scholarly journals The Lower Precambrian in the structure of paleozoic in the Subpolar Urals

2019 ◽  
Vol 486 (5) ◽  
pp. 572-576
Author(s):  
Yu. I. Pystina ◽  
A. M. Pystin ◽  
V. B. Hubanov
Keyword(s):  
Southern Urals ◽  
Western Slope ◽  
Geochronological Data ◽  
The Urals ◽  
The Southern Urals ◽  
Early Precambrian ◽  
Subpolar Urals ◽  
Late Precambrian ◽  
Lower Riphean ◽  
First Time

In many polymetamorphic complexes of the Urals, rocks with Early Precambrian age marks have been established. But only with respect to the two polymetamorphic complexes located on the western slope of the Southern Urals: the Taratash and Aleksandrov, their indisputable belonging to the Archean-Paleoproterozoic section is recognized. They are framed by weakly metamorphosed Lower Riphean sediments and reliable geochronological data are obtained from them, which unambiguously indicate the Early Precambrian age of rock metamorphism. The available Early Precambrian age datings for other Ural polymetamorphic complexes (with the prevailing number of Late Precambrian and Paleozoic age values) are interpreted differently. Therefore, their attitude to the Lower Precambrian section has been disputed by many researchers. In the article, for the first time, based on the results of mass U-Pb dating of metamorphic zircons from the gneiss of the Nyrtin polymetamorphic complex of the Subpolar Urals, taking into account the available data, the Paleoproterozoic age of the earliest stage of rocks metamorphism (2127 ± 31 Ma) is substantiated. This gives grounds to assert that the complex under consideration, as well as the Taratash and Alexandrov complexes of the Southern Urals, belongs to the Lower Precambrian formations involved in the structure of Uralides.

scholarly journals The sources of zircons in clastic rocks of the Riphean deposits of the Urals

2019 ◽  
Vol 488 (4) ◽  
pp. 413-419
Author(s):  
A. A. Krasnobaev ◽  
V. N. Puchkov ◽  
N. D. Sergeeva ◽  
S. V. Busharina
Keyword(s):  
Southern Urals ◽  
Detrital Zircons ◽  
The Other ◽  
The Urals ◽  
The Southern Urals ◽  
Clastic Rocks ◽  
Lower Riphean ◽  
Age Variations ◽  
Age Determinations

New age determinations of detrital zircons of sandstones augmented the possibilities of interpretation of their provenance. This interpretation is often restricted by a formal comparison of age-and-composition characteristics of detrital crystals with any very distant model objects. A different situation arises when the role of a source of a detritus is claimed by local objects. The analysis of SHRIMP and TIMS - datеs of zircons and U and Th concentrations in them, and also a comparison of histograms of primary zircons from Riphean volcanics and rocks of the Taratash complex on one hand and the detrital zircons from the sandstones of Vendian (Asha series) and Lower Riphean (Ai Formation) on the other, have shown that the age variations of sources and clastics are comparable in many aspects. It means that the age characteristics of primary zircons from the Riphean volcanics and rocks of the Taratash complex as sources of zircon clastics for the Riphean and Vendian sandstones in the Southern Urals are regulated by processes of resedimentation, though the influence of distant sources is not excluded.

scholarly journals The Source of Ore Fluids and Sm–Nd Age of Siderite from the Largest Bakal Deposit, Southern Urals

2021 ◽  
Vol 63 (4) ◽  
pp. 324-340
Author(s):  
M. T. Krupenin ◽  
A. B. Kuznetsov ◽  
M. V. Chervyakovskaya ◽  
T. Ya. Gulyaeva ◽  
G. V. Konstantinova
Keyword(s):  
Age Estimation ◽  
Iron Ore ◽  
Southern Urals ◽  
Western Slope ◽  
The Southern Urals ◽  
Crustal Source ◽  
First Time

Abstract— Based on Sm–Nd data, a crustal source of iron-ore fluid was substantiated and the probability of age estimation for hydrothermal–metasomatic siderite of the Bakal Group, Southern Urals, was shown for the first time. The εNd (Т) values of siderite (from –13.4 to –17.6) plot in the field of Riphean shale and not the Precambrian rift gabbro and granite of this region. The obtained Sm–Nd age of the Bakal siderite is 970 ± 40 Ma, which is consistent with the Pb–Pb age of siderite from the major ore phase (~1000 Ma). The established age boundary coincides with tectonic restructuring, including the formation of a number of barite–polymetallic deposits, as well as ferruginous magnesite and fluorite in the Riphean deposits on the western slope of the Southern Urals.

