A supercontinent is a single, massive landmass incorporating most or all of Earth’s continental crust. The most recognizable example in recent geological history is Pangea, which existed approximately 335 million years ago before breaking apart into the continents we know today. The history of the planet is marked by this recurring process of continental assembly and dispersal, a phenomenon scientists call the Supercontinent Cycle. This cycle, which typically spans between 300 and 500 million years, is a fundamental driver of Earth’s climate, sea level, and biological evolution.
The Mechanism Driving Supercontinent Assembly
The movement of continents is governed by plate tectonics, powered by the slow flow of heat within the planet’s mantle, known as mantle convection. Hot material rises and cooler material sinks, creating conveyor-belt-like motions that drag the rigid tectonic plates across the surface. Supercontinent formation occurs when these plates converge, eliminating the oceanic crust that once separated them.
Oceanic crust is destroyed at subduction zones, where a denser oceanic plate slides beneath a lighter continental plate, sinking back into the mantle. This consumption closes ocean basins and forces continental collision. The final assembly of a supercontinent is a global-scale mountain-building event, where continents weld together along immense fault lines.
Geologists categorize the assembly process into two end-members based on which ocean closes: introversion or extroversion. Introversion involves the closure of the internal ocean—the one that formed when the previous supercontinent broke apart—to reassemble in a similar location. Extroversion describes the closure of the external ocean, or “superocean,” that surrounded the previous landmass, causing the new supercontinent to form on the opposite side of the planet. Distinguishing between these two models is crucial for predicting the shape and location of the next global landmass.
Estimated Timeline for the Next Supercontinent
The next supercontinent is predicted to form approximately 200 to 250 million years from now. Current continental movement provides the initial clues for this prediction, showing which oceans are beginning to close and which are expanding. The Atlantic Ocean is currently widening due to seafloor spreading along the Mid-Atlantic Ridge, pushing the Americas westward away from Europe and Africa at a rate of a few centimeters per year.
Conversely, the Pacific Ocean is being consumed at its edges by a ring of subduction zones, often called the “Ring of Fire.” This gradual consumption means the Pacific is destined to close entirely as the surrounding continents converge. Australia is also moving rapidly northward, on a collision course with Southeast Asia, an early step in the global reassembly process.
The closing of the world’s oceans will occur in a specific sequence, beginning with the Pacific and potentially the Arctic. As the Atlantic continues to widen, it will eventually reach a point where new subduction zones form along its margins, initiating its closure and pulling the continents back together. This reversal of the Atlantic’s expansion will finalize the formation of the new supercontinent.
Competing Models for the New Global Landmass
The configuration of the new global landmass depends on which ocean dominates the closing process, leading to distinct scientific models for the resulting supercontinent.
Novopangea (Introversion)
The Novopangea scenario, also referred to as Pangea Proxima, is based on the introversion model, predicting the closure of the Atlantic and Indian Oceans. In this model, the Americas collide with the merged Africa-Eurasia landmass, creating a supercontinent that encircles a remnant central ocean basin, sometimes called the “Medi-Pangaean Sea.”
A supercontinent formed by introversion, like Novopangea, would feature a massive, arid continental interior due to its distance from oceanic moisture. This arrangement would generate extreme continental climates with high temperatures, possibly exceeding 55 degrees Celsius. The limited coastline and increased volcanism could make the planet inhospitable to most mammals.
Amasia (Extroversion)
The Amasia model follows an extroversion path, where the Pacific and Arctic Oceans close, causing the Americas to move across the Pacific to collide with Asia. This configuration predicts a supercontinent centered near the North Pole, leaving Antarctica isolated. This polar landmass would alter global ocean circulation, disrupting the heat transport that moderates global temperatures.
An Amasia-like supercontinent would lead to a colder global climate, with the concentration of land at high northern latitudes promoting the growth of extensive, year-round ice sheets. This accumulation of ice would lower global sea levels.
Aurica (Equatorial Convergence)
A third model, Aurica, suggests the continents could converge near the equator, resulting in a warmer planet (approximately 3 degrees Celsius higher than today) due to the land absorbing more solar radiation.