Archean eon

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• Archean Eon — or Archaean Eon or Archeozoic Eon Older of the two divisions of Precambrian time. The Archean begins with the formation of the Earth s crust с 3.8 billion years ago and extends to с 2.5 billion years ago, up to the start of the Proterozoic Eon,… …   Universalium

• Archean eon — noun the time from 3,800 million years to 2,500 million years ago; earth s crust formed; unicellular organisms are earliest forms of life • Syn: ↑Archean, ↑Archean aeon, ↑Archeozoic, ↑Archaeozoic, ↑Archeozoic eon, ↑Archaeozoic aeon •… …   Useful english dictionary

• Eón Arcaico — Saltar a navegación, búsqueda Supereón Eón M. años   Fanerozoico 542,0 ±1,0 Precámbrico Proterozoico 2.500 …   Wikipedia Español

• Archean — [är kē′ən] adj. [< Gr archaios, ARCHAIC] [sometimes a ] designating or of the geologic eon characterized by the development of the first igneous and metamorphic rocks and the first marine microorganisms; Precambrian, esp. early Precambrian… …   English World dictionary

• Archean — The Archean (pronEng|ɑrˈkiːən, also spelled Archaean, formerly called the Archaeozoic (IPA|/ɑrkiəˈzoʊɪk/), also spelled Archeozoic or Archæozoic) is a geologic eon before the Proterozoic and Paleoproterozoic, before 2.5 Ga (billion years ago, or… …   Wikipedia

• Archean aeon — noun the time from 3,800 million years to 2,500 million years ago; earth s crust formed; unicellular organisms are earliest forms of life • Syn: ↑Archean, ↑Archean eon, ↑Archeozoic, ↑Archaeozoic, ↑Archeozoic eon, ↑Archaeozoic aeon •… …   Useful english dictionary

• eon — /ee euhn, ee on/, n. 1. an indefinitely long period of time; age. 2. the largest division of geologic time, comprising two or more eras. 3. Astron. one billion years. Also, aeon. [see AEON] * * * I Long span of geologic time. In formal usage,… …   Universalium

• Archean — or Archaean adjective Etymology: Greek archaios Date: 1872 1. of, relating to, or being the earliest eon of geological history or the corresponding system of rocks see geologic time table 2. Precambrian • Archean noun …   New Collegiate Dictionary

• Archeozoic eon — noun the time from 3,800 million years to 2,500 million years ago; earth s crust formed; unicellular organisms are earliest forms of life • Syn: ↑Archean, ↑Archean eon, ↑Archean aeon, ↑Archeozoic, ↑Archaeozoic, ↑Archaeozoic aeon • Derivationally… …   Useful english dictionary

• Precambrian eon — noun the eon following the Hadean time and preceding the Phanerozoic eon; from about 3,800 million years ago until 544 million years ago • Syn: ↑Precambrian, ↑Precambrian aeon, ↑Precambrian period • Instance Hypernyms: ↑eon, ↑aeon • Part Meron …   Useful english dictionary

• Proterozoic Eon — Younger of the two divisions of Precambrian time, from 2. 5 billion to 543 million years ago. Proterozoic rocks have been identified on all the continents and often constitute important sources of metallic ores, notably of iron, gold, copper,… …   Universalium