What was the Boring Billion?

The Boring Billion is an informal geological time period spanning from 1.8 to 0.8 billion years ago during the middle Proterozoic eon. It is characterized by tectonic stability, climatic stasis, very low oxygen levels, and slow biological evolution. Despite its name, this era saw critical evolutionary developments such as the rise of eukaryotes and early proto-lichens.

What we know

• The Boring Billion lasted from 1.8 to 0.8 billion years ago during the middle Proterozoic eon. [1, 2]
• The period featured tectonic stability, climatic stasis, very low oxygen levels, and no geological evidence of glaciations. [1, 2]
• Oceans during this time may have been oxygen-poor, sulfidic, nutrient-deficient Canfield oceans populated mainly by purple bacteria. [2] · medium confidence
• Eukaryotes likely evolved via symbiogenesis and diversified into algae, fungi, and protists around the beginning of this interval. [2] · medium confidence

Still open

• The exact environmental triggers and mechanisms that maintained such prolonged climatic stasis and low oxygen levels throughout the entire billion-year span remain open to interpretation.

Where to go next

• whenWhat was the Great Oxygenation Event?
• how it workedHow did the Canfield ocean model work?
• the bigger pictureWhat defines the Proterozoic eon?
• a case in pointWhat happened during the Mesoproterozoic Era?
• whoWho proposed the Canfield ocean model?
• an unexpected connectionHow did purple bacteria color ancient oceans?During the Boring Billion, sulfidic Canfield oceans were populated mainly by purple bacteria using hydrogen sulfide instead of water, creating black-and-milky-turquoise waters rather than the familiar blue or green.

Sources

• [1]Boring Billion (Wikidata Q23579307) · CC0 1.0
• [2]Boring Billion · CC BY-SA 4.0
• [3]Proterozoic · CC BY-SA 4.0
• [4]Canfield ocean · CC BY-SA 4.0
• [5]Mesoproterozoic · CC BY-SA 4.0