Next Article in Journal
In Situ Hyperspectral Raman Imaging of Ternesite Formation and Decomposition at High Temperatures
Next Article in Special Issue
Trace-Element and Pb Isotope Evidence on Extracting Sulfides from Potassic Melts beneath Longmenshan and Molabushan Volcanoes, Wudalianchi, Northeast China
Previous Article in Journal
Microbial Gold Biosortion and Biomineralization from Aqueous HAuCl4 Solution
Previous Article in Special Issue
The Paleoproterozoic Kandalaksha-Kolvitsa Gabbro-Anorthosite Complex (Fennoscandian Shield): New U–Pb, Sm–Nd, and Nd–Sr (ID-TIMS) Isotope Data on the Age of Formation, Metamorphism, and Geochemical Features of Zircon (LA-ICP-MS)
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Minerals
Volume 10
Issue 3
10.3390/min10030286
minerals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

The Origin and Evolution of Ore-Bearing Rocks in the Loypishnun Deposit (Monchetundra Massif, NE Fennoscandian Shield): Isotope Nd-Sr and REE Geochemical Data

by
Evgeniy Kunakkuzin
*,
Elena Borisenko
,
Luydmila Nerovich
,
Pavel Serov
,
Tamara Bayanova
and
Dmitry Elizarov
Geological Institute of Kola Science Center of Russian Academy of Sciences, 184209 Apatity, Russia
*
Author to whom correspondence should be addressed.
Minerals 2020, 10(3), 286; https://doi.org/10.3390/min10030286
Submission received: 28 January 2020 / Revised: 17 March 2020 / Accepted: 19 March 2020 / Published: 21 March 2020
(This article belongs to the Special Issue Crust and Mantle Magmas as Response on Mantle Dynamics: Genesis, Geochemistry and Ores)
Browse Figures
Versions Notes

Abstract

:
The Monchetundra massif is located in the north-eastern Fennoscandian Shield and refers to Paleoproterozoic massifs of the East-Scandinavian Large Igneous Province. The general section of the massif comprises two parts, the lower norite-orthopyroxenite and the upper mafic zones. The lower zone is of great interest due to its associated industrial platinum group elements (PGE) mineralization. The structure and peculiar features of rocks in the lower zone were studied using a drill core from the borehole MT-70 in the south-eastern slope of the Monchetundra massif intersecting the ore zone 1 of the Loypishnun deposit (according to the CJSC Terskaya Mining Company data). A comparison of the barren and ore-bearing varieties of norites and pyroxenites in the Loypishnun deposit shows that the ore samples have the lowest negative εNd values, a relatively more differentiated distribution spectrum with the Light rare earth elements (LREE) dominating over the Heavy REE (HREE), Eu/Eu* ≥ 1, and a higher mean content of alkali and large-ion lithophile elements (Ba, Rb, and Cs). New geochemical data indicated an origin of magmas for rocks from a layered series in the Loypishnun deposit by a high degree of melting of a LREE-rich source with a low mean content of REE. Negative εNd values, low ISr values, and a marked negative Nb indicate that the crustal material affected the evolution of rocks in the lower zone of the massif more than in the upper zone. The formation of ore bodies in the Loypishnun deposit was governed by the crust-mantle interaction, magmatic differentiation, and association with the most differentiated varieties, and by further concentration of the ore at the late and post-magmatic stages in a highly permeable environment for fluids in the Monchetundra fault zone.

1. Introduction

Paleoproterozoic mafic-ultramafic massifs in the Fennoscandian Shield have been long considered promising for the platinum group elements (PGE), Cu-Ni and Cr-Ti-V, mineralization. The best-known deposits and ore occurrences confined to the Fedorovo-Panskiy massif, Monchepluton, Mt. Generalskaya in the Kola region, several massifs in Karelia (Olanga intrusion group), and Finland (Portimo, Penikat, Kemi, etc.). The evolution of these massifs is associated with intense magmatic activity in the early Proterozoic, which allowed them to integrate into the East-Scandinavian Large Igneous Province [1,2]. Geochronological (U-Pb, Sm-Nd, Rb-Sr, and Re-Os), isotope-geochemical and geochemical (Rare Earth Elements (REE), Nd-Sr-He, γOs) data [1,2,3,4] indicated that these massifs were subject to intense mantle plume activity. Nevertheless, the primary composition and mode of occurrence of the mantle source is still debated. Paleoproterozoic mafic-ultramafic intrusions are similar in a general geological section and occur as a differentiated rock series. However, as shown by the Monchetundra massif, mafic rocks are geochemically heterogeneous and formed at different times, which indicates a more complicated pattern of the massif evolution [5,6,7,8]. The aim of this study was to define peculiar features of rock formation in the Loypishnun PGE deposit on the basis of the Nd-Sr isotope and the geochemical data.

