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Four scenarios for the next supercontinent
The arc of geological history is long, but it bends towards supercontinents – so, what will the next one look like?
- We're halfway through a 'supercontinent cycle'.
- The next one is due in 200-300 million years.
- Here are four plausible scenarios of what it will look like.
Moving at fingernail speed
How the American, African and European continents once fit together before the Atlantic – and may one day again, if and when the local 'Wilson cycle' reverses.
Credit: Jacques Kornprobst, after E. Bullard et al. (1965), CC BY-SA 4.0
For things so massive and seemingly immovable, continents are pretty hard to pin down. Of course, that's because they do move, if only at the speed at which your fingernails grow: about two inches (5 cm) per year.
Accelerate the film of Earth's geology, and you see the landmasses dance across the globe like islands of foam on a running bath. One peculiarity of our drifting continents is that they tend to combine, over massive amounts of time, into one single supercontinent. It helps that the Earth is round, unlike your bath.
Then, millions of years later, tectonic forces cause the supercontinent to break up again – only for the individual continents to recombine much, much later. All at fingernail speed.
The usual suspects
Norwegian map of what the supercontinent of Columbia/Nuna may well have looked like, 1,590 million years ago.
Credit: Bjoertvedt, CC BY-SA 3.0
Here's one question with an un-pin-downable answer: How many supercontinents have there been in Earth's deep past? At least three or at least seven; as many as 11 or perhaps even a few more. Like the continents themselves, scientific theories diverge. Here are some of the usual suspects (most recent first, ages are approximate):
- Pangea (300-180 million years ago)
- Gondwana (600-180 mya)
- Pannotia (630-540 mya)
- Rodinia (1.1 bya-750 mya)
- Columbia, a.k.a. Nuna (1.8-1.5 billion years ago)
- Kenorland (2.7-2.1 bya)
- Ur (2.8-2.4 mya)
- Vaalbara (3.6-2.8 bya)
That's if we spool back the tape. What happens if we fast-forward? Even though Pangea, the last supercontinent, broke up almost 200 million years ago, geologists are pretty sure there will be another one, but not for some time to come. Right now, we're about halfway through a 'supercontinent cycle'. The next one will be around between 200 and 300 million years from now.
John Tuzo Wilson (1908-93) refined and championed the theory of plate tectonics in the 1960s, when it was still controversial. He was the first non-U.S. citizen to become president of the American Geophysical Union.
Credit: UC Davis
That brings us to the next question with an answer that's hard to pin down: What will that next supercontinent look like? That is, of course, unknowable, as no one alive today will be around to check. But one can speculate. Using what we know about the tectonic forces that power the movements of continental plates, three scientists line up four plausible scenarios for the formation of the next supercontinent.
In "Back to the future: Testing different scenarios for the next supercontinent gathering," Hannah S. Davies, J.A. Mattias Green, and Joāo C. Duarte present four supercontinents, each the outcome of a different tectonic what-if.
Each scenario is a different combination of two basic drivers of continental conglomeration (and fragmentation): the supercontinent cycle itself, and the so-called Wilson cycle.
In 1966, Canadian geologist John Tuzo Wilson proposed that the Atlantic had opened up along a zone where another ocean had previously existed. A 'Wilson cycle' therefore describes the cyclical opening and closing of ocean basins. Since those aren't necessarily in sync with supercontinent cycles, they can lead to various outcomes – supercontinents of different shapes and at different types.
The next supercontinent will take shape when at least one ocean closes. That can happen in one of two ways:
- Introversion: the 'internal', expanding ocean starts to contract and closes up again; or
- Extroversion: the 'exterior' ocean keeps expanding, closing an 'internal' ocean elsewhere.
In the first option, the Wilson cycle and the supercontinent cycle coincide, creating the possibility that the new supercontinent will have more or less the same dimensions as the old one. In the second option, the Wilson and supercontinent cycles do not coincide.In their paper, the researchers line up and standardise the evidence for four well-known scenarios on future supercontinent formation:
- The closure of the Atlantic Ocean, leading to Pangea Ultima;
- The closure of the Pacific Ocean, giving rise to Novopangea;
- The closure of both the Atlantic and Pacific Oceans, creating Aurica; and
- The closure of the Arctic Ocean, forming Amasia.
