archean

An obsolete adjective referring to the earliest geological eon (the Archean Eon), or something belonging to that ancient time; now primarily used as a proper noun in geology.

• 🇫🇷Adjectif désignant ce qui appartient à l'éon géologique le plus ancien (l'Archéen), ou par extension ce qui est extrêmement ancien, primitif, originel. En français, il s'emploie surtout comme nom propre (Archéen) en géologie.

1. Geological eon C2 formal scientific

   Relating to the Archean Eon, the second major division of Precambrian time, spanning from about 4 billion to 2.5 billion years ago, characterized by the formation of the Earth's earliest known rocks and the emergence of primitive life.

   • The Archean rocks in this region contain some of the oldest minerals on Earth.
   • Geologists study Archean formations to understand the early development of the planet's crust.
   • Fossil evidence from the Archean eon is extremely rare and difficult to find.

   🇫🇷Archéen (éon)

   Synonymes: archaeanarchaeozoicarcheozoic

indénombrable · nom propre

A proper noun referring to a specific geological eon, the Archean Eon, which spans from about 4.0 to 2.5 billion years ago, representing the time when the Earth's crust formed and early life appeared.

• 🇫🇷Nom propre relatif à une période géologique particulière, l'éon Archéen, qui s'étend d'environ 4,0 à 2,5 milliards d'années, représentant le temps où se sont formées la croûte terrestre et les premières traces de vie.

1. Geological eon C2 formal scientific

   The earlier of the two divisions of the Precambrian supereon, spanning from about 4 billion to 2.5 billion years ago, characterized by the formation of the Earth's crust and the appearance of the first life forms.

   • The Archean eon saw the formation of the first stable continents.
   • Fossils from the Archean are extremely rare due to metamorphism.
   • The atmosphere during the Archean was largely devoid of free oxygen.

   🇫🇷Archéen

   Synonymes: archaeanarchaeozoicarcheozoic