2. Geological Settings

The Monchetundra massif occurs in the north-eastern Fennoscandian Shield as the south-eastern part of the Main Ridge and the Monchegorsk ore area [3]. The intrusion is located at the junction of the Central Kola and Belomorian (White Sea) Blocks as a fragment of the Imandra-VarzugaPaleorift [9]. The general section of the massif can be divided into two parts [2,5,10]. The lower zone is mainly composed of alternating norites and orthopyroxenites; the upper zone hosts gabbroids. Rocks in the upper part have various ages and complicated interrelations. Four main rock groups can be detected in it, based on the interpretation of the geological and isotope U-Pb age data: metagabbro (2521–2516 Ma [5,6,11]), trachytoid gabbronorites (2507–2501 Ma [3,5,7]), massive gabbronorites (2476–2471 Ma [5,7,12]) and gabbro-pegmatites (2456–2453 Ma [5,6,11,12]). Additionally, there are later veins of gabbro-pegmatites (2445 Ma [6]) and aplites (1900 Ma [6]). Noteworthy, the occurrence of metagabbroids (2521–2516 Ma) in the upper part of the section seems to be linked to the tectonic processes. They are sometimes identified as “an early gabbroic series” [6].
The upper mafic part of the section is well-exposed; while outcrops of the lower zone are rare. The lower part of the Monchetundra massif was studied in detail during the prospecting for noble mineralization in the south-eastern part and at drilling of deep structural boreholes (М1, 765, etc., Figure 1).The lower norite-pyroxenite zone is represented by alternating orthopyroxenites, norites, and harzburgites. This zone is ~250 m thick in the south-east of the massif. The contacts between the rocks are gradational, with no sharp boundaries. However, near a contact with the Monchepluton, these rocks produce irregular alternating lenses and interlayers of varied size and thickness that lie among the gabbroids of the upper mafic zone [13]. The lower part of the section is of interestdue to the noble PGE mineralization associated mainly with orthopyroxenites, plagio-orthopyroxenites, and norites. The Western Nittis and Loypishnun deposits were discovered as a result of geological prospecting. According to Chashchin [13], they belong to a low-sulfide basal type of structure. The deposits are confined to the sulfide mineralization with a mean Pt + Pd content of up to 2 ppm; the ores have a Pd/Pt ratio of 1.7 and low contents of Ni and Cu.

3. Materials and Methods

Geochemical features of rocks in the lower zone of the massif were studied using drill core samples from the borehole MT-70 in the south-eastern slope of the Monchetundra massif. According to the data of the CJSC Terskaya Mining Company (Monchegorsk), the borehole intersects the ore zone 1 of the Loypishnun deposit (Figure 1).
Concentrations of petrogenic elements were estimated by atomic absorption spectrometer AAnalyst 400 (PerkinElmer Inc., Waltham, MA, USA) (wt.%) in the Laboratory for Chemical Analysis No. 33 of GI KSC RAS, Head of Laboratory L.I. Konstantinova. Analytical errors were 0.02–0.05%.The content of REE and disseminated elements was estimated by the ICP-MS method (ELEMENT, Thermo Fisher Scientific Inc., Waltham, MA, USA) for multi-element and isotope research in the Analytical Centre of V.S. Sobolev Institute of Geology and Mineralogy (IGM SB RAS, Novosibirsk, Russia), analyst I.V. Nikolaeva. The precision of the ICP-MS measurements was better than ±3% for most elements. The PGE content in the massif rocks was measured by ICP-MS at ELAN-6100 DRC-e (PerkinElmer Inc., Waltham, MA, USA) in the Central Laboratory of A.P. Karpinsky Russian Geological Research Institute (VSEGEI, St. Petersburg, Russia), analysts V.A. Shilov and V.L. Kudryashov. The precision of the ICP-MS measurements was ±5%.
The isotope Nd and Sr content was estimated with a Finnigan-MAT 262 (RPQ) (Thermo Fisher Scientific Inc., Waltham, MA, USA) solid-phase multicollector mass-spectrometer and a MI-1201 (NPO “Electron”, Sumy, Ukraine) mass-spectrometer in the Kola Centre for Geochronological and Isotope-Geochemical Research of GI KSС RAS (Apatity).

3.1. Sm-Nd Method

The samples for Sm-Nd analysis were treated using the ordinary techniques: dissolution in HF + HNO3 (or + НСlO4) in Teflon beakers at 100 °C following the extraction of Sm and Nd by ion-exchange column chromatography. Nd and Sm were measured by the isotopic dilution technique with a mixed 149Sm/150Nd tracer on double Re + Re filaments. The measured reproducibility for the seven-parallel analysis of Nd-isotope composition for the standard JNdi-1 [14] was 0.512089 ± 14. The blanks for laboratory contamination for Nd and Sm were 0.3 and 0.06 ng, respectively. The reproducibility of measurements was ±0.3% (2σ) for 147Sm/144Nd ratios in BCR-2 standard (N = 7; [15]). The reproducibility of measurements for Nd-isotope composition was up to 0.01% (2s) in an individual analysis. All 147Sm/144Nd and 143Nd/144Nd ratios were normalized to 146Nd/144Nd = 0.7219 and adjusted to 143Nd/144Nd = 0.512115 using the JNdi-1 standard [14]. The εNd(T) values were calculated using the following parameters of CHUR [16]: 143Nd/144Nd = 0.512630 and 147Sm/144Nd = 0.1960 and DM [17]: 143Nd/144Nd = 0.513151 and 147Sm/144Nd = 0.2136.

3.2. Rb-Sr Method

The Sr isotope compositions and Rb and Sr content were from aMI-1201 mass spectrometer by the isotopic dilution technique with the derived 85Rb and 84Sr tracers in a two-band mode using Re filaments. The isotope Sr composition in all measured samples was normalized to a value of 0.710235 as recommended by NBS SRM-987. The errors in the Sr isotope analysis (confidence interval of 95%) were up to 0.04%, and those of the Rb-Sr ratio determination were 1.5%. The blank laboratory contamination was 2.5 ng for Rb and 1.2 ng for Sr. The adopted Rb decay constant of [18] was used for the ISr calculations.