Pangea Ultima: keystone Africa
'Ultimate' Pangea would be a remake of the 'old' Pangea, more or less.
Credit: Pilgrim-Ivanhoe, reproduced with kind permission
'Ultimate Pangea' will come about via an introversion scenario, with the closing of the Atlantic and the re-formation of the 'old' Pangea – sort of. Introversion is the 'classic' scenario for supercontinent formation; in fact, Pangea itself was likely formed by introversion, with the closing of the Rheic and Iapetus Oceans.
Africa is the key continent here; first by colliding with Europe to form the new continent of Eurafrica, and ultimately as the keystone tying South and North America, Europe and Asia together. Remnants of the Atlantic and Indian oceans reincarnate as the 'ultimate' Mediterranean, closed off from the world ocean by East Antarctica.
Novopangea: Rift becomes Ocean
How Novopangea might come to be: the Pacific closes and a new ocean forms along the East African Rift.
Credit: Pilgrim-Ivanhoe, reproduced with kind permission
A 'classic' extroversion scenario leads to the closure of the Pacific Ocean, and to a 'new' Pangea – not just a re-forming of the old one. The East African Rift keeps growing, developing into a new ocean, replacing the Indian one. East Africa gets stuck against India's west coast.
Aurica: America in the middle
Two Wilson cycles in sync with a supercontinent cycle, and hey presto: Aurica.
Credit: Pilgrim-Ivanhoe, reproduced with kind permission
The Aurica scenario presupposes two Wilson cycles in sync with the supercontinent cycle. Both the Atlantic and Pacific Oceans close, helping to form the supercontinent of Aurica, with the Americas in the middle.
This requires the opening-up of at least one new ocean – for example, at a large rift along the present-day border between India and Pakistan. This new Pan-Asian Ocean, merged with the Indian Ocean, pushes these areas apart, turning them from next-door neighbors into lands on either side of Aurica.
Australia is now entirely landlocked, between Antarctica, East Asia, and North America. Europe and Africa have collided with the Americas from the other side. To the south, Madagascar stubbornly continues its separate course.
Amasia, the Arctic supercontinent
In the Amasian scenario, almost all continents would be joined 'at the top'.
Credit: Pilgrim-Ivanhoe, reproduced with kind permission
The Arctic Ocean closes. Almost all continents are joined at the 'top of the world', with the exception of Antarctica, the only one not drifting northward. It'll be a short hop from North America to North Africa, with Southern Europe acting as a land bridge in between. South America has repositioned itself, with its western edge against the eastern flank of North America.
These images produced by Pilgrim-Ivanhoe, reproduced with kind permission. Original context here. Images based on the aforementioned article: Back to the future: Testing different scenarios for the next supercontinent gathering, by Hannah S. Davies, J.A. Mattias Green and João C. Duarte, published in Global and Planetary Change (Vol. 169, October 2018).
Strange Maps #1064
Got a strange map? Let me know at firstname.lastname@example.org.
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"You dream about these kinds of moments when you're a kid," said lead paleontologist David Schmidt.
- The triceratops skull was first discovered in 2019, but was excavated over the summer of 2020.
- It was discovered in the South Dakota Badlands, an area where the Triceratops roamed some 66 million years ago.
- Studying dinosaurs helps scientists better understand the evolution of all life on Earth.
David Schmidt, a geology professor at Westminster College, had just arrived in the South Dakota Badlands in summer 2019 with a group of students for a fossil dig when he received a call from the National Forest Service. A nearby rancher had discovered a strange object poking out of the ground. They wanted Schmidt to take a look.
"One of the very first bones that we saw in the rock was this long cylindrical bone," Schmidt told St. Louis Public Radio. "The first thing that came out of our mouths was, 'That kind of looks like the horn of a triceratops.'"
After authorities gave the go-ahead, Schmidt and a small group of students returned this summer and spent nearly every day of June and July excavating the skull.
