originally published October 22, 2012
I promised my wife I could make an article about geology interesting. In my defense, I’d downed two delicious pints of Alleykat’s Chili-Pepper lager, and where some men get beer muscles I tend to get a beer writing ability. Plate tectonics? Hell yeah! This shit’ll be riveting!
Now that the passage of a few hours has siphoned the alcohol from my bloodstream, I’m faced with a daunting task. Yet I can’t help but be drawn to this topic. I didn’t even know there was such a thing as a supercontinent cycle.
The basics of supercontinents are pretty easy to grasp. The plates that make up the earth’s continental crust are always moving, shimmying under our feet and causing earthquakes that range from the catastrophic down to those tiny ones that stoned people aren’t entirely sure didn’t just happen in their heads. Once upon a time – about 300 million years ago – all our continents were bunched together in a single clump, like the hard candies in my grandmother’s candy dish. We call this clump Pangea.
How do we know this happened? It’s more than just a guess. First of all, the pieces fit together. It’s not a perfect click, but it’s pretty damn close. Second, there are similar sedentary rocks found where these continents used to be connected. Third… well, there are a lot more reasons, ranging from fossils to glaciology to something called paleomagnetics. Let’s just call this a fact and move on. Sciencey people have written in down in text books and it’s on the internet – what more evidence do we need?
What I didn’t know was that this happened before Pangea. The supercontinent cycle glops our continents together and pulls them apart like a kid setting up and knocking down a stack of creamers at a diner. Go back another three hundred million years and you’d come across this monstrosity, known as Pannotia:
This looks like someone cut up a world map and pieced it together arbitrarily, with the Congo somehow ending up larger than Europe. It’s kind of like one of those dreams where you’re in a familiar location, but it doesn’t look right. It’s that ever-present line in the scientific sand, when science crosses over into mind-fuckery. I love that line.
Before Pannotia, the continents hooked up and split up erratically, like a high school couple. Rodinia happened just 150 million years before Pannotia, and before that was Columbia, Kenorland, Ur, and Vaalbara. Before Vaalbara, I guess the planet was mostly a heap of molten goo.
One of the reasons we know all this wizardry actually happened is because of this guy:
That’s John Tuzo Wilson, a Canadian scientist who came up with the idea of plate tectonics. This guy was, if not the Elvis of geology, at the very least he was geology’s Little Richard. Maybe even its Buddy Holly. Wilson discovered the concept of the transform fault, which is when two continental plates move horizontally up against one another, as opposed to moving toward or away from each other. This helped us understand the science behind the San Andreas Fault, or that jagged little stripe of land that keeps Californians neck-deep in earthquake insurance.
The supercontinent cycle messes with the sea level. When all the continents are snugly together, the sea level drops. If you’re looking for the math behind this, it’s right here:
Fortunately, I’m not looking for the math. I’m never looking for the math. I don’t care about the math. I do know that the continental plates are moving at varying speeds around the globe, the fastest being about 18.3 centimeters (that’s just over seven inches) per year between South America and New Zealand.
This constant continental boogie has an effect on global climate as well. Climatologists tell us we have two kinds of global climate, an Icehouse Climate and a Greenhouse Climate. An icehouse climate occurs when the continents are moving together, giving us continental glaciations and some severe desert environments. A greenhouse climate happens as the continents are dispersed. Which are we in? Well, we’re in a greenhouse phase of an icehouse climate. Confused? That’s okay, it won’t matter once humankind turns the environment from an icehouse into a shithouse over the next century.
Whoa, got a little preachy there. Sorry about that. Let’s change things up and look at how this all relates to evolution.
When the continents are split up with a north-south configuration, kind of like what we have now, it fosters a major bump in the evolutionary process. This makes sense – whatever is living in the Atlantic Ocean remains isolated from the population in the Pacific, so they’ll develop seperately. If the continents are running east-west – or for that matter, if they’re all grouped together – you have less diversification, less isolation, and therefore less species trying to make it on their own in a new neighborhood.
So what happens next? There has to be another supercontinent on the horizon, right? Sure, meet Amasia:
Well, you won’t actually be able to meet Amasia for another 200 million years. The most recent estimates by the white-coats at Yale University say this bunching together will occur over the north pole, which will really cut down on the flying time for Santa, I suppose. North and South America will finally break all that romantic tension and get together. Australia will find its way north, landing somewhere in between India and Japan. The Arctic Ocean will disappear (no one will miss it), as will the Caribbean (which will just murder the all-inclusive travel industry).
The Yale team looked at the effects of the Earth’s magnetic field on the magnetic minerals in a bunch of ancient rocks, and using that evidence (and perhaps consulting an oracle – I have no idea how they figure these things out), they completely blew apart the previous theory, which stated that our next supercontinent will tuck itself around the equator, roughly where Africa is today.
It’s all quite fascinating, in that same way it can be fascinating to speculate about sentient life on other planets. We’ll never live to see the future effects of the supercontinent cycle, but it’s good to know someone has put the time in to figure it out. Also, it’s good to know someone took the time to design a mascot to accompany the theory. That’s science, dammit.