4. Results

4.1. Petrography

The top part of the section is represented by medium-grained amphibolized gabbronorites (Figure 2) of the upper zone trachytoid gabbronorites (2.5 Ga). These rocks host poorly preserved primary magmatic minerals; pyroxenes are highly amphibolized, secondary minerals are formed on plagioclase (groups of epidote, apatite, etc.), almost completely replacing the grains. This rock group contains bodies of coarse-grained, rarely pegmatoid melanocratic amphibolized gabbroids that seem to be related to massive gabbronorites (2.47 Ga) or gabbro-pegmatites (2.45 Ga). The lower zone is represented by intercalated rocks of the norite and pyroxenite groups. The norite group comprises melano-, meso-, rarely leucocratic norites, including olivine-bearing varieties. The pyroxenite group is represented by orthopyroxenites and Pl-orthopyroxenites, mainly. Both groups contain amphibolized rock varieties. According to Chashchin [19], the rocks were altered by the intense impact of fluids at the late and post-magmatic stages of the ore formation. The sulfide mineralization with a pentlandite-chalcopyrite-pyrrhotite composition dominates in rocks of this layered series and associates with the PGE mineralization [13].
Bodies of dunites and harzburgites occur as 10-m thick interlayers in a stratified series of the lower zone. Dunites show well-preserved olivine grains with serpentine-magnetite and carbonate veinlets in them (Figure 2). Chromite grains are present in the amount of 1–3%. Harzburgites consist of olivine (50%), orthopyroxene (40%), plagioclase (5%), and clinopyroxene (2%). Additionally, there are rounded chromite grains associated with orthopyroxenes and olivines (Figure 2).
The interval of ~270 m is marked with a tectonic zone, where rocks are transformed into mylonites (Figure 2). Coarse-grained amphibolized gabbronorites are widespread under and over this zone. Primary mafic minerals are almost completely replaced by amphibole; isometric grains of garnet are abundant (up to 10%) here (Figure 2). Garnet occurs both as individual grains up to 3 mm in size and as their 3-cm long clusters. The rocks differ from amphibolized gabbronorites of the upper borehole section in their mineralogical composition (plagioclase, garnet, amphibole, and biotite), structural, and textural features. These rocks are more like gabbro-pegmatites from the upper parts of the Monchetundra massif section (2.45 Ga).

4.2. PGE Content

The PGE content was determined in order to reveal the relation between geochemical features and the PGE content in rocks (Table 1). Three areas with an elevated total PGE content were detected within the studied borehole section. They were confined to rocks in the lower zone, i.e., the intervals 177–194 m, 225–259 m, and 318–320 m. These areas host intercalated pyroxenites and norites; the rocks are often metamorphically altered, and primary pyroxenes are replaced by amphiboles. The elevated PGE content was directly related to an increase in the content of sulfide minerals in the rock. An elevated PGE content was also observed in the interval of 264–275 m, but in gabbro-pegmatites. Notably, all rocks in the borehole section exhibited the prevalence of Pd over Pt.

4.3. Whole Rocks Geochemistry

The SiO2 vs. (Na2O + K2O) plot [21] (Table S1; Figure 3) shows that rocks from the MT-70 borehole section mainly occurred in the gabbroid field, and that amphibolized gabbronorites had a higher total alkali content compared to norites, pyroxenites, and harzburgite. The composition of one gabbro-pegmatite sample is similar to that of diorites. Dunites are low in alkali and silica. Ore-bearing rocks have a slightly elevated alkali content compared to their barren analogues.
Variation plots on the MgO content (Figure 4) indicate that rocks from the МТ70 borehole section produced quite regular increasing trends in Al2O3, Na2O, and CaO with a decrease in MgO. Notably, there were also increasing trends in the iron content (except for amphibolized gabbronorites), K2O and TiO2 with a decrease in MgO.
In general, the variation plots exhibited clear differentiation trends, i.e., dunites-harzburgites-orthopyroxenites-norites; these were less obvious for the gabbronorites. Ore-bearing rocks have quite similar content of main oxides, except for Al2O3 and FeOt, which vary greatly (Table S1). Additionally, the alkali content is generally higher in ore varieties.
Multi-element distribution plots of primitive mantle-normalized REE and rare elements [22] show that the harzburgite, pyroxenites, and norites, including ore samples, have similar distribution spectra (Table S1; Figure 5). The spectra exhibited a weak negative slope, clear negative Nb anomaly, and weak positive Sr anomaly. However, the ore samples had a high mean content of large-ion lithophile elements (Ba, Rb, and Cs). We assumed that diverse compositions of norites in the lower zone, the mentioned features of ore norites and pyroxenites, were caused by the significant impact of fluids on the ore formation [19]. The spectra of amphibolized gabbronorites are similar to those of gabbronorites in the upper parts of the massif section [5]. They are characterized by negative Nb and positive Sr anomalies. Dunites are low in REE and disseminated elements compared to other rocks. Harzburgite occupies an intermediate position between the dunite and orthopyroxenites spectra. Ultramafic rocks, except for one sample of dunites, have a negative Nb anomaly as well. The form of spectra in gabbro-pegmatites is similar to that described for the section rocks, but as crystallization products of the residual melt, these rocks are irregularly enriched in almost all REE and rare elements (Figure 5).
The plots of chondrite-normalized REE distribution [23] (Table S2; Figure 5) in barren norites and pyroxenites show similar weakly differentiated spectra (the mean values of (La/Yb)n are 2.39 and 1.60, respectively) and an almost complete absence of Eu anomalies (the mean values of Eu/Eu* are 0.95 and 0.87, respectively). However, there are more and less REE-rich samples of norites. The total REE content varies from 6.06 to 47.51 ppm; enriched varieties have a more differentiated spectrum (La/Yb)n = 3.31–5.56. Compared to barren varieties, ore norites and pyroxenites (ΣPGE > 0.5 ppm) exhibit a more differentiated distribution spectrum with LREE prevalent over HREE; the mean values of (La/Yb)n are 3.64 and 2.88, respectively. Additionally, most samples of ore norites and ore pyroxenites show Eu/Eu* ≥ 1 and a weak positive Eu anomaly.
Dunites are characterized by a low REE content of 0.67 to 1.97 ppm and a negative Eu anomaly Eu/Eu* of 0.36–0.80. The spectrum slope fluctuates from weakly positive ((La/Yb)n = 0.81) to negative in varieties rich in chromite mineralization ((La/Yb)n = 3.11). Harzburgite exhibits an elevated total REE content compared to dunites (3.96 ppm), a weakly positive Eu anomaly (Eu/Eu* = 1.20), and a negative slope of the REE distribution spectrum ((La/Yb)n = 2.05). Amphibolized gabbronorites in the upper part of the borehole section show a moderate REE content (mean value—14.20 ppm), a positive Eu anomaly (Eu/Eu* = 1.27–1.78) and a slight prevalence of LREE over HREE (mean values (La/Yb)n = 1.78). Amphibolized gabbronorites significantly differ from gabbro-pegmatites, which have similar characteristics with later gabbro-pegmatites in the upper parts of the massif sections [6].

