Skip to main content

About this free course

Download this course

Share this free course

An introduction to geology
An introduction to geology

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

1.10 What is plate tectonics? Continental drift and sea floor spreading - part 2

As you saw in the previous section, the stripes in the sea floor are caused because some of the rocks cooled at times when the magnetic field was reversed, and the stripes are symmetrical because as new rock is formed in the centre, it pushes the rest of the sea floor out of the way. This is shown in the video below (note: this video has no sound).

Download this video clip.Video player: Video 1.5 Magnetic reversal stripes
Video 1.5 Magnetic reversal stripes
Interactive feature not available in single page view (see it in standard view).

This is how the continents moved apart. New sea floor is created, which pushes the continents apart. This isn’t just happening in the middle of the Atlantic, but all over the world’s oceans, in areas called ‘mid-ocean ridges’.