EESA06H3 Study Guide - Final Guide: Lithosphere, Gneiss, Cryosphere
Document Summary
At mor, there are only shallow earthquakes, at trenches, there are deep earthquakes. Found by: measuring the accumulation of the oceans salt content over time, measuring the time it took molten to cool to the present temperature of the earth. How we found the age of the earth: early ideas of stratigraphy, fossils, relative age of rocks, absolute age, the geologic timescale. Radioactive dating of the earth: daughter products form from parents at characteristic rates of decay (half-lives, ratio of daughter products to remaining parent material tells how much time has elapsed, present estimate: 4. 56 billion years old. Layer 3 less than 135 000 years old: are not rocks they are sediments, famous in ontario, glacial and interglacial (current) sediments. Layer 4 in to, hundreds of years old. It consists of what we are doing to the planet, building roads gas stations etc. Underground mine: deeper, blasted loose then carried by elevators and trucks.
