scholarly journals Limestones of the Uk Formation (Upper Riphean, the Southern Urals): Effect of contamination and diagenetic fluids on the distribution of rare-earth elements and yttrium

LITOSFERA ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 23-31
Author(s):  
A. V. Maslov
Keyword(s):  
Trace Elements ◽  
Carbonate Rocks ◽  
Southern Urals ◽  
Strong Positive Correlation ◽  
The Southern Urals ◽  
Positive Correlation ◽  
Fine Grained ◽  
Upper Riphean ◽  
Diagenetic Fluids ◽  
The Uk

Research subject. A study was conducted into the geochemical features of various lithotypes of carbonate rocks (granular and clastic limestones, limestones with planar, planar-columnar and columnar stromatolites) from the upper subformation of the Uk Formation. This formation crowns the Upper Riphean Karatau Group on the Western slope of the Southern Urals (Bashkir meganticlinorium). Material and methods. The research material was two collections of carbonate rocks (11 and 32 samples), the general geochemical features of which were previously considered in publications in 2019. The main research method was the analysis of the correlation relationships of the main rock-forming components, trace elements and their indicator relationships. Research results. It was established that all lithotypes are characterized by a significant content of both the main rock-forming components and the trace elements that make up the insoluble residue/fine-grained terrigenous admixture. This suggests that the area of accumulation of carbonate sediments was located near the continent, which served as a source of a significant amount of fine-grained/clay suspension. Conclusions. A strong positive correlation was observed between K2O and REE in the carbonate rocks of the Upper Uk Subformation, and a strong negative correlation was observed between REE and CaO. This suggests that the REE content in carbonate rocks is controlled mainly by terrigenous/clay admixture. A positive correlation is also observed between REE and Th, Zr, and Al2O3. All this shows that REE in carbonate rocks are mainly present in clay admixtures. The correlation coefficient between Ce/Ce* and (Dy/Sm)N is 0.20, while this coefficient for Eu/Eu* and (Pr/Sm)N equals 0.12. Thus, a definite conclusion about the effect of diagenetic fluids on the distribution of REE cannot be made. The data obtained show that the distribution of REE and Y in our collection of carbonate rocks of the Upper subformation of the Uk Formation of the Southern Urals is controlled mainly by clay admixtures.

scholarly journals Sedimentology and geochemistry of the Uk Formation, Upper Riphean, the Southern Urals

LITOSFERA ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 659-686 ◽  
Author(s):  
A. V. Maslov ◽  
D. V. Grazhdankin ◽  
S. A. Dub ◽  
D. S. Melnik ◽  
T. M. Parfenova ◽  
...  
Keyword(s):  
Organic Matter ◽  
Acetic Acid ◽  
Southern Urals ◽  
Depositional Environments ◽  
Gas Liquid Chromatography ◽  
The Southern Urals ◽  
Thin Sections ◽  
Fine Grained ◽  
Upper Riphean ◽  
The Uk

Research subject. This article presents new data on carbonate facies of the upperUk subformation, Upper Riphean of theSouth Urals. A particular attention is paid to the distribution of rare-earth elements (REE) and yttrium (Y) in stromatolitic and intraclastic limestones and calcareous shales (bulk samples and their acetic acid leachates).Materials and methods. We have studied lithological features of limestones in the geological section and in thin sections. The contents of trace elements in rocks were determined by the ICP-MS method at the IGG UB RAS (Yekaterinburg), the composition of organic matter was determined at the IPGG SB RAS (Novosibirsk) by gas-liquid chromatography and chromatography-mass spectrometry.Results. The most representative section of the Upper Uk Subformation located along the eastern edge of the town Ust-Katav can be subdivided into several members of different lithology and thickness: (1) biohermdominated member comprising large microbialitic build-ups and inter-bioherm sediments (intraclastic limestones, calcareous biolaminites); (2) transitional member characterised by small bioherms alternating with other carbonates; (3) interbedded coarseand fine-grained limestones. The presence of molar-tooth structures in the carbonate rocks of Uk Formation made it possible to constrain the age of thisUpper Riphean formation to pre-CryogenianConclusions. There are similarities in REE and Y distribution in both clean (devoid of siliciclastic component) bulk limestone samples and in their acetic acid leachates. PAAS-normalised REE + Y patterns demonstrate positive La, Gd, Y anomalies and negative Eu, Ce anomalies. The latter suggest marine depositional environments for theUpper Uk stromatolitic limestones. The results of the pioneering research into the composition of bitumens and biomarkers from the Upper Uk Subformation have shown that carbonates and shales are depleted in the organic matter. The source material for the organic matter was provided by two types of communities comprising both eukaryotes and prokaryotes and inhabiting well aerated environment, perhaps with lowered salinity of marine water. 

