scholarly journals Stistaites of the South Urals

LITOSFERA ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 894-911
Author(s):  
V. G. Korinevsky ◽  
V. A. Kotlyarov ◽  
S. V. Kolisnichenko ◽  
D. A. Artemiev

Research subject. Rare minerals of tin and antimony – stistaites from natural lead plates from the Severo-Svetlinskaya placer in the Chelyabinsk region and from microspherules of intermetallic compounds in the products of erosion of granites of the Kisegach complex in the Ilmeny Mountains.Materials and methods. Electron probe analysis and laser ablation with inductively coupled plasma were used to study the composition of the predominant minerals of intermetallic compounds in lead plates extracted during the washing of a gold-bearing placer, as well as from metal microspherules in the sandy fraction of eroded granites.Results. Two types of stistaite were identified: lead and arsenic-lead. Lead stistaites is sharply predominant, with its average composition (wt %) being Sb – 47.39, Sn – 38.75, Pb – 13.24, Cu – 0.06. The average composition of arsenic-lead stystaite (wt %) was found to be Sb – 43.89, Sn – 41.06, Pb – 11.02, As – 3.05, Cu – 0.47. Tin-lead microspherules from the destruction products of biotite granites of the Kisegach massif (Ilmeny Mountains) occasionally contain crystals and spotted precipitates of lead stistaite with the composition (wt %) of Sn 53.54, Sb 38.45, and Pb 7.42.Conclusions. It is assumed that, in both cases, the formation of alloys of intermetallic compounds of tin, lead and antimony with inclusions of native copper and iron was associated with granite magmatism.

2019 ◽  
Vol 10 (2) ◽  
pp. 289-308 ◽  
Author(s):  
T. A. Osipova ◽  
G. A. Kallistov ◽  
M. V. Zaitseva

The article is focused on the morphology, trace element composition, U‐Pb and Lu‐Hf systems in zircon in high‐Mg diorite of the Chelyabinsk granitoid massif. Our analytical studies of the U‐Pb and Lu‐Hf isotope systems and the trace element composition were performed using mass spectrometry (MS) with inductively coupled plasma (ICP) and laser ablation (LA) of samples. It is established that the zircon formed at the last stages of crystallization of the basic melt under subsolidus conditions at low (600–700 °C) temperatures, which distinguishes it from the zircon of most other high‐Mg rocks of the intermediate composition. The internal structure of the zircon and the concentration of trace elements are locally altered under the influence of a fluid, which led to a partial disruption of the U‐Pb and Lu‐Hf isotopic systems. For the least altered areas in the zircon crystals, the age of crystallization of the parent high‐Mg melt is 362±2 Ma, which coincides with the age estimated from the geological data. Considering the isotope composition of Hf in the zircon and the trace element concentrations, there are grounds to relate the formation of high‐Mg diorite in the Chelyabinsk granitoid massif with a mixed mantle‐crustal source.


2021 ◽  
Author(s):  
Frederico Sousa Guimarães ◽  
Rongqing Zhang ◽  
Bernd Lehmann ◽  
Alexandre Raphael Cabral ◽  
Francisco Javier Rios

Abstract The Mesoproterozoic Rondônia Tin Province of the Amazonian craton records a protracted history of about 600 m.y. of successive rare-metal granite intrusions and hosts the youngest known event of tin-granite emplacement of the craton—a rare-metal granite suite known as the Younger Granites of Rondônia intrusive suite. The ~1 Ga suite is currently interpreted as intracratonic magmatism resulting from a Grenvillian-age orogeny during the assembly of Rodinia. The Santa Bárbara massif is a tin-granite system of the Younger Granites of Rondônia intrusive suite that hosts Sn-Nb-Ta-W–bearing endogreisen and stockwork, as well as important placer deposits. The Santa Bárbara mine produces about 800 to 1,000 t Sn/year from placers and weathered greisen and represents about 20% of the tin mine output of the Rondônia Tin Province. Here, we report laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) cassiterite U-Pb ages of 989 ± 3 and 987 ± 6 Ma for the Santa Bárbara greisen and the cassiterite-quartz vein system, respectively. Alluvial cassiterite from placer mining has a U-Pb age of 995 ± 4 Ma, which is, within uncertainty, indistinguishable from those of primary cassiterite. These ages agree well with the previously published zircon and monazite U-Pb ages for the Santa Bárbara granite (978 ± 13 and 989 ± 13 Ma), which indicate a coeval relationship between hydrothermal tin mineralization and granite magmatism. The previously suggested 20- to 30-m.y. time span between granite magmatism and hydrothermal tin mineralization, which was based on mica K-Ar and Ar-Ar age data, is likely due to younger thermal disturbance of the isotopic systems.


