scholarly journals Zircons of fenites of Ilmeno-Vishnevogorsky Complex (Southern Urals)

LITOSFERA ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 306-322
Author(s):  
A. A. Krasnobaev ◽  
P. M. Valizer ◽  
N. N. Farrakhova
Keyword(s):  
Mass Spectrometer ◽  
Southern Urals ◽  
Research Subject ◽  
Shear Deformations ◽  
Metasomatic Process ◽  
Geochemical Study ◽  
Ree Distribution ◽  
Shear Strains ◽  
Secondary Ion ◽  
Ti Content

Research subject. U-Pb zircon dating, as well as a petrological and geochemical study of pyroxene-amphibole-, pyroxeneamphibole- biotite- and biotite-bearing fenites from the Central Alkaline Band Ilmeno-Vishnevogorsky Complex.Methods. The age of zircons was determined by an ion mass spectrometer (SHRIMP II, Centre of Isotopic Research VSEGEI). The content of REE and trace elements was estimated by secondary ion mass spectrometer methods (CAMECA IMS-4F, Valiev Institute of Physics and Technology RAS).Results. The mineralogical and geochemical (U, Th, REE) features of zircons, as well as fenites, reflect their polygenic-polychronous nature. Most zircon crystals have a metastable matrix and are characterized by averaged REE contents between igneous and hydrothermal types. These crystals are distinguished from magmatic zircons by high LREE contents and low values of Ce anomalies, and from hydrothermal zircons – by differentiated REE distribution spectra. Three ages of zircon were established: 2066–1686 (PR1), 425–404 (S2) and 284–266 (P1) Ma. PR1 zircons reflect the primary features and the degree of changes in the fenite substrate. S2 zircons, limited only to the biotite- bearing fenite, correspond to the age of the miaskite formation process. The P1 zircons clearly reflect the metasomatic process of fenitization initiated by late shear deformations. The temperature of the phenitization processes (based on the Ti content in zircons) was estimated at 630–670°C for S2 and ≤ 600°C for P1 fenites, respectively.Conclusions. Central Alkaline Band fenites were formed by the metasomatic process of PR1 substrate fenitization in the late stage (P1) of shear strains, which are widely expressed in the Ilmeno-Vishnevogorsky Complex.

scholarly journals Early Permian granitoids of the East Magnitogorsk zone (South- ern Urals): petrology, geochemistry, and geodynamic formation environment

2020 ◽  
Vol 1 (1) ◽  
pp. 47-62
Author(s):  
Timofey Nikolaevich SURIN ◽  
Keyword(s):  
Water Pressure ◽  
Southern Urals ◽  
Geodynamic Setting ◽  
Type I ◽  
Early Permian ◽  
The Southern Urals ◽  
Quartz Syenite ◽  
Crystallization Differentiation ◽  
Geochemical Study

The relevance of the problem. The Early Permian magmatism of the Southern Urals is poorly studied with the help of modern methods. The granitoid massifs of this age locally developed in the East Magnitogorsk zone contain important information about the geodynamic conditions of their formation. Clarification of this issue makes an important contribution to the understanding of the geodynamic development of the Urals. The nature of granitoids is still debatable. The connection with the massifs combined in the Balkan complex of gold-tungsten mineralization indicates the need for a comprehensive study. The purpose of the study is to determine the petrological and geochemical features of the rocks of the Balkan complex, to identify the mechanism of their petrogenesis and to establish the geodynamic conditions of their formation. Results. The petrological and geochemical study of the formations of the Balkan complex was carried out and their place in the typical taxonomy of granitoids was determined. Their belonging to the I-type is shown. Mineralogical and petrogeochemical methods were first studied for shonkinite xenoliths in granitoids. The mechanism of petrogenesis of rocks is proposed and the geodynamic setting of their formation is determined. It is shown that the monzonitemonzodiorite-quartz syenite-granosyenite-leucogranite series of rocks was formed as a result of crystallization differentiation of a single parental melting, and it was also concluded that the massifs of the complex are formed under conditions of early collision conditions with the important role of the subduction process. The mechanism of formation of the massifs of the complex is largely similar to mechanism for granitoids in other conflict areas, although it has its own specifics. Conclusions. 1). The Early Permian granitoids of the Balkan complex relates to type I. 2). All rocks of the complex, from monzonites to quartz syenites and leucogranites, including xenolith shonkinites, form a petrogenetic series formed as a result of crystallization differentiation of a single parent alkaline-gabbroic melting with increased water pressure. 3). The Balkan complex was formed in an early collisional setting under the action of deep subduction. 4). Transpression in the upper part of the crust induced formation of the massifs of the complex. 5). The Balkan complex is a kind of indicator of the growth of the newly formed crust as a result of collision and accretion processes.

A new thermal emission cesium primary ion source for secondary ion mass spectrometer

1992 ◽  
Vol 63 (4) ◽  
pp. 2414-2416 ◽  
Author(s):  
J. M. Zinkiewicz ◽  
M. Sowa ◽  
R. Baranowski ◽  
L. Glusiec ◽  
K. Kiszczak
Keyword(s):  
Mass Spectrometer ◽  
Thermal Emission ◽  
Ion Source ◽  
Secondary Ion
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