scholarly journals Trace element behaviour in acidic leachates (acetic, nitric and hydrochloric) from siliciclastic-carbonate rocks of the Upper Riphean Uk formation in the Southern Urals

LITOSFERA ◽  
2020 ◽  
Vol 19 (6) ◽  
pp. 919-944
Author(s):  
S. A. Dub ◽  
N. V. Cherednichenko ◽  
D. V. Kiseleva ◽  
N. P. Gorbunova ◽  
T. Ya. Gulyaeva ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Rare Earth ◽  
Main Tool ◽  
Southern Urals ◽  
The Southern Urals ◽  
X Ray ◽  
Upper Riphean ◽  
Siliciclastic Rock ◽  
The Uk ◽  
Ree Pattern

Research subject. 14 samples of limestone and one sample of carbonate-siliciclastic rock from siliciclastic-carbonate deposits of the Upper Riphean Uk Formation (the Southern Urals) were studied.Methods. Mineral and chemical composition of the samples were determined; the main tool for detecting the concentrations of trace elements was the ICPMS method. X-ray diffraction analysis was carried out using a Shimadzu XRD-7000 diffractometer, the content of major (rock-forming) oxides in bulk samples was established by X-ray fluorescence spectrometry on the SRM-35 and Shimadzu XRF 1800 spectrometers. Microelement composition of bulk samples and acidic leachates obtained with using acetic (10%), nitric (36%) and hydrochloric (17%) acids was determined on a Perkin Elmer ELAN 9000 spectrometer.Results. The distribution of lithophile, rare-earth and a number of other elements (Sr, Ni, U) both in bulk samples and in acidic leachates was analyzed. The main carrier phases of these elements were revealed.Conclusions. 1. The use of any listed acids leads to the non-carbonate component entering the solution, including contamination of the “carbonate” leachates by lithophile elements. In particular, a transition Rb, Zr, Li, Th, Ti, Sc to leachates was noted. This process is most active in nitric and hydrochloric acids, less intensive in acetic acid. 2. Among the carriers of rare earth elements (REE) in the studied rocks are clays (1), accessory minerals (2), including phosphate-bearing grains, secondary carbonate phases represented by dolomite and, possibly (3), finely disseminated iron and manganese (oxy)hydroxides (4). It is assumed that the REE pattern in limestones is determined by the content of the epigenetic dolomite. The contribution of lanthanides bound in the sedimentary calcite crystal lattice in the total REE pattern is rather large only in relatively “pure” limestones. However, the use of acids with such concentrations did not allow to obtain a leachate, which the REE pattern with high probability corresponds to the distribution of REE in the Uk time seawater. But acetic acid is more effective for achieving this goal than the others. 3. In addition to Sr, sedimentary calcite also contains Ni and U.

Mössbauer characteristics, mineralogy and isotopic age (Rb-Sr, K-Ar) of Upper Riphean glauconites from the UK Formation, the southern Urals

2008 ◽  
Vol 16 (3) ◽  
pp. 227-247 ◽  
Author(s):  
T. S. Zaitseva ◽  
I. M. Gorokhov ◽  
T. A. Ivanovskaya ◽  
M. A. Semikhatov ◽  
A. B. Kuznetsov ◽  
...  
Keyword(s):  
Southern Urals ◽  
Isotopic Age ◽  
The Southern Urals ◽  
Upper Riphean ◽  
The Uk

scholarly journals Isotope Systematics and the Age of Authigenic Minerals in Shales of the Inzer Formation, the Southern Urals

2019 ◽  
Vol 27 (2) ◽  
pp. 3-30
Author(s):  
I. M. Gorokhov ◽  
T. S. Zaitseva ◽  
A. B. Kuznetsov ◽  
G. V. Ovchinnikova ◽  
M. M. Arakelyants ◽  
...  
Keyword(s):  
Crystallinity Index ◽  
Southern Urals ◽  
Coarse Grained ◽  
The Southern Urals ◽  
Fine Grained ◽  
Geological Processes ◽  
Upper Riphean ◽  
Isotopic Methods ◽  
Data Points ◽  
Size Of Particles

