On the melt differentiation in the intermediate chamber (by the example of differentiated intrusives of the western slope of the Southern Urals)

The article provides materials on the analysis of the chemical composition of silicates and aluminosilicates that make up the differentiated body of the Misaelga complex, which made it possible by calculation methods to restore the thermobaric parameters of crystallization of the melt in the intermediate chamber. The presence of high-temperature (1472 ºC) intratelluric olivine crystals characterizing the process of magma generation in the mantle and olivine crystallizing under the conditions of the intermediate chamber (1050–1183 ºC) has been established. The calculated crystallization temperature of pyroxenes indicates that they crystallized together with olivine from the bulk of the rocks, and the established variations in the P–T parameters (T = 950–1045 ºC, P = 4.0–7.4 kbar) for plagioclase and amphibole complete the quantitative characteristics of high-temperature melt crystallization processes. It is shown that the calculated Р–Т parameters of the crystallization of the melt that formed the intrusive massif make it possible to classify its ultrabasic horizon as picrite complexes of the second type that we identified earlier. Modeling of the crystallization process carried out using two models – according to the algorithm of H.D. Nathan and K.K. Van Kirk and the software product KOMAGMAT – made it possible to establish that the most probable mechanism for the formation of a differentiated body of the Misaelga complex was directional crystallization with gravitational deposition of olivine at the initial stages of the formation of the massif.

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

Moscow University Bulletin. Series 4. Geology ◽

10.33623/0579-9406-2018-5-24-34 ◽

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.

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ORDOVICIAN DEPOSITS ON THE WESTERN SLOPE OF THE SOUTHERN URALS AND THEIR CORRELATION BASED ON CONODONTS AND CHITINOZOANS

Геология и геофизика ◽

10.15372/gig20160204 ◽

2016 ◽

Vol 57 (02) ◽

Keyword(s):

Southern Urals ◽

Western Slope ◽

The Southern Urals

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A new type of noble metal mineralization in terrigenous rocks of the Shatak graben, western slope of the southern Urals

Lithology and Mineral Resources ◽

10.1134/s0024490206040079 ◽

2006 ◽

Vol 41 (4) ◽

pp. 371-377 ◽

Cited By ~ 2

Author(s):

S. G. Kovalev ◽

I. V. Vysotskii

Keyword(s):

Noble Metal ◽

Southern Urals ◽

Western Slope ◽

The Southern Urals ◽

Terrigenous Rocks ◽

Noble Metal Mineralization ◽

New Type

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

Geology of Ore Deposits ◽

10.1134/s1075701521040048 ◽

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.

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

LITOSFERA ◽

10.24930/1681-9004-2020-20-2-212-223 ◽

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.

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