Knowra Paleoproterozoic Paleoproterozoic The first era of the Proterozoic Eon, spanning approximately 2.5 to 1.6 billion years ago. It includes major atmospheric oxygenation, global glaciations, and early complex biological change.
Huronian glaciation : A series of ancient glaciations recorded in rocks of the Huronian Supergroup in Canada. These glaciations followed the onset of atmospheric oxygenation during the era.
Cyanobacteria : A group of bacteria that perform oxygenic photosynthesis, releasing oxygen from water. Their photosynthesis supplied the oxygen whose accumulation reshaped the era.
Proterozoic : The eon from about 2.5 billion to 538.8 million years ago, between the Archean and Phanerozoic eons. The Paleoproterozoic is its earliest era.
Great Oxidation Event : A major rise in atmospheric oxygen, beginning about 2.4 billion years ago, driven chiefly by oxygen-producing microbes. This defining transition began during the Paleoproterozoic and transformed surface environments.
Paleoproterozoic glaciation : Episodes of extensive glaciation during the Paleoproterozoic, including the Huronian glaciations. Their precise timing, duration, and relationship to oxygenation remain debated.
Siderian : The first period of the Paleoproterozoic Era, lasting from about 2.5 to 2.3 billion years ago. It marks the era’s opening interval and overlaps the onset of the Great Oxidation Event.
Oxygenic photosynthesis : Photosynthesis that uses water as an electron donor and releases molecular oxygen. It explains the biological source of the oxygen associated with the era’s largest transition.
Geologic time scale : The system scientists use to organize Earth's history into nested units based on rock records and chronology. It places the Paleoproterozoic among eons, eras, periods, and smaller intervals.
Oxygen catastrophe : A historical term for the ecological disruption associated with rising oxygen in the early atmosphere and oceans. It emphasizes biological costs of oxygenation, unlike accounts focused on its later benefits.
Atmospheric oxygen : Molecular oxygen present in a planet’s atmosphere. The amount and pace of its Paleoproterozoic rise remain difficult to reconstruct.
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