Thesaurus Geographicus Antonio Snider-Pellegrini Italian geographer 1858 Edward Suess Austrian geologist 1885 Gondwanaland Alfred Wegener German meteorologist 1912 Pangaea The Origin of Continents and Oceans 1915. The ocean floor was much more rugged than previously thought. The sediment layer on the floor of the Atlantic was much thinner than originally thought.
Heat destroys magnetism.
The Earth's magnetic field is generated by a turbulent motion in the Earth's liquid-iron outer core which produces both electric and magnetic fields. Rocks generally belong to two groups according to their magnetic properties Normal polarity Characterized by the magnetic minerals in the rock having the same polarity as that of the Earth's present magnetic field. Reversed polarity Indicated by a polarity alignment opposite to that of the Earth's present magnetic field. During the last ten million years or so the average duration of polarity intervals has been about 300,000 years and the polarity. Transform Boundaries Rocks are strongly deformed and metamorphosed but no new lithosphere is created nor destroyed.