2018 ◽  
Vol 82 (S1) ◽  
pp. S281-S306 ◽  
Author(s):  
Olga Y. Plotinskaya ◽  
Vera D. Abramova ◽  
Elena O. Groznova ◽  
Svetlana G. Tessalina ◽  
Reimar Seltmann ◽  
...  

ABSTRACTMineralogical, electron microprobe analysis and laser ablation-inductively coupled plasma-mass spectrometry data from molybdenite within two porphyry copper deposits (Kalinovskoe and Birgilda) of the Birgilda-Tomino ore cluster (South Urals) are presented.† The results provide evidence that molybdenites from these two sites have similar trace-element chemistry. Most trace elements (Si, Fe, Co, Cu, Zn, Ag, Sb, Te, Pb, Bi, Au, As and Se) form mineral inclusions within molybdenite. The Re contents in molybdenite vary from 8.7 ppm to 1.13 wt.%. The Re distribution within single molybdenite flakes is always extremely heterogeneous. It is argued that a temperature decrease favours the formation of Re-rich molybdenite. The high Re content of molybdenite observed points to a mantle-derived source.


Minerals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 36 ◽  
Author(s):  
Elena Sorokina ◽  
Mikhail Rassomakhin ◽  
Sergey Nikandrov ◽  
Stefanos Karampelas ◽  
Nataliya Kononkova ◽  
...  

Blue sapphire of gem quality was recently discovered in spinel–chlorite–muscovite rock within meta-ultramafites near the Ilmenogorsky alkaline complex in the Ilmen Mountains of the South Urals. More than 20 minerals were found in the assemblage with the blue sapphire. These sapphire-bearing rocks are enriched in LREE and depleted in HREE (with the negative Eu anomalies) with REE distribution similar to those in miascites (nepheline syenite) of the Ilmenogorsky alkaline complex. 87Sr/86Sr ratios in the sapphire-bearing rocks varied from 0.7088 ± 0.000004 (2σ) to 0.7106 ± 0.000006 (2σ): epsilon notation εNd is −7.8. The Rb-Sr isochrone age of 289 ± 9 Ma was yielded for the sapphire-bearing rocks and associated muscovite. The blue sapphires are translucent to transparent and they have substantial colorless zones. They occur in a matrix of clinochlore-muscovite as concentric aggregates within spinel-gahnite coronas. Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) analyses showed values with trace elements typical for “metamorphic” blue sapphires, with Ga/Mg < 2.7, Fe/Mg < 74, Cr/Ga > 1.5 (when Cr is detectable), and Fe/Ti < 9. Sapphires overlap “metasomatic” at “sapphires in alkali basalts” field on the FeO–Cr2O3–MgO–V2O3 versus FeO + TiO2 + Ga2O3 discriminant diagram. The sapphires formed together with the spinel-chlorite-muscovite rock during metasomatism at a contact of orthopyroxenites. Metasomatic fluids were enriched with Al, HSFE, and LILE and genetically linked to the miascite intrusions of Ilmenogorsky complex. The temperature required for the formation of sapphire–spinel–chlorite–muscovite rock was 700–750 °C and a pressure of 1.8–3.5 kbar.


LITOSFERA ◽  
2020 ◽  
Vol 19 (6) ◽  
pp. 861-888 ◽  
Author(s):  
V. G. Sakhno ◽  
L. S. Tsurikova ◽  
S. O. Maksimov

Research subject. This study was devoted to magmatic complexes in Northwestern Chukotka associated with the largest gold and silver deposits across Kupol’skii (Kupol field) and Ilirnei (Dvoinoe and September fields) ore junctions. Materials and methods. The petrogenic elements of ore-containing igneous rocks were determined using a spectrometer ICAP 6500Duo (USA). An elemental analysis of igneous and ore samples was performed by inductively coupled plasma spectrometry (ICP-MS). The age was determined by zircons (SHRIMP-II, VSEGEI isotope research center, St. Petersburg) using a laser ablation system NWR-213 (USA). Results. New information concerning the dating of magmatic complexes and gold-bearing magmatic systems in the ore junctions under study was obtained. It was established that the manifestations of magmatism in the Kupol and Ilirnei ore junctions differ in terms of the main phase formation age. The age of the Ilirnei ore junction, which is represented by large-volume intrusions of granitoids, leucogranites and volcanites of medium-basic composition, was determined to be 124–114 Ma. The age of mineralization, which is associated with later magmatism phases – small intrusions and a dike complex of predominantly granodiorite composition –, was estimated to be (93– 92) ± 2.0 Ma. In the Kupol ore junction, the magmatism associated with mineralization was dated 91.0 ± 1.4 Ma, while the age of rhyolite dikes containing mineralization was estimated to be 88.9–89.0 Ma.Conclusion. The results of the RMS analysis of the Kupol and Ilirney ore junctions suggest that ore formation in this region was connected with a single stage of activation of deep processes and mantle-crust interaction with participation of deep (mantle) fluids. 


