Proterozoic eon

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• 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

• Proterozoic eon — noun from 2,500 to 544 million years ago; bacteria and fungi; primitive multicellular organisms • Syn: ↑Proterozoic, ↑Proterozoic aeon • Derivationally related forms: ↑proterozoic (for: ↑Proterozoic) …   Useful english dictionary

• Proterozoic — [prät΄ə rə zō′ik, prōt΄ə rō zō′ik] adj. [< Gr proteros, former, compar. of pro, forward (see PRO 1) + ZO + IC] [sometimes p ] designating or of the geologic eon characterized by the development of sedimentary rock, shallow seas, and the first… …   English World dictionary

• Proterozoic — The Proterozoic (pronEng|ˌproʊtərəˈzoʊɪk) is a geological eon representing a period before the first abundant complex life on Earth. The Proterozoic Eon extended from 2500 Ma to 542.0 ± 1.0 Ma (million years ago), and is the most recent part of… …   Wikipedia

• Proterozoic aeon — noun from 2,500 to 544 million years ago; bacteria and fungi; primitive multicellular organisms • Syn: ↑Proterozoic, ↑Proterozoic eon • Derivationally related forms: ↑proterozoic (for: ↑Proterozoic) …   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

• Proterozoic — 1. adjective Of, or relating to the geologic eon from about 2,500 to 570 million years ago; comprises the Paleoproterozoic, Mesoproterozoic and Neoproterozoic eras; marked by the build up of oxygen in the atmosphere and the emergence of primitive …   Wiktionary

• Eón Proterozoico — Saltar a navegación, búsqueda Supereón Eón M. años   Fanerozoico 542,0 ±1,0 Precámbrico Proterozoico 2.500 Arcaico 3.800 …   Wikipedia Español

• Proterozoic — adjective Etymology: Greek proteros former, earlier (from pro before) + International Scientific Vocabulary zoic more at for Date: 1899 of, relating to, or being the eon of geologic time or the corresponding segment of rocks that includes the… …   New Collegiate Dictionary

• proterozoic —   an eon of geologic time lasting from 2500m to 570m years ago …   Geography glossary

• 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