My earlier post bemoaning the Pacific Northwest’s lack of preparation for a megathrust-style earthquake led to a long description of the basics of plate tectonics. Revisit that post to remind yourself how Earth’s tectonic plates move, sliding past one another, moving apart, or colliding head on. Over our short lives, we see only a tiny bit of evidence of this awesome process. But, over the hundreds of millions of years that life has been thriving on this planet, the face of Earth has changed dramatically.
The embedded video below gives a nice summary of the major continental motions that have shaped Earth’s recent past (a mere 450 million years out of the planet’s 4.6 billion year history). Please excuse the soundtrack — the first movement of Grieg’s Peer Gynt Suite No. 1 would not have been my choice. Anyway, in addition to exploring Earth’s past, the video’s authors (I have no idea who they are) also predict how plate movements in the future will affect the positions of the continents. I recognize the end results (a new supercontinent) from a book I read time and again as a child: Time-Life Books’ Planet Earth: Continents in Collision. The last few pages of this book mapped out Earth’s future continent positions in 50 or 100 million year increments, culminating in the formation of a new supercontinent 250 million years from now. Apparently, this idea is still alive, with some minor revisions over the past few decades.
A supercontinent is an overused term for a large landmass that is made up of smaller landmasses that collided with one another. Some could argue, for example, that Asia and Europe today make up a supercontinent, especially after the Indian subcontinent smashed into south Asia about 35 million years ago. However, the largest supercontinent existed in the early days of the dinosaurs, when all the continents had been smashed together by the tectonic plate movements of the day, resulting in a massive landmass geologists christened Pangaea (“Entire Earth”). About halfway through the dinosaurs’ reign, new tectonic plate movements began to tear Pangaea apart, creating the young Atlantic Ocean.
Geologists predict that around 50-100 million years from now, current tectonic plate movements will again shift. The Atlantic Ocean, rather than expanding, will begin to shrink, drawing the Americas closer to Europe, Asia, and Africa. Africa will apparently crash northwards into Europe, crumpling the Italian boot and making flights to Cape Town much shorter in duration. My copy of Planet Earth: Continents in Collision and the above video disagree on a few minor points (as does this outdated NASA article) about the positions of Australia and Antarctica, and on whether or not Africa will split into two pieces. But, they agree on one major point: by 250 million years from now, the major continents will again be one. A new Pangaea will apparently emerge, surrounded by a single massive ocean. Apparently, what happens beyond 250 million years is anyone’s guess. Stay tuned!
James Urton
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