Assess the reliability of evidence used to prove plate tectonic theory

Plate tectonic theory is the idea that the world has been broken up into large, jagged chunks of lithosphere called tectonic plates. The idea has been proposed since the early 20th century, and has become more widely accepted since the 1950s and 1960s. Nowadays, there is a plethora of evidence to prove this theory, some of which are more convincing than others.

Palaeomagnetism is the study of past magnetic fields and their impact on the geology of the earth. As new crust for the earth cools, it “locks on” to the magnetic field of the earth, meaning all poles within the rock are permanently facing the same direction as the magnetic field was at the time of creation. If all land, crust and lithosphere had always been there, it would be expected that it would all be “locked on” to the same magnetic field. However, since different areas of the lithosphere have different polarities, it can be inferred that it was all created at different times. By itself, this is not evidence for plate tectonic theory, however it is reliable as evidence that plates were all formed at different times in global history, which strongly corroborates this plate tectonic theory

Possibly the strongest piece of evidence is the fossils of non-aquatic animals being found in different continents. Cynognathus is a now-extinct mammal, which existed in the Triassic period. It would have no means of swimming the distance between South America and Africa, and yet its fossils have been found in both. This is strong and reliable evidence for plate tectonic theory, as this was the discovery that forced most of the world’s leading scientists to consider continental drift as being true. This, when coupled with Wegener’s continental drift theory and the complementary continental shelf shapes found mean that plate tectonic theory is a certain truth.

In conclusion, there is no single piece of evidence for plate tectonic theory that can be fully reliable. However, when multiple pieces of concrete evidence are put forward, this creates a very reliable bank of evidence. As a result, the present evidence for plate tectonic theory is overwhelmingly positive and reliable.