scholarly journals Zircons of the Permian age (280–290 Ma) from intrusive magmatic rocks in Riphean structure of the Southern Urals

LITOSFERA ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 601-608
Author(s):  
A. A. Krasnobaev ◽  
V. N. Puchkov ◽  
N. D. Sergeeva ◽  
S. V. Busharina
Keyword(s):  
Southern Urals ◽  
Lower Permian ◽  
The Urals ◽  
Shrimp Dating ◽  
The Southern Urals ◽  
Lower Paleozoic ◽  
Magmatic Rocks ◽  
Lower Riphean ◽  
Granite Complex ◽  
A Chain

Research subject. Magmatic complexes that are developed in the lower (volcanogenic-sedimentary) part of the Ai Formation of the Lower Riphean of the Taratash anticline in the Southern Urals. Results. For the frst time, the Lower Permian SHRIMP dating (288.6 ± 3.1 Ma by U-Pb method on zircon from monzogabbro) was obtained for a dike cutting the basalts of the Lower Paleozoic (420–450 Ma) age. Conclusions. On the eastern slope of the Urals there is a chain of massifs which are close in the age. The chain belongs to the Lower Permian Stepninsky monzogabbro-granosyenite-granite complex, represented by the Uiski, Vandyshevski, Biryukovski and Stepninski intrusions with the age of 281 ± 2, 280 ± 2 and 286 ± 2 Ma, correspondingly (U-Pb method after zircons, SHRIMP-II, VSEGEI) and earlier obtained dates 281 ± 4 Ma (Rb-Sr isochrone) and 283 ± 2 Ma (isotope Pb-Pb method after zircons). The Stepninsky complex was described earlier as plume-dependent. The monzogabbro dike, described in this paper, although being at a considerable distance from the Sepninsky complex, is situated at a strike of the chain of the stepninsky intrusions, is close to them by the composition and age and can be ascribed to the same plume episode. The idea of the plume character of the complex was ехрressed by us relatively long ago based on a superimposed character of the chain of the intrusions over the earlier, collisional Uralian structures. As for the geochemical character (monzogabbro) the dike conforms with one of two standard trends of the Stepninsky complex – monzonite (monzogabbro, monzodiorites, syenites).

First data on lichens of Zyuratkul National Park (Chelyabinsk Region)

2011 ◽  
Vol 45 ◽  
pp. 223-236 ◽  
Author(s):  
I. N. Urbanavichene
Keyword(s):  
Eastern Europe ◽  
National Park ◽  
Southern Urals ◽  
The Urals ◽  
The Southern Urals ◽  
Chelyabinsk Region ◽  
First Time ◽  
Lichen Flora

The first data on the lichen flora of Zyuratkul National Park (Chelyabinsk Region) are provided. The preliminary list includes 263 species of lichens and allied fungi. Parmelia barrenoae and Pyxine sorediata were found for the first time for the Eastern Europe, 22 species are new for the Urals and 23 for the Southern Urals.

scholarly journals Comparison of Lower and Middle Riphean sparry magnesite deposits of the Southern Urals province

2002 ◽  
Vol 50 ◽  
Author(s):  
MIKHAIL T. KRUPENIN
Keyword(s):  
Southern Urals ◽  
Ultramafic Rocks ◽  
Western Slope ◽  
South Urals ◽  
The Southern Urals ◽  
Humid Climate ◽  
Ore Formation ◽  
Ore Body ◽  
Lower Riphean ◽  
Average Size

Sparry magnesite deposits (SMD) of the Lower Riphean (LR) and Middle Riphean (MR) sequences in the western slope of the South Urals have some distinguished peculiarities, which allows to compare them and speculate about the mechanism of ore formation and Mg-source origin. LR magnesites are located in some stratigraphic levels and lie within widespread dolostone horizons. MR magnesites that occur in the lower carbonate member of Avzyan fm. are represented by dolomitized limestones. The shape of LR magnesite body is very often layer-like with sharp contacts. The shape of MR one is sometimes lens like, contacts of ore body are complecated with zones of impregnable magnesites near the hosting dolomites. The crystalline structures of LR magnesites are typically corse-grained with average size of crystalls 10 mm. The magnesite grains of the MR one have 1-3 mm of average size. The chemical composition of MR magnesite ore shows increase of SiO 2 , Al 2 O 3 , FeO and decrease of LREE fractionation in comparison with the LR magnesites. As we assume, metasomatic magnesites of the Lower Riphean time are connected with sedimentation/early diagenesis stage. The source of Mg 2+ came from a crust of weathering of basic and ultramafic rocks in humid climate. Magnesite occurrences in Middle Riphean time are connected with high Fe-contents metasomatic fluids, which were resulted of evaporite Mg-enriched solutions transformation during kathagenesis.

