GEOL107 Lecture Notes - Lecture 16: Geographical Pole, Paleomagnetism, Motonori Matuyama
5 Dec 2017
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Document Summary
Evidence that led to development of plate tectonics. Explanation for apparent wandering of earth"s magnetic poles. New ocean crust created at mid-ocean ridge, moves away, gets older, colder, ~70% of all earth"s volcanic activity occurs denser, sinks depth increases away from mid-ocean ridge. Mapping of world - encircling mid-ocean ridge (where new oceanic crust created) Age of oceanic crust increasing away from mid-ocean ridge. Lot"s of mapping started after wwii using echo-sounders. Discovered by correlating marine magnetic anomalies with known times of reversals of earth"s magnetic fields. Mapping of ocean basins - lot"s of mapping started after wwii using echo-sounders depth increases away from mid-ocean ridges. Generated by complex interactions of moving currents of liquid iron/nickel in. Reversals of earth"s magnetic field ages of reversals were estimated. In early 1900"s, reversals of earth"s internal magnetic field were discovered and. Record of when reversals of earth"s internal magnetic field have occurred.
