scholarly journals A Trace Element Classification Tree for Chalcopyrite from Oktyabrsk Deposit, Norilsk–Talnakh Ore District, Russia: LA-ICPMS Study

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 716 ◽  
Author(s):  
Alexander E. Marfin ◽  
Alexei V. Ivanov ◽  
Vera D. Abramova ◽  
Tatiana N. Anziferova ◽  
Tatiana A. Radomskaya ◽  
...  

The Oktyabrsk PGE-Cu-Ni deposit is one of the largest resources in the Norilsk–Talnakh ore district, Russia, and it is viewed as an ore giant on a global scale. It contains three types of ores: massive, disseminated and veinlet-disseminated. The two former ore types were formed by a liquation process, whereas the latter was associated with fluid-induced selective metasomatic replacement of metamorphosed wall rocks. One of the major ore minerals in all ore types is chalcopyrite. In this study, we determined concentrations of trace elements in this mineral using laser ablation inductively coupled plasma mass spectrometry. It appeared that standard geochemical tools, such as plotting the data in the form of diagrams of normalized concentrations, binary and ternary plots, do not allow one to distinguish chalcopyrite from visually and genetically different ore types. In contrast, more advanced statistical methods such as cluster analysis show different groupings of elements for each ore type. Based on the element clustering, a classification tree was suggested, which allowed for the differentiation of massive, disseminated and veinlet-disseminated ore types of the Oktyabrsk deposit by Se, Te, Cd and Pb concentrations in chalcopyrite with a success rate of 86%. The general feature is that chalcopyrite of veinlet-disseminated ore is poorer in these elements compared to chalcopyrite of the two other ore types. Chalcopyrite of massive ore is poorer in Se and Te when compared to chalcopyrite of disseminated ore.

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 630
Author(s):  
Christos L. Stergiou ◽  
Vasilios Melfos ◽  
Panagiotis Voudouris ◽  
Lambrini Papadopoulou ◽  
Paul G. Spry ◽  
...  

The Vathi porphyry Cu-Au±Mo deposit is located in the Kilkis ore district, northern Greece. Hydrothermally altered and mineralized samples of latite and quartz monzonite are enriched with numerous rare and critical metals. The present study focuses on the bulk geochemistry and the mineral chemistry of pyrite, chalcopyrite, magnetite, and titanite. Pyrite and chalcopyrite are the most abundant ore minerals at Vathi and are related to potassic, propylitic, and sericitic hydrothermal alterations (A- and D-veins), as well as to the late-stage epithermal overprint (E-veins). Magnetite and titanite are found mainly in M-type veins and as disseminations in the potassic-calcic alteration of quartz monzonite. Disseminated magnetite is also present in the potassic alteration in latite, which is overprinted by sericitic alteration. Scanning electron microscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of pyrite and chalcopyrite reveal the presence of pyrrhotite, galena, and Bi-telluride inclusions in pyrite and enrichments of Ag, Co, Sb, Se, and Ti. Chalcopyrite hosts bornite, sphalerite, galena, and Bi-sulfosalt inclusions and is enriched with Ag, In, and Ti. Inclusions of wittichenite, tetradymite, and cuprobismutite reflect enrichments of Te and Bi in the mineralizing fluids. Native gold is related to A- and D-type veins and is found as nano-inclusions in pyrite. Titanite inclusions characterize magnetite, whereas titanite is a major host of Ce, Gd, La, Nd, Sm, Th, and W.


2020 ◽  
Vol 115 (6) ◽  
pp. 1213-1226 ◽  
Author(s):  
Alexander E. Marfin ◽  
Alexei V. Ivanov ◽  
Vadim S. Kamenetsky ◽  
Adam Abersteiner ◽  
Tamara Yu. Yakich ◽  
...  

Abstract The Norilsk-Talnakh ore district in the northwestern Siberian platform contains globally unique reserves of Cu-Ni-sulfides with Pt and, especially, Pd. The Oktyabrsk deposit, which is one of the largest in the district, is spatially and genetically associated with the Kharaelakh mafic-ultramafic intrusion and its exceptionally large metamorphic and metasomatic aureoles. In this study, we employed in situ laser ablation-inductively coupled plasma-mass spectrometry U-Pb isotope dating of apatite, titanite, garnet, and perovskite that cocrystallize with disseminated sulfides within the aureole of metasomatic and contact metamorphic rocks. The calculated isotopic ages for apatite (257.3 ± 4.5 and 248.9 ± 5.1 Ma), titanite (248.6 ± 6.8 and 249.1 ± 2.9 Ma), garnet (260.0 ± 11.0 Ma), and perovskite (247.3 ± 8.2 Ma), though with large uncertainties, indicate that sulfide mineralization within metasomatic and contact-metamorphic rocks is coeval with the emplacement of the Kharaelakh intrusion. These isotopic dates are in complete agreement with the published isotope dilution-thermal ionization mass spectrometry U-Pb zircon ages for the Norilsk intrusions and, at the same time, notably older than available Re-Os isochron ages of sulfides. The latter ages have been long interpreted as evidence for a prolonged duration of magmatic ore-forming processes; however, our data narrow their life span. Trace elements in titanite and garnet allow distinguishing late- and postmagmatic grains, which show indistinguishable U-Pb isotope ages.


