Hadean

Meanings

1. 1adjectivebefore a nounspecialist

   Belonging to the first stage of Earth's history, from its formation about 4.6 billion years ago to roughly 4 billion years ago, when the surface was extremely hot.

   Grammar: Usually comes before a noun: the Hadean eon, Hadean rocks.

   Patterns

   • the Hadean eon
   • Hadean zircons

   Tiny Hadean crystals are among the oldest materials ever found on Earth.

   Scientists debate whether Hadean oceans existed on the young planet.

   Few rocks survive from the Hadean period because the crust was constantly reshaped.

2. 2nounsingularspecialist

   The first eon of Earth's history, which came before the Archean.

   Grammar: Used with the: during the Hadean.

   Patterns

   • during the Hadean
   • the end of the Hadean

   Asteroids pounded the planet throughout the Hadean.

   Life may have begun near the end of the Hadean.

Common combinations

Hadean eon

The Hadean eon lasted about 600 million years.

Hadean zircon

A Hadean zircon from Australia is more than 4 billion years old.

Hadean Earth

Hadean Earth was covered in magma in many places.

Hadean conditions

Hadean conditions were too hot for most chemistry we know today.

Synonyms and how they differ

Precambrian

Precambrian is a far wider term covering all time before about 540 million years ago, so Hadean names only its earliest part.

primordial

Primordial means existing from the very beginning in a general sense, while Hadean is a precise geological term.

hellish

Hellish describes any harsh or terrible place, whereas Hadean is a scientific label that only suggests that idea through its name.

Word family

Hades proper noun

the Greek god of the underworld, and the underworld itself

Archean adjective

relating to the eon that followed the Hadean

Proterozoic adjective

relating to the eon after the Archean

Commonly confused: Hadean or Archean?

Practice

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