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 ?
Maozhuang Formation, forming the base of Series 3 in North China Platform is missing in the Kouquan section, and instead the Xuzhuang Formation, overlying the Archean metamorphic rocks, marks the base of Cambrian in the area.
We reviewed b values recorded on large transcrustal active strike-slip faults in oblique convergent margins, which may be considered as modern analogues of the Archean CLLF deformations modelled in our study: the San Andreas Fault (b = 0.86 [+ or -] 0.01 and b = 0.72 [87, 88], resp.), the North Anatolian Fault (b = 0.55 [88]), the Central Japanese Median Tectonic Line (b = 0.86 [87]), and the Sagaing Fault area, Myanmar (0.5 < b < 0.9 [85]).
In addition to initial capital, Archean is providing operational support to Petrichor.
Especially, during the Indosinian-Early Yanshanian period, tectonic-magmatic activities caused the upwelling of the mantle materials, the mantle materials interacted with the previous crust materials (such as the rock series of Archean Jiaodong Group and Neoproterozoic Linglong granite) existing in the lithosphere, then formed a crust-mantle mixed-source type of magma, i.e.
All five analyzed sandstone samples from Estonia share more or less the same Archean to Mesoproterozoic signatures even with the consistent absence in the Early Paleoproterozoic ages of 2400-2000 Ma (Fig.
In the reconstructed version of the ancient Archean ocean, these metabolic reactions were particularly sensitive to the presence of ferrous iron that helped catalyze many of the chemical reactions that we observed, he said.
The Providence Greenstone Belt covers an area of around 120 kilometres long and 30 kilometres wide, over an under-explored Archean greenstone belt.
Eventually he would bring this experience to the interpretation of profiles across the Archean of South Africa, especially the Witswatersrand Basin with its huge gold deposits.
The Pearl Industrial Chemicals Company (PIC) has been established by Bahrain's EBH Holding and India's Archean Group of Companies.
The plant, when fully operational, is expected to produce 60,000 metric tonnes of aluminium fluoride, which is a critical chemical ingredient in the aluminium smelting process, said Chennai-based Archean Group executive director C G Sethuram.
Pegmatites are widespread in the Archean and Proterozoic terranes of Western Australia, a state that covers one-third of the Australian continent.