced by gravity from heavenly bodies. The orbit of the moon, for example, creates tidal patterns and larger bodies could have exhibited a larger influence that allowed for continental drift.
Although Wegener had several ideas about how the mechanisms of continental drift occurred, he did not pursue each one as he developed his theory. Eventually, he would come to suggest that Polflucht would be the primary method of movement.
The One Main Problem with Wegener’s Continental Drift Theory
When you put a puzzle together, there is only one solution that is the correct one. When you’re trying to find where a piece should go, however, there may be places in the puzzle which seem to be correct, but are eventually proven to be incorrect. Much of the resistance to Wegener’s continental drift theory came about because of how he suggested the continents once fit together.
Wegener used fossil patterns to help shape the map of Pangaea as he saw it. This meant that Antarctica would be used as the root continent and the others would be formed around it. He suggested that Australia would make up the eastern-most continent, while Africa was on the West. Asia would then be between Australia and Africa, while South America would be the furthest west. North America and the upper stretches of Asia and Europe would be the northernmost points, with portions of sea stretched between them.
This is contrary to the modern version of Pangaea, which has Africa as the foundation of the content. The Americas then wrap around Africa, with Eurasia in the North, Antarctica to the South, and Australia even further south when using conventional continental borders.
What Is Unique About the Pangaea Concept?
Forming supercontinents seems to be a pattern of behavior for the planet. There may have been 5 total supercontinents that were on our planet and each one of them are believed to have broken apart. Using the concepts of continental drift theory by Wegener, we are about halfway toward the formation of a sixth supercontinent.
This is because the current rate of drift, based on how the continental plates move on Earth, is estimated to be 2.5 centimeters per year. Wegener found resistance to his theory because his first proposals estimated drift rates to be at 250 centimeters per year.
At that rate of drift, the next supercontinent is believed to be connected in the north, with bridging between Eurasia and North America occurring. The name of this potential new supercontinent has been dubbed “Amasia.”
Since it is estimated that Pangaea, the last great supercontinent, existed about 300 million years ago, estimates for the new supercontinent to form using continental drift theory range from 50 million years to 200 million years from now.
Alfred Wegener’s continental drift theory faced fierce resistance initially, partially because of his outsider status, and partially due to his ideas of how the continents fit together. As we’ve studied this idea over the decades, however, it has come to be the accepted theory of why our land areas are in their current location.