scholarly journals Latitudes of the Eastern Ural microcontinent and Magnitogorsk island arc in the Paleozoic Ural Ocean

LITOSFERA ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 842-850
Author(s):  
V. S. Burtman ◽  
A. V. Dvorova ◽  
S. G. Samygin
Keyword(s):  
Middle Devonian ◽  
Volcanic Belt ◽  
Early Carboniferous ◽  
Southern Urals ◽  
Island Arc ◽  
Middle Urals ◽  
The Southern Urals ◽  
Tectonic Zone ◽  
Middle Ordovician ◽  
The Baltic

Research subject. Rocks of the Paleozoic Eastern Ural microcontinent and Magnitogorsk island arc occupy a significant part of the Southern Urals and some part of the Middle Urals. The Western Urals are composed of rocks of the ancient Baltic continent and overthrust oceanic rocks. In the Eastern Urals and Trans-Urals rocks of the accretion complexes, oceanic crust, island arcs, the Eastern Ural microcontinent and the Kazakhstan Paleozoic continent are widespread. Rocks are exposed in the Denisov tectonic zone. The Magnitogorsk simatic Island Arc originated in the Ural Ocean, near the Baltic continent, in the early Devonian, developing from the Emsian to the Famennian. A collision between the Magnitogorsk arc and the Baltic continent occurred in the Famennian century. In the pre-Carboniferous age, the Eastern Ural microcontinent was located in the Ural Ocean. In the Tournaisian period, the Eastern Ural microcontinent accreted with the Baltic continent. The Kazakhstan continental massif was located on the other side of the Ural Ocean. The volcanic belt above the subduction zone was active on the edge of the Kazakhstan continent in the Early–Middle Devonian and in the Early Carboniferous. A subduction under the Baltic and Kazakhstan continents consumed most of the crust of the Ural Ocean by the middle of the Bashkir century. As a result, the Baltic continent (together with the Eastern Ural microcontinent) came into contact with the Kazakhstan continent. The formation of folded orogen began in the Moscow century following the collision of sialic terrains.Materials and methods. The research was based on the relevant data obtained by several researchers in 2000–2018 on rock paleomagnetism. Results. The paleolatitudinal positions of the Eastern Ural microcontinent were determined, comprising 5.3 ± 7.4°) in the Middle Ordovician and 8.2 ± 7.2° in the Early–Middle Silurian. The respective paleolatitudinal positions for the Early–Middle Devonian comprised: the Ural margin of the Baltic paleocontinent (7.7 ± 3.7°), the Magnitogorsk island arc (3.2 ± 3.1°) and the Ural margin of the Kazakhstan paleocontinent (20.6 ± 3.8°).Conclusion. According to the analysed paleomagnetic data, in the Early–Middle Devonian, the distance between the latitudes of the margins of the Baltic and Kazakhstan continents was not less than 600 km provided they were in the same hemisphere, and more than 2,300 km provided they were in different hemispheres. The convergence of the terrains was associated with the subduction of the Ural Ocean crust before its closure, which occurred in the Tournaisian century.

History of the formation of the early Carboniferous gabbro-granite formation, Southern and Middle Urals

2019 ◽  
pp. 10-18
Author(s):  
A. V. Snachev ◽  
V. I. Snachev ◽  
M. A. Romanovskaya
Keyword(s):  
Early Carboniferous ◽  
Southern Urals ◽  
Island Arc ◽  
Middle Urals ◽  
The South ◽  
The Southern Urals ◽  
Granite Formation ◽  
History Of

The article presents new data on the geology and petrogeochemistry of the Magnitogorsk, Nepljuevsk and Kanzafarov rock complexes. Their belonging to the gabbro-granite formation has been proved. These data give opportunity to combine the South Ural and Middle Ural segments of the Early Carboniferous subduction rift into a single submeridional structure. Its formation took place at the Devonian island arc rear basin. The arc was overthrusted on the western edge of the East Ural Rise during the collision stage of the Southern Urals development. The Cu-Mo specialization of granitoids of the Magnitogorsk and Nepljuevsk complexes has been established.