The 2–5, 0.6–2, 0.3–0.6, 0.2–0.3 and 0.1–0.2 µm clay subfractions (SFs) separated from two shale samples of the Upper Riphean Inzer Formation, the southern Urals, were studied by the TEM, XRD, and U–Pb, Sm–Nd, Rb–Sr and K–Ar isotopic methods. All the SFs consist of the low-temperature 1Md illite; admixtures of quartz, chlorite and 2M1 illite occur only in the coarsest SFs. The clay particles are isometric, regardless of their size. The CIS (Crystallinity Index Standard) illite values for the all SFs are typical for the dia(kata)genetic zone. As the size of particles in the SF decreases from 2–5 to 0.1–0.2 µm, the CIS rises, the I002/I001 ratio on the XRD diagrams decreases, and the K content and the K/Rb ratio increase. Leaching with 1N HCl and 1N ammonium acetate (NH4OAc) and subsequent U–Pb, Sm–Nd and Rb–Sr analyses of the untreated SF, acid (acetate) leachate and residue made possible to study the mixing systematics in mobile and silicate materials of the shales. The 238U/204Pb and 87Rb/86Sr ratios in the acid and acetate leachates are below, and the 147Sm/144Nd ratio is above those in the residues. Less radiogenic Pb and Sr and more radiogenic Nd are also common for the leachates compared to the residues. As the size of particles in the SFs decreases, the U, Pb, Sm, Nd and Sr contents in the residues are smoothly reduced, whereas the Rb content shows an increase. The 87Rb/86Sr and 87Sr/86Sr values in the residues for fine-grained SFs are well above, and the 238U/204Pb value is well below those for coarse-grained SFs. What is more, in the 87Rb/86Sr–87Sr/86Sr and 1/86Sr–87Sr/86Sr diagrams, data points for the residues of variable size are arranged on the mixing lines. The data points of respective acid and acetate leachates also form linear trends in the 238U/204Pb–206Pb/204Pb, 206Pb/204Pb–207Pb/204Pb, 147Sm/144Nd–143Nd/144Nd, and 87Rb/86Sr–87Sr/86Sr coordinates. The apparent Rb–Sr age values, calculated from the slopes of “inner isochrons” (“leachochrons”), along with the K–Ar ages are smoothly lowered from 835–836 and 721–773 m.y. for the 2–5 µm SF to 572–580 and 555–580 m.y. for the 0.1–0.2 µm SF. Hence the XRD and isotopic data testify that the clay as well as the mobile material of the shale represent the mixtures of at least two components, the silicate phase containing authigenic illites of different ages. The first illite generation enriched in coarse-grained 2–5 and 0.6–2 µm SFs was formed shortly after deposition of the Inzer sediments, and its age of 803–836 m.y. is in agreement with the stratigraphic age of the formation. Simple lithostatic burial or intensive lateral fluid flow induced by tectonic inversion in the eastern regions of the Urals paleobasin may be considered as the geological processes responsible for the forming of this illite. The second illite generation was formed 572–580 m.y. ago. As the starting points for its formation, alternatively, may be concerned either vertical tectonics or renewal of pore fluid compositions during deformations and metamorphism on the southern Urals area related to evolution of the Beloretsk metamorphic complex.

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

Stratotype of the Lower Riphean, the Burzyan Group of the Southern Urals: Lithostratigraphy, paleontology, geochronology, Sr- and C-isotopic characteristics of its carbonate rocks

2009 ◽  
Vol 17 (6) ◽  
pp. 574-601 ◽  
Author(s):  
M. A. Semikhatov ◽  
A. B. Kuznetsov ◽  
A. V. Maslov ◽  
I. M. Gorokhov ◽  
G. V. Ovchinnikova
Keyword(s):  
Carbonate Rocks ◽  
Southern Urals ◽  
The Southern Urals ◽  
Lower Riphean ◽  
Burzyan Group

Formation Conditions of Ferromagnesian Metasomatic Carbonates in the Lower Riphean Terrigenous–Carbonate Rocks of the Southern Urals

2019 ◽  
Vol 54 (3) ◽  
pp. 248-261
Author(s):  
M. T. Krupenin ◽  
S. V. Michurin ◽  
A. A. Sharipova ◽  
A. A. Garaeva ◽  
D. A. Zamyatina ◽  
...  
Keyword(s):  
Carbonate Rocks ◽  
Southern Urals ◽  
The Southern Urals ◽  
Lower Riphean ◽  
Formation Conditions

Tauride Carbonate Platform Bauxite Deposits (Turkey) as an Alternative Source for Gallium

2021 ◽  
Author(s):  
Hatice Nur Bayram ◽  
Ali Erdem Bakkalbasi ◽  
Zeynep Doner ◽  
Ali Tugcan Unluer ◽  
Huseyın Kocaturk ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Carbonate Rocks ◽  
Carbonate Platform ◽  
Primary Source ◽  
Geochemical Data ◽  
Strong Positive Correlation ◽  
Alternative Source ◽  
Positive Correlation ◽  
Bayer Liquor

