NATS 1540 Lecture Notes - Lecture 10: Ordovician, Marine Regression, Escape Velocity
20 Dec 2016
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Document Summary
Iridium is not found in the core of the earth. Or that a massive volcanic eruption took place and pushed the iridium into the layer of the earth. 70% of all species are yet to be catalogued. 4 causes of massive physical change to the environment: The single most ecological change in the environment: invention of agriculture. Underlying cause of sixth extinction: explosion of human population with unequal distribution of wealth. Without going into volcanism, explain some factors that cast doubt on the alvarez asteroid theory. These factors include: land plants, freshwater communities (turtles didn"t die), esd, high latitude dinosaurs (would survive winter), birds. (relate these to microwave summer or nuclear winter) Microwave summer: some of the material produced in a very large asteroid impact was blasted upward at a velocity greater than earth"s escape velocity, although most of it eventually fell back into the atmosphere on ballistic trajectories (2 marks)
