scholarly journals Main and rare earth elements of amphibolites of the Ray-Iz massif (Polar Urals)

2020 ◽  
pp. 19-27
Author(s):  
Alyona Romanovna BOGDANOVA ◽  
◽  
Nadezhda Vladimirovna VAKHRUSHEVA ◽  
Pavel Borisovich SHIRYAEV ◽  
◽  
...  
Keyword(s):  
Metamorphic Rock ◽  
Central Zone ◽  
Ultramafic Rocks ◽  
Work Study ◽  
Garnet Amphibolite ◽  
Ore Deposit ◽  
Polar Urals ◽  
Chromium Ore ◽  
Quantitative Content ◽  
Ree Distribution

Relevance. The Ray-Iz massif contains the Tsentralnoye chromium ore deposit and is unique in terms of variety of metamorphic rock associations. It has been studied since 1932. However, some aspects of geology and petrology in the literature are not fully covered. One of these areas is a vein series of rocks localized in ultramafic rocks. The spatial confinement of amphibolites to the Central zone of metamorphism, which is consistent with the zone of distribution of deposits and ore occurrences of chromites, determines the need for a detailed study. Purpose of work. Study of mineralogical and petrographic characteristics, as well as the geochemistry of lanthanides of amphibolites of the Ray-Iz massif (Polar Urals). Results. The study of the nature of REE distribution in rock-forming minerals made it possible to determine that the variation in the amount of REE (33–75 g/t) within one rock is associated with the quantitative content of the main minerals-concentrators. The main mineral concentrator lanthanides in garnet amphibolites is garnet, while amphibole is in garnet-free pyroxene-bearing amphibolites. Based on the results of the chemical composition of amphibole and coexisting plagioclases and amphibolite garnets, the temperature was calculated using amphiboleplagioclase by T. Holland, J. Blundy, as well as the garnet amphibolite by L. L. Perchuk geothermometers and pressure based on amphibole geobarometer by M. W. Schmidt. Conclusion. The nature of the distribution of lanthanides in the main rock-forming minerals, amphibole and garnet, has been revealed. Comparison of parameters and compositional features of amphiboles made it possible to conclude that there is a direct relationship between temperature, pressure, the sum of REE and TiO2 , as well as (La/Yb)n , in the mineral.

scholarly journals Zonality of ore-forming chrome spinels of medium-chrome and aluminous chromitites of the Voikaro-Syninsky massif

2021 ◽  
pp. 39-47
Author(s):  
Pavel Borisovich SHIRYAEV ◽  
◽  
Nadezhda Vladimirovna VAKHRUSHEVA ◽  
Keyword(s):  
Oxidation State ◽  
Chromium Content ◽  
Ultramafic Rocks ◽  
Work Study ◽  
Chemical Zoning ◽  
Polar Urals ◽  
The Core ◽  
Ore Bodies ◽  
Scientific Papers ◽  
The Polar Urals

Relevance of the work. The conditions for the formation of chromium ores in alpine-type ultramafites remain a topical subject of research. In recent years, scientific papers have focused on the issue of changing the chemical composition of ore-forming minerals and chromium ores under the influence of deformation and dynamic recrystallization processes accompanying metamorphism. The results of such studies make it possible to formulate a new model of the formation of chromium mineralization taking into account a significant amount of geological data indicating that alpine-type ultramafic rocks are “mantle tectonites”. In our work, we have studied zonal ore-forming spinels from chrome ores of the Polar Urals. The results of the study make it possible to associate the formation of chemical zoning in minerals and ore bodies with recrystallization under the influence of stress tension. Purpose of the work – study of the conditions for the formation of chemical zoning of chromium spinels from alumina and medium chromium ores of the Voikaro-Syninsky massif. Results. Zonal ore-forming spinels from medium-chromium and aluminous chromitites of the Voikaro-Syninsky massif (Polar Urals) have been studied. It was found that replacement rims are developed along the grains of oreforming spinels with an increased content of Cr2 O3 and an oxidation state of iron in relation to the core, as well as a reduced content of Al2 O3 . The oxidation state of iron in the rims of most grains does not exceed the values typical for unaltered ore-forming spinels. T–fO2 parameters of zoning formation in spinels were determined by oxythermobarometry. Comparison with zoned chrome spinels of the Golyamo Kamenyane massif (Bulgaria). Conclusion. Metamorphic transformations of alumina and medium-chromium chromitites of the Voikaro-Syninsky massif, occurring under subcrustal conditions under the action of directional stress at relatively constant T–fO2 parameters, lead to an increase in the chromium content of the ore mineral.

scholarly journals Ultramafic rocks of the Aganozero chromium ore deposit (South Karelia) as a non-conventional magnesium-silicate raw material for the production of new ceramic materials

2019 ◽  
Author(s):  
V.P. Ilyina ◽  
P.V. Frolov
Keyword(s):  
Raw Materials ◽  
Practical Interest ◽  
Magnesium Silicate ◽  
Ceramic Materials ◽  
Raw Material ◽  
Ultramafic Rocks ◽  
Practical Application ◽  
Ore Deposit ◽  
Chromium Ore ◽  
Technological Level

Ultramafic rocks of the Aganozero chromium ore deposit located in South Karelia are of practical interest as a high-Mg raw material for industrial application. The preliminary results of the study of high-Mg rocks and minerals from the Aganozero deposit for the production of new materials are reported. The high technological level and economic efficiency of the ceramic materials produced, based on Karelia’s high-Mg rocks and industrial minerals, were achieved by reducing energy consumption and simplifying the technological process. The practical application of local types of mineral products will increase the raw materials potential for the production of various types of refractories and industrial ceramics.

