ASTR 101 Lecture Notes - Lecture 33: Geologic Time Scale, Soot, Volcanism

• School: Queen's University
• Department: Physics, Engineering Physics and Astronomy
• Course: ASTR 101
• Professor: David Alan Hanes

Document Summary

Lecture 33 - leftovers: impacts and mass extinctions. Large meteors car ~size of a city. Hypothesis of the extinct of the dinosaurs; climate change and they couldn"t adapt. Extinction was quick within a geological time scale. Hard to tell whether it happened in a week or a month because the scales of the rock formations are so small. Thin kt layer; we nd it all over the world. High in iridium (like pt; quite rare) Typically several cm thick but in southern parts of north america, they"re considerable thick (1m) Different fossil above and below; including microorganisms. More iridium that you would expect (but just ppb, not pure or large quantities, just. Iridium is rare and it has signi cantly more in that layer than any other place on. Helpful analogy; it"s like in a crime scene nding a small trace of your dna even though you claimed you haven"t been in the scene of the crime.