Volcanism of the transitional stage from the Late Devonian island arc to Early Carboniferous rifts in the Southern Urals

2008 ◽  
Vol 63 (6) ◽  
pp. 359-367 ◽  
Author(s):  
N. V. Pravikova ◽  
E. A. Matveeva ◽  
Al. V. Tevelev ◽  
A. B. Veimarn ◽  
A. V. Rudakova
Keyword(s):  
Early Carboniferous ◽  
Southern Urals ◽  
Island Arc ◽  
Late Devonian ◽  
Transitional Stage ◽  
The Southern Urals

scholarly journals Parautochthonic paleooceanic and island-arc complexes of the Southern Urals

LITOSFERA ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 542-556
Author(s):  
V. G. Korinevsky
Keyword(s):  
Deep Structure ◽  
Southern Urals ◽  
Island Arc ◽  
The Urals ◽  
The Southern Urals ◽  
Early Devonian ◽  
Middle Ordovician ◽  
Sedimentary Deposits ◽  
Middle Paleozoic ◽  
Structural Zones

Research objects. Paleozoic (Ordovician–Middle Devonian) volcanic-sedimentary complexes of the contiguous Sakmara and Mugodzharskaya structural zones of the Southern Urals, which have a paleo-oceanic and island-arc nature. Мaterials and methods.The work was carried out on the basis of many years of personal research of the author with the involvement of literature data on other folded zones of the Southern Urals. Main results. In the early Devonian, the first intense clustering of different facies complexes of rocks took place, which determined the tectonic face of the modern western part of the fold belt. The uniformity and set of Paleozoic formations in all structures of the Urals are maintained along its entire strike and are not repeated in neighboring zones.The drilling data showed the primary character of bedding of the rocks of the Upper Devonian Zilair Formation on the dislocated volcanogenic-sedimentary deposits of the Lower-Middle Paleozoic. Thrust contacts are observed only in the marginal parts of the zone. The almost textbook views on the cover bedding of the Kraka and Kempirsai hyperbasite massifs are in contradiction with the data on the presence of “roots” up to 4–8 km deep in them. By the beginning of the Devonian, the Kempirsai massif was located within the Sakmara zone and was “cross-linked” with the surrounding effusive rocks of the Middle Ordovician by gabbro-diabase dykes. According to the results of seismometric studies, features of similarity of the deep structure of the base of the Sakmara zone with the structure of the Magnitogorsk-Mugodzharskaya zone, which also revealed a melanocratic basement, have been established. Conclusions. The formed structural zones of the Southern Urals are distinguished by a set of rocks of the same age, their stratigraphic range, and the autonomy of feeding areas. These differences have survived to this day. All subsequent tectonic episodes, including the sharpening epochs, only complicated the appearance and structure of the Southern Urals, without changing the relative position of structures that arose in the Early Devonian. There was no transfer, swarming of rocks from one zone through another in any of the subsequent stages of compression. The Early Devonian stage was the first, but at the same time the most intense, which determined the tectonic face of the modern western part of the Urals.

scholarly journals New representatives of the species Kerpia samarica from the location Novyi Kuvak (kazanian stage, Samara Region)

2016 ◽  
Vol 5 (2) ◽  
pp. 11-15
Author(s):  
Liubov Mikhailovna Bukhman ◽  
Nikolay Sergeevich Bukhman
Keyword(s):  
New Species ◽  
Southern Urals ◽  
Species Level ◽  
Middle Urals ◽  
The Southern Urals ◽  
Kazanian Stage ◽  
New Findings ◽  
The One ◽  
Kungurian Stage ◽  
A New Species

The article is devoted to the study of new representatives of the genus Kerpia Naugolnykh from Novyi Kuvak located in Shentalinsky district (northeast of Samara region). The genus Kerpia for ginkgo similar leaves was set by S.V. Naugolnykh in 1995 on the material from the Kungurian stage of the Middle Urals. Typical species of this genus is Kerpia macroloba Naugolnykh. In the diagnosis of the genus S.V. Naugolnykh showed the most important signs of this genus: presence of lobes and sinuses of the 1st and 2nd order, distinct petiole and two veins included in lamina from the petiole. Later, in 2001, from the sediments of Kazanian stage of the Southern Urals S.V. Naugolnykh described a new species Kerpia belebeica Naugolnykh. In 2013 in Novyi Kuvak location we found impressions of ginkgo similar leaves with on the one hand a great similarity with the known members of the genus Kerpia ( Kerpia macroloba and Kerpia belebeica ), but on the other hand they are clearly not identical to this representative at the species level. According to the results of the study of these impressoins in 2014 we described a new species of the genus Kerpia - Kerpia samarica N.S. Bukhman et L.M. Bukhman, 2014. In this paper we give description of both known and new findings of species Kerpia samarica and a comparison of this species with other species of the genus Kerpia .

