112-pp21 - UNIVERSITY OF SOUTH ALABAMA Last time we...

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1 GY 112: Earth History Proterozoic Fossils UNIVERSITY OF SOUTH ALABAMA Last time we covered… 1) Glaciations: what happens and why 2) Glaciations in the Proterozoic 3) Snowball Earth Hypothesis (neato cool!) Paleoclimate Phases 1) Greenhouse Earth (no continental glaciers present) 2) Icehouse Earth (continental glaciers present) 3) Snowball Earth (Frozen oceans at equator) We now recognize three major Earth phases ht p:/ www.snowbal earth.org/end.html The Varangian glaciation was weird; many of the best glaciated sites were near the equator! This lead several people to conclude that the Earth literally froze over… 2 or 3 times It was a Snowball Earth Snowball Earth ht p:/ zebu.uoregon.edu/2002/ph123/snowbal .gif Stable isotope geochemistry implies a dramatic change in temperature… …from -50ºC to +50ºC (-60ºF to 122 ºF) Snowball Earth Today’s Agenda The Proterozoic Part 4 1) Eukaryotes (Acritarchs) 2) Metazoans (Ediacarin Fauna) (web notes 21)
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2 Proterozoic Fossils During the Archean, we saw the rise of the prokaryotes: Proterozoic Fossils During the Archean, we saw the rise of the prokaryotes: •Small Proterozoic Fossils During the Archean, we saw the rise of the prokaryotes: •Small •No nucleus Proterozoic Fossils During the Archean, we saw the rise of the prokaryotes:
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This note was uploaded on 02/04/2012 for the course GLY 112 taught by Professor Haywick during the Spring '12 term at S. Alabama.

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112-pp21 - UNIVERSITY OF SOUTH ALABAMA Last time we...

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