Ever looked at a map and thought everything stayed put? It hasn't. Not even close. If you could hop in a time machine and set the dial for 150 million years ago, a jurassic map of the world would look like a complete mess compared to what we see on Google Maps today. You'd be staring at a planet that was basically one giant jigsaw puzzle being ripped apart by a very slow, very angry toddler.
The Jurassic period wasn't just about big lizards with teeth. It was about the literal foundation of our modern world breaking into pieces.
The Atlantic Ocean? Didn't exist yet. Well, not really. It was just a narrow, salty rift valley starting to leak water between what we now call Africa and North America. Most people imagine the dinosaurs roaming across the seven continents we have today, but for a huge chunk of the Jurassic, those continents were still huddled together in the supercontinent Pangea. Or at least, they were trying to stay together. It's kinda wild to realize that a Brachiosaurus could have potentially walked from New York to Morocco without ever getting its feet wet.
The messy breakup of Pangea
The Earth's crust is basically a bunch of cracked eggshells floating on hot goo. During the Jurassic, these shells started sliding. This wasn't a clean break. It was more of a messy divorce where everyone was fighting over the furniture.
Geologists like Christopher Scotese have spent decades mapping this out through projects like the PALEOMAP Project. What they found is that during the Early Jurassic, the supercontinent Pangea began to unzip. Imagine a giant zipper starting at the Tethys Ocean in the east and tearing westward. This created two massive landmasses: Laurasia in the north (North America, Europe, Asia) and Gondwana in the south (South America, Africa, Antarctica, India, Australia).
But here’s the thing that gets me.
Even though we talk about "Laurasia" and "Gondwana," they weren't solid blocks. They were riddled with shallow, epicontinental seas. Because the planet was so warm—there were no ice caps at the poles—sea levels were insanely high. Large parts of what is now Western Europe were just a series of tropical islands. London? Underwater. Paris? A reef. If you were looking at a jurassic map of the world, you’d see more blue than green in places that are now bustling metropolitan hubs.
Where the giants actually walked
When we talk about "the world" back then, we have to talk about the climate because that determined where things could actually live. The Jurassic was a greenhouse world. Carbon dioxide levels were roughly four to five times higher than they are today.
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This created a planet with no winter.
Seriously. You could find ferns and lush forests in Antarctica. Fossil evidence from the Prince Charles Mountains proves that even the most southern reaches of Gondwana were teeming with life. On a real jurassic map of the world, the "frozen wastes" simply didn't exist. Instead, you had massive coniferous forests of Araucaria (think Monkey Puzzle trees) stretching from pole to pole.
This warmth drove the massive size of the sauropods. These animals needed huge amounts of vegetation to fuel their bodies. The map of their world was a buffet. In the Morrison Formation of the western United States—which was a vast, semi-arid floodplain at the time—we find the remains of Diplodocus and Allosaurus. But back then, that part of the U.S. was much closer to the equator. It was hot, dusty, and seasonally flooded.
It’s also worth noting that "India" was nowhere near Asia. It was a giant island chilling out near Madagascar and Antarctica. It wouldn't crash into Asia to form the Himalayas for another hundred million years. So, on your Jurassic map, the roof of the world is flat, and the Indian Ocean is just a tiny puddle.
Why the oceans looked "wrong"
The Pacific was there, sure, but it was called Panthalassa. It was a monstrous, planet-spanning ocean that covered nearly an entire hemisphere. But the stars of the show were the interior seaways.
The Tethys Ocean is the one you really need to know about. It was a wedge-shaped sea that poked into the side of Pangea from the east. It’s basically the ancestor of the Mediterranean, but it was much bigger and much more important. It acted as a global highway for marine reptiles like Ichthyosaurs and Plesiosaurs.
As the continents drifted, they created "corridors."
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One of the most famous is the Hispanic Corridor. This was a narrow seaway that opened up between North and South America, finally connecting the Tethys to the Pacific. This was a massive deal for evolution. Suddenly, species that had been trapped in the "Old World" could swim to the "New World." It was the Jurassic version of the Panama Canal, but natural and much more terrifying because of the 50-foot predators swimming through it.
The problem with most "dinosaur maps"
Honest truth? Most maps you see in textbooks are oversimplified. They show clean lines. Earth is never clean.
During the Late Jurassic, the world was a series of transition zones.
- North America was getting squeezed on its western edge, starting to push up the very beginnings of the Rocky Mountains (the Nevadan orogeny).
- Africa was beginning to pull away from South America, creating the "South Atlantic" which was basically just a series of stinking, stagnant salt lakes at first.
- Europe was a flooded archipelago, more like the modern-day Bahamas than a continent.
If you’re looking at a jurassic map of the world to find where your house would be, you’d likely find it was either under a few hundred feet of water or a thousand miles away from its current neighbors. For example, if you live in Florida, you weren't even part of North America yet. Florida was actually tucked between Africa and South America, part of the Gondwanan plate, and only got "left behind" when the continents split.
The actual science of mapping the past
How do we even know this? We can't exactly go back and take a photo.
It’s all about paleomagnetism. When rocks form—especially volcanic rocks—the magnetic minerals inside them line up with the Earth's magnetic field. This locks in a "signature" of where that rock was on the planet at that exact moment. By reading these signatures in old crust, scientists like those at the International Commission on Stratigraphy can piece together the movement.
We also use "index fossils." If you find the same tiny shelled creature (an Ammonite) in both England and Utah from the same time period, you know there was a marine connection between them. It’s like a giant forensic crime scene spread across 150 million years.
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Practical takeaways for your own research
If you want to actually see this for yourself without a PhD, there are a few things you should do.
First, go check out the Ancient Earth Globe (dinosaurpictures.org). It’s an interactive tool created by Ian Webster that lets you plug in your current address and see exactly where it sat on a jurassic map of the world. It’s humbling to see your hometown sitting in the middle of a vast, empty ocean or jammed against a continent you've never visited.
Second, understand that "Jurassic" covers 55 million years. The map at 200 million years ago is radically different from the map at 145 million years ago. Don't settle for a single image. Look for the "Early," "Middle," and "Late" distinctions.
Third, pay attention to the "Large Igneous Provinces." These were massive volcanic eruptions, like the Central Atlantic Magmatic Province (CAMP), that literally cracked the crust open. These events are the "why" behind the map's changes.
The world is constantly moving. We’re just living in a very short, very still frame of a much longer movie. The Jurassic was one of the most action-packed scenes in that film.
Actionable Next Steps:
- Locate your coordinates: Use a plate tectonic simulator to find your specific city's location 150 million years ago.
- Compare the seaways: Research the "Western Interior Seaway" to see how it eventually split North America in two, a process that started with Jurassic shifts.
- Track the fossils: Look up your local geological survey to see if your region has Jurassic-aged "outcrops"—places where this ancient map is actually visible on the surface today.