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The Archean Eon (IPA: / ɑːr ˈ k iː ə n / ar-KEE-ən, also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history, preceded by the Hadean Eon and followed by the Proterozoic. The Archean represents the time period from (million years
Archean felsic volcanic activities commonly occur in submarine environments. [7] The composition of Archean felsic volcanic rocks are equivalent to a spectrum between dacite and rhyolite. [5] They can be distinguished by their mineral assemblages, rock chemistry and rock layer relationship in the sequences. [7]
The location map of the Dharwar Craton. The shaded area represents the Dharwar Craton. Generated from GeoMapApp (Ryan et al., 2009). [1]The Dharwar Craton is an Archean continental crust craton formed between 3.6-2.5 billion years ago (), which is located in southern India and considered the oldest part of the Indian peninsula.
One of the oldest Martian meteorites found on Earth, Allan Hills 84001 has been measured to have crystallized from molten rock 4.091 billion years ago. [17] The Genesis Rock (Lunar sample 15415), obtained from the Moon by astronauts during Apollo 15 mission, has been dated at 4.08 billion years. [18]
The Archean Superior Craton extends over 1572000 km 2 of the North American continent. [3] Forming the core of the Canadian Shield, the Archean Superior craton is encompassed by early Proterozoic orogens. [1] The western to the northeastern part of the craton is bound by the Trans-Hudson orogens. [9]
The Canadian Shield is a collage of Archean plates and accreted juvenile arc terranes and sedimentary basins of the Proterozoic Eon that were progressively amalgamated during the interval 2.45–1.24 Ga, with the most substantial growth period occurring during the Trans-Hudson orogeny, between c. 1.90–1.80 Ga. [5] The Canadian Shield was the ...
Garnet paragneiss, Nuvvuagittuq Greenstone Belt, Canada. 4.28 Ga old: the oldest known Earth rock of which direct samples are available. The Eoarchean (IPA: / ˌ iː oʊ. ɑːr ˈ k iː ə n / EE-oh-ar-KEE-ən; also spelled Eoarchaean) is the first era of the Archean Eon of the geologic record.
The oldest felsic rocks that are currently exposed intruded pre-existing, even older, mafic crustal rock and crystallized well beneath the Earth's surface. Later, these rocks were thermally metamorphosed, intruded by additional felsic magma, and partially melted during Eoarchean thermal events occurred about 3.85 to 3.72 Ga and 3.66 to 3.59 Ga.