Credit: David Schmidt / Westminster College
"We had to be really careful," Schmidt told St. Louis Public Radio. "We couldn't disturb anything at all, because at that point, it was under law enforcement investigation. They were telling us, 'Don't even make footprints,' and I was thinking, 'How are we supposed to do that?'"
Another difficulty was the mammoth size of the skull: about 7 feet long and more than 3,000 pounds. (For context, the largest triceratops skull ever unearthed was about 8.2 feet long.) The skull of Schmidt's dinosaur was likely a Triceratops prorsus, one of two species of triceratops that roamed what's now North America about 66 million years ago.
Credit: David Schmidt / Westminster College
The triceratops was an herbivore, but it was also a favorite meal of the Tyrannosaurus rex. That probably explains why the Dakotas contain many scattered triceratops bone fragments, and, less commonly, complete bones and skulls. In summer 2019, for example, a separate team on a dig in North Dakota made headlines after unearthing a complete triceratops skull that measured five feet in length.
Michael Kjelland, a biology professor who participated in that excavation, said digging up the dinosaur was like completing a "multi-piece, 3-D jigsaw puzzle" that required "engineering that rivaled SpaceX," he jokingly told the New York Times.
Morrison Formation in Colorado
James St. John via Flickr
The Badlands aren't the only spot in North America where paleontologists have found dinosaurs. In the 1870s, Colorado and Wyoming became the first sites of dinosaur discoveries in the U.S., ushering in an era of public fascination with the prehistoric creatures — and a competitive rush to unearth them.
Since, dinosaur bones have been found in 35 states. One of the most fruitful locations for paleontologists has been the Morrison formation, a sequence of Upper Jurassic sedimentary rock that stretches under the Western part of the country. Discovered here were species like Camarasaurus, Diplodocus, Apatosaurus, Stegosaurus, and Allosaurus, to name a few.
|Credit: Nobu Tamura/Wikimedia Commons|
As for "Shady" (the nickname of the South Dakota triceratops), Schmidt and his team have safely transported it to the Westminster campus. They hope to raise funds for restoration, and to return to South Dakota in search of more bones that once belonged to the triceratops.
Studying dinosaurs helps scientists gain a more complete understanding of our evolution, illuminating a through-line that extends from "deep time" to present day. For scientists like Schmidt, there's also the simple joy of coming to face-to-face with a lost world.
"You dream about these kinds of moments when you're a kid," Schmidt told St. Louis Public Radio. "You don't ever think that these things will ever happen."
We spend much of our early years learning arithmetic and algebra. What's the use?
- For the average person, math seems to play little to no role in their day-to-day life.
- But, the fanciest gadgets and technologies are all heavily reliant on mathematics.
- Without advanced (and often obscure) mathematics, modern society would not be possible.
The following is an adapted excerpt from the book What's the Use? It is reprinted with permission of the author and Hachette Book Group.
What is mathematics for?
What is it doing for us, in our daily lives?
Not so long ago, there were easy answers to these questions. The typical citizen used basic arithmetic all the time, if only to check the bill when shopping. Carpenters needed to know elementary geometry. Surveyors and navigators needed trigonometry as well. Engineering required expertise in calculus.
Today, things are different. The supermarket checkout totals the bill, sorts out the special meal deal, adds the sales tax. We listen to the beeps as the laser scans the barcodes, and as long as the beeps match the goods, we assume the electronic gizmos know what they are doing. Many professions still rely on extensive mathematical knowledge, but even there, we have outsourced most of the mathematics to electronic devices with built-in algorithms.
My subject is conspicuous by its absence. The elephant isn't even in the room.
It would be easy to conclude that mathematics has become outdated and obsolete, but that view is mistaken. Without mathematics, today's world would fall apart. As evidence, I am going to show you applications to politics, the law, kidney transplants, supermarket delivery schedules, Internet security, movie special effects, and making springs. We will see how mathematics plays an essential role in medical scanners, digital photography, ﬁber broadband, and satellite navigation. How it helps us predict the effects of climate change; how it can protect us against terrorists and Internet hackers.
