EESA06H3 Lecture 2: Lecture 2 and 8
Document Summary
Aeromagnetic maps- gives magnetic anomalies; picking out deeply buried faults. Magnetic reversals occur on average every 500,000 years. Takes approximately 10,000 or less for the reversal to occur. The core rotates slightly faster than the rest of the mantle, which makes the magnetic field. Broad scale origin of these flips(magnetic reversals) is the changes in the pattern of mantle convection. Oceanic crust acts essentially as a tape recorder. Volcanic material comes up through mantle, and is erupted on the ocean floor, and inorder for it to be erupted, it"d have to go through older rocks. And it comes up along fractures, conduits, which are called dykes. Sea floor spreading is entirely the result of the continuous intrusion as dykes of new volcanic rocks. Sea floor spreading is what drives plate tectonics. Ridge push- the pushing process which is acting to displace the ocean floor away from the mid-ocean ridge.
