What happened during the Proterozoic eon?

The Proterozoic is the third and longest eon of Earth's history, spanning from 2500 to 538.8 million years ago. It marked major planetary transformations, including the accumulation of free oxygen in the atmosphere, global glaciations, and the appearance of early eukaryotes and multicellular life. This eon bridges the ancient Archean eon and the complex life explosion of the Phanerozoic.

What we know

• The Proterozoic eon spans the time interval from 2500 to 538.8 million years ago and is the longest eon of Earth's geologic time scale. [2]
• The Proterozoic is the final eon of the Precambrian, an informal time span that accounts for 88% of Earth's geologic time. [1, 5]
• The eon is subdivided into three geologic eras: the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic. [2]
• Key events during the Proterozoic include the transition to an oxygenated atmosphere, the evolution of eukaryotes via symbiogenesis, and global glaciations. [2]
• The Ediacaran period in the late Neoproterozoic featured the evolution of soft-bodied multicellular organisms, providing obvious fossil evidence of life on Earth. [2]

Still open

• The exact severity and global extent of late Neoproterozoic glaciations are framed as a hypothesis of a Snowball Earth.

Where to go next

• compared withWhat was the Archean eon like?
• what followedHow did the Cambrian Explosion change life on Earth?
• what caused itWhat caused the Snowball Earth glaciations?
• the bigger pictureHow does the geologic time scale work?
• a case in pointWhat organisms make up the Ediacaran biota?
• an unexpected connectionHow does the Precambrian supereon connect to Wales?The Precambrian is named after the Cambrian, which derives its name from Cambria, the Latinized name for Wales where rocks from that timeframe were originally studied.

Sources

• [1]Proterozoic (Wikidata Q104162) · CC0 1.0
• [2]Proterozoic · CC BY-SA 4.0
• [3]Geologic time scale · CC BY-SA 4.0
• [4]Timeline of Earth · CC BY-SA 4.0
• [5]Precambrian · CC BY-SA 4.0

Your path

1. How did mathematical notation evolve over time?
2. /What happened during the Proterozoic eon?