Results 51 to 60 of about 49,177 (301)
Neoproterozoic subduction along the Ailaoshan zone, South China : geochronological and geochemical evidence from amphibolite [PDF]
, 2014 This study was supported by China Natural Science Foundation (41190073 and 41372198), National Basic Research Program of China (2014CB440901) and Natural Environment Research Council (grant NE/J021822/1).Lenses of amphibolites occur along the Ailaoshan ...
Cai, Yongfeng +6 more
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Geochemical characterization of Gubanovskaya intrusion of rapakivi granites (Wiborg massif)
Vestnik MGTUThe paper presents new data on geology and composition of rapakivi granites of Gubanovskaya intrusion (Wiborg massif). Petrographic and geochemical characteristics of rapakivi granites of the second (ovoid) and third (trachytoid) phases of intrusion, as ...
Rogova I. V. +3 more
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A secular increase in continental crust nitrogen during the Precambrian [PDF]
, 2017 Recent work indicates the presence of substantial geologic nitrogen reservoirs in the mantle and continental crust. Importantly, this geologic nitrogen has exchanged between the atmosphere and the solid Earth over time. Changes in atmospheric nitrogen (i.
Goldblatt, Colin, Johnson, Benjamin W
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Pressure, temperature and time constraints on tectonic models for southwestern Sweden [PDF]
, 2010 In this work, a number of key localities have been investigated in detail in order to provide precise constraints on models for the tectonic evolution of southern Sweden.
Austin Hegardt, Eric
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Deep Underground Science and Engineering, EarlyView.In this work, we propose an improved particle swarm optimization (PSO) algorithm and develop an improved PSO‐relevance vector machine (RVM) model as a substitute for traditional true‐triaxial testing. The model's high prediction accuracy was validated through comparisons with two other machine learning methods and five three‐dimensional Hoek–Brown type
Qi Zhang +4 more
wiley +1 more source
Geologica Acta, 2020 Northern Portugal is characterized by the occurrence of numerous W hydrothermal deposits spatially associated with granites. The primary goal of this work is to establish a relationship between the magnetic behavior of the granites and the redox ...
C. Cruz, H. Sant’Ovaia, F. Noronha
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Brazilian Journal of Geology, 2020 The Vieirópolis pegmatite field is characterized by amazonite pegmatites inserted in the Borborema Province. The Serra Branca pegmatite is hosted by the Serra Branca granites, which intruded partially the Serra Negra granites, and stands out by its ...
Igor Manoel Belo de Albuquerque e Souza +4 more
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Correlation of magnetic susceptibility with 18O data in magnetite- and ilmenite-type granites from Iberian massif [PDF]
, 2012 The relationship between oxygen isotopic values and magnetic susceptibility composition on 11 Variscan Portuguese granites has been investigated. Whole-rock oxygen-isotope (18O ) values for Vieira do Minho (VM), Vila Pouca de Aguiar (VPA), Chaves ...
Lopes, José Carrilho +4 more
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Deep Underground Science and Engineering, EarlyView.Hydraulic fracturing in tight sandstone and fracture propagation characteristics using backscattered electron‐scanning electron microscope (BSE‐SEM) images. Abstract This study focuses on hydraulic fracturing experiments conducted under triaxial conditions on tight sandstone specimens from Shivpuri district, Madhya Pradesh, India.
Pankaj Rawat, Narendra Kumar Samadhiya
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Creep properties and constitutive model of diabase in deep water conveyance tunnels
Deep Underground Science and Engineering, EarlyView.The axial and lateral creep characteristics of diabase were analyzed based on compression creep tests. The nonlinear viscoelastic‐plastic model capable of describing the whole creep process was established based on the fractional derivative and damage theories.
Zhigang Tao +5 more
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