scholarly journals Geochemical Features and Mineral Associations of Differentiated Rocks of the Norilsk 1 Intrusion

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 688
Author(s):  
Nadezhda Tolstykh ◽  
Gennadiy Shvedov ◽  
Aleksandr Polonyankin ◽  
Vladimir Korolyuk
Keyword(s):  
Sulfide Liquid ◽  
Olivine Gabbro ◽  
Two Stage ◽  
Sulfur Fugacity ◽  
Rock Types ◽  
Common Trend ◽  
Mineral Associations ◽  
Liquid Fractionation ◽  
Monoclinic Pyrrhotite ◽  
Low Sulfur

The purpose of this study is to show the patterns of distribution of disseminated sulfide in layered rocks based on the numerous geochemical and mineralogical data obtained for eight boreholes of the Norilsk intrusion (southern part of the Norilsk 1 deposit). There is a common trend of sulfide liquid fractionation in the Main Ore Horizon, which is composed of picritic and taxite (or olivine) gabbro-dolerites: the Ni/Cu in both rock types decreases down all sections, indicating an increase in the degree of fractionation of the sulfide liquid from top to bottom. On the contrary, the Ni/Fe ratios in pentlandite increase in this direction due to an increase in sulfur fugacity. However, picrite and taxite/olivine gabbro-dolerites are very distinctly separated by Ni/Cu values: these values are >1 in picritic gabbro-dolerite while they are always <1 in taxite/olivine gabbro-dolerite. These rock types are distinguished by sulfide assemblages. The first includes troilite, Fe-rich pentlandite, chalcopyrite, cubanite, talnahite, bornite and copper (low sulfur association); the second one is composed of monoclinic pyrrhotite, chalcopyrite, Ni-rich pentlandite and pyrite (high sulfur association). A two-stage magma injection with different ore specializations is supposed for picritic and taxite/olivine gabbro-dolerites.

Distribution of sulfides and PGE minerals in the picritic and taxitic gabbro-dolerites of the Norilsk 1 intrusion

2021 ◽  
Vol 59 (6) ◽  
pp. 1437-1451
Author(s):  
Nadezhda Tolstykh ◽  
Jonathan Garcia ◽  
Gennadiy Shvedov
Keyword(s):  
Platinum Group Element ◽  
Group Element ◽  
Olivine Gabbro ◽  
Native Copper ◽  
Sulfur Fugacity ◽  
Cu Content ◽  
Geochemical Zoning ◽  
Monoclinic Pyrrhotite ◽  
Low Sulfur ◽  
Reverse Zoning

ABSTRACT Disseminated ores in the Norilsk 1 intrusion were studied to elucidate the typomorphic features of sulfides and noble metal mineralizations in picritic and taxitic (or lower olivine) gabbro-dolerites. The former are characterized by the development of a low-sulfur sulfide association (troilite, Fe-rich pentlandite, talnakhite, chalcocite, native copper) while the latter exhibits a high-sulfur association (monoclinic pyrrhotite, Ni-rich pentlandite, pyrite, heazlewoodite). The contact between these types of rocks is geochemically and mineralogically contrasting. The mineralogical and geochemical zoning directed from the roof to the base of each layer is expressed by an increase in the Cu content (and chalcopyrite) in ores, an increase in the concentration of Ni in pentlandite and S in pyrrhotite in line with a decrease of the crystallization temperature, and an increase in sulfur fugacity in the same direction. Zoning of Pd(Pt) mineralization in picritic and taxitic (olivine) gabbro-dolerites is uniform and characterized by the distribution of Pd-Sn compounds in the upper parts (together with Pd-Pb minerals in picritic rocks) and Pd-As compounds in the lower parts of the sections according to a drop in temperature. Such reverse zoning contradicts the typical mechanism of differentiation by fractional crystallization, and possibly suggests a fluid-magmatic nature. Mineralogical and geochemical features in platinum group element-Cu-Ni-bearing rocks are consistent with the idea that different stages of multi-pulse intrusions of mafic-ultramafic magmas with different compositions formed the picritic and taxitic gabbro-dolerites of the Norilsk region.

scholarly journals Anorthosites of the low-sulfide platiniferous horizon (Reef I) in the upper riphean Yoko-Dovyren massif (Northern Cisbaikalia): new data on the composition, PGE-Cu-Ni mineralization, fluid regime and formation conditions

2019 ◽  
Vol 61 (4) ◽  
pp. 15-43
Author(s):  
D. A. Orsoev
Keyword(s):  
Noble Metals ◽  
Decisive Role ◽  
Platinum Metal ◽  
Thermal Shrinkage ◽  
Volatile Components ◽  
Sulfide Liquid ◽  
Upper Riphean ◽  
Mineral Associations ◽  
Composition And Structure ◽  
Formation Conditions