4.4. Nd-Sr Isotope Composition

According to the isotope-geochemical Nd-Sr data (Table 2, Figure 6), dunites have weakly positive εNd(2500) values of +0.81 and low ISr(2500) values of 0.69232 at the moment ca. 2.5 Ga. Clearly, such low values of Isr are hardly possible for dunites. Considering an intersecting mode of olivinite occurrence in the lower zone, they can be younger than 2.5 Ga. The εNd(2500) value in norites ranges from −4.13 to −2.16, while the ISr(2500) value ranges from 0.70149 to 0.70433, respectively. Ore norites exhibit lower negative values of εNd(2500) (−5.72, −6.20) and ISr(2500) = 0.704. Ore pyroxenites, on the contrary, have positive εNd(2500) values from +0.88 to +2.16 with similar ISr(2500) values of about 0.704. The gabbro-pegmatites are characterized by low values of εNd(2500) = −11.65 and ISr(2500) = 0.7031 (ISr0 = 0.7191). Amphibolized gabbronorites in the upper parts of the borehole section exhibit εNd(2500) = +1.6 and ISr(2500) = 0.70253, while rocks breaking the lower zone rocks (interval 157 m) have higher ISr(2500) values of 0.70494 (Table 2).

5. Discussion

The obtained geochemical and isotope-geochemical data indicate that rocks in the lower zone of the Monchetundra massif have a moderate total REE content, which increases in the ore samples (Figure 7). Such pattern is observed in the (La/Yb)n ratio, and the εNd(2500) in ore varieties decreases from positive to low negative values. Compared to other rocks, ore-bearing norites and pyroxenites show a weak positive Eu/Eu* anomaly. Noteworthy, rocks at the interval of 100–170 m of the lower zone have a negative Eu/Eu* anomaly, in contrast to the positive anomaly in superposed rocks of the upper zone. The initial ISr(2500) ratios in ore-bearing rocks have similar values and tend to be similar with barren analogues, except for one analysis of norite and dunite.
As shown by the Nb/Yb vs. Th/Yb plot, the rocks of the lower zone layered series (harzburgite-norite-pyroxenites groups) are derivates of the crust-mantle relation (Figure 8a). This position of points indicates contamination with matter, whose composition conforms to the lower and middle continental crust, and ore-bearing rocks that are highly contaminated. The same trend is observed in the La/Sm vs. Nb/Th plot (Figure 8b). Notably, rocks in the upper part of the section show a lower degree of contamination, while some points correspond to fields of mantle sources, like N-MORB and E-MORB. This may indicate, not only a lower degree of contamination with the crustal material, but also a heterogeneous inflow of the matter from sublithospheric reservoirs to the source.
According to data on isotope Nd composition, rocks in the Loypishnun deposit show widely varied εNd values (Figure 9). The most probable reason for this is the crustal contamination of the initial mantle melt with products of the continental crust, i.e., rocks of the Central-Kola Block that are host rocks in the massif. Some rocks have low positive εNd values, which can be explained by the contamination processes. However, as the plot shows (Figure 9), some rocks have far lower negative εNd values than rocks in the Central-Kola Block [22,23,24]. It is possible that the isotope Sm-Nd system in these rocks was affected by other factors, such as fluidization during the ore formation or tectonic activation. Interestingly, ore pyroxenites have positive εNd values, while barren and ore norites have only negative εNd values, though some of the rocks neighbor each other (Figure 9). Considering this fact, we may conclude that ore-bearing systems are characterized by an “instable” isotope Sm-Nd system. Amphibolized gabbronorites show positive εNd values, which is common for rocks in the upper part of the massif section [5,6,8]. Gabbro-pegmatites have very low negative εNd values, which is quite uncommon for gabbro-pegmatites in the upper parts of the section [5,6].
According to [4,5,8,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51], the intrusive magmatism at 2.53–2.39 Ga was widespread in the Fennoscandian Shield, Canada [52,53,54,55], and Zimbabwe [56]. The Paleoproterozoic massifs of the Fennoscandian Shield have similar initial isotope Nd-Sr values (Figure 10): the εNd(i) values vary from −5 to +3, the ISr(i) values range from 0.700 to 0.706, and their formation is related to the activity of the long-lived plume. In general, the isotope Nd-Sr compositions of rocks in the upper zone of the Monchetundra massif [4,5,6,8,29] are close to those in similar massifs, and the values of the Amp-gabbronorite sample of the MT-70 borehole coincide as well. However, new studies of rocks in the lower zone indicate a wide range of values, first, on the isotope Nd composition. The ore norites show the greatest difference in values; however, as noted above, ore-bearing rocks have an “instable” isotope composition of Nd. The pattern of the gabbro-pegmatite isotope composition can be explained by transformation of the Sm-Nd system caused by the impact of fluids in the fault zone [34].
According to [1,2,4], the evolution of Paleoproterozoic Monchepluton and Monchetundra massifs is confined to the long-lived mantle plume that preconditioned a high melting degree of rocks in the upper mantle [6]. As defined in [3], initial mantle melts were contaminated by the matter in the lower crust. New data on rocks from the lower zone of the Monchetundra massif show the contamination degree of their source to be higher than that of rocks from the upper part of the intrusion and the Monchepluton. New geochemical and isotope-geochemical data indicate that rocks from the layered intrusion of the Loypishnun deposit originated from a source with a generally low REE content, but a relatively LREE-rich. A clear Nb minimum, low Nb/Th ratios, high La/Sm, Nb/Yb, Th/Yb ratios, as well as relatively high ISr values and dominating low negative εNd values indicate a considerable input of the crustal material to the source of initial magmas of these rocks.
The comparison of barren and ore-bearing varieties of norites and pyroxenites in the Loypishnun deposit shows that ore samples have the lowest negative εNd values, a relatively more differentiated distribution spectrum with LREE dominating over HREE, Eu/Eu* ≥ 1, and higher mean contents of alkali and large-ion lithophile elements (Ba, Rb, and Cs).
The formation of ore bodies in the Loypishnun deposit with the basal type of structure [13] appears to be governed both by the crust-mantle interaction, magmatic differentiation, and association with the most differentiated varieties, and by further concentration of the ore at the late and post-magmatic stages in a highly permeable environment for fluids in the Monchetundra fault zone.
We also assumed that the initial melt of trachytoid gabbronorites in the upper zone (2.5 Ga) injected into already cooled rocks of the lower zone with no or a minimal amount of rocks from the continental crust. Rocks in the upper part mainly interacted with those in the lower zone; therefore, they exhibit more “mantle” isotope characteristics.

