First era of the Archean Eon
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Name formality Formal Alternate spelling(s) Eoarchaean Celestial body Earth Regional usage Global (ICS ) Time scale(s) used ICS Time Scale Chronological unit Era Stratigraphic unit Erathem Time span formality Formal Lower boundary definition Ten oldest U-Pb zircon ages Lower boundary GSSA Along the Acasta River, Northwest Territories , Canada 65°10′26″N 115°33′14″W / 65.1738°N 115.5538°W / 65.1738; -115.5538 Lower GSSA ratified 2023[1] Upper boundary definition Defined Chronometrically Upper GSSA ratified 1991[citation needed ]
Eoarchaean (3.8 b.y.) Greenlandite specimen (fuchsite-quartz gneiss), Nuup Kangerlua , Greenland.
Garnet paragneiss , Nuvvuagittuq Greenstone Belt, Canada. 4.28 Ga old: the oldest known Earth rock of which direct samples are available.
The Eoarchean ( EE -oh-ar-KEE -ən ; also spelled Eoarchaean ) is the first era of the Archean Eon of the geologic record . It spans 431 million years, from the end of the Hadean Eon 4031 Mya to the start of the Paleoarchean Era 3600 Mya. The beginnings of life on Earth have been dated to this era and evidence of archaea and cyanobacteria date to 3500 Mya, comparatively shortly after the Eoarchean. At that time, the atmosphere was without oxygen and the pressure values ranged from 10 to 100 bar (around 10 to 100 times the atmospheric pressure today).[2] [3] [4]
^ "Global Boundary Stratotype Section and Point" . International Commission of Stratigraphy. Retrieved 29 October 2023 .
^ Mulkidjanian, Armen Y. (August 2009). "On the origin of life in the zinc world: 1. Photosynthesizing, porous edifices built of hydrothermally precipitated zinc sulfide as cradles of life on Earth" . Biol. Direct . 4 : 26–. doi :10.1186/1745-6150-4-26 . PMC 3152778 . PMID 19703272 .
^ Mulkidjanian, A. Y.; Bychkov, A. Y.; Dibrova, D. V.; Galperin, M. Y.; Koonin, E. V. (2012). "Origin of first cells at terrestrial, anoxic geothermal fields" . Proc. Natl. Acad. Sci. USA . 109 (14): E821–30. Bibcode :2012PNAS..109E.821M . doi :10.1073/pnas.1117774109 . PMC 3325685 . PMID 22331915 .
^ Mulkidjanian, A. Y. (2011). "Energetics of the First Life". In Egel, R.; Lankenau, D.-H.; Mulkidjanian, A. Y. (eds.). Origins of Life: The Primal Self-Organization . Heidelberg: Springer Verlag. pp. 3–33. ISBN 978-3-642-21625-1 .