scholarly journals Geology, physical-chemical and geodynamic conditions for the formation of Sokolovsk and Krasnokamensk granitoid massifs (South Ural)

Georesursy ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 85-93
Author(s):  
Vladimir I. Snachev ◽  
Aleksandr V. Snachev ◽  
Boris A. Puzhakov
Keyword(s):  
Early Carboniferous ◽  
Southern Urals ◽  
Geological Structure ◽  
Rift System ◽  
Second Phase ◽  
The Southern Urals ◽  
Lower Carboniferous ◽  
Sedimentary Deposits ◽  
Granite Formation ◽  
Physical Chemical

The article describes the geological structure of the Sokolovsk and Krasnokamensk massifs located in the central part of the Western subzone of the Chelyabinsk-Adamovka zone of the Southern Urals. They are of Lower Carboniferous age and break through the volcanogenic-sedimentary deposits of the Krasnokamensk (D3kr) and Bulatovo (S1-D1bl) strata. It was found that these intrusions belong to the gabbro-syenite complex and are composed of gabbroids (phase I) and syenites, quartz monzonites, less often monzodiorites (phase II). The rocks of the second phase predominate (90–95%). Gabbros belong to the normal alkaline series of the sodium series and are close to tholeiitic mafic rocks, the formation of which is associated with riftogenic structures; syenites correspond to moderately alkaline series with K-Na type of alkalinity. It has been proved that in terms of their petrographic, petrochemical, geochemical, and metallogenic features (content of TiO2, K2O, Na2O, Rb, Sr, distribution of REE, the presence of skarn-magnetic mineralization), the rocks of the massifs under consideration undoubtedly belong to the gabbro-granite formation. Crystallization of the Sokolovsk and Krasnokamensk intrusions occurred at a temperature of 880–930 °С in the mesoabyssal zone at a depth of about 7–8 km (P = 2.2–2.4 kbar). At the postmagmatic stage, the transformation parameters of the initially igneous rocks were, respectively, T = 730–770 °C, P = 4.0–4.2 kbar. The fact that these massifs belong to the gabbro-granite formation makes it possible to include them, together with Bolshakovsk, Klyuchevsky, Kurtmaksky and Kambulatovo, into the Chelyabinsk-Adamovka segment of the South Ural Early Carboniferous rift system.

scholarly journals Geological structure and petrology of the Nizhne-Sinyachikhinsky granitoid massif (Alapayevsk-Sukhoi Log porphyry copper zone, the Middle Urals)

LITOSFERA ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 212-223
Author(s):  
S. V. Pribavkin ◽  
A. V. Коrovko ◽  
I. A. Gottman
Keyword(s):  
Inductively Coupled Plasma ◽  
Porphyry Copper ◽  
Southern Urals ◽  
Geological Structure ◽  
Main Phase ◽  
Middle Urals ◽  
The Southern Urals ◽  
Rock Composition ◽  
Inductively Coupled ◽  
Intermediate Chamber

Research subject. The geological structure and rock composition of the Nizhne-Sinyachikhinsky plagiogranite massif, which is part of the Alapaevsk-Sukholozhsky zone, is promising for the Cu(Au,Mo)-porphyric mineralization type, were studied. The aim was to determine the formation features of these rocks and compare them with the productive granitoids of Ural porphyry deposits of similar age. Materials and methods. The mineral composition of the rocks was determined using a JEOL JSM 6790LV scanning electron microscope with an INCA Energy 450 X-Max 80 EDS spectrometer and a CAMECA SX-100 electron microprobe analyser. The rock composition was obtained by X-ray fluorescence spectrometry on a SRM-35 and XRF-1800 spectrometers with the titrimetric determination of FeO. The concentrations of rare and rare-earth elements were determined on an ELAN 9000 inductively coupled plasma mass spectrometer at the Geoanalitik Center for Collective Use of the Ural Branch of the Russian Academy of Sciences. Results. For the first time, an early tonalite-plagiogranite series was identified in the structure of the massif. This series is represented by tonalites of the hypabyssal appearance, broken through by the dikes of plagiogranite-porphyry. It was shown that the separation of plagiogranite-porphyry melts from magmas of the mafic composition occurred at the base of the island-arc construction, and their crystallisation was carried out in an intermediate chamber at a pressure of 1.8–2.3 kbar. In contrast, the plagiogranites of the main phase of the massif were separated from the parent melt in an intermediate chamber located at the level of the upper crust, and their crystallisation occurred at a pressure of 1.5–2.0 kbar. Conclusions. A comparison of the main phase plagiogranites and the isolated early-series plagiogranite-porphyry indicates their similar composition, as well as their similarity in age with the granitoids of the Southern Urals, productive in terms of the porphyry mineralisation type. The concentrations of F, Cl and S in the apatites and amphiboles of the rocks under study is an argument in favour of their belonging to andesitoid formations that are productive in terms of the Cu (Au)-porphyry mineralisation type. The absence of the sulphide mineralisation of this type can be explained by a more significant depth of rock formation and their erosion section.

