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’!
Continents are one of seven giant land masses on the surface of the Earth, divided by oceans. Geologically, a continent is composed of rocks with lower density than those on the seafloor or the Earth’s mantle.
The planet began with one single land mass in the Mesozoic Era. Plate tectonics and continental drift have changed continental composition over time. To understand continents better, first we need to understand how they were formed.
When talking about continents, we also need to learn about Earth’s surface. As the Earth was forming out of space debris, the intensity of the Earth’s gravity made the inside of the planet heat up.
As the heat kept increasing, the rocky material melted and started to rise to the surface. Once they rose up and cooled down, they formed into the Earth’s crust. Material that was heavier sank toward the Earth’s core. This process created the Earth’s three main layers: the core, the mantle, and the crust.
The crust and the top portion of the mantle are more rigid and act like a shell around the planet. That shell is broken up into massive sections called tectonic plates. The heat emanating from the core causes these plates to slide around on the molten mantle that is below, as they have been for millions of years. Scientists believe that the interaction of these plates through a process called plate tectonics is what contributed to the creation of continents.
Scientists have also put forth the theory that continents formed as tectonic plates collided, and the edges of the plate slid beneath one another. The material then continued to build up along the edges or boundaries of tectonic plates during a process called subduction.
As heavier parts of the crust subducted toward the mantle, they would melt in the intense heat. Eventually, these melted bits or magma rose through the overlying plate, burst out as lava, and hardened into igneous rocks when they cooled again.
These rocks formed into small volcanic islands on the ocean’s surface, growing over time as more and more lava flowed. But that’s not where the process ends; even these plates carrying islands would subduct! Although the islands did not descend into the mantle, the material of one would fuse with that of other islands on neighbouring plates. This created bigger landmasses leading to the continents!
And finally, we reach the most curious question: what makes a continent, a continent? For a long time continents were generally understood to be continuous expanses of land. These include Africa, Antarctica, Asia, Australia, Europe, North America, and South America. A continent today is defined more by the plate it’s on, and sometimes a smaller plate next to it.
When it comes to geological designation, scientists also include islands associated with that continent as a part of it. For example, Japan is included as a part of the continent of Asia, and Greenland and as well as all the islands in the Caribbean Sea are defined as being part of North America.
Depending on which education system your country follows, you could either learn that there are six or seven continents! For example, if you studied geography in Russia, Eastern Europe, and Japan you’d learn the six-continent model that combines Eurasia. While if you were studying it in Latin America and many parts of Europe, you would learn another six-continent model that combines North and South America.
Ultimately, answering the question ‘what is a continent’ comes down more to convention that is followed than strict definition. We must also remember that tectonic plates are continuing their movement, just like advancements in scientific discoveries and understanding!
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Adrija is a writer, dancer, and artist, who loves to learn (about everything). She has grown up in many places and still carries a big love for all things travel and culture. Adrija loves fantasy, science-fiction and anything that transports her to magical worlds. Her favourite books include Harry Potter and The Hitchhiker’s Guide to the Galaxy. She’s always on the lookout for cute animals to pet, places to explore, and good humans to share stories, laughter, and joy with.
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