The Earth Contents

2. Plate Tectonics

Plate movement creates oceans

The regions where two plates move apart are of special interest to oceanographers because they represent the sites where new oceans are created. A good example of which is the Atlantic Ocean, which first opened up when Africa and Europe began to split from the Americas 135 million years ago. As the two oceanic plates separated, a long rift valley formed at the junction and basalt welled up to the surface from a series of volcanoes. At present there is a series of volcanic islands on the 'Mid-Atlantic ridge' including Iceland, Helena and Tristan. There is also a series of volcanoes and hot springs and vents on the Mid-Atlantic ridge which do not reach the surface.

Why is plate movement of interest to oceanographers?