Oxygen Catastrophe
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The Oxygen Catastrophe was a massive environmental change believed to have happened during the Siderian period at the beginning of the Paleoproterozoic era, about 2500 million years ago. It is also called the Oxygen Crisis.
When evolving life forms developed photosynthesis, molecular oxygen was produced in large quantities. The plentiful oxygen caused an ecological crisis.
The newly produced oxygen was first tied up in chemical reactions in the oceans, primarily with iron. After the supply of oxidizable materials was exhausted, the modern high-oxygen atmosphere developed. Older rocks contain massive banded iron formations that were apparently laid down as iron and oxygen first combined.
From the point of the view of the anaerobic organisms already present on earth and in the oceans, the environment was poisoned with oxygen, and the oceans were scrubbed free of important nutrients. It is from their point of view, and because of the drastic change that the oxygen caused to the air and oceans, that the Oxygen Catastrophe gets its name.
| Proterozoic eon | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Paleoproterozoic era | Mesoproterozoic era | Neoproterozoic era | |||||||
| Siderian | Rhyacian | Orosirian | Statherian | Calymmian | Ectasian | Stenian | Tonian | Cryogenian | Ediacaran |
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