What is continental drift?
Imagine you are a delivery driver asked to ship a parcel from New York to Africa.
But the catch is:
You have a time-traveling stopwatch that changes seconds into millions of years. So if you set the stopwatch to 1 second, it transports you 1 million years in the past.
So the question is:
If you could time travel to the past, how many years ago would give you the closest distance from New York to Africa? And how many seconds should you set your stopwatch for?
Because, if you’re going to deliver a parcel with a time-travelling watch, you want the time when these two continents are closest.
We’ll get back to our delivery in just a second. But first, let’s talk about continental drift.
Continental drift and moving continents
Continental drift is the idea that continents passively move due to the movement of plate tectonics. Like a conveyor belt, the whole lithosphere rides on a plasticky layer known as the asthenosphere.
We know continents move because we use GPS sensors to track their movements. We’ve calculated that continents move about 5-10 cm per year on average. So this is about the same length your fingernails grow every year.
Now, let’s think in geological time:
Instead of just years, how far have continents moved over millions of years? Because when you think of Earth in a geologic time scale, it’s the continents that have moved thousands of kilometers. And if you compare to millions of years in the past, the Earth we know today doesn’t resemble anything remotely what it did back then.
Geologic time periods and continental drift
About 250 million years ago, there was just one massive chunk of land known as Pangaea. If you look at a world map, you can still piece together our continents like a giant jigsaw puzzle and recreate Pangaea.
Over millions of years, plate tectonics have torn apart Pangaea creating distinct continents and oceans. Plate tectonics are always moving. As you’re about to see, they never stay still.
Permian Period – 250 million years ago
If you travelled back in time 250 million years ago, this was when Pangaea formed. All the continents were together as a single land mass.
Triassic Period – 200 million years ago
About 200 million years ago, Pangaea started tearing apart. Continents started drifting away from each other and oceans were starting to take shape.
Jurassic Period – 145 million years ago
In the Jurassic Period, we traced back dinosaur fossils. Based on where we find these fossils, we can better understand where land was still connected and apart.
Cretaceous Period – 65 million years ago
65 million years ago, the Cretaceous period ended with a mass extinction. About ¾ of plants and animals went extinct and continental boundaries were more prominent.
Finally, the present day Earth is what we are all familiar with. Plate tectonics have carved out 7 distinct continents and 5 oceans where we live today.
Back to our delivery driver…
If you were in the Permian Period, it would be a short delivery from New York to Africa. You wouldn’t even need a boat or airplane.
Slowly after this period, continental drift really began to shape Earth. It was plate tectonics that really drove continental movement.
So what would you set your stopwatch for the quickest delivery.
If one second equaled 1 million years, you’d set the stopwatch to about 250 seconds. Or just over 4 minutes. You’d be transported to Pangaea where New York and Africa are just a stone’s throw away.