2021 ◽  
Vol 33 (4) ◽  
pp. 373-387
Author(s):  
Jochen Schlüter ◽  
Stephan Schuth ◽  
Raúl O. C. Fonseca ◽  
Daniel Wendt

Abstract. An electrum–quartz pebble with a weight of 10.4 g was discovered in a cliff of Saalian glaciogenic sediments on the west coast of the German North Sea island of Sylt in 2012. It has a roundish water-worn appearance and consists of intergrown electrum and milky quartz. It is the largest known electrum find in Germany, and regarding its weight it also ranks amongst the largest gold finds discovered in Germany. We document and characterize this unusual discovery. Furthermore, an attempt is made to investigate its provenance. Therefore, reference samples of southern Scandinavian gold and electrum deposits and occurrences have been studied and compared to the Sylt find. The Au–Ag content determined by electron microprobe (EMP), trace element signature measured by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and Pb isotope compositions by multi-collector ICP MS (MC-ICP-MS) suggest a southern Norwegian origin. The most probable source might be the Kongsberg ore district or an adjacent, yet undiscovered, mineralization in the Oslo region. In general, Saalian glaciogenic sediments in Schleswig-Holstein (northern Germany) are dominated by rocks of Swedish provenance. Due to the intake of older Elsterian sediments by younger Saalian glaciers, southern Norwegian rocks are also not uncommon in Saalian sediments. A Saalian ice advance or a combination of Elsterian and Saalian ice advances might have provided a transport mechanism for an electrum sample from a south Norwegian mineralization to the island of Sylt.


2007 ◽  
Vol 71 (4) ◽  
pp. 371-387 ◽  
Author(s):  
H. G. Dill ◽  
A. Gerdes ◽  
B. Weber

AbstractIron played a decisive part when uranyl phosphates (‘yellow U ores’) formed during supergene alteration of the aplitic and pegmatitic rocks of the Hagendorf Pegmatite Province. Three different supergene U mineral successions, referred to in the current study as pathways I to III, were identified. Pathway I began with the release of PO42– by the dissolution of rockbridgeite and ended after shortdistance transport under alkaline reducing or slightly acidic oxidizing conditions in the precipitation of bassetite. Pathway II is an advanced form of pathway I that did not stop with the precipitation of bassetite, but progressed by acidic Cu-bearing meteoric waters under oxidizing conditions up to the torbernite precipitation stage. Minor amounts of Mn or Ca may have led to a deviation from the normal pathway into the stability fields of lehnerite or autunite, respectively, both of which may occur either as solid solution series or in a layered intergrowth with torbernite. Limonite-cored torbernite has been described for the first time and only exists in pathway III. Unlike its counterpart pathways I and II, which appeared at the end of a complex polystage element recycling process of secondary Fe phosphates under fluctuating redox and pH conditions, limonite-cored torbernite resulted from a monostage transformation of primary ‘black Fe-U ore minerals’ under strongly oxidizing conditions and short-distance element transport. These restricted physicochemical conditions caused the immediate stabilization of the Fe-U-P system and by doing so the U-Pb ratios of the black ore progenitor were well preserved in the limoniticc ore. Torbernite was analysed for U, Th and Pb isotopes by laser ablation inductively coupled plasma mass spectrometry techniques. For one domain the data yielded a formation age of 4.55±0.02 Ma, which corresponds to Miocene-Pliocene weathering and geomorphological processes in the study area. A second domain gave a discordia with an upper intercept age of 549±12 Ma, interpreted to represent a thermal event at the Precambrian-Cambrian boundary. Ferrocolumbite is found exclusively in the mineralization of pathway III. Due to the proximity of ferrocolumbite to torbernite, limonite-cored torbernite probably inherited the 549 Ma age from ferrocolumbite during supergene alteration.


2020 ◽  
Author(s):  
Daniel Bůžek ◽  
Slavomír Adamec ◽  
Kamil Lang ◽  
Jan Demel

<div><p>UiO-66 is a zirconium-based metal-organic framework (MOF) that has numerous applications. Our group recently determined that UiO-66 is not as inert in aqueous dispersions as previously reported in the literature. The present work therefore assessed the behaviour of UiO-66 in buffers: 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS), 4-(2-hydroxyethyl)piperazine-1-ethane sulfonic acid (HEPES), N-ethylmorpholine (NEM) and phosphate buffer (PB), all of which are commonly used in many UiO-66 applications. High pressure liquid chromatography and inductively coupled plasma mass spectrometry were used to monitor degradation of the MOF. In each buffer, the terephthalate linker was released to some extent, with a more pronounced leaching effect in the saline forms of these buffers. The HEPES buffer was found to be the most benign, whereas NEM and PB should be avoided at any concentration as they were shown to rapidly degrade the UiO-66 framework. Low concentration TRIS buffers are also recommended, although these offer minimal buffer capacity to adjust pH. Regardless of the buffer used, rapid terephthalate release was observed, indicating that the UiO-66 was attacked immediately after mixing with the buffer. In addition, the dissolution of zirconium, observed in some cases, intensified the UiO-66 decomposition process. These results demonstrate that sensitive analytical techniques have to be used to monitor the release of MOF components so as to quantify the stabilities of these materials in liquid environments.</p></div>


2019 ◽  
Author(s):  
Ingo Strenge ◽  
Carsten Engelhard

<p>The article demonstrates the importance of using a suitable approach to compensate for dead time relate count losses (a certain measurement artefact) whenever short, but potentially strong transient signals are to be analysed using inductively coupled plasma mass spectrometry (ICP-MS). Findings strongly support the theory that inadequate time resolution, and therefore insufficient compensation for these count losses, is one of the main reasons for size underestimation observed when analysing inorganic nanoparticles using ICP-MS, a topic still controversially discussed.</p>


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