History of Earth - Cryogenian Period

		CRYOGENIAN
		THE PROTEROZOIC EON (Cryogenian Period) 850 to 635 Million Years Ago
		The Age of "Snowball Earth" The Sturtian and Marinoan Global Ice Ages
He hurls down his hail like pebbles. Who can withstand His icy blast? - Psalms 147:17
Meso- Proterozoic				Ediacaran
\|----\| Paleo-Geography
Worst ice age in Earth's history - "Snowball Earth" Glaciers a mile thick reach the equator Earth surface temperature averages -70° F. Sturtian Ice Age: 750 - 700 million years ago, followed by "Hothouse Earth" event (temperature 110° F. with huge hurricanes and acid rain) Marinoan Ice Age: 660 - 635 million years ago, followed by another "Hothouse Earth" event
Life
Life barely survives, confined to undersea volcanic vents and sunlit cracks in the ice sheet. Survivors include bacteria, archaea and cyanobacteria. Eukaryotic red and green algae survive (below)
	Eukaryotic red algae (left) and green algae (right). They flourished before the Cryogenian and survived after. (Sources: UCMP Berkeley left UCLA Astrobiology right)
			The frozen landscape of Snowball Earth (Source: NASA/Wallops)


SOURCES: University of California Museum of Paleontology - Tour of Geologic Time Wikipedia - Geologic Time Scale Palaeos - Geological Time IInternational Commission on Stratigraphy Corey Zak - CORZAK INTERACTIVE

THE PROTEROZOIC EON (Cryogenian Period)
850 to 635 Million Years Ago