Supplementary Materials

The following materials are available online at https://www.mdpi.com/2075-163X/10/3/286/s1, Table S1: Main oxides composition of Loypishnun area rocks, Table S2: Trace and rare earth elements of Loypishnun area rocks.

Author Contributions

Conceptualization, Visualization, Investigation and Writing—Original Draft Preparation E.K., E.B., L.N., P.S.; Investigation, P.S.; Methodology, P.S., D.E.; Supervision and Editing, T.B. All authors have read and agreed to the published version of the manuscript.

Funding

The study was funded by the Russian Foundation for Basic Research, grants No. 18-35-00152 mol_a; 18-05-70082, research project No.0226-2019-0053.

Acknowledgments

The authors are grateful to L.I. Koval (GI KSC RAS) for sample preparation, L.I. Konstantinova, S.N. Dyakov, O.G. Sherstennikova, G.M. Sherstobitova (GI KSC RAS), I.V. Nikolaeva (IGM SBRAS), V.A. Shilov, V.L. Kudryashov (VSEGEI) for analytical works; M.S. Lyulko (CKE) for consultations and materials.The study was carried out with materials and the consent of CJSC Terskaya Mining Company (Monchegorsk).

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Bayanova, T.; Ludden, J.; Mitrofanov, F. Timing and duration of Palaeoproterozoic events producing ore-bearing layered intrusions of the Baltic Shield: Metallogenic, petrological and geodynamic implications. Geol. Soc. Lond. Spec. Publ. 2010, 323, 165–198. [Google Scholar] [CrossRef] [Green Version]
  2. Mitrofanov, F.P.; Bayanova, T.B.; Korchagin, A.U.; Groshev, N.Y.; Malitch, K.N.; Zhirov, D.V.; Mitrofanov, A.F. East Scandinavian and Noril’sk plume mafic large igneous provinces of Pd-Pt ores: Geological and metallogenic comparison. Geol. Ore Depos. 2013, 55, 305–319. [Google Scholar] [CrossRef]
  3. Layered Intrusions of Monchegorsk Ore Region: Petrology, Ore-Forming, Isotopy, Deep Structure; Mitrofanov, F.; Smolkin, V. (Eds.) KSC RAS: Apatity, Russia, 2004; p. 177. [Google Scholar]
  4. Yang, S.-H.; Hanski, E.; Li, C.; Maier, W.D.; Huhma, H.; Mokrushin, A.V.; Latypov, R.; Lahaye, Y.; O’Brien, H.; Qu, W.-J. Mantle source of the 2.44–2.50 Ga mantle plume-related magmatism in the Fennoscandian Shield: Evidence from Os, Nd, and Sr isotope compositions of the Monchepluton and Kemi intrusions. Miner. Depos. 2016, 51, 1055–1073. [Google Scholar] [CrossRef]
  5. Nerovich, L.I.; Bayanova, T.B.; Savchenko, Y.E.; Serov, P.A. Monchetundra massif: Geology, petrography, geochronology, geochemistry, PGE mineralization (new data). In An Interreg-Tacis Project: Strategic Mineral Resources of Lapland – Base for the Sustainable Development of the North; Project Publication; Mitrofanov, F., Iljina, M., Zhirov, D., Eds.; KSC RAS: Apatity, Russia, 2009; Volume II, pp. 97–112. [Google Scholar]
  6. Nerovich, L.I.; Bayanova, T.B.; Serov, P.A.; Elizarov, D.V. Magmatic sources of dikes and veins in the Moncha Tundra massif, Baltic Shield: Isotopic-geochronologic and geochemical evidence. Geochem. Int. 2014, 52, 605–624. [Google Scholar] [CrossRef]
  7. Borisenko, E.S.; Bayanova, T.B.; Nerovich, L.I.; Kunakkuzin, E.L. Paleoprotrozoic mafic Monchetundra massif (Kola Peninsula): New geological and geochronological data. Dokl. Earth Sci. 2015, 465, 68–72. [Google Scholar] [CrossRef]
  8. Kunakkuzin, E.L.; Bayanova, T.B.; Nerovich, L.I.; Borisenko, E.S.; Serov, P.A.; Elizarov, D.V. New Nd-Sr isotope-geochemical research of the paleoproterozoic PGE-bearing Monchetundra massif rocks (Fennoscandian Shield). Vestn. MSTU 2015, 18, 269–279. [Google Scholar]
  9. Mitrofanov, F.P.; Pozhilenko, V.I.; Smolkin, V.F.; Arzamastsev, A.A.; Yevzerov, V.Y.; Lyubtsov, V.V.; Shipilov, E.V.; Nikolayeva, S.B.; Fedotov, Z.A. Geology of Kola Peninsula; Kola Science Centre RAS: Apatity, Russia, 1995; p. 145. [Google Scholar]
