Archean


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Related to Archean: archaean, Proterozoic

Archean

[är′kē·ən]
(geology)
A term, meaning ancient, which has been applied to the oldest rocks of the Precambrian; as more physical measurements of geologic time are made, the usage is changing; the term Early Precambrian is preferred.
References in periodicals archive ?
Burgess said that if the greenhouse gas composition of the atmosphere was comparable to current levels then the Earth should have been permanently glaciated but geological evidence suggests there were no global glaciations before the end of the Archean and that liquid water was widespread.
Given the Hadean's sparse geologic record, climate scientists tend to focus on ways to explain the paradox during the better understood Archean.
Connecting to customers was not the only end goal of Archean Design and Development.
Aluminium fluoride when produced in Bahrain will give much needed support to the aluminium smelting industry which is flourishing in the GCC countries, said Archean chief financial officer S M Sundaram.
Komatiites were first identified by Viljoen and Viljoen (1969) in the Archean greenstone belt in the Barberton Mountainland of South Africa as a distinctive and "new" class of magnesium-rich (20-30 wt% MgO) volcanic rocks.
Archean outcrops in western Australia and in Zimbabwe show altered rocks interleaved with more pristine rocks.
With only sporadic and discontinuous thin veneers of glacial drift, bedrock is exposed over much of the land surface allowing for systematic mapping and examination of well-exposed Archean geological features.
As the exposed Archean b asement is approached, the relative abundances of some low field strength elements (K, Rb, Ce, total REE and Pb) as well as high field strength elements (Y, Nb, Zr and Th) increase, indicating a larger crustal component to the magmas.
International petroleum activity is a new endeavor for Archean Energy.
Currently, with combined estimated reserves in excess of 800 million tons and a successful track record of production, Archean is on the path of expansion.
KKR made an undisclosed amount of investment in Chennai s Archean Group.
Two researchers from University of Colorado Boulder say all that may have been required to sustain liquid water and primitive life on Earth during the Archean eon 2.