Definitions

from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Variant of Archean.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. of, or relating to the geologic eon from about 3,800 to 2,500 million years ago; comprises the Eoarchean, Paleoarchean, Mesoarchean and Neoarchean eras; marked by an atmosphere with little oxygen, the formation of the first continents and oceans and the emergence of simple life
  • proper n. the Archaean eon.

Etymologies

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Examples

  • The area coloured terra cotta surrounding Hudson Bay like a great horse-shoe is known as the Archaean Protaxis, composed of preCambrian rocks, the ancient back bone of the continent.

    Mineral Resources of Northern Ontario

  • This rocky highland stretches from a little north of the St. Lawrence River to Hudson Bay, around which it laps in the form of a V, and so is known as the Archaean V or shield.

    The Red Man's Continent: a chronicle of aboriginal America

  • He states that what is known as the Archaean protaxis, or that rugged, rocky region which stretches away from the St. Lawrence River, expanding to the northwestward, and occupying a large part of Northern Ontario, has produced and is constantly producing, a group of what may be called unique, or at least comparatively rare, economic minerals.

    Our Northern Heritage

  • Stromatolite reef from the Early Archaean era of Australia.

    SuperCooperators

  • The oldest rocks of Victoria Land are apparently banded gneiss and gneissic granite, which may be taken as Archaean.

    Perspective of Antarctica in 1911

  • As regards Kaiser Wilhelm Land, the Gaussberg is a volcanic cone mainly composed of leucite-basalt, but its slopes are strewn with erratics presumably transported from the south and these include gneiss, mica-schist and quartzite, apparently Archaean.

    Perspective of Antarctica in 1911

  • In the Graham Land region there seems to be a fundamental rock closely resembling the Archaean.

    Perspective of Antarctica in 1911

  • The mounds in the foreground are stromatolites, colonies of photosynthetic bacteria which have been found as fossils in Early Archaean rocks of South Africa and Western Australia.

    Archaean

  • Stromatolites increased in abundance throughout the Archaean, but began to decline during the Proterozoic.

    Archaean

  • If you were able to travel back to visit the Earth during the Archaean, you would likely not recognize it is the same planet we inhabit today.

    Archaean

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