Aristotelia balticaA. Šulcs & I. Šulcs, 1983 (Lepidoptera: Gelechiidae) new to Croatia and with observations on the larva

2020 ◽  
Vol 71 (1) ◽  
pp. 21-26
Author(s):  
R. J. Heckford ◽  
S. D. Beavan
Keyword(s):  
First Record ◽  
Southern Urals ◽  
European Russia ◽  
Baltic States ◽  
The Southern Urals ◽  
The Baltic

An account is given of finding larvae of Aristotelia baltica A. Šulcs & I. Šulcs, 1983 (Gelechiidae) in a limestone area of Croatia, a different habitat from that previously known. This is apparently the first record from Croatia of a species that otherwise occurs from the Baltic States and European Russia eastwards to the southern Urals, apart from two moths reared in 1965 from Bosnia-Herzegovina.

scholarly journals Subduction, collision and plumes in the epoch of the Late Paleozoic magmatism of the Magnitogorsk zone (the Southern Urals)

LITOSFERA ◽  
2019 ◽  
pp. 191-208
Author(s):  
D. N. Salikhov ◽  
V. V. Kholodnov ◽  
V. N. Puchkov ◽  
I. R. Rakhimov
Keyword(s):  
Late Phase ◽  
Active Continental Margin ◽  
Southern Urals ◽  
Island Arc ◽  
Late Paleozoic ◽  
Time Interval ◽  
Geochemical Type ◽  
The Southern Urals ◽  
European Continent ◽  
East European

Subject. A systematization of Late-Paleozoic magmatic formations of the Magnitogorsk zone of the Southern Urals in the process of an accretion of the Magnitogorsk paleoarc to the margin of the East European continent (EEC) with formation in Famenian and Carboniferous active continent margin of South-Uralian accretionary-collisional belt was given in the work. Materials and methods. A generalization of published and manuscript materials characterizing magmatism and ore-mineralization of Magnitogorsk zone for the Devonian-Carboniferous-Permian time carried out, additional investigations of chemical composition of rocks (XRF, ISP-MS) characterizing process of accretion, subduction and plume activity, microelement distribution in them was made, the composition of rock-forming and accessory minerals (EPMA) was studied. Results. It is found that the South-Uralian accretionary-collisional belt was beginning to form in the late phase of the development of the Magnitogorsk island arc in the process its collision with EEC margin with formation in the Frasnian and Carboniferous of active continental margin. The products of Late-island-arc volcanism are represented by the porphyrite formation and in the eastern frame of the arc - by subalkaline monzonite-shoshonite-latite volcanic-intrusive association with intermediate characteristics between the subductional and interplate formations. Synchronously with them, in the backarc setting, picrite and meymechite volcanics − derivatives of a mantle plume are formed. In process of substitution of tectonic-magmatic regime from island-arc to margin-continental intraplate-type mantle series were forming. During this period, hot asthenospheric diapirs (plumes) were rising to the bottom of new-formed (accreted) margin-continental lithosphere. Along with the magmatic associations of intraplate type and rock series of intermediate geochemical type, this geodynamic situation in the Southern Urals is characterized by a presence of great volumes of mantle-crust granitoids of gabbro-tonalite-granodiorite-granite type, that were formed with a manifold manifestation of anatexis in a time interval of 365-290 Ma. Conclusion. On the whole the originality of Magnitogorsk zone geological history in the Devonian and Carboniferous, peculiarities of magmatic complexes formed here due to various geodynamic settings, are making this zone an extraordinary interesting and important object to study of processes of plume-lithosheric and mantle-crust interaction.

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