It would seem that there is nothing more stable and sustainable than the ground under your feet. The appearance of the planet is gradually changing, as it has been since ancient times.
The continents drift from the very moment the planet cooled down after the process of its formation, and a stable crust formed on it. Scientists say that at first a thin oceanic crust formed, and only then did the gradual formation of a thicker continental layer begin.
Plates of the earth's crust drift, the surface of the planet because of this is constantly changing. Curious people would be interested to know what the Earth looked like in the past.
Theory of continental drift
Reflecting on what the surface of the planet was in the past, one cannot ignore the fundamental theory that makes it possible to clarify this. The theory of continental drift was worked out by the scientist Alfred Wenger, who drew attention to the similarity of the outlines of South America and the African continent. After all, the coastlines of these continents look like two pieces of one puzzle and can make up a single continent. Initially, the scientific world accepted the new theory critically, but then it was proved.
The earth’s crust is really not a single entity, as people thought in the past. It consists of fragments, which, in turn, lie on molten magma, which is a kind of slippery layer on which movement is really possible.Plates of the earth's crust, and with them the continents are moving - but at a very low speed. Part of the earth's crust goes into the mantle, melting again - sometimes plates move one on top of another, forming subduction zones. In other places, the plates move away from one another, induction occurs, and a new crust is born. These are slow, but inevitable processes that take place on the planet for billions of years, constantly changing its appearance.
Interesting fact: there are about 20 plates of various sizes on the planet, the largest of them is the Pacific. Due to its enormous mass, earthquakes constantly occur in the zone of its junction with other parts of the earth's crust, volcanic activity is observed. This is the so-called "fire belt" of the Pacific Ocean. At the junctions of other plates there are also seismically active zones.
Supercontinents of the Earth and their destruction
So, in the past, Africa and South America constituted a single continent, the contour of the rupture of these land areas is traced and completely coincides to this day. Other continents also at one time were grouped as a single piece of land. The Earth from time to time experiences periods of land unification into the so-called supercontinent, which then again splits. The last of them was Pangea - it remained united until the beginning of the Mesozoic.
Its split occurred approximately 200 million years ago, at which time its two parts were separated - Laurasia and Gondwana. After some time, Laurasia broke up into modern North America and Eurasia, while Gondwana formed all the southern continents.The continents diverged, the space between them increased, oceans gradually formed. But certain similarities remained - both in the breaks of the coastline, and in the structures, properties of rocks, fossil objects lying in them.
Scientists believe that Pangea was far from the only supercontinent in the history of the planet. It is assumed that the formation of the huge continent takes place cyclically, every 300 million years, and there were 5 or 6 of all such periods in the history of the planet. However, to prove this is problematic, at the moment there are only two officially recognized ones - Pangea and Rodinia, which existed at the end of the Cambrian . But even the reconstruction of Rodinia is difficult.
Problems of reconstruction of ancient continents
Today, computer programs exist and are actively used that can instantly present the appearance of the planet for any period of time, given the data on the movement of plates that scientists have long had. After all, the dynamics of all processes have really been studied, and hypothetically these data allow us to form the appearance of the planet for any prehistoric time.
However, in addition to slowly ongoing processes in the form of plate movements, there are other, instantaneous ones. Floods, landslides, explosions of volcanoes and supervolcanoes - they are unpredictable, they may not be known, they are difficult to enter into programs. In addition, the dynamics of the movement of plates in the past could be different.
Will the planet change in the future?
The movement of the continents does not stop, in the future the appearance of the Earth will change.Africa and South America will continue to move away from each other, as Eurasia from North America. Eurasia will split into two continents - the fault will pass along the tectonic crack of Lake Baikal, which is expanding inexorably. Other changes will occur.
Thus, the face of the planet has changed throughout history. This happened and is happening due to the drift of the continents. In the future, the process will continue.
