GPHY 102 Lecture Notes - Lecture 28: Laurentide Ice Sheet, Cordilleran Ice Sheet, Cenozoic
GPHY 102 verified notes
28/28View all
Document Summary
Gphy102 lecture 28: glacier and glacial processes cont. The late cenozoic ice age: during the wisconsin glaciation (12,000 to 110,000 years ago) most of canada was engulfed by the vast laurentide ice sheet. Ice resulted in the drop of sea levels: depression of sea levels (200 m drops at peak) during the wisconsin glaciation. Causes of glaciation: variation in the earth"s orbit and tilt, known as milankovitch cycle, eccentricity changes from being more circular (now) to more elliptical; cycle take ca. 100,000 years: earth"s tilt also varies from 21. 5 degrees to maximum of 24. 5 degrees; cycle takes ~41,000 years, procession- wobble in erath"s rotation cycles every ~22,000 years. Like a spinning top, spins slower starts to wobble: changes in insolation that occur result in glaciation as less winter snow melts. Not in textbook: eccentricity, tilt and procession all shown together.
