[Dog Gone]

Some reversals occurred withina few 10,000 years of each other,"

So what would the quickest be? Perhaps 30,000 years, maybe 80,000 years. Something like that.

It should be really hard to interpret that as every 1,000 years, but it obviously can be done.

[SunkenCiv]

The shift itself happens in circa 1000 years -- but there are long periods of stability, lasting 10,000 to millions of years. Of course, these duration estimates are based on remanent magnetism in old volcanic floes.