GEOL 150Lg Lecture Notes - Lecture 9: Oligocene, Pleistocene, Himalayas
Document Summary
After this warming the earth returned to the icehouse. Return to the icehouse: sea level falling, temp falling, co2 falling, mountains growing, ice sheets growing. Oligocene epoch- antarctica became isolated and an ice sheet, asia and india collided and an uplift of the himalayas was the result. Temps at the end of the oligocene were 4* warmer than today. Evidence points to possible antarctic ice sheet instability that could inform us how the ice sheet will behave. There is a critical threshold. (600ppm) ours rn is 400ppm. When it was above 600ppm, the antarctic ice sheet was unstable. 600ppm appears to be a critical tipping point for earth"s climate. Above this number ice appears to not be stable. Below the earth is cool enough to maintain ice. Co2 based on the evidence we have has been the primary driver of earth"s climate. Each of the epoch boundaries are classified by the extinction of some organism.