Hadean
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The Hadean is the first and oldest of the four geologic eons of Earth's history, starting with the planet's formation about 4.6 Ga, and ending 4.031 Ga, the age of the oldest known intact rock formati
Artist's depiction of a collision between two planetary bodies, similar to the hypothesized collision between Theia and Proto-Earth
Backscatter electron micrograph of detrital zircons from the Hadean (4.404 ± 0.008 Ga) metasediments of the Jack Hills, Narryer Gneiss terrane, Western Australia
Geologic time scale
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The geologic time scale or geological time scale describes how geologic time is divided into standardised intervals. It uses the rock record together with the principles of chronostratigraphy to place
Hadean
…The Hadean ( hay-DEE-ən, HAY-dee-ən) is the first and oldest of the four geologic eons of Earth's history, starting with the planet's formation about 4.6 Ga (estimated 4567.30 ± 0.16 Ma set by the age of the oldest solid material in the…
Sketch of the Succession of Strata and their Relative Altitudes (William Smith)
One example of an obsolete geological time scale (France, mid-1940s).
Marine sandglass MMM