EESA06H3 Lecture Notes - Lecture 4: Oceanic Crust, Continental Crust, Shield Volcano
Document Summary
Week 4: lecture #4: monday january 26, 2015 importance of oceans opening: In the newly formed basin, we get new settlement, important for oil and gas exploration. A lot of oil and gas found in these ancient ocean openings. Canadian gold comes from canada ocean opening, buried deep now. The life cycle of ocean basins: 1. embryonic 2. mature 3. dying. Embryonic ocean would be red sea, east african ridge. Dying ocean: pacific, surrounding continent are being pushed over; subduction. Pacific rim of fire: large volcanoes & major eq mega large thurst eq. Pacific surrounded by subduction zone, where it s floor is being pushed down by continents. Asthenosphere: weak sphere, the layer which allows rigid plate to move around the earth"s surface; warm toffee-like composition, not liquid but plastic, underneath the crust. Differing densities of oceanic (2. 9 g/cc) and continental crust (2. 7 g/cc) Decompression melting" of dry mantle rock to produce basaltic magma.
