Observing the shape of the coastline of the Atlantic Ocean. The symmetry matches
of the coastlines on either side of the ocean. No wonder, many scientists thought of this similarity and considered the possibility of the two Americas, Europe and Africa, to be once joined together. From the known records of the
history of science, it was Abraham Ortelius, a Dutch map maker, who first proposed such a possibility as early as 1596.
However, it was Alfred Wegener—a German
meteorologist who put forth a comprehensive argument in the form of “the continental drift theory” in 1912. This was regarding the distribution of the oceans and the continents.
According to Wegener, all the continents
formed a single continental mass and mega ocean surrounded the same. The super continent was named PANGAEA, which meant all earth. The mega-ocean was called PANTHALASSA, meaning all water. He argued that, around 200 million years ago, the super continent, Pangaea, began to split. Pangaea first broke into two large continental masses as Laurasia and Gondwanaland forming the
northern and southern components
respectively. Subsequently, Laurasia and
Gondwanaland continued to break into various smaller continents that exist today.
A variety of evidence was offered in support of the continental drift are mentioned below:
The Matching of Continents (Jig-Saw-Fit)
The shorelines of Africa and South America facing each other have a remarkable and unmistakable match.
Rocks of Same Age Across the Oceans were found.
The belt of ancient rocks of 2,000 million years from Brazil coast matches
with those from western Africa. The earliest marine deposits along the coastline of South America and Africa are of the Jurassic age.
It is the sedimentary rock formed out of
deposits of glaciers. The Gondawana system of sediments from India is known to have its counterparts in six different landmasses of the Southern Hemisphere. At the base, the system has thick tillite indicating extensive and
prolonged glaciation. Counterparts of this
succession are found in Africa, Falkland Island, Madagascar, Antarctica and Australia. Overall resemblance of the Gondawana-type sediments clearly demonstrates that these landmasses
had remarkably similar histories.
The occurrence of rich placer deposits of gold in the Ghana coast and the absolute absence of source rock in the region is an amazing fact. The gold bearing veins are in Brazil and it is obvious that the gold deposits of the Ghana are derived from the Brazil plateau when the two continents lay side by side.
Distribution of Fossils
When identical species of plants and animals adapted to living on land or in fresh water are found on either side of the marine barriers, a problem arises regarding accounting for such distribution. The observations that Lemurs
occur in India, Madagascar and Africa led some to consider a contiguous landmass ‘Lemuria’ linking these three landmasses.
All this provided evidences of this theory.
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