The carried out studies based on new data allowed to give mineralogical, petro- and geochemical characteristics to anorthosites, which are the main link and the major concentrator of PGE and Au in the composition of low-sulfide platinum metal mineralization, localized in a specific taxitic horizon (Reef I) of the Yoko-Dovyren massif. The revealed features of the composition and structure of this horizon indicate that the formation of anorthosites is caused by both the actual magmatic and the late- and postmagmatic processes with a high activity of volatile components. The horizon occurrence can be explained in terms of the “compaction” hypothesis and thermal shrinkage phenomenon. At the boundary of the rocks contrasting in composition and characteristics, when they are cooled, weakened zones form up to cracks and cavities, into which the interstitial leucocratic melt and volatiles squeezed out of the underlying horizons of the massif sucked as a result of the decompression effect. The revealed patterns of changes in the compositions of Pl (82-88% An), Ol (78-81% Fo), Cpx (40-44% En, 9-18% Fs, 41-47% Wo) and Opx (74-78% En, 16-24% Fs, 2-5% Wo) indicate fractional crystallization of the detrital melt. The processes of fluid-magmatic interaction led to a considerable heterogeneity of anorthosites and other rocks, the formation of disequilibrium mineral associations and concentration of ore-generating components. Sulfide associations are considered as products of the subsolidus transformation of solid solutions (mss and iss + poss) formed during the crystallization of an immiscible sulfide liquid enriched in Cu. It is demonstrated that noble metals were associated not only with a limited amount of sulfide liquid. The major part of noble metals with “crust” components (Sn, Pb, Hg, Bi, As, Sb, Te, S, etc.) entered the anorthosite cavities along with volatile components and chlorine, thus causing an abundance of native minerals among platinoids. The decisive role of reduced gases (H2, CH4, CO), H2O and Cl in the genesis of precious metal minerals is estimated.

Liquid immiscibility and the origin of alkali-poor carbonatites

1988 ◽  
Vol 52 (364) ◽  
pp. 43-55 ◽  
Author(s):  
B. A. Kjarsgaard ◽  
D. L. Hamilton
Keyword(s):  
Liquid Immiscibility ◽  
Raw Material ◽  
Coarse Grained ◽  
Rock Types ◽  
Liquid Fractionation ◽  
Ring Complexes ◽  
The Common ◽  
Melt Cooling ◽  
Carbonate Melt ◽  
Common Sequence

AbstractThe work on liquid immiscibility in carbonate-silicate systems of Freestone and Hamilton (1980) has been extended to include alkali-poor and alkali-free compositions. Immiscibility is shown to occur on the joins albite-calcite and anorthite-calcite at 5 kbar. These results make it possible to interpret ocellar structure between calcite-rich spheroids in lamproite or kimberlite host rock as products of liquid immiscibility. The common sequence of rock types found in carbonatite complexes of melilitite-ijolite-urtite-phonolite is interpreted as being the result of both fractional crystallization and liquid fractionation, the corresponding carbonatite composition changing from nearly pure CaCO3 (±MgCO3) progressively to natrocarbonate. A carbonate melt cooling in isolation will suffer crystal fractionation, the residual liquid producing the rarer ferrocarbonatites, etc., whilst the crystal accumulate of calcite (dolomite) plus other phases such as magnetite, apatite, baryte, pyrochlore, etc., are the raw material for the coarse-grained intrusive carbonatites commonly found in ring complexes.

Whole-rock and mineral chemistry of cumulates from the Kızıldağ (Hatay) ophiolite (Turkey): clues for multiple magma generation during crustal accretion in the southern Neotethyan ocean

2005 ◽  
Vol 69 (1) ◽  
pp. 53-76 ◽  
Author(s):  
U. Bağci ◽  
O. Parlak ◽  
V. Höck
Keyword(s):  
Tectonic Setting ◽  
Mineral Chemistry ◽  
Chromian Spinel ◽  
Olivine Gabbro ◽  
Crustal Accretion ◽  
Magma Generation ◽  
The North ◽  
Rock Types ◽  
Suprasubduction Zone ◽  
Ocean Ridge

