ERS111H5S Lecture Notes - Lecture 4: Snowball Earth, Neoproterozoic, Hadean
Document Summary
Since we know rate of decay, we can know half lives: relative: stenos principles, index fossils. Solids only: happen close to earth surfaces, density of rock must increase in depth, when a p-wave hits the outer core and refracts in different directions it creates shadow zones. If the earth is a balloon, the crush is as thin as the outer layer of the balloon: dense due to iron and magnesium, where the crust becomes the moho. Deep along mountains shallow along oceans: defined by change in seismic velocity, makes us most volume of earth. Like a silly putty, solid but can flow: pretty thin compared to rest of the earth, goes down into the transition zone, outer core is a liquid. Smaller volume than the mantle: heavy metal elements would be sunk down into the core, geographic poles are on the axis, magnetic field is asymmetric due to solar winds.
