Results 61 to 70 of about 9,495 (248)

Investigation of Archean gamma-ray fingerprint: Methodology and tectonic application in central Brazil

Journal of the Geological Survey of Brazil
Gamma-ray spectrometric responses of Archean rocks were studied in order to define a characteristic signature for these rocks. As the half-life of the most frequent Thorium isotope (232Th – half life of 14.05 Ga) is more than 3 times longer relative to ...
Marcus Flavio Nogueira Chiarini, Loiane Gomes de Moraes, Elton Luiz Dantas, Reinhardt Adolfo Fuck, Elias Prado, Raphael Teixeira Corrêa, Jaime Scandolara, Antônio Frasca, Joseneusa Rodrigues, Andre Menezes Saboia   +9 more
doaj   +1 more source

Archean phosphorus liberation induced by iron redox geochemistry

Nature Communications, 2018
Phosphorus is presumed to have been a limiting nutrient in the Archean ocean due to binding to iron oxides. Here, the authors show the heating of iron with phosphate results in the reduction of phosphate to the ion phosphite, which is solubilized and ...
Barry Herschy, Sae Jung Chang, Ruth Blake, Aivo Lepland, Heather Abbott-Lyon, Jacqueline Sampson, Zachary Atlas, Terence P. Kee, Matthew A. Pasek   +8 more
doaj   +1 more source

Hf-Nd Isotopes in Archean Marine Chemical Sediments: Implications for the Geodynamical History of Early Earth and Its Impact on Earliest Marine Habitats

Geosciences, 2018
The Hf-Nd isotope systems are coupled in magmatic systems, but incongruent Hf weathering (‘zircon effect’) of the continental crust leads to a decoupling of the Hf-Nd isotope systems in low-temperature environments during weathering and erosion processes.
Sebastian Viehmann
doaj   +1 more source

Decoding palaeodepositional setting and redox conditions from the microbialites of the Archean Gamohaan Formation, South Africa. [PDF]

, 2023
Ansahmbom Nke, Rosalie Tostevin, Harilaos Tsikos   +2 more
openalex   +1 more source

Magnetic Circular Dichroism in Archean Stratospheric Oxygen: Enantiomeric Excess of Amino Acids Produced in Volcanic Plumes [PDF]

, 2023
Anuj K. Sharma
openalex   +1 more source

Low volcanic outgassing rates for a stagnant lid Archean earth with graphite-saturated magmas [PDF]

, 2021
Claire Marie Guimond, Lena Noack, Gianluigi Ortenzi, F. Sohl   +3 more
openalex   +1 more source

Geological and isotopic characteristics of granites from the Western Pernambuco-Alagoas Domain: implications for the crustal evolution of the Neoproterozoic Borborema Province

Brazilian Journal of Geology
The Western Pernambuco-Alagoas Domain is a complex tectonic domain of the Southern part of the Neoproterozoic Borborema Province. It borders the Northern margin of São Francisco Craton. U-Pb and Sm-Nd data discussed in this work show that, in the Western
Rodrigo Fabiano da Cruz, Márcio Martins Pimentel, Ana Cláudia de Aguiar Accioly, Joseneusa Brilhante Rodrigues   +3 more
doaj   +1 more source

Potassium Isotope Evidence for Origin of Archean TTG Rocks From Seawater‐Hydrothermally Altered Oceanic Crust

Geochemistry, Geophysics, Geosystems
Tonalite‐trondhjemite‐granodiorite (TTG) rocks constitute a crucial part of the Archean continental crust, yet their origins remain contentious. It is critical to decipher their source nature and hydration mechanism.
D.‐Y. Xiong, X.‐L. Wang, W. Li, Y.‐F. Zheng, C. R. Anhaeusser, A. Hofmann, D. Wang, J.‐Y. Li   +7 more
doaj   +1 more source

PALEOARCHEAN MAFIC ROCKS OF THE SOUTHWESTERN SIBERIAN CRATON: PRELIMINARY GEOCHRONOLOGY AND GEOCHEMICAL CHARACTERIZATION

Геодинамика и тектонофизика, 2017
The Siberian craton consists of Archean blocks, which were welded up into the same large unit by ca 1.9 Ga [Gladkochub et al., 2006; Rojas-Agramonte et al., 2011].
A. V. Ivanov, I. V. Levitsky, V. I. Levitsky, E. I. Demonterova, L Z. Reznitsky   +4 more
doaj   +1 more source

Marine Phosphate Level During the Archean Constrained by the Global Redox Budget

Geophysical Research Letters
Understanding the oceanic phosphate concentration is critical for understanding marine productivity and oxygen evolution throughout Earth history. During the Archean, estimates of marine phosphate levels range from scarce to enriched conditions. However,
Yasuto Watanabe, Kazumi Ozaki, Eiichi Tajika   +2 more
doaj   +1 more source