Super Continental Theory (Pangaea)

By Reshma Dahal

The aim of this article is to inform readers about the process in which the continents of the globe drifted to their current positions explaining the geological discovery and its impact to human kind.

The Earth is a truly extraordinary planet. There are rivers, the lakes that flourish onto the beaches. There are colossal mountains which stand strong and proud marking their territory. The hills, the forests, the seas; they are all remarkable puzzle pieces that unite to create the spherical globe, which we call Planet Earth.

Our planet is astonishing and beautiful. But it is also very mysterious. Unlike in the past, now in the twenty first century our understanding of our planet has grown significantly due to the numerous discoveries scientist have unravelled. It is clear that, in the early days, the reasoning of natural disasters such as tsunamis, earthquakes and volcanic eruptions were not properly understood. Even the most famous geologists in those times could not begin to comprehend the cause of these occurrences. Why would the ground shake so abruptly? What was the reason for gallons of water to splatter and sweep away the precious lives and essential resources? These all questions which deserve evidence based answers, but none were given until the year of 1915.

Professor Alfred Wegener, a German scientist, was always fascinated in geophysics.  He accumulated evidence to answer the question as to why the land masses on earth stand where they are today. For example: why Australia is situated near the South Pole and not the North Pole. There are four principle evidences^1,2 which Professor Wegener accumulated that gave birth to the “Pangaea” or “Super Continental” theory.  They are:

1.  There is a close fit between the coastlines of Africa and South America (see Figure 1). 

2. There are identical plants and animal fossils found on opposite sides of the Atlantic, on South America and Africa.  

      3.  There are the same types of mountains on both sides of the Atlantic Ocean, the Appalachian mountains of Eastern North America and the Scottish Highlands, and the distinctive rock strata of the Karroo system of South Africa are identical to those of the Santa Katarina system in Brazil

      4. 250 million years ago there was ice that covered south Africa, India, Australia and South America. The only way these warm climate countries, could have had ice is if they were closer to the South Pole. 

The basis of Pangaea theory is that about 300 million years ago, the continents had formed a single mass, called Pangaea (See Figure 2). Though slowly, Pangaea begun to split (See Figure 3-5), and now rests in the position of our current continents (See Figure 6).

He also has reason to believe that even until now, the shape of the Earth surface is still changing, and it will be forever, as long as the mantle underneath the Earth's crust gets heated and convection currents in the magma keeps dragging the plates.  When the Pangaea theory was first proposed, it was treated with much scepticism, but since then, there have been many forms of evidence to support Wegener’s Theory^1,2. 

Our Earth is a fascinating Planet, and as the years go by we discover more and more information about the construction of our Globe. Alfred Wegener, made a significant contribution in 1915, and it is due to his theory and reasoning that scientists have now expanded on this theory and have proven that the Earth’s present continents were once together as Pangaea.

What impact has this innovation made to Global Society? Firstly, it has expanded our understanding on the gradual change of the continental positions, which lead to the drastic change of weather from region to region thereby forcing inhabitants to adapt according to their respective environment.  Secondly, this innovation influenced urbanization, the development of scientific technology, global communication, and transportation.  However, this innovation has also increased the risk factor of possible natural calamities due to the continuous change in the shape of the earth’s surface. 

References:

      1.  Miller, R. 1983. Continents in Collision. Time-Life Books, Alexandria, Virginia
2. Hughes, P.  1994. The Meteorologist Who Started a Revolution, Vol. 47, Weather-wise.