The Huronian glaciation (or Makganyene glaciation) extended from 2400 Mya to 2100 Mya (~300 million years), during the Siderian and Rhyacian periods of the Paleoproterozoic era. The Huronian glaciation followed after the Great Oxygenation Event (GOE), a time when increased atmospheric oxygen decreased atmospheric methane.
It is the oldest known ice age, occurring at a time when only simple, unicellular life existed on Earth.
The Huronian glaciation was one of the most severe and longest ice ages in geologic history, similar to the shorter proposed Snowball Earth ice ages that happened in the Cryogenian, a geologic period that occurred .   
It is possible that there were multiple contributing factors.
As the Sun was notably weaker at the time, the Earth's climate may have relied on methane, a powerful greenhouse gas, to maintain surface temperatures above freezing. The Huronian glaciation occurred at around the time the earth became aerobic, the oxygen catastrophe. This rise of oxygen resulted in the elimination of methane in the atmosphere, which in turn could have led to decreased temperatures.
Drawdown of atmospheric carbon dioxide has also been suggested. CO2 levels, also a greenhouse gas, could have been reduced due to increased silicate weathering of fresh basaltic surfaces or due to a 250 million year lull in volcanic activity reducing the amount of released CO2.
Finally, the placement of the continental landmasses, as is a probable cause of the Cryogenian glaciation, and the Earth's orbit the Sun may have been contributing factors.
In popular culture
Planet-wide glaciation has been identified under the term "Snowball earth". However, the more recent global glaciation during the Cryogenian period (650-850 Mya) may be better known. Descriptions of the Huronian glaciation are noted in the following.
- The BBC/CBC/NHK "Miracle Planet : Snowball Earth" (2010s) episode covers the Huronian glaciation era 
- The NASA lecture "New and Emerging Perspectives on Late Precambrian 'Snowball Earth' Glaciation" (2007)  covers this era and several other glaciation events in detail.
- Lane, Nick (5 February 2010). "First breath: Earth's billion-year struggle for oxygen". New Scientist (2746).
- Williams G.E.; Schmidt P.W. (1997). "Paleomagnetism of the Paleoproterozoic Gowganda and Lorrain formations, Ontario: low palaeolatitude for Huronian glaciation" (PDF). EPSL 153 (3): 157–169. Bibcode:1997E&PSL.153..157W. doi:10.1016/S0012-821X(97)00181-7.
- Evans, D.A.; Beukes, N.J.; Kirschvink, J.L. (March 1997). "Low-latitude glaciation in the Palaeoproterozoic era". Nature 386 (6622): 262–6. Bibcode:1997Natur.386..262E. doi:10.1038/386262a0.
- Kopp, Robert E.; Kirschvink, Joseph L.; Hilburn, Isaac A.; Nash, Cody Z. (2005). "The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis". Proc. Natl. Acad. Sci. U.S.A. 102 (32): 11131–6. Bibcode:2005PNAS..10211131K. doi:10.1073/pnas.0504878102. PMC 1183582. PMID 16061801.
- Melezhik, V.A. (2006). "Multiple causes of Earth's earliest global glaciation". Terra Nova 18 (2): 130–137. doi:10.1111/j.1365-3121.2006.00672.x.
|Paleoproterozoic Era||Mesoproterozoic Era||Neoproterozoic Era|
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