If Earth's history were a calendar year, humans would not appear until the last few minutes before midnight on Dec. 31. During the Proterozoic Eon—2.5 billion years to 543 million years ago ...

Geologists have been able to identify crucial episodes in life’s history.

PHANEROZOIC HADEAN EON ARCHEAN EON PROTEROZOIC EON 4.6 billion 4 billion years ago 2.5 billion years ago ...

The Proterozoic Eon is also called the Cryptozoic ("age of hidden life"). About 2.5 billion years ago, enough shield rock had formed to start recognizable geologic processes such as plate tectonics.

Our current dilemmas require overcoming existential risk through new forms of cooperation and innovation as Earth potentially enters a new eon, the "Sapiezoic," says guest blogger David Grinspoon.

It turns out that eras are subsets of geologic eons. The Phanerozoic eon is known as the eon of visible life, consisting of more than 540 million years, from the Proterozoic eon to the present. 54A.

Article #2021-01544: "Petrographic carbon in ancient sediments constrains Proterozoic Era atmospheric oxygen levels," by Donald E. Canfield et al.

Or we could have said Two-phase increase in the maximum size of life over Phanerzoic plus the Archaean and Proterozoic reflects biological innovation and environmental opportunity Better would be a ...

For a billion years Earth's mountains stopped growing, and may have starved the sea of nutrients, new research finds.

During the Proterozoic, Earth grew no taller - the tectonic processes that form mountains stalled, leaving continents devoid of high mountains for nearly 1 billion years, according to a new study.