Many scientists in the past have wondered about the factors that determine the shapes and sizes of continents on our planet. The question that why they take the shape they are today may have a detailed answer in plate tectonic behaviour. However, so far I have not come across a good explanation for the process of continental shape evolution. It appears and is considered to be a complex, random phenomenon. For the time being, let us not try and explain the reasons behind continental shapes.
All of us have grown up looking at a standard world atlas and there are some standard printed ways of looking at continents. I will try to portray a collection of continents that I believe are very similar in shape and appearance. I will be rotating them on a 2D plane to my convenience. The continents will be resized (either enlarged or shrunken) to enhance the feel of similarity in shape. The images will not be tampered with in any other way.
I have always liked South America’s shape as a continent. Given a choice, in high school geography classes, I would always draw South America’s map. It is a large landmass standing on its own in the southern hemisphere in the vast oceans flanked by Pacific and Atlantic. It has a beautiful southern tail with tiny bits of land decorating the southwestern side of the tail….
….It also reminds me of a free-floating Indian subcontinent before it collided and merged with Asia. For all these reasons (though completely unscientific), South America will be my model continental shape (I still need to develop this thought).
Follow the continent shapes grouped in the given image below (click on it). The top row consists of South America, Antarctica, Greenland and Madagascar. The bottom row is Australia and Africa.
I have not given angles of rotation since they are relative. I could not find a reliable map of a free-floating Indian land mass (late Jurassic period). If you can imagine a crude rhomboidal shape with features similar to an air-filled human cheek, then it would come close (sorry, it is a bad attempt to explain a shape). The striking similarity between Australia and Africa probably puts them under a different class of continental shapes. Yes, we know that some of these landmasses were part of a bigger continent some time in the past. Nevertheless, given the limited number of large landmasses on our planet, the similarity in their ‘so called’ random shapes cannot be ignored. I don’t think I am trying to compare apples and oranges, am I?