GEO 1111 Lecture Notes - Lecture 3: Mantle Convection, Seafloor Spreading, Rock Magnetism

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: David Schneider

Document Summary

Geo1111 - lecture 3 - magnetic field and minerals. Earth"s magnetic field: caused by the core, the magnetic properties of rocks (rock magnetism and paleomagnetism) is used to determine the position of the magnetic poles through time. The switching position in between the poles resulted in minor extinctions. 1965 j. tuzo: earth is composed of plates that move on the asthenosphere because of the convection in the mantle. Due to gravity, old tectonic plates sink at convergent margins in the mantle where they get recycled. The mantle convection could either be the cause or effect of circulation caused by: Slab-push: the pushing of crust caused by the elevated positions of the oceanic ridge that makes the crust slide down. Slab-pull: the pulling of crust into the mantle by downward slab during the subduction. https://www. bgs. ac. uk/discoveringgeology/hazards/earthquakes/whatdrivestectonicplates. html. Elements: a type of matter that can"t be broken down or simplified. 1- abundance of elements in the crust (the big 8)