Snowball Earth Episodes: Global Glaciations
c. 720-635 MYA · Prehistoric
Between 720 and 635 million years ago, Earth experienced two major global glaciation events during the Cryogenian Period. The Sturtian glaciation (720-660 million years ago) and the Marinoan glaciation (645-635 million years ago) were so extensive that most of Earth's surface was covered by ice sheets extending from poles to equator. These extreme ice ages, often called 'Snowball Earth' episodes, may have triggered important evolutionary innovations. The glaciations ended through massive volcanic outgassing of carbon dioxide, creating an extreme greenhouse effect.
Locations
Sturtian GlaciationMarinoan Glaciation
Topics
geologyclimateglaciationcryogenian period
Connected Events — 3 Connections
Established the precedent for global glaciation mechanisms and demonstrated Earth's capacity for extreme climate states that would be repeated in Snowball Earth episodes, showing how atmospheric composition changes can trigger planetary-scale ice ages Huronian Glaciation: Earth's First Global Ice Age
Rifting exposed fresh volcanic rock to weathering, drawing down CO2 and triggering runaway glaciation Rodinia Supercontinent Breakup Begins
The Ordovician glaciation was Earth's first major ice age since the Snowball Earth episodes roughly 230 million years earlier, though far less severe in extent Late Ordovician Glaciation and Mass Extinction
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