Results 21 to 30 of about 9,317 (244)
The Sedimentary Origin of Black and White Banded Cherts of the Buck Reef, Barberton, South Africa
Geosciences, 2019 The Buck Reef is a 250−400 m thick sequence of banded black and white (B&W) cherts deposited ca. 3416 Ma ago in a shallow basin. We provide field, petrological and geochemical constraints on the chert-forming process and the origin of the ...
Morgane Ledevin +4 more
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2200 million years of crustal evolution: The Baltic Shield [PDF]
Bulletin of the Geological Society of Finland, 1986 The crustal history of the Baltic shield is interpreted in the light of the plate tectonic concept. Five tectonic cycles, each characterized by special lithological and structural features, are distinguished: The Early Archean (> 2900 Ma), the Late ...
G. Gaál
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Drilling for the Archean Roots of Life and Tectonic Earth in the Barberton Mountains [PDF]
Scientific Drilling, 2009 In the Barberton Scientific Drilling Program (BSDP) we successfully completed three drill holes in 2008 across strategically selected rock formations in the early Archean Barberton Greenstone Belt, South Africa.
Nicola McLoughlin +3 more
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Rare-earth elements in the Archean iron formation and associated schists in Ukkolanvaara, Ilomantsi, SE Finland [PDF]
Bulletin of the Geological Society of Finland, 1977 This study describes the La, Ce, Nd, Sm, Eu, Tb, Yb and Lu concentrations in six iron-formation rocks (Fetot >> 15 %), four ferriferous schists (Fetot ~ 10—15 %) and two schist interbeds of the Archean Ukkolanvaara iron formation, as well as in seven ...
K. Laajoki, S. Lavikainen
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Building Archean cratonic roots
Frontiers in Earth Science, 2022 Geophysical, geochemical, and geological investigations have attributed the stable behaviour of Earth's continents to the presence of their Archean cratonic roots. These roots are likely composed of melt-depleted, low density residual peridotite with high Magnesium number (Mg#), while devolatilisation from the upper mantle during magmatic events might ...
Charitra Jain +6 more
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Archean continental crust formed by magma hybridization and voluminous partial melting
Scientific Reports, 2021 Archean (4.0–2.5 Ga) tonalite–trondhjemite–granodiorite (TTG) terranes represent fragments of Earth’s first continents that formed via high-grade metamorphism and partial melting of hydrated basaltic crust. While a range of geodynamic regimes can explain
Juan David Hernández-Montenegro +3 more
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Organosulfur Aerosols Likely Carried Sulfur MIF Signatures in the Early Earth’s Atmosphere
Geochemistry, Geophysics, Geosystems, 2023 Signatures of mass‐independent fractionation (MIF) of sulfur in Archean sulfide and sulfate minerals are widely thought to record an anoxic early Earth’s atmosphere.
Harry Oduro +3 more
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Geochemistry, Geophysics, Geosystems, 2023 Copper isotope analysis has emerged as a promising tool for understanding genetic processes in Cu ore deposits. However, applications of this analytical technique to Archean Cu deposits have been extremely limited, even though Archean terranes are among ...
David C. M. Fox +6 more
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Archean versus Phanerozoic oceanic crust formation and tectonics: Ophiolites through time
Geosystems and Geoenvironment, 2022 A global compilation of structural, lithological, and geochemical data on a selection of Archean, Proterozoic and Phanerozoic magmatic complexes, interpreted as ophiolites, is presented.
Harald Furnes, Yildirim Dilek
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Geophysical Research Letters, 2023 The origins of Archean continents and subcontinental lithospheric mantle (SCLM) were important events in the early Earth. The mechanisms for the origins of Archean continents and the SCLM remain unclear.
Zhongqing Wu +3 more
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