  10. Sharkov, E.V. Formation of Layered Intrusions and Related Mineralization; Nauchniy Mir: Moscow, Russia, 2006. [Google Scholar]
  11. Bayanova, T.B.; Nerovich, L.I.; Mitrofanov, F.P.; Zhavkov, V.A.; Serov, P.A. The Monchetundra basic massif of the Kola region: New geological and isotope geochronological data. Dokl. Earth Sci. 2010, 431, 288–293. [Google Scholar] [CrossRef]
  12. Mitrofanov, F.P.; Balagansky, V.V.; Balashov, Y.A.; Gannibal, L.F.; Dokuchaeva, V.S.; Nerovich, L.I.; Radchenko, M.K.; Ryungenen, G.I. U-Pb age of gabbro-anorthosite of the Kola Peninsula. Dokl. Earth Sci. 1993, 331, 95–98. [Google Scholar]
  13. Chashchin, V.V.; Petrov, S.V.; Drogobuzhskaya, S.V. Loypishnyun low-sulfide Pt-Pd deposit of the Monchetundra basic massif, Kola Peninsula, Russia. Geol. Ore Depos. 2018, 60, 418–448. [Google Scholar] [CrossRef]
  14. Tanaka, T.; Togashi, S.; Kamioka, H.; Amakawa, H.; Kagami, H.; Hamamoto, T.; Yuhara, M.; Orihashi, Y.; Yoneda, S.; Shimizu, H.; et al. JNdi-1: A neodymium isotopic reference in consistency with LaJolla neodymium. Chem. Geol. 2000, 168, 279–281. [Google Scholar] [CrossRef]
  15. Raczek, I.; Jochum, K.P.; Hofmann, A.W. Neodymium and strontium isotope data for USGS reference materials BCR-1, BCR-2, BHVO-1, BHVO-2, AGV-1, AGV-2, GSP-1, GSP-2 and eight MPI-DING reference glasses. Geostand. Geoanal. Res. 2003, 27, 173–179. [Google Scholar] [CrossRef]
  16. Bouvier, A.; Vervoort, J.D.; Patchett, P.J. The Lu–Hf and Sm–Nd isotopic composition of CHUR: Constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets. Earth Planet. Sci. Lett. 2008, 273, 48–57. [Google Scholar] [CrossRef]
  17. Goldstein, S.J.; Jacobsen, S.B. Nd and Sr isotopic systematics of river water suspended material implications for crystal evolution. Earth Planet. Sci. Lett. 1988, 87, 249–265. [Google Scholar] [CrossRef]
  18. Steiger, R.; Jäger, E. Subcommission on geochronology: Convention on the use of decay constants in geo - and cosmochronology. Earth Planet. Sci. Lett. 1977, 36, 359–362. [Google Scholar] [CrossRef]
  19. Chashchin, V.V.; Kul’chitskaya, A.A.; Elizarova, I.R. Fluid regime of the formation of low-sulfide PGM Loipishnyun deposits, Monchetundra mafic massif (Kola Peninsula, Russia). Litosfera 2017, 17, 91–109. [Google Scholar]
  20. Lulko, M.S. Geological structure of Monchetundra massif Loypishnun area. Tr. FNS 2009, 180–184. [Google Scholar]
  21. Middlemost, E.A.K. Naming materials in the magma/igneous rock system. Earth Sci. Rev. 1994, 37, 215–244. [Google Scholar] [CrossRef]
  22. Sun, S.; McDonough, W.F. Chemical and isotopic systematics of oceanic basalts: Implications for mantle composition and processes. Geol. Soc. Lond. Spec. Publ. 1989, 42, 313–345. [Google Scholar] [CrossRef]
  23. Boynton, W.V. Cosmochemistry of the rare earth elements; meteorite studies. In Rare Earth Element Geochemistry; Henderson, P., Ed.; Elsevier Sci. Publ. Co.: Amsterdam, The Netherlands, 1984; pp. 63–114. [Google Scholar]
  24. Pearce, J.A. Geochemical fingerprinting of oceanic basalts with applications to ophiolite classification and the search for Archean oceanic crust. Lithos 2008, 100, 14–48. [Google Scholar] [CrossRef]
  25. Rudnick, R.L.; Fountain, D.M. Nature and composition of thecontinental crust—A lower crustal perspective. Rev. Geophys. 1995, 33, 267–309. [Google Scholar] [CrossRef] [Green Version]
  26. Timmerman, M.J.; Daly, S.J. Sm-Nd evidence for late Archean crust formation in the Lapland-Kola Mobile Belt, Kola Peninsula, Russia and Norway. Precambrian Res. 1995, 72, 97–107. [Google Scholar] [CrossRef]
