2020-10-31

The next Pangea:what the earth’s future supercontinent will look like

By yqqlm yqqlm

getInterUrl?uicrIvZQ=6ecfde9f16d272b0d1fee66de12cb3bc - The next Pangea:what the earth’s future supercontinent will look like

(Image source:Hannah S. Davies/University of Lisbon, Portugal)

Before the incredible age, all the continents of the earth were not in their current position. A huge continent occupies the entire earth, and a supercontinent is retrospectively called Pangea (or Pangaea if you prefer; either way, it is the Greek word for”whole earth”). After a long and infinitely slow process of rupture and continental drift, we finally came to the seven continents we are familiar with.

This is the story you might learn-but it’s not all. From a human perspective, the current world map seems to be a fait accompli. But plate tectonics is a continuous process. Even now, we are still experiencing long-term changes that we cannot detect, and this change has lasted for hundreds of millions of years. There were supercontinents before Pangea. Such an unfathomable age, so there may be others.

The shaker of the revolution

The 16th century cartographer Abraham Ortelius (Abraham Ortelius) first envisioned the United States, Europe and The coastlines of Africa can work together like a puzzle. The geological similarity in the bedrock further indicates that these continents were once part of a single block. Geophysicist and meteorologist Alfred Wegener elaborated on this idea in the early 1900s, calling it”continental drift.”

However, because Wegener’s model lacked a reasonable mechanism for continental movement, most thinkers in this era did not realize his drift. Indeed, Wegener’s ideas were basically rejected until the 1950s, when British geologist Arthur Holmes proposed that convection in the earth’s mantle promoted seafloor diffusion.

Holmes’ insights inspired follow-up research by physicists, geologists and seismologists worldwide. By the late 1960s, more and more evidence led the consensus to develop in the direction of accepting the new science of plate tectonics. This paradigm shift is so rapid and complete that some people call it a”plate tectonic revolution.”

In highly simplified terms, continental drift occurs because only a relatively small part of the earth’s material is solid. The surface of the planet, including the land and the sea floor, is actually composed of rock slabs, each with a thickness of about 100 kilometers. This is the lithosphere, located on a layer of overheated rock, the asthenosphere. At the boundary between the two regions at a temperature of about 1300°C, the mantle acts as a dense, highly viscous fluid, making the rigid crust float. The various parts of the lithosphere (seven major plates and dozens of microplates) slide on the asthenosphere at extremely slow speeds, just like a hockey puck on an air hockey table, in the common heat convection, gravity and rotation force Move under the action.

The cycle of supercontinent

The movement of these continental plates may have started about 3.5 billion years ago. With the development of the times, many structures have been produced. The details are largely speculative. Early supercontinents were formed while the land was still emerging from the ocean, so they were much smaller than Pangea. The first is Ur (the only land on earth at the time), which was formed 3 billion years ago. Its remains form part of Australia, India and Madagascar. In the next 300 million years, additional land was formed through volcanism, and Ur was brought together to form Kenorland. 100 million years later, Kenorland fell apart and the cycle started again.

With the formation of new tectonic plates, they collided with existing land blocks, forming a series of larger and larger supercontinents:Colombia, Rodania And most recently Pangea, they were formed about 335 million years ago, extending from extreme to extreme along mid-latitude. Atlantic.

Duel hypothesis

What will the next Pangea look like? Hard to say. The human-observable impact of plate tectonics is minimal-the annual displacement is about 4 cm, which is the width of the bee’s wingspan-so lucky that it can be tracked by a calendar and a ruler. Nevertheless, researchers have theoretically speculated on many possible results.

In 1982, American geologist Christopher Scotese (Christopher Scotese) proposed Pangea Proxima (literally”the next Pangea”). (The Scots initially called his hypothesis Pangea Ultima, meaning”the final Pangea,” and then finally hedged his bet.) Based on research on the formation of previous supercontinents, Scotese imagined a ring-shaped continent. In his case, the Americas docked with Africa and tilted eastward to meet the Eurasian continent; the latter had flipped vertically; South America and India formed the coastline of the inland sea.

In the next decade, researchers in the United States and South Africa proposed another arrangement called Amasia. Inferring from the gradual expansion of the Atlantic Ocean, they envisioned that the Pacific Ocean would drift westward with the Americas, merge with Australia, and then”close” by turning clockwise to Siberia. Eurasia and Africa maintain their current vertical position, but move north, and the entire mass circled around the North Pole. Antarctica is still an independent continent.

In the late 1990s, British geophysicist Roy Livermore (Roy Livermore) proposed what he called Novopangaea (Novopangaea) structure. Here, the Americas form its eastern edge, their western coastline swaying together like pincers, embracing the docking of Antarctica and Australia at the hub. Africa extends northwest.

The latest prediction Aurica proposed in 2016 is based on the research of the American Geophysical Union, which connects ocean tides with supercontinent cycles. Aurica is roughly similar to Novopangaea, but it created a rift between China and India and the rest of Eurasia, causing the former to collide with Australia from the west, while the latter circumnavigated the earth eastward and then docked with the new supercontinent.

Evolutionary prosperity

However, the next supercontinent appears, and the cycle will produce catastrophic environmental impact. Violent consequences occur whenever two plates meet. Collision can produce mountains or volcanoes; parallel sliding plates can produce seismically unstable fault lines. The disintegration of Kenorland and Rodinia triggered weather patterns that led to the ice age for millions of years.

However, the dissolution of Rodinia 550 million years ago also created the necessary conditions for terrestrial life. The collision of continental plates raised the seabed and formed shallower basins, allowing aquatic organisms to evolve into dry land. Future iterations of the cycle may also trigger an evolutionary boom.

The current tectonic activity seems to be relatively stable and may remain for thousands of years. Any change will be at least within the next 100 million years-by then we will no longer be cared for. (As Livermore quipped in 2007:”The beauty of all this is that no one can prove that I did it wrong.”) But thinking about the world we leave to those who follow us The shape is fascinating-distant creatures are like humans from dinosaurs.