Author(s):  
E. I. Yartsev ◽  
I. V. Vikentyev ◽  
N. I. Eremin

The sulfur isotopic composition was studied for the main morphological types and generation of sulfides composing the ore of the Dzhusinsky deposit, and the content of trace elements was analyzed using the highly sensitive method of mass spectrometry with inductively coupled plasma and laser sampling (LA-ICP-MS). Both types of studies were performed for ore deposits for the first time. According to the geochemistry of sulfur isotopes, its deep magmatic source was reconstructed, which made a predominant contribution to the ore-forming fluid. Using the modules of the STATISTICA, correlations were calculated and the patterns of distribution of micro impurities in sulfide minerals were revealed.


LITOSFERA ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 409-430
Author(s):  
S. V. Berzin ◽  
K. A. Dugushkina ◽  
M. V. Chervyakovskaya ◽  
V. S. Chervyakovskiy ◽  
E. A. Pankrushina ◽  
...  

Research subject. Fragments of the Severny Kolchim meteorite.Materials and methods. The study was performed in the Geoanalyst Centre for Collective Use, Institute of Geology and Geochemistry, UB RAS. The clast and inclusions were studied using a scanning electron microscope JSM-6390LV from JEOL with an energy dispersing attachment INCA Energy 450 X-Max 80. The bulk chondrule compositions were obtained by EDS analysis of whole chondrule areas in thin sections. The composition of minerals was studied using an electron microprobe analyser Cameca SX100 equipped with five wavelength spectrometers. The concentrations of trace elements in olivine were measured using a mass spectrometer with inductively coupled plasma NexION 300S (PerkinElmer) with a laser ablation attachment NWR 213 (ESI) at a crater diameter of 25 microns.Results. According to the revealed set of petrographic and mineralogical features, the meteorite was clarified as H3.4. In addition, this meteorite can be further classified as genomict breccia. In the Severny Kolchim meteorite, a 6×6 mm clast fragment composed of chondrite H3.9 was studied. This inclusion has a slightly higher degree of S2 shock transformations compared to the host rock. Refractory forsterite-rich objects were found and studied. These inclusions are composed of low-ferroan forsterite (f = 0.004–0.2, f – ratio Fe/(Fe + Mg)mol).Conclusion. The porphyry olivine chondrules consisting of refractory forsterite and high-calcium glass in mesostasis are likely to be parental to the refractory forsterite-rich inclusions. Al-rich chondrules and pyroxene chondrule with tridymite identified in the matrix of the chondrite are likely to be xenogenic, originating from the formation area of enstatite chondrites.


Author(s):  
Hasria Hasria ◽  
Arifudin Idrus ◽  
I Wayan Warmada

In Indonesia, gold is commonly mined from porphyry, epithermal and skarn type deposits that are commonly found in volcanic/magmatic belts. However, were recently numerous gold prospects discovered in association with metamorphic rocks. This paper is intended to describe an alteration and ore mineralogy hosted by metamorphic  rocks at Rumbia mountains, Bombana regency, Southeast Sulawesi province, Indonesia. The study area is found the placer and primary gold hosted by metamorphic rocks. The placer gold is evidently derived from gold-bearing quartz veins hosted by Pompangeo Metamorphic Complex (PMC). This study is conducted in three stages, three stages including desk study, field work and laboratory analysis. Desk study mainly covers literature reviews. Field work includes mapping of surface geology, alteration and ore mineralization as well as sampling of representative rocks types, altered rocks and gold-bearing veins. Laboratory analysis includes the petrologic observation of handspecimen samples, petrographic analysis of the thin section and ore microscopy for polished section, XRD (X-ray diffraction), ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy), ICP-MS (Inductively Coupled Plasma Emission Mass Spectrometry and FA/AAS (Fire Assay/Atomic Absorbtion Spectophotometry) analysis. The results shows that the alteration characteristics of hydrothermal gold deposits in Mendoke and Rumbia mountain consist of 3 (three) alterations namely sericitic, argillic dan propylitic. Characteristics of mineralization hydrothermal gold deposits in the research area are generally p related to gold-bearing quartz veins/veinlets consist of chalcopyrite, pyrite, chrysocolla, covellite, cinnabar, magnetite, hematite and goetite in rocks categorized into greenschist facies. There are three generations of veins identified including the first is parallel to the foliations, the second crosscut the first generation of veins/foliations, and the third is of laminated deformed quartz+calcite veins at the late stage. The  quartz veins commonly deformed, segmented, massive, laminated,   irregular, brecciated, and occasionally sigmoidal. The veins contain erratic gold in various grades from below detection limit <0.0002 ppm to 18,4000 at found in third generation veins which are laminated quartz±calcite in argillic alteration. ppm. The protoliths of metamorphic rocks in Rumbia Mountain, which comes from sedimentary rocks, spesifically pelitic rocks and graywacke. Based on those characteristics, it obviously indicates that the primary gold deposit present in the study area is of orogenic gold deposits type. The orogenic gold deposit is one of the new targets for exploration in Indonesia.


