EAE1011 Lecture Notes - Lecture 4: Plate Tectonics, Continental Crust, Oceanic Crust
6 Aug 2018
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Eae1011 lecture 4 - earth, atmosphere and environment. Increases in temperature and pressure as you go deeper. Outer layers richer in si and o. Plate tectonics is the earth"s way of losing heat! Earth"s for(cid:373)atio(cid:374) a molten ball 4. 567 billion years ago. Take a long time to cool core still retains heat from formation ~ 6000 c at boundary between inner and outer core. Extra heat generated in crust by radioactive minerals. Since ~ 1-1. 5bya colder, denser, lithosphere subducts under more buoyant crust, and slowly sinks into mantle. Early (hot) earth >2. 5bya colder, denser, lithosphere material drips back through mantle. Early maps of atlantic showed coasts fit together. Thought to be coincidence, as everyone (even geologists) knew that continents were immovable. In 1858, geographer antonio sniderpellegrini made these two maps showing his version of h ow the american and african continents may once have fit together. Jigsaw fit of many continental pieces not just atlantic coasts.