  27. Petrovskaya, L.S.; Mitrofanov, F.P.; Bayanova, T.B.; Petrov, V.P.; Petrovsky, M.N. NeoarchaeanEnderbite-Granulite Complex of the Pulozero-Polnek-Tundra Region, Central-Kola Block: Stages and Thermodynamic Regime of Evolution (Kola Peninsula); Print. Kola Science Centre RAS: Apatity, Russia, 2010; p. 78. [Google Scholar]
  28. Myskova, T.A.; Milkevich, R.I. The aluminous gneisses of Kola series, Baltic Shield (geochemistry, nature and age of protolith). Tr. Kar. NC 2016, 10, 34–62. [Google Scholar]
  29. Bayanova, T.; Korchagin, A.; Mitrofanov, A.; Serov, P.; Ekimova, N.; Nitkina, E.; Kamensky, I.; Elizarov, D.; Huber, M. Long-lived mantle plume and polyphase evolution of palaeoproterozoic PGE intrusions in the Fennoscandian Shield. Minerals 2019, 9, 59. [Google Scholar] [CrossRef] [Green Version]
  30. Balashov, Y.A.; Bayanova, T.B.; Mitrofanov, F.P. Isotope data on the age and genesis of layered basic-ultrabasic intrusions in the Kola Peninsula and Northern Karelia, Northeastern Baltic Shield. Precambrian Res. 1993, 64, 197–205. [Google Scholar] [CrossRef]
  31. Amelin, Y.V.; Semenov, V.S. Nd and Sr isotopic geochemistry of mafic layered intrusions in the eastern Baltic shield: Implications for the evolution of Paleoproterozoic continental mafic magmas. Contrib. Mineral. Petrol. 1996, 124, 255–272. [Google Scholar] [CrossRef]
  32. Revyako, N.M.; Kostitsyn, Y.A.; Bychkova, Y.V. Interaction between a mafic melt and host rocks during formation of the Kivakka layered intrusion, North Karelia. Petrology 2012, 20, 101–119. [Google Scholar] [CrossRef]
  33. Mitrofanov, F.P.; Bayanova, T.B.; Ludden, J.N.; Korchagin, A.U.; Chashchin, V.V.; Nerovich, L.I.; Serov, P.A.; Mitrofanov, A.F.; Zhirov, D.V. Origin and exploration of the Kola PGE-bearing Province: New constraints from geochronology. In Ore Deposits: Origin, Exploration, and Exploitation; Sophie Decree, S., Robb, L., Eds.; Geophysical Monograph Series; Wiley: Hoboken, NJ, USA, 2019; pp. 3–36. [Google Scholar]
  34. Sharkov, E.V.; Chistyakov, A.V.; Smol’kin, V.F.; Belyatskii, V.B.; Fedotov, Z.A. Age of the Moncha Tundra fault, Kola Peninsula: Evidence from the Sm-Nd and Rb-Sr isotopic systematic of metamorphic assemplages. Geochem. Int. 2006, 44, 317–326. [Google Scholar] [CrossRef]
  35. Amelin, Y.V.; Heaman, L.M.; Semenov, V.S. U–Pb geochronology of layered mafic intrusions in the eastern Baltic Shield: Implications for the timing and duration of Paleoproterozoic continental rifting. Precambrian Res. 1995, 75, 31–46. [Google Scholar] [CrossRef]
  36. Bayanova, T.; Mitrofanov, F.; Serov, P.; Nerovich, L.; Yekimova, N.; Nitkina, E.; Kamensky, I. Layered PGE Paleoproterozoic (LIP) intrusions in the N-E part of the Fennoscandian Shield—Isotope Nd–Sr and 3He/4He data, summarizing U–Pb ages (on Baddeleyite and Zircon), Sm–Nd data (on Rock-Forming and Sulphide Minerals), duration and mineralization. In Geochronology—Methods and Case Studies; Morner, N.-A., Ed.; INTECH: London, UK, 2014; pp. 143–193. [Google Scholar]
  37. Hanski, E.; Walker, R.J.; Huhma, H.; Suominen, I. The Os and Nd isotopic systematics of c. 2.44 Ga Akanvaara and Koitelainen mafic layered intrusions in northern Finland. Precambrian Res. 2001, 109, 73–102. [Google Scholar] [CrossRef]
  38. Huhma, H.; Hanski, E.; Kontinen, A.; Vuollo, J.; Maänttaäri, I.; Lahaye, Y. Sm–Nd and U–Pb isotope geochemistry of the Palaeoproterozoic mafic magmatism in eastern and northern Finland. Geol. Surv. Finl. Bull. 2018, 405, 150. [Google Scholar]
  39. Huhma, H.; Clift, R.A.; Perttunen, V.; Sakko, M. Sm–Nd and Pb isotopic study of mafic rocks associated with early Proterozoic continental rifting: The Perapohja schist belt in northern Finland. Contrib. Mineral. Petrol. 1990, 104, 369–379. [Google Scholar] [CrossRef]