2021 ◽  
Vol 25 (3) ◽  
pp. 212-221
Author(s):  
M. V. Chervyakovskaya ◽  
◽  
S. L. Votyakov ◽  
V. S. Chervyakovskiy ◽  
◽  
...  

A technique of analyzing the isotopic composition of Lu and Hf and for determining the Lu/Hf and Hf/Hf isotopic ratios in zircons is presented using a Neptune Plus (Thermo Scientific) mass spectrometer with inductively coupled plasma with an NWR 213 (ESI) laser ablation attachment. On the example of Mud Tank, GJ-1, 91500, Plesovice and Temora-2 standard zircon samples, the uncertainty of a single measurement of the 176Hf/177Hf ratio has been obtained in the range of 0.002-0.008% in the form of 2σ (with a crater diameter of 50 μm; when it decreased to 25 μm the measurement uncertainty of the 176Hf/177Hf ratio increased by 1.5-2 times). Under the optimum parameters of the NexION 300S with NWR213 with the aim of increasing the locality of the sequential study of U/Pb and Lu/Hf isotope systems, a comparative characteristic of the application of two approaches has been obtained: in adjacent grain areas (approach 1) and in one crater (approach 2). The metrological characteristics of analyzing the isotopic composition of Lu and Hf and for determining the Lu/Hf and Hf/Hf isotopic ratios in zircons have been determined. To establish the application limits of the developed technique, the factor planning of the experiment has been developed. It was established that with a Lu/Hf ratio of 1/50 or more, the technique is not recommended to be applied due to the incorrect allowance of the isobaric effect. The procedures for measuring and calculating the Lu/Hf isotopic ratios of the isotope system in zircon have been tested on zircon grains (samples NP-46 and NP-47) of the Neplyuevsky pluton (South Urals). The data obtained was in satisfactory agreement with the data of the A. P. Karpinsky Russian Geological Research Institute (VSEGEI).


Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 234 ◽  
Author(s):  
Maria I. Filina ◽  
Elena S. Sorokina ◽  
Roman Botcharnikov ◽  
Stefanos Karampelas ◽  
Mikhail A. Rassomakhin ◽  
...  

Kyshtymites are the unique corundum-blue sapphire-bearing variety of anorthosites of debatable geological origin found in the Ilmenogorsky-Vishnevogorsky complex (IVC) in the South Urals, Russia. Their mineral association includes corundum-sapphire, plagioclase (An61–93), muscovite, clinochlore, and clinozoisite. Zircon, churchite-(Y), monazite-(Ce), and apatite group minerals are found as accessory phases. Besides, churchite-(Y) and zircon are also identified as syngenetic solid inclusions within the sapphires. In situ Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) U-Pb zircon geochronology showed the ages at about 290–330 Ma linked to the Hercynian orogeny in IVC. These ages are close to those of the syenitic and carbonatitic magmas of the IVC, pointing to their syngenetic origin, which is in agreement with the trace element geochemistry of the zircons demonstrating clear magmatic signature. However, the trace element composition of sapphires shows mostly metamorphic signature with metasomatic overprints in contrast to the geochemistry of zircons. The reason for this discrepancy can be the fact that the discrimination diagrams for sapphires are not as universal as assumed. Hence, they cannot provide an unambiguous determination of sapphire origin. If it is true and zircons can be used as traces of anorthosite genesis, then it can be suggested that kyshtymites are formed in a magmatic process at 440–420 Ma ago, most probably as plagioclase cumulates in a magma chamber. This cumulate rock was affected by a second magmatic event at 290–330 Ma as recorded in zircon and sapphire zoning. On the other hand, Ti-in-zircon thermometer indicates that processes operated at relatively lower temperature (<900 °C), which is not enough to re-melt the anorthosites. Hence, zircons in kyshtymites can be magmatic but inherited from another rock, which was re-worked during metamorphism. The most probable candidate for the anorthosite protolith is carbonatites assuming that metamorphic fluids could likely leave Al- and Si-rich residue, but removed Ca and CO2. Further, Si is consumed by the silicification of ultramafic host rocks. However, kyshtymites do not show clear evidence of pronounced metasomatic zonation and evidence for large volume changes due to metamorphic alteration of carbonatites. Thus, the obtained data still do not allow for univocal reconstruction of the kyshtymite origin and further investigations are required.


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