Spurred by a recent reference question, I became curious about Pangaea, the supercontinent that existed about 200 million years ago before breaking up into the continents we know today, and went on a search in our collections to find maps drawn to represent this large landmass. The scientific theories of plate tectonics and continental drift, while common knowledge today, were not always universally recognized and it is only in the recent past these theories have gained widespread acceptance.
The first suggestion that the continents appeared to fit together was made 430 years ago by the well known cartographer Abraham Ortelius in his publication Thesaurus Geographicus. Abraham Ortelius (1527-1598) was born in Antwerp, Belgium. He began his career as an engraver and map colorist. He became a map publisher during the 1560s. Ortelius published the first modern atlas, the Theatrvm orbis Terrarvm or Theatre of the World in Antwerp in 1570. It is perhaps this intimate knowledge with mapmaking that led to his musing that
“the Americas were torn away from Europe and Africa . . . by earthquakes and floods…The vestiges of the rupture reveal themselves, if someone brings forward a map of the world and considers carefully the coasts of the three [continents].”
300 years later, the theory was taken up again by Antonio Snider-Pellegrini, a French geographer and geologist. In 1858, Snider-Pellegrini published a book, La Création et ses mystères dévoilés or The Creation and its Mysteries Unveiled, proposing that the continents were once connected. As evidence for his theory of one continent, Snider-Pellegrini highlighted identical plant fossils he had found in both Europe and America, attributing the breakup to the biblical Great Flood. In his book, he published the two maps seen below depicting his vision of how the continents were once joined together.
Over the next decades, evidence to support the hypothesis for one continent grew. While other scientists of the time also pursued this theory, it was a German meteorologist, Alfred Wegener, who became known as the originator of the scientific theory of continental drift with his publication of three articles in 1912 suggesting that the continents are slowly moving around the earth. He further expanded on the ideas of his original publication in his 1915 book, Die Entstehung der Kontinente und Ozeane [The Origin of Continents and Oceans]. Wegener argued that not only the shape of Earth’s landmasses proved his theory but that fossil records, glacial indicators, and distinctive rock features pointed to one continent in the distant past. For example, fossil specimens of the mesosaurus, an ancient freshwater reptile, were found only along the east coast of South America and the west coast of Africa, proof in Wegener’s opinion of a supercontinent.
Wegener originally named this supercontinent “Urkontinent,” German for “primal continent”. Wegener’s book was published several times over the next decade, expanding on his theory with each edition. In his 1920 edition, he uses the German name “Pangäa,” derived from the ancient Greek word meaning “all lands” or “all earth”. The name entered the lexicon of the scientific community, using the spelling “Pangaea” that we know today. The map below was published in his 1922 third edition and pictures his conception of Pangaea. The caption translates as “reconstruction of the map of the world according to drift theory for three epochs,” with Figure 1 and 2 showing different projections and the dotted areas representing shallow seas.
While widely accepted today, Wegener’s theories were originally met with deep skepticism from many in the scientific community though it quicky grew in popularity. In 1930, the New York Times published an article, seen below, titled “Scientists Build the Story of the Drifting Continents” with several maps illustrating the evidence for continental drift. The article states
“In 1910 F.B. Taylor at Yale first proposed some rather hazy ideas on the drifting of continents, while Alfred Wegener in Germany worked out a similar theory to much greater detail soon afterward. More recently Daly and Joly put the finishing touches on this theory of “sliding continents.” As with so many other theories, this one too had its origin in an accident Wegener once noticed how extraordinarily alike are the west coast of Africa and the east coast of South America…These were the beginnings of the theory. The difficulties were great, the skeptics many. Yet the more geologists studied it, the more modern methods came into use in examining the surface of the earth, the more evidence in favor of Wegener’s theory has grown to maturity; it is the only one that is at all acceptable, though still far from perfect.”
The big weakness of Wegener’s work was he could not account for the mechanism that allowed for continental drift. He proposed that the continents moved somehow due to the forces from the rotation of the earth, plowing through the ocean floor. Wegener tragically died in 1930 during an expedition crossing Greenland and so did not live to see his theories proven. It took several more decades for the majority of scientists to accept continental drift but to also discover its cause, what we now know as the theory of plate tectonics. An important contribution to this paradigm shift in thought was the work in the 1960s of Marie Tharp and Bruce Heezen in their mapping of the ocean floor and proof of seafloor spreading in the Mid-Atlantic Ridge. The 1994 map below depicts the intricacies of the world’s plates and movement, showing how far human understanding grew from Wegener’s initial 1912 proposal.
What started as an ordinary research question propelled me into learning more about the pre-historic world and the foundational principles of how the land we occupy drifts ever onwards. While this post can only give a broad overview, there is much more out there to explore!
Learn More:
- Watch a presentation given at the Library of Congress by Vicki Ferrini, a senior research scientist at the Lamont-Doherty Earth Observatory at Columbia University, tracing the history of ocean mapping, and highlighting pioneering figures like Marie Tharp, whose work revolutionized our understanding of the seafloor and contributed to the plate tectonics revolution.
- Read the 1924 English translation of Alfred Wegener’s book, The origin of continents and oceans, through HathiTrust.
- Picture what the Earth looked like millions of years ago with this map visualization created by Ian Webster.
- Learn more about Marie Tharp in an article in the latest Library of Congress magazine.
Comments (2)
Hi Julie, glad to see you were interested in this idea of Pangaea, most are not aware of its possible importance. Most don’t see conditioning going on in the first paragraph of your blog. From that point you end up right where you’re at now. There is much more to learn about maps minus the conditioning. Hope you find it!
As a lifelong geologist, I really appreciate learning some of the earlier ideas for how the continents fit together. I was unaware of the two ideas that were presented long before Wegner. Thank you for providing these interesting stories.