Remarkably, many of these applications rely on mathematics that originated for totally different reasons, often just the sheer fascination of following your nose. While researching this book, I was repeatedly surprised when I came across uses of my subject that I had never dreamed existed. Often, they exploited topics that I would not have expected to have practical applications, like space-ﬁlling curves, quaternions, and topology.
Mathematics is a boundless, hugely creative system of ideas and methods. It lies just beneath the surface of the transformative technologies that are making the twenty-ﬁrst century totally different from any previous era — video games, international air travel, satellite communications, computers, the Internet, mobile phones. Scratch an iPhone, and you will see the bright glint of mathematics.
Please don't take that literally.
There is a tendency to assume that computers, with their almost miraculous abilities, are making mathematicians, indeed mathematics itself, obsolete. But computers no more displace mathematicians than the microscope displaced biologists. Computers change the way we go about doing mathematics, but mostly they relieve us of the tedious bits. They give us time to think, they help us search for patterns, and they add a powerful new weapon to help advance the subject more rapidly and more effectively.
In fact, a major reason why mathematics is becoming ever more essential is the ubiquity of cheap, powerful computers. Their rise has opened up new opportunities to apply mathematics to real-world issues. Methods that were hitherto impractical, because they needed too many calculations, have now become routine. The greatest mathematicians of the pencil-and-paper era would have ﬂung up their hands in despair at any method requiring a billion calculations. Today, we routinely use such methods, because we have technology that can do the sums in a split second. Mathematicians have long been at the forefront of the computer revolution — along with countless other professions, I hasten to add. Think of George Boole, who pioneered the symbolic logic that forms the basis of current computer architecture. Think of Alan Turing, and his universal Turing machine, a mathematical system that can compute anything that is computable. Think of Muhammad al-Khwarizmi, whose algebra text of 820 AD emphasized the role of systematic computational procedures, now named after him: algorithms.
Most of the algorithms that give computers their impressive abilities are ﬁrmly based on mathematics. Many of the techniques concerned have been taken "off the shelf" from the existing store of mathematical ideas, such as Google's PageRank algorithm, which quantiﬁes how important a website is and founded a multi-billion-dollar industry. Even the snazziest deep learning algorithm in artiﬁcial intelligence uses tried and tested mathematical concepts such as matrices and weighted graphs. A task as prosaic as searching a document for a particular string of letters involves, in one common method at least, a mathematical gadget called a ﬁnite-state automaton.
The involvement of mathematics in these exciting developments tends to get lost. So next time the media propel some miraculous new ability of computers to center stage, bear in mind that hiding in the wings there will be a lot of mathematics, and a lot of engineering, physics, chemistry, and psychology as well, and that without the support of this hidden cast of helpers, the digital superstar would be unable to strut its stuff in the spotlight.
The importance of mathematics in today's world is easily underestimated because nearly all of it goes on behind the scenes. Walk along a city street, and you are overwhelmed by signs proclaiming the daily importance of banks, greengrocers, supermarkets, fashion outlets, car repairs, lawyers, fast food, antiques, charities, and a thousand other activities and professions. You do not ﬁnd a brass plaque announcing the presence of a consulting mathematician. Supermarkets do not sell you mathematics in a can.
Dig a little deeper, however, and the importance of mathematics quickly becomes apparent. The mathematical equations of aerodynamics are vital to aircraft design. Navigation depends on trigonometry. The way we use it today is different from how Christopher Columbus used it, because we embody the mathematics in electronic devices instead of pen, ink, and navigation tables, but the underlying principles are much the same. The development of new medicines relies on statistics to make sure the drugs are safe and effective. Satellite communications depend on a deep understanding of orbital dynamics. Weather forecasting requires the solution of equations for how the atmosphere moves, how much moisture it contains, how warm or cold it is, and how all of those features interact. There are thousands of other examples. We do not notice they involve mathematics, because we do not need to know that to beneﬁt from the results.
A socially minded franchise model makes money while improving society.
- A social enterprise in California makes their franchises affordable with low interest loans and guaranteed salaries.
- The loans are backed by charitable foundations.
- If scaled up, the model could support tens of thousands of entrepreneurs who are currently financially incapable of entering franchise agreements.
