Mountain ranges and other large scale features of the Earth have puzzled geologists and geophysicists for centuries. The fact that many mountain ranges contain oceanic rocks that formed miles below sea-level, and that land living species seemed to be able to walk across the oceans, as evidenced by the fossil record, confused many and led to theories based on a shrinking Earth.

Today we know that the Earth has not been shrinking significantly through its past, but geophysical evidence points towards continents that have been moving across the Earth for billions of years. Today, the theory of Plate Tectonics, which is based largely on geophysical evidence such as the magnetic signatures of marine volcanic rocks, and our knowledge of the interior of the Earth, provides a (mostly) coherent framework to explain the existence of continents and oceans as well as the distribution of volcanoes, mountain ranges and earthquakes.

In this talk I will introduce you to some of the geophysical evidence that led to the development of plate tectonics and its acceptance in the earth-science community over the past few decades.