Eoarchean
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 Eoarchaean (3.8 b.y.) Greenlandite specimen (fuchsite-quartz gneiss), Nuup Kangerlua , Greenland.paragneiss , Nuvvuagittuq Greenstone Belt, Canada. 4.28 Ga old: the oldest known Earth rock of which direct samples are available.The Eoarchean ( ChronologyThe Eoarchean Era was formerly officially unnamed and informally referred to as the first part of the Early Archean Eon (which is now an obsolete name) alongside the Paleoarchean Era.[4] The International Commission on Stratigraphy now officially recognizes the Eoarchean Era as the first part of the Eon, preceded by the Hadean Eon, during which the Earth is believed to have been essentially molten.
The Eoarchaean's lower boundary or starting point of 4 billion years ago) is officially recognized by the International Commission on Stratigraphy.[5]
The name comes from two Greek words: eos (dawn) and archaios (ancient). The first supercontinent candidate Vaalbara appeared around the end of this period at about 3,600 million years ago. GeologyThe beginning of the Eoarchean is characterized by heavy Nuvvuagittuq Greenstone Belt in northern Québec, Canada which has been dated to be 4,280 million years ago.[6] These formations are presently under intense investigation.[clarification needed][7]
Atmosphere3,850 million years old Greenland apatite shows evidence of Carbon-12 enrichment. This has sparked a debate whether there might have been photosynthetic life before 3.8 billion years.[8][needs update?] Proposed subdivisions
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