The underdog challenging McDonald’s & Wall Street | Hard Reset by Freethink www.youtube.com
Social responsibility is becoming a major focus of many businesses. While turning a profit is always the ultimate goal — nobody can eat good intentions, after all — having a positive impact on society is becoming an equally important goal.
A restaurant chain in California, already focused on providing healthy food at a competitive cost, is testing a new way to create more entrepreneurs. Specifically, it is working with charitable foundations to provide business opportunities to those who normally would not have access.
When a company wants to expand without paying all of the upfront costs itself or taking on the entire risk of operating in a new market, it can enter into a franchise agreement with an entrepreneur. In exchange for a share of the profits (as well as some fees and adherence to certain quality standards), the entrepreneur — now a franchisee — can open their own branch of a larger brand. The entrepreneur enjoys the benefits of owning a business, while the brand owner can cash in on intellectual property.
This model is wildly successful. There is a reason you can find fast food joints like McDonald's everywhere from Times Square to Prague (next to the Museum of Communism, no less). According to the International Franchise Association, there were more than 733,000 franchised business establishments in the United States in 2018, accounting for nearly 3 percent of GDP.
The franchise model — in which a local agent keeps some earnings while handing over a portion to a central authority — isn't new. Indeed, variations have been around since the Middle Ages, though it only took off after WWII. Franchising is now a recognized system in many countries and is used in all manner of industries, including restaurants, pet supply stores, automotive repair shops, hotels, and even senior care.
The Catch-22: you have to spend money to make money
The biggest problem with franchising is the high cost of becoming a franchisee.
While the costs vary, opening a restaurant as a franchisee can easily cost $500,000. A franchise car repair shop can require $250,000, and opening a hotel under a franchise's banner can set a person back millions. In some cases, the franchiser also will set a minimum net worth requirement or insist that the money that pays their fees not be borrowed. Even if a person can find a way around that, most new businesses do not turn a profit for quite some time after opening. These limitations essentially rule out all but the wealthy from becoming a franchisee.
As a result, there are some social enterprises that are looking to make franchising more accessible to the less affluent.
As a business that hopes to rapidly expand, they looked to franchising. However, the idea of seeking out a bunch of rich people to support a business like theirs struck CEO Sam Polk as out of step with its vision. So, the company came up with a better idea.
Their Social Equity Franchise Program helps tenured Everytable employees open their own franchise locations through free training and assistance in securing low interest loans to finance the store. To help the entrepreneurs survive the difficult early years, participants in the program are assured an income of $40,000 in their first three years of operations. Repayments on the loans do not begin until after the business is turning a profit.
The capital for all these low interest loans comes from a number of foundations such as the California Wellness Foundation (Cal Wellness). Foundations like these are required to give away a small portion of their endowments every year on causes aligned with their missions. However, most of the rest of it is simply invested in the stock market to assure the endowment continues to exist.
People like Cal Wellness CEO Judy Belk have begun to invest that money elsewhere, like in loans to provide the money needed to open an Everytable franchise. As she explained to FreeThink:
"Cal Wellness and many other foundations are saying, 'I think we can do a little better with that [money]. Why not use that capital to invest in the communities that we're supposed to serve?'"
In the end, Everytable gets a new restaurant that expands the brand, foundations get returns on their investment, and the franchisee gets an opportunity that they likely never would have had without the program.
Expanding the Everytable model
If even a small share of the $2 trillion foundations in the U.S. have are invested into this sort of social cause, tens of thousands of loans could be given to those less affluent people who are looking to start a business. While this model likely would lower returns to institutional investors like charities, they could enjoy more tangible results in the communities they exist to serve. According to a report published by the Federal Reserve Bank of Atlanta, local entrepreneurship increases income and employment and decreases poverty.
At the individual level, this would help a lot of people who otherwise never would be able to seriously consider going into business for themselves. By a number of measures, business owners make more than wage workers and can also claim ownership of the assets that comprise the business. Beyond that, many small business owners enjoy the non-financial benefits of their position as well, including the independence and autonomy that often come with business ownership.
When working optimally, good business is good for society.
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