We Don't Talk Enough About Pangaea

If I had gone into geology, I would’ve studied supercontinents and their cycles. It’s wild stuff and surprisingly underappreciated. Let’s change that.

A Puzzle from the Past: The Origins of Pangaea

The idea of a supercontinent goes back centuries. While the concept may have been hinted at by Abraham Ortelius in the 1500s, it was Alfred Wegener, a German scientist, who really put it on the map… haha.

Driven by curiosity and observation (those “what if” moments, like wondering why stars move), Wegner noticed how continents seemed to fit together like puzzle pieces. This led to his groundbreaking 1915 book, The Origin of Continents and Oceans, where he introduced the idea of continental drift and coined the term “Urkontinent”, meaning “supercontinent” in German. 

By the 1920 edition, he referred to it as “Pangäa of the Carboniferous”, meaning “all Earth”. According to current science, Pangaea existed from around 355 million to 175 million years ago, spanning Early Carboniferous through the Middle Jurassic. Instead of the seven continents we know today, Earth was one giant continent surrounded by a single ocean, called Panthalassa.

It made intuitive sense that the continents once fit together, but the bigger hurdle was answering “how did they drift apart?” 

Early theories suggested Earth’s rotation caused the separation via centripetal force, but this was quickly dismissed as implausible, making it harder to prove that Pangaea ever existed at all. So what evidence is there to support Pangaea besides that they look like they fit together?

Geological Evidence for Pangaea

Thanks to decades of geological research, we now have a range of evidence:

• Polar Ice Cap Traces in Tropical Zones

  • Glacial deposits, normally found near the poles, have been discovered in now-tropical places like India, South America, Africa, and Australia. The patterns in these deposits radiate outward from what would have been a central South Pole, suggesting these continents were once connected and positioned near the actual South Pole. 

• Matching Mountain Ranges Across Continents

  • One of the most compelling clues is the alignment of mountain ranges. There are mountain ranges of the same age and composition that are found on continents now widely separated. When reassembled into Pangaea, the Appalachians in North America line up perfectly with the Caledonian Mountains in Scotland and Scandinavia. These form part of a massive collision zone known as the Central Pangaea Mountains. 

• Fossil Records in Odd Places

  • Fossils of species that couldn’t have crossed oceans are found on continents now separated by vast distances: 

    • Fossils for a fern called Glossopteris have been found across South America, Africa, India, Antarctica, and Australia. How did tropical plant fossils end up in now-frozen Antarctica? 

    • Fossils of a freshwater reptile called Mesosaurus have been found in both South America and Africa. Since these species couldn’t have crossed oceans, their presence on separate continents suggests the landmasses were once joined. 

• Continental Plate Movement

  • While Wegner’s idea of “continental drift” laid the groundwork, modern geology has refined it into the theory of plate tectonics. The Earth’s crust isn’t one solid shell but rather multiple rigid plates that move due to forces like seafloor spreading, subduction, and faulting. This also explains how Pangaea broke apart in stages, and not all at once. 

• Magnetic Minerals

  • Iron-rich materials in ancient lava flows align with Earth’s magnetic field at the time they cooled. Rocks on different continents show matching magnetic signatures, providing a kind of “magnetic fingerprint” proving they were once connected. 

A Quasi-Periodic Family Reunion

The formation of Pangaea is not the first time that the continents have met up for a family reunion, and it won’t be the last. 

The Earth’s crust is constantly being reconfigured and actually has a quasi-periodic supercontinent cycle. One cycle is said to take 300-500 million years, and the next one is expected to occur within the next 250 million years. Many have made predictions of the configuration, suggesting that it will likely exist at the equator and the most common prediction being called Pangaea Ultima.

Climate Chaos: What Will Pangaea Ultima Be Like?

It’s a wild thing to think about what the world will be like in 250 million years. Will humans be around to experience it? Say we will… What would the climate even look like?

As you can imagine, a supercontinent has major climate consequences. Large landmasses tend to have more extreme temperatures and arid climates (consider Siberia, the Sahara, the Great Plains, etc.), with little rain reaching the interior, because of the large distance from oceans. When continents collide, there will be more carbon dioxide (CO2) in the atmosphere to warm the planet because of increased volcanic activity and a decrease in the chemical reactions between rock and water that normally trap CO2 in minerals. Together, this means more greenhouse gases and warmer global temperatures. 

Simulating the Future

In a 2023 study at the University of Bristol, researchers ran climate simulations for Pangaea Ultima as a means to predict the climate impact of the next supercontinent. Their models accounted for a 2.5% brighter sun and CO2 levels rising to 410-816 ppm (today’s level is ~420 ppm). An important note is that these simulations are done with the exclusion of human influence, as that adds a difficult level of prediction. Measures are compared to “pre-human climate change”, or Earth’s climate before humans began significantly altering it (prior to the industrial revolution), where CO2 levels were around 280 ppm.