EARTH 10 Lecture Notes - Lecture 10: West Antarctic Ice Sheet, West Antarctic Rift, Milankovitch Cycles
Document Summary
Uplifted during the opening of the west antarctic rift ~65 mya. Consists of sedimentary layers: sandstones, siltstones, and coal. As late as the mid-late cretaceous (~85 ma) Antarctica has flowering plants in a subtropical climate. Summer temperatures averaged 20-24 c (68 -76 f) In, paleocene (~60 ma), starts to cool , gradual loss of warm plants. By the late paleocene (~50 ma), cooled to average of 13 c. Eocene (~40 ma), cool marine maritime climate (10 c) Strong seasonality (25 c summer, 2 c winter) (like san francisco) A few refugia still exist and the ice sheets were largely temperate (experienced periods of waxing and waning) Tundra-type vegetation hangs on in most of antarctica until the middle miocene (~13 ma) Hold on a little longer in the antarctic peninsula (~12 ma) By 14 ma, east antarctic ice sheet"s permanent (prior to that it looks like it came and went with milankovitch cyclicity)
