Wegener's Theory of Continental Drift and the Coastline Puzzle

In order to understand how and why Alfred Wegener’s hypothesis of continental drift came to be considered as a ‘scientific revolution’, firstly it must be understood that prior to year 1960 the majority of scientists were of the belief that the Earth’s continents and ocean basins held fixed, non- moving geographical positions. (Lutgens and Tarbuck 2011)

Although this concept of continental drift had appeared to first come out in the 1600’s when better world mapping became available, it wasn’t until 1915 that people had begun to pay attention to this concept due to the publishing of Wegener’s book ‘The origin of continents and oceans’. As this concept did not fit in with every geologist’s views as it had undone much of the work they had completed, Wegener compiled many pieces of evidence to support his hypothesis. In the following piece, I will be discussing and examining the several pieces of evidence obtained by Wegener. (Lutgens and Tarbuck 2011)

A Continental Jigsaw Puzzle:

Wegener’s first piece of evidence is said to have come to him during an ice break he witnessed on a research trip to Greenland. Wegener suggested that there once was a supercontinent landmass he called ‘Pangaea’. Then noticing, that several coastlines on opposite shores of oceans appeared to be able to fit perfectly together. Wegener suggested that almost 200 million years ago in the early Mesozoic period that this landmass Pangaea began to split and fragment leading to the continents to then ‘drift’ to their locations today. (Lutgens and Tarbuck 2011). Although the above photo seems to suggest that the coastlines indeed were a perfect fit together, this concept came under scrutiny from Wegener’s oppositions as the argument that these coastlines would have been dramatically changed from their shape 200 MYA due to deposition and erosion constantly changing the shape of our coastlines.

It wasn’t until many years later that scientists came to the conclusion that a much more accurate shaping of the outward side of the continental shelves could be taken by looking at a continents seaward shelf outer boundary. This lies approximately a few hundred metre below the sea-level. In the year 1965, with the relevant equipment now available, Sir Edward Bullard and two of associates published a global map of the continental jigsaw fit when measurements were taking from the seaward continental shelf, below sea-level. This map was instantly met with great success as it showed an almost perfect fit. Bullard’s work was continuing and similar to work done by scientist and geologist ‘Boris Choubert’ done 30 years prior, although Bullard took a more sophisticated and data-led approach leading to much success in the rise of the hypothesis of continental drift.( Kornprobst, J., 2017.)