Results 41 to 50 of about 2,944 (200)

Petrogenesis of the Kanker Granites From the Bastar Craton: Implications for Crustal Growth and Evolution During the Archean-Proterozoic Transition

Frontiers in Earth Science, 2020
Archean-Proterozoic boundary represents a significant transitional phase in the Earth's history. Bastar Craton is one of the major Archean cratons in the Indian subcontinent with voluminous granites, supracrustal rocks, and tectonic belts.
Ajay Dev Asokan, R. Elangovan, Neeraj Vishwakarma, K. R. Hari, M. Ram Mohan   +4 more
doaj   +1 more source

Nature, origin, and phosphorylation potential of the phosphorus/sulfur‐bearing nanoscale multiphasic assemblages in the CM chondrites Murchison and Murray

Meteoritics &Planetary Science, EarlyView.
Abstract Carbonaceous chondrites contain phosphorus, whose speciation and thus history remain to be investigated. Phosphorus/sulfur‐bearing assemblages have been reported in carbonaceous CM chondrites, but there is no consensus about their exact compositions and origins.
Valentine Megevand, Sylvain Bernard, Corentin Le Guillou, Roberto Conconi, François Guyot   +4 more
wiley   +1 more source

Geophysical update of the diameter of the Zhamanshin impact structure, Kazakhstan

Meteoritics &Planetary Science, EarlyView.
Abstract The rim of the 0.9‐Ma‐old Zhamanshin impact crater in Kazakhstan is considered to be almost completely exposed via a series of hills surrounding a central flat area, indicating an apparent diameter of 14 km. This would make Zhamanshin the second largest impact crater of the Quaternary period. However, the overall geometry of these hills is not
Yoann Quesnel, Dilyara M. Kuzina, Jérôme Gattacceca, Minoru Uehara, Ayrat G. Kharisov, Dmitry D. Badyukov, Pierre Rochette   +6 more
wiley   +1 more source

The Medicine Hat Block and the Early Paleoproterozoic Assembly of Western Laurentia

Geosciences, 2020
The accretion of the Wyoming, Hearne, and Superior Provinces to form the Archean core of western Laurentia occurred rapidly in the Paleoproterozoic. Missing from Hoffman’s (1988) original rapid aggregation model was the Medicine Hat block (MHB).
Jennifer N. Gifford, Shawn J. Malone, Paul A. Mueller   +2 more
doaj   +1 more source

Paleomagnetism of the Great Dyke of the Kola Peninsula (2.68 Ga): New Evidence of Ultra-Low Paleointensity of the Earth’s Magnetic Field in the Late Archean

Учёные записки Казанского университета: Серия Естественные науки
Giant mafic dykes are the key markers of the Earth’s evolution in the Precambrian and have been the subject of extensive research. This article presents the results of the paleomagnetic, rock-magnetic, and paleointensity Banc studies of the Great Dyke of
V. V. Shcherbakova, R. V. Veselovskiy, G. V. Zhidkov, N. A. Aphinogenova, A. V. Samsonov, A. V. Stepanova, M. A. Smirnov   +6 more
doaj   +1 more source

ISOTOPIC-GEOCHEMICAL ASPECTS OF THE OCCURRENCE OF LIFE ON EARTH IN THE EARLY PRECAMBRIAN

Геохімія техногенезу
The time of the appearance of life and oxygen on Earth is debatable. In order to search for signs of the presence of life and the evolution of the Earth’s outer shells, in particular the time of the appearance of oxygen in the atmosphere,
Demikhov Yu.M., Verkhovtsev V.G., Musich O.G., Borisova N.M., Kravchuk Z.N   +4 more
doaj   +1 more source

Komatiites From Mantle Transition Zone Plumes

Frontiers in Earth Science, 2020
During the Archean, episodic volcanism commonly included both plume- and arc-type magmatism, raising the issue of a possible link between “bottom up” and “top down” geodynamic processes.
Derek Wyman
doaj   +1 more source

Evolution of the Archean atmosphere

16 pages, 1 figure. Accepted for publication as: Colin Goldblatt, Jake K. Eager-Nash, and Julia E. Horne (in press) "Evolution of the Archean Atmosphere", in: "The Archean Earth" (ed.: Martin Homan, Paul Mason, Richard Ernst, Timothy Lyons, Christoph Heubeck, Dominic Papineau, Eva Stueeken, Rajat Mazumder, Alexander Webb, Wladyslaw Altermann ...
Colin Goldblatt, Jake K. Eager-Nash, Julia E. Horne   +2 more
openaire   +2 more sources

Gamma-ray spectrometry, magnetic and gravity signatures of Archean nuclei of the Borborema Province, Northeastern Brazil

Journal of the Geological Survey of Brazil
Gamma-ray spectrometry, as well as magnetic and gravity data, are used to investigate the geophysical signatures of the Archean nuclei of the Borborema Province.
Roberto Gusmão de Oliveira, Nitzschia Regina Rodrigues Domingos, Walter Eugênio de Medeiros, Vladimir Cruz de Medeiros, Frank Gurgel Santos, Marcus Flavio Nogueira Chiarini, Marília de Araújo Costa Rodrigues   +6 more
doaj   +1 more source

UV radiation limited the expansion of cyanobacteria in early marine photic environments

Nature Communications, 2018
The means by which planktonic cyanobacteria were able to persist through the Archean despite high fluxes of UV radiation are unclear. Here, the authors show that Fe(III)-Si rich precipitates in the Archean photic zone could have provided early planktonic
Aleksandra M. Mloszewska, Devon B. Cole, Noah J. Planavsky, Andreas Kappler, Denise S. Whitford, George W. Owttrim, Kurt. O Konhauser   +6 more
doaj   +1 more source