<p>Mediterranean type karstic bauxite deposits are considered as the primary source for aluminum (Al) production in Europe. During the Al production, Gallium (Ga) is extracted from the so called Bayer-liquor during the processing of bauxite to alumina. Ga, a rare metal, is widely used in modern chemistry and electronic industry. During the past decades, the worldwide demand for Ga has been continuously increasing. In Turkey, karstic bauxite deposits are generally found with shallow marine carbonate rocks which were deposited during Mesozoic period and located in Tauride Carbonate platform. Most of these karstic bauxite deposits can be hosted considerable Ga enrichments, with other immobile elements such as rare earth elements (REE), titanium (Ti), lithium (Li), and iron (Fe). This work focuses on the revealing of the potential Ga enrichments in bauxides from different deposits of Turkey (Mortaş-Doğankuzu, Konya; Küçükkoraş, Karaman; Acıelma-Yoğunoluk, Kahramanmaraş bauxite deposits). Geochemical data of major and trace elements of studied bauxite deposits show that these deposits have significant Ga enrichments (up to 72.6 ppm), as well as the REE (up to 580 ppm), Ti (up to 1.8%), and Li (up to 428 ppm) enrichments. In addition, the Ga enrichments show strong positive correlation with heavy rare earth elements (HREE) and moderate positive correlation with Al, Fe, Ti, Li and Sn elements. In this context, it can be concluded that the most probable source for Ga is rock forming aluminosilicates of the source rock due to the substitution with Al<sup>3+</sup> and Fe<sup>3+</sup>. During weathering process Ga exhibiting immobile behavior much like Al and Fe. Gallium is than incorporated into Al-bearing phases and thus enriched in the bauxite. Presence of Li content can be also interpreted as a contribution from micaceous source such as meta-carbonate rocks of Tauride platform. Moreover, geochemical association between Ga, Ti, Li, tin (Sn) and HREE can be explained by the redox and pH conditions causing other ions seperated from shallow environments.</p>

scholarly journals Physicochemical Model of Formation of Gold-Bearing Magnetite-Chlorite-Carbonate Rocks at the Karabash Ultramafic Massif (Southern Urals, Russia)

Minerals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 306 ◽  
Author(s):  
Valery Murzin ◽  
Konstantin Chudnenko ◽  
Galina Palyanova ◽  
Aleksandr Kissin ◽  
Dmitry Varlamov
Keyword(s):  
Carbon Dioxide ◽  
Carbonate Rocks ◽  
Southern Urals ◽  
Ultramafic Rocks ◽  
Physicochemical Model ◽  
The Southern Urals ◽  
Model Calculations ◽  
Ultramafic Massif ◽  
Copper Gold ◽  
Gold Bearing

We present a physicochemical model for the formation of magnetite-chlorite-carbonate rocks with copper gold in the Karabash ultramafic massif in the Southern Urals, Russia. The model was constructed based on the formation geotectonics of the Karabash massif, features of spatial distribution of metasomatically altered rocks in their central part, geochemical characteristics and mineral composition of altered ultramafic rocks, data on the pressure and temperature conditions of formation, and composition of the ore-forming fluids. Magnetite-chlorite-carbonate rocks were formed by the hydrothermal filling of the free space, whereas chloritolites were formed by the metasomatism of the serpentinites. As the source of the petrogenic and ore components, we considered rocks (serpentinites, gabbro, and limestones), deep magmatogenic fluids, probably mixed with metamorphogenic fluids released during dehydration and deserpentinization of rocks in the lower crust, and meteoric waters. The model supports the involvement of sodium chloride-carbon dioxide fluids extracting ore components (Au, Ag, and Cu) from deep-seated rocks and characterized by the ratio of ore elements corresponding to Clarke values in ultramafic rocks. The model calculations show that copper gold can also be deposited during serpentinization of deep-seated olivine-rich rocks and ore fluids raised by the tectonic flow to a higher hypsometric level. The results of our research allow predicting copper gold-rich ore occurrences in ultramafic massifs.

scholarly journals Enstatite nodules in the harzburgites of the Southern Urals

LITOSFERA ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 386-408
Author(s):  
V. G. Korinevsky
Keyword(s):  
Southern Urals ◽  
Research Subject ◽  
The Southern Urals ◽  
Fine Grained ◽  
Composition And Structure ◽  
Northern Shore

Research subject. At two points on the northern shore of Lake Uvil’dy in the Southern Urals, two outcrops of unique rocks – nodular harzburgites – were discovered in the tectonic lenses of serpentinite melange among garnet-biotite gneisses of the Ilmenogorsko-Vishnevogorsky Сomplex. These outcrops form a body of about 9 m in thickness among amphibolized orthopyroxenites.Results. The fine-grained serpentinized enstatite-olivine matrix of the harzburgites under study contains numerous spherical formations (nodules) 2–7 cm in diameter, composed of large enstatite crystals and rare forsterite grains. The composition and structure of these spheroids are highly similar to the enstatite chondrules from stony meteorites, although differing in size (ten times larger).Conclusions. Such structures are very rare in hyperbasites and occur in slightly altered varieties. Judging by the microstructural features and relationships of the main minerals, it is concluded that these minerals were crystallized from a magmatic melt.

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