AbstractThe late Cretaceous Kızıldağ ophiolite forms one of the best exposures of oceanic lithospheric remnants of southern Neotethys to the north of the Arabian promontory in Turkey. The ultramafic to mafic cumulate rocks, displaying variable thickness (ranging from 165 to 700 m), are ductiley deformed, possibly in response to syn-magmatic extension during sea-floor spreading and characterized by wehrlite, olivine gabbro, olivine gabbronorite and gabbro. The gabbroic cumulates have an intrusive contact with the wehrlitic cumulates in some places. The crystallization order of the cumulus and intercumulus phases is olivine (Fo86–77)± chromian spinel, clinopyroxene (Mg#92–76), plagio-clase(An95–83), orthopyroxene(Mg#87–79). The olivine, clinopyroxene, orthopyroxene and plagioclase in ultramafic and mafic cumulate rocks seem to have similar compositional range. This suggests that these rocks cannot represent a simple crystal line of descent. Instead the overlapping ranges in mineral compositions in different rock types suggest multiple magma generation during crustal accretion for the Kızıldağ ophiolite. The presence of high Mg# of olivine, clinopyroxene, orthopyroxene, and the absence of Ca-rich plagioclase as an early fractionating phase co-precipitating with forsteritic olivine, suggest that the Kızıldağ plutonic suite is not likely to have originated in a mid-ocean ridge environment. Instead the whole-rock and mineral chemistry of the cumulates indicates their derivation from an island arc tholeiitic (IAT) magma. All the evidence indicates that the Kızıldağ ophiolite formed along a slow-spreading centre in a fore-arc region of a suprasubduction zone tectonic setting.

Scrap tire pyrolysis using a new type two-stage pyrolyzer: Effects of dolomite and olivine on producing a low-sulfur pyrolysis oil

Energy ◽  
2016 ◽  
Vol 114 ◽  
pp. 457-464 ◽  
Author(s):  
Gyung-Goo Choi ◽  
Seung-Jin Oh ◽  
Joo-Sik Kim
Keyword(s):  
Pyrolysis Oil ◽  
Scrap Tire ◽  
Two Stage ◽  
New Type ◽  
Low Sulfur

Compositions and Ni-Cu-Platinum Group Element Tenors of Nova-Bollinger Ores with Implications for the Origin of Pt Anomalies in Platinum Group Element-Poor Massive Sulfides

2022 ◽  
Author(s):  
Stephen J. Barnes ◽  
Clifford R. Stanley ◽  
Valentina Taranovic
Keyword(s):  
Platinum Group Element ◽  
Massive Sulfide ◽  
Group Element ◽  
Sulfide Liquid ◽  
Partial Explanation ◽  
Sampling Artifacts ◽  
Platinum Group Minerals ◽  
Liquid Fractionation ◽  
Platinum Group ◽  
Relative Errors

Abstract The Nova-Bollinger Ni-Cu-platinum group element (PGE) deposit in the Fraser zone of the Albany-Fraser orogen consists of two main orebodies, Nova and Bollinger, hosted by the same tube-shaped intrusion but having distinctly different Ni tenors of around 6.5 and 4.8 wt %, respectively. Nova is also higher in Pd, but Cu and Pt tenors are similar. Both deposits have very low PGE tenors, with average Pd concentrations of 110 ppb in massive sulfide at Bollinger and 136 ppb at Nova. The Nova and Bollinger orebodies show relatively little internal differentiation overall on deposit scale but show strong differentiation into chalcopyrite-rich and chalcopyrite-poor regions at a meter scale. This differentiation is more prevalent at Nova, where massive sulfide-filled vein arrays are more extensively developed, and in massive ores, particularly veins, than in net-textured ores. Net-textured and disseminated ores have on average Ni and Cu grades and tenors similar to those of massive, semimassive, and breccia ores in the same orebody but a smaller range of variation, largely due to a more limited extent of sulfide liquid fractionation and higher average concentrations of Pt and Pd than adjacent massive ores. Unusually for differentiated magmatic sulfides, there is no systematic positive correlation between Pt, Pd, and Cu. A partial explanation for the lack of a Pd-Cu correlation is that Pd was partitioned into peritectic pentlandite in the middle stages of sulfide liquid solidification. This explanation is not applicable to Pt, as Pt characteristically forms its own phases rather than residing in base metal sulfides. PGE tenors are very low in both orebodies, very similar to those observed in other Ni-Cu-Co sulfide ores in orogenic settings, notably the Savannah and Savannah North orebodies. This depletion is attributed to sulfide retention in the mantle source of the parent magmas rather than to previous fractional extraction of sulfide liquid in staging chambers or feeder networks. The higher Ni and Pd tenors at Nova are attributed to reworking and upgrading of precursor sulfide liquid originally deposited upstream at the Bollinger site. Replicate analyses of multiple jaw-crusher splits returned highly variable Pt and Au assays but much smaller relative errors in the other PGEs. The poor Pt and Au reproducibilities are attributed to nugget effects, explicable by much of the Pt and Au in the samples being present in sparse Pt- and Au-rich grains. This is principally true for Pt in massive rather than disseminated ores, accounting for a strong contrast in the distribution of Pt/Pd ratios between the two ore types. Numerical simulation suggests that Pt is predominantly resident in Pt-rich platinum group minerals with grain diameters of 100 μm or more and that at the low (&lt;100 ppb) concentrations in these ores, this results in most assays significantly underreporting Pt. This is likely to be true in other low-PGE ores, such that apparent negative Pt anomalies in massive ores may in such cases be attributable to sampling artifacts.

