Hi- I'm currently (re)working on a global scale map. I just had a few small question, as I've never really done this before. I'm using CC3 to start- and will then turn over and trace the main shapes by hand. But first, There's an Idea I wanted to run by you guys.

I want a vein of magnetized cobalt in the sea that runs down an entire side of the planet. I want the magnetism to be strong enough to confuse compass's and lead ships astray to keep travel from going in that direction. Does that seem plausible, or should I just forgo the idea? If I keep it, How would I mark that on a map?