Useful english dictionary. 2012.
Priscoan aeon — noun the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life • Syn: ↑Hadean,… … Useful english dictionary
Priscoan eon — noun the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life • Syn: ↑Hadean,… … Useful english dictionary
Hadean — I noun the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life • Syn: ↑Hadean time … Useful english dictionary
Hadean aeon — noun the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life • Syn: ↑Hadean,… … Useful english dictionary
Hadean eon — noun the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life • Syn: ↑Hadean,… … Useful english dictionary
Hadean time — noun the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life • Syn: ↑Hadean,… … Useful english dictionary
Geologic time scale — This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga.[1] Other… … Wikipedia
Oldest dated rocks — The oldest dated rocks on Earth, as an aggregate of minerals that have not been subsequently melted or disaggregated by erosion, are from the Archean Eon. Such rocks are exposed on the surface in very few places.[1] There is some controversy… … Wikipedia
Earth — This article is about the planet. For other uses, see Earth (disambiguation). Earth … Wikipedia
Hadean — The Hadean (pronEng|ˈheɪdiən) is the geologic eon before the Archean. It started at Earth s formation about 4.6 billion years ago (4600 Ma), and ended roughly 3.8 billion years ago, though the latter date varies according to different sources.… … Wikipedia
