Results 61 to 70 of about 15,483 (211)

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

Archean Variolitic Lavas from Munro Township, Ontario [PDF]

, 1982
Chemical variations between the matrix and variole fractions of variolitic lavas are quite distinct. Analyses for major. and trace elements and trace gold content was carried out on separated fractions of matrix and varioles from several handspecimens.
Saunders, David
core  

Sulfate was a trace constituent of Archean seawater [PDF]

, 2014
In the low-oxygen Archean world (>2400 million years ago), seawater sulfate concentrations were much lower than today, yet open questions frustrate the translation of modern measurements of sulfur isotope fractionations into estimates of Archean ...
Katsev, Sergei, Nomosatryo, Sulung, Crowe, Sean Andrew, Adkins, Jess F., Crowe, Sean A., Paris, Guillaume, Jones, CarriAyne, Canfield, Donald E., Jones, Carri Ayne, Kim, Sang-Tae, Canfield, Donald Eugene; id_orcid, Kim, Sang Tae, Farquhar, James, Zerkle, Aubrey L., Sessions, Alex L., Fowle, David A.   +15 more
core   +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

Dating the cyanobacterial ancestor of the chloroplast [PDF]

, 2009
Cyanobacteria have played a pivotal role in the history of life on Earth being the first organism to carry out oxygenic photosynthesis, which changed atmospheric chemistry and allowed the evolution of Eukarya.
Luisa Falcon, Susana Magallon, Amanda Castillo   +2 more
core  

Geodynamic oxidation of Archean terrestrial surfaces

, 2023
One of the paradoxes of the Archean rock record is how evidence for oxidative continental weathering is plausible when the atmosphere lacked oxygen prior to the Great Oxidation Event ca. 2.5 billion years ago.
Zhu, Jianxi, Xiaoju Lin, Xiao Wu, Hongping He, Lingya Ma, Haiyang Xian, Lin, Xiaoju, Liang, Xiaoliang, Jianxi Zhu, Xiaoliang Liang, Ma, Lingya, Yang, Yiping, Wu, Xiao, Xian, Haiyang, Li, Shan, Yiping Yang, He, Hongping, Yiliang Li, Konhauser, Kurt O, Li, Yiliang, Shan Li, Konhauser, Kurt O. O., Kurt O. Konhauser   +22 more
core   +1 more source

Archean Domes topology comparison.

, 2022
A. Distributions obtained from simulated random (red), scale-free (blue) and small-world (green) networks and its comparison to the metrics found in the Archean Domes network for: degree variance, modularity, average path length, small-world index, and ...
Jazmín Sánchez-Pérez (12475032), David Madrigal-Trejo (12475047), Valeria Souza (273805), Natalia Favila (12936672), Laura Espinosa-Asuar (5600357), Daniel Legorreta (12936675), Luis E. Eguiarte (8026820)   +6 more
core   +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