Rare earth elements in the bimodal Mount Peyton batholith: Evidence of crustal anatexis by mantle-derived magma

1982 ◽  
Vol 19 (2) ◽  
pp. 308-315 ◽  
Author(s):  
D. F. Strong ◽  
C. Dupuy
Keyword(s):  
Trace Elements ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Mafic Magma ◽  
Crustal Melting ◽  
Crustal Anatexis ◽  
Fractionation Process ◽  
Rock Types ◽  
Liquid Fractionation ◽  
Representative Samples

The Mount Peyton batholith of central Newfoundland is one of many Siluro-Devonian ("Acadian") plutons of the Appalachians with contrasting mafic and silicic compositions. The distributions of rare earth and other trace elements in 18 representative samples indicate that the contrasting rock types are not genetically related by any crystal–liquid fractionation process. Rather they support earlier suggestions that the granitic melt was generated by crustal melting due to intrusion of the mantle-derived mafic magma, and the two evolved independently through processes involving some crystal fractionation and contamination with country rocks during ascent.

scholarly journals Learning hierarchically organized science categories: simultaneous instruction at the high and subtype levels

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Robert M. Nosofsky ◽  
Colin Slaughter ◽  
Mark A. McDaniel
Keyword(s):  
Past Research ◽  
Classification Performance ◽  
Practical Significance ◽  
Training Procedure ◽  
Two Stage ◽  
Rock Types ◽  
Large Sets ◽  
The Hierarchical Structure ◽  
Comparison Groups ◽  
High Level

Abstract Background Most science categories are hierarchically organized, with various high-level divisions comprising numerous subtypes. If we suppose that one’s goal is to teach students to classify at the high level, past research has provided mixed evidence about whether an effective strategy is to require simultaneous classification learning of the subtypes. This past research was limited, however, either because authentic science categories were not tested, or because the procedures did not allow participants to form strong associations between subtype-level and high-level category names. Here we investigate a two-stage response-training procedure in which participants provide both a high-level and subtype-level response on most trials, with feedback provided at both levels. The procedure is tested in experiments in which participants learn to classify large sets of rocks that are representative of those taught in geoscience classes. Results The two-stage procedure yielded high-level classification performance that was as good as the performance of comparison groups who were trained solely at the high level. In addition, the two-stage group achieved far greater knowledge of the hierarchical structure of the categories than did the comparison controls. Conclusion In settings in which students are tasked with learning high-level names for rock types that are commonly taught in geoscience classes, it is best for students to learn simultaneously at the high and subtype levels (using training techniques similar to the presently investigated one). Beyond providing insights into the nature of category learning and representation, these findings have practical significance for improving science education.

scholarly journals Origin of the Pd-Rich Pentlandite in the Massive Sulfide Ores of the Talnakh Deposit, Norilsk Region, Russia

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1258
Author(s):  
Valery Kalugin ◽  
Viktor Gusev ◽  
Nadezhda Tolstykh ◽  
Andrey Lavrenchuk ◽  
Elena Nigmatulina
Keyword(s):  
Massive Sulfide ◽  
Sulfide Liquid ◽  
Isomorphic Substitution ◽  
Sulfide Ores ◽  
Sulfur Fugacity ◽  
Marginal Areas ◽  
Deming Regression ◽  
Individual Grains ◽  
Palladium Content ◽  
Talnakh Deposit

Pd-rich pentlandite (PdPn) along with ore-forming pentlandite (Pn) occurs in the cubanite and chalcopyrite massive sulfide ores in the EM-7 well of the Southern-2 ore body of the Talnakh deposit. PdPn forms groups of small grains and comprises marginal areas in large crystals of Pn. The palladium content in PdPn reaches up to 11.26 wt.%. EDS elemental mapping and a contour map of palladium concentrations indicate distinct variations in the palladium content within and between individual grains. Palladium distribution in the large grains is uneven and non-zoned. PdPn was formed as the result of a superimposed process, which is not associated with either the sulfide liquid crystallization or the subsolidus transformations of sulfides. Deming regression calculations demonstrated the isomorphic substitution character of Ni by 0.71 Pd and 0.30 Fe (apfu), leading to PdPn occurrence. The replacement of Ni by Fe may also indicate a change in sulfur fugacity, compared to that taking place during the crystallization of the primary Pn. The transformation of Pn into PdPn could have occurred under the influence of a Pd-bearing fluid, which separated from the crystallizing body of the massive sulfide ores.

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