There are records that show that the poles were not always where they are now. The scientists can only guess why they moved. One popular theory is that the ice caps got so big they 'wobbled' and shifted. Another popular theory is that one ice cap melted and the other didn't which shifted the crust. This theory was scoffed at because what could melt and ice cap? The countered with the theory that a meteor hit an ice cap melting it. They didn't know about the vulcano....