We all know which the continents are when we look at a map of the world. We have seven of them as we learn in school. But do we all know what a continent is? What about the how of continents? If your curiosity has been piqued, let's dive into finding out how continents are formed and what really makes a continent a 'continent'!
What are continents?
The continents are one of seven giant landmasses on the Earth's surface, divided by oceans. Geologically, a continent is composed of rocks of lower density than the seafloor or the Earth's mantle.
The planet began with a single land mass in the Mesozoic Era. Plate tectonics and continental drift have changed continental composition over time. To better understand the continents, we must first understand how they were formed. What is the earth made of?
When talking about the continents, we also need to know more about the Earth's surface. As Earth formed from space debris, Earth's gravity caused the planet's interior to heat up.
Core, mantle and crust
As the temperature rises, the rock material melts and begins to rise to the surface. As they rise and cool, they form in the earth's crust. Heavier matter flows into the Earth's core. This process created three main layers of the Earth:
core, mantle and shell.
tectonic plate
The crust and upper part of the mantle are harder and act as a crust around the planet. This crust is divided into large sections called tectonic plates. Heat radiating from the core pulls these plates above the molten mantle below, as if they had existed for millions of years. Scientists believe that the interaction of these plates through a process called plate tectonics helped create the continents.
How were continents formed?
subduction
Scientists also theorize that continents form when tectonic plates collide and the edges of the plates slide against each other. Then, matter continues to form along the edges or boundaries of tectonic plates in a process called subduction.
As the heavier parts of the crust sink into the mantle, they melt in the intense heat. Eventually, these molten blocks or magma broke through the upper plate, erupting as lava, and hardening into igneous rock as they cooled again. These rocks form small volcanic islands on the ocean's surface, expanding over time as more and more lava flows through. But that's not where the process ends; even the island bearing the disc will subdue! Although the islands do not enter the mantle, material from one island will merge with material from other islands on nearby plates. This creates larger swaths of land leading to continents!
What makes a continent a continent?
And finally, we come to the most curious question:
what makes a continent, a continent? For a long time, continents were often understood to be expanses of continuous land. These include Africa, Antarctica, Asia, Australia, Europe, North America and South America. A continent today is more defined by the plate on which it lies, and sometimes by a smaller plate next to it.
When it comes to geological designations, scientists also include the islands attached to the continent as part of it. For example, Japan is part of mainland Asia, Greenland and all the islands in the Caribbean Sea are identified as part of North America.
Depending on the education system your country pursues, you may know that there are six or seven continents!
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