- ... that a world map by Gerardus Mercator attributes the Earth's magnetic field to a magnetic mountain (pictured) above the Arctic Circle?
- .. that tectonic subsidence, the sinking of the Earth's crust, can be caused by extension, cooling, or loading?
- ... that tectonic plates in the Earth's crust are not completely rigid but can be deformed by the melting of an ice cap?
- ... that substorms were first described in 1964?