How do we know Earth’s magnetic fields flip in intervals of 200,000-300,000 years?

Question

Came across a (https://www.youtube.com/watch?v=g6thUIR3_rI) which describes Earth’s magnetic field having switched hundreds if not thousands of times during Earth’s 4.5 billion years.

So, how do we know thats a fact? What are scientists looking at that helped them determine this?

In: 2148

Answer 1

I remember learning about this in my college geology class. Good question – if this sort of question is frequent, go study geology, it’s fun, technical and you can make lots of $$! So cool how the spreading floor of the ocean tells us the answer.