The first data on possible Mezozoic magmatism within the Western slope of the Southern Urals

2018 ◽  
pp. 24-34
Author(s):  
A. O. Khotylev ◽  
N. B. Devisheva ◽  
Al. V. Tevelev ◽  
V. M. Moseichuk
Keyword(s):  
Southern Urals ◽  
Western Slope ◽  
Isotopic Age ◽  
The Southern Urals ◽  
Early Proterozoic ◽  
Carbonate Formations ◽  
Two Bodies

Within the Western slope of the Southern Urals, there are plenty of basite dyke complexes of Riphean to Vendian among Precambrian terrigenous-carbonate formations. In metamorphic formations of the Taratash complex (Archean to Early Proterozoic, the northern closure of the Bashkirian meganticlinorium) there was observed the andesitic dyke with isotopic age of 71±1 Ma (U-Pb SHRIMP II on zircons) and near Bakal two bodies of gabbroids with zircons of similar ages were found. These are the first evidence of possible Mezozoic magmatism in this region.

The Sr isotopic characterization and Pb-Pb age of carbonate rocks from the Satka formation, the Lower Riphean Burzyan Group of the southern Urals

2008 ◽  
Vol 16 (2) ◽  
pp. 120-137 ◽  
Author(s):  
A. B. Kuznetsov ◽  
G. V. Ovchinnikova ◽  
M. A. Semikhatov ◽  
I. M. Gorokhov ◽  
O. K. Kaurova ◽  
...  
Keyword(s):  
Carbonate Rocks ◽  
Southern Urals ◽  
The Southern Urals ◽  
Lower Riphean ◽  
Isotopic Characterization ◽  
Burzyan Group

scholarly journals The First Find of Cr2O3 Eskolaite Associated with Marble-Hosted Ruby in the Southern Urals and the Problem of Al and Cr Sources

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 101
Author(s):  
Aleksander Kissin ◽  
Irina Gottman ◽  
Sergei Sustavov ◽  
Valery Murzin ◽  
Daria Kiseleva
Keyword(s):  
Granite Gneiss ◽  
Southern Urals ◽  
X Ray Diffraction ◽  
The Southern Urals ◽  
Near Surface ◽  
X Ray ◽  
Gneiss Domes ◽  
Electron Probe Microanalyzer ◽  
Formation Zone ◽  
First Time

The results of the study of eskolaite associated with marble-hosted ruby found for the first time in the Kuchinskoe occurrence (Southern Urals) are presented. Here, eskolaite was located on the surface and near-surface regions of ruby crystals. Eskolaite diagnostics was confirmed by powder X-ray diffraction (URS-55). The morphology and chemical composition of eskolaite and associated ruby was studied using a JSM-6390LV scanning electron microscope and a Cameca SX 100 electron probe microanalyzer. The eskolaite crystals were hexagonal and tabular, up to 0.2 mm in size. Ruby mineralization was formed during prograde and retrograde dynamothermal metamorphism. The eskolaite associated with the prograde stage ruby contained Al2O3 (9.1–23.62 wt %), TiO2 (0.52–9.66 wt %), V2O3 (0.53–1.54 wt %), FeO (0.03–0.1 wt %), MgO (0.05–0.24 wt %), and SiO2 (0.1–0.21 wt %). The eskolaite associated with the retrograde stage ruby was distinguished by a sharp depletion in Ti and contained Al2O3 (12.25–21.2 wt %), TiO2 (0.01–0.07 wt %), V2O3 (0.32–1.62 wt %), FeO (0.01–0.08 wt %), MgO (0.0–0.48 wt %), and SiO2 (0.01–0.1 wt %). The associated rubies contained almost equal amounts of Cr2O3 (2.36–2.69 wt %) and were almost free from admixtures. The identification of the eskolaite associated with the marble-hosted rubies from the Kuchinskoe occurrence is a new argument in favor of introduction of Al and Cr into the mineral formation zone. The mineralization was localized in the metamorphic frame of the granite gneiss domes and was formed synchronously with them.

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