Petrogenesis of ultramafic rocks of komatiitic composition from the Central Zone of the Limpopo Belt, South Africa: Evidence from O and H isotopes

2018 ◽  
Vol 147 ◽  
pp. 68-77
Author(s):  
Tapabrato Sarkar ◽  
Elena O. Dubinina ◽  
Chris Harris ◽  
Wolfgang D. Maier ◽  
Hassina Mouri
Keyword(s):  
South Africa ◽  
Central Zone ◽  
Ultramafic Rocks ◽  
Limpopo Belt

A red-corundum-bearing vein in the Rai–Iz ultramafic rocks, Polar Urals, Russia: the product of fluid activity in a subduction zone

Lithos ◽  
2018 ◽  
Vol 320-321 ◽  
pp. 302-314 ◽  
Author(s):  
Fancong Meng ◽  
Vladimir R. Shmelev ◽  
Ksenia V. Kulikova ◽  
Yufeng Ren
Keyword(s):  
Subduction Zone ◽  
Ultramafic Rocks ◽  
Polar Urals

scholarly journals Apoultramafic metasomatites of the Enganepe Uplift (the Polar Urals)

2021 ◽  
Vol 3 ◽  
pp. 11-20
Author(s):  
S. A. Onishchenko ◽  
◽  
A. A. Soboleva
Keyword(s):  
Ultramafic Rocks ◽  
Chrome Spinel ◽  
High Chromium ◽  
Polar Urals ◽  
Magmatic Stage ◽  
The Polar Urals

Ultramafic rocks of the Enganepe Uplift are transformed into serpentinites, magnesite-dolomite-talc and quartz-magnesite-dolomite metasomatites belonging to the beresite-listvenite formation. All apoultramafic rocks contain high chromium and nickel inherent in protolith. Chrome-spinel of the magmatic stage is represented by alumochromite, which, in the process of metamorphic and metasomatic transformation of rocks, has been replaced by secondary chrome-spinel (subferrialumochromite, ferrichromite) and chromium-bearing magnetite. The main nickel minerals are millerite and gersdorffite. In quartz-magnesite-dolomite rocks, nickel is party contained in Ni-Cr-chlorite.

scholarly journals Mafite-ultramafites (Peridotitovy stream, Polar Urals): mineralogy, estimation of P–T-parameters of formation

2021 ◽  
Vol 4 ◽  
pp. 10-19
Author(s):  
N. S. Ulyasheva ◽  
◽  
O. V. Udoratina ◽  
A. S. Shuisky
Keyword(s):  
Low Temperature ◽  
Ultramafic Rocks ◽  
Thrust Faults ◽  
Temperature Changes ◽  
Polar Urals ◽  
Metamorphic Facies ◽  
Primary Minerals ◽  
The Polar Urals

The petrographic features and conditions of the formation of metamorphosed mafic-ultramafic rocks of the Ampelshor complex, which are part of a small massif in the southern part of the Marunke u block of the Polar Urals (Peridotitovyi stream) and are controlled by tectonic thrust faults, have been studied. Muscovite-albite-clinozoisite-amphibole rocks (metabasites) and pyroxene-amphibole-chlorite (metautramafic) rocks are described. Structural, textural, and mineralogical features of metamagmatites indicate the hypabyssal nature of metabasite and plutonic nature of metaultramaphite. In metabasites, primary minerals are represented by relics of amphiboles (pargasite, edenite), and in metaultramaphites — by olivine and, possibly, clinopyroxene (augite, diopside). Magnesiohastingsite and chermakite in metautramafite were formed either at the late magmatic or metamorphic stages of rock transformation. The studied rocks underwent low-temperature changes (t — 468–380 °C, P — 2–3 kbar), corresponding to the greenschist metamorphic facies.

scholarly journals High pressure metamorphism in the peridotitic cumulate of the Marun-Keu complex, Polar Urals

2019 ◽  
Vol 27 (2) ◽  
pp. 138-160
Author(s):  
Y. Y. Liu ◽  
A. L. Perchuk ◽  
A. A. Ariskin
Keyword(s):  
High Pressure ◽  
Crystallization Process ◽  
Ultramafic Rocks ◽  
Magmatic Chamber ◽  
Polar Urals ◽  
Tectonic Model ◽  
Facies Metamorphism ◽  
Formation Conditions ◽  
Eclogite Facies ◽  
Cumulate Texture

The Marun-Keu Complex of high-pressure rocks comprises granitoids, gneisses, schists, gabbroids and peridotites, which are unevenly and variably metamorphosed to the eclogite facies. A representative sample of garnet–amphibole lherzolite from the Mount Slyudyanaya area shows a cumulate texture and well preserved magmatic mafic minerals (olivine and pyroxenes) but practically no preserved plagioclase. The eclogite-facies metamorphism produced corona textures of newly formed minerals: amphibole, garnet, orthopyroxene and spinel. The metamorphic parameters of the garnet–amphibole lherzolite were estimated by geothermobarometry and by modeling phase equilibria at Р ~ 2.1 GPa and T ~ 640–740°C and are well consistent with our earlier estimate of the formation conditions of eclogites in the area. Computer simulation of the crystallization process of the gabbroic melt with the COMAGMAT program package, using literature data on the composition of the least altered plagioclase peridotites and gabbroids from the Marun-Keu Complex, shows that the mafic and ultramafic rocks are genetically interrelated: they crystallized in a single magmatic chamber. According to the modeling, the origin of the cumulate texture in the lherzolite was controlled by the peritectic reaction Ol + melt → Opx at a pressure of 0.7–0.8 GPa and a temperature of 1255–1268°C. Differences between thermodynamic parameters in the eclogites and garnet peridotites are discussed within the framework of a tectonic model for subduction and subsequent exhumation of the Baltica paleocontinent.

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