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| OVERVIEW |
Approximate
Dates: 4.6–4.0 bya |
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Defining Characteristics:
- • formation of Earth’s
crust and main bombardment
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Secondary Characteristics:
- • continuing erosion
and plate tectonics have destroyed Hadean rocks
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The name Hadean Eon comes from Hades, the underworld
of Greek mythology. It refers to the “hellish” conditions
of the Earth during the earliest part of its history, when much of
the Earth’s surface remained molten. The Hadean Eon of geologic
time began with the birth of the solar system, including our planet,
Earth, and ended with the formation of the oldest rocks that are still
preserved on the surface of Earth.
The Hadean is the first period in Earth history, but one for which
we have little record. The Earth began to form about 4.6 billion years
ago through the condensation of material around the sun. As this material
collected, further cosmic material was drawn to it by gravity from
all directions, increasing the size of the Earth. This process created
an enormous amount of heat, which melted these materials and eventually
allowed them to separate into different layers. As the Earth cooled,
it acquired the structure we know today—an iron core, silicate
mantle, and thin outer crust. |

Eon Overview |
Formation of the Earth |
Earth’s Atmosphere
Earth’s Surface

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