How did the continents form

What is the origin of the continents? Alfred Wegener, German meteorologist and astronomer, was the one who published the book called ” The origin of the continents and oceans .” Wegener’s theory of how the continents were formed, also called the ” Continental Drift ” theory , was based on a large number of geodetic, geological, lithological, geophysical, paleoclimatic, and paleontological observations and studies. The veracity of this theory was mainly supported by the finding of certain fossils of plants and animals with similar patterns, on separate continents. In addition, the fact that, if we unite the current continents, they fit together like a puzzle, reinforces the idea that they start from a single continent called Pangea .

What are the continents

The continents are each one of the great extensions of land in which the terrestrial surface is divided , being these separated from each other by the great masses of water that are the oceans .

Etymologically, the word continent comes from the Latin verb continere , whose meaning is “to hold”, “to contain” or “to hold together”. Hence, the continents receive this name, giving the sense of land that remains united or uninterrupted, delimited by geographical accidents.

How the continents and oceans were formed

The formation of the oceans on planet Earth is the indirect result of the fragmentation of the earth’s crust by the convection processes that occur in the earth’s mantle.

The magma found in the upper mantle exerts pressure on the earth’s crust , this region causes a weakening of the earth’s crust and later its fragmentation. The pressure that is exerted is vertical, although a horizontal force is produced from the axis of maximum pressure of the magma, causing the fragmentation of the crust. The result is the formation of an extensive fracture that continually widens over time.

The blocks of the earth’s crust are separating, the surface gradually sinks and large depressions end up being formed, due to the separation efforts produced. Volcanism originates in depressions due to the outflow of magma and, over time, these depressions widen, filling with water , giving rise to what we now know as the oceans . These fractures that are created by the exit of the magma are called ocean ridges.

The evolution of the continents is constant as the Earth moves, but how were the continents divided? The current continents were united forming a supercontinent called Pangea . This supercontinent was divided by the action of magma , as previously explained, and the different pieces of earth began to move (movements of the tectonic plates) until the present continents were formed., they keep moving. The motor of this movement are the convective currents that occur in the earth’s mantle. These displacements have consequences such as, for example, the modification of the terrain, emerging new geographical features, such as new valleys, new mountains, forming volcanoes , changing the course of rivers, the climate, etc. This separation also affected living beings, since many populations were separated by the oceans, evolving separately and thus new species appeared.

In total, there are 15 main plates and 43 secondary ones that move on the mantle with a speed of approximately 15 cm per year. The movement of the plates can be of different types depending on their limits. If the boundaries are divergent it means that they are moving apart, if they are convergent, it means that the boundaries of the plates are moving closer together and, finally, if they are transformative, it means that the plates are moving sideways with each other.

There are different continental models, which vary in the territory and the number of continents. These are the theories about how many continents there are :

Model of the 4 continents

In this model Asia, Africa and Europe are united since they are not separated by oceans, so the continents are divided into four being:

  • Euraphrasia 
  • America
  • Oceania
  • Antarctica

Model of the 5 continents

It is a very widespread model, contemplating only those inhabited continents:

  • Africa
  • America
  • Asia
  • Europe
  • Oceania

Model of the 6 continents

This model includes the same continents as in model 5 plus Antarctica, it is the model that currently has the greatest diffusion in the world.

  • Africa
  • America
  • Antarctica
  • Asia
  • Europe
  • Oceania

Model of the 7 continents

Used by Anglo-Saxon countries, as well as Pakistan, India, the Philippines, and China.

  • Africa
  • North America
  • South America
  • Antarctica
  • Asia
  • Europe
  • Australian continent, which in the rest of the models is known as Oceania.

Model of the 8 continents

More recent studies show the existence of a new continent near Australia, called Zealand, which is submerged.

  • Africa
  • North America
  • South America
  • Antarctica
  • Asia
  • Europe
  • Oceania
  • Zealand

One Comment

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