  40. Krivolutskaya, N.A.; Svirskaya, N.M.; Belyatsky, B.V.; Smolkin, V.F.; Mamontov, V.P.; Fanygin, A.S. Geochemical Specifics of Massifs of the Drusite Complex in the Central Belomorian Mobile Belt: II. Sm–Nd Isotopic System of the Rocks and the U–Pb Isotopic System of Zircons. Geochem. Int. 2010, 48, 1064–1083. [Google Scholar] [CrossRef]
  41. Maier, W.D.; Hanski, E.J. Layered mafic-ultramafic intrusions of Fennoscandia: Europe’s treasure chest of magmatic metal deposits. Elements 2017, 13, 415–420. [Google Scholar] [CrossRef] [Green Version]
  42. Mitrofanov, F.; Golubev, A. Russian Fennoscandian metallogeny. In Abstracts of the 33 IGC; Norwegian Academy of Science and Letters: Oslo, Norway, 2008. [Google Scholar]
  43. Schissel, D.; Tsvetkov, A.A.; Mitrofanov, F.P.; Korchagin, A.U. Basal platinum-group element mineralization in the fedorovpansky layered mafic intrusion, Kola Peninsula, Russia. Econ. Geol. 2002, 97, 1657–1677. [Google Scholar] [CrossRef]
  44. Serov, P.A. Frontiers of Age Forming PGE Mineralization Fedorovo-Pansky Layered Intrusions in Sm–Nd and Rb–Sr Isotopic Characteristics. Ph.D. Thesis, Voronezh State University, Voronezh, Russia, 2008. [Google Scholar]
  45. Serov, P. Comparison between Sm–Nd Rock-Forming Mineral and U–Pb Zircon and Baddeleyite Data of the Fedorovo-Pansky Pt-bearing Layered Intrusion; European Geosciences Union: Vienna, Austria, 2007; EGU2007-A-01156. [Google Scholar]
  46. Serov, P. New Sm–Nd isotope-geochemical data for the Fedorovo-Pansky PGE-bearing layered intrusion (N-E Fennoscandian Shield). In Geophysical Research Abstracts; European Geosciences Union: Vienna, Austria, 2012; EGU2010–8143. [Google Scholar]
  47. Serov, P.; Bayanova, T. Palaeoproterozoic Fedorovo-Pansky PGE-bearing layered intrusion of the N-E Baltic Shield: New isotope data. In 33 IGC; Norwegian Academy of Science and Letters: Oslo, Norway, 2008. [Google Scholar]
  48. Serov, P.; Ekimova, N.; Bayanova, T. Isotope-geochemical Nd–Sr evidence of Palaeoproterozoic plume magmatism in Fennoscandia and mantle-crust interaction on stages of layered intrusions formation. In Geophysical Research Abstracts; European Geosciences Union: Vienna, Austria, 2012; Volume 14, EGU2012–9113. [Google Scholar]
  49. Serov, P.A.; Ekimova, N.A.; Bayanova, T.B.; Mitrofanov, F.P. Sulfide minerals as new geochronometers during Sm–Nd dating of the ore genesis for layered mafic and ultramafic intrusions. Lithosphere 2014, 4, 11–21. [Google Scholar]
  50. Vogel, D.C.; Vuollo, J.I.; Alapieti, T.T.; James, R.S. Tectonic, stratigraphic and geochemical comparison between ca. 2500–2440 Ma mafic igneous events in the Canadian and Fennoscandian Shields. Precambrian Res. 1998, 92, 89–116. [Google Scholar] [CrossRef]
  51. Ernst, R.E. Large Igneous Provinces; Cambridge University Press: Cambridge, UK, 2014; p. 653. [Google Scholar]
  52. Heaman, L.M. 2.5–2.4 Ga global magmatism: Remnants or supercontinents or products of superplumes. Geol. Soc. Am. 2004, 36, 255. [Google Scholar]
  53. James, R.S.; Easton, R.M.; Peck, D.C.; Hrominchuk, J.L. The East Bull Lake intrusive suite: Remnants of a 2.48 Ga large igneous and metallogenic province in the Sudbury area of the Canadian Shield. Econ. Geol. 2002, 97, 1577–1606. [Google Scholar] [CrossRef]
  54. Ciborowski, T.J.R.; Kerr, A.C.; Ernst, R.E.; McDonald, I.; Minifie, M.J.; Harlan, S.S.; Millar, I.L. The early proterozoicMatachewan large Igneous Province: Geochemistry, petrogenesis, and implications for earth evolution. J. Petrol. 2015, 56, 1459–1494. [Google Scholar] [CrossRef] [Green Version]
  55. Iljina, M.J.; Lee, C.A. PGE deposits in the marginal series of layered intrusions. In Exploration for Platinum-Group Elements Deposits; Mineralogical Association of Canada: Québec City, QC, Canada, 2005; pp. 75–96. [Google Scholar]
  56. Söderlund, U.; Hofmann, A.; Klausen, M.B.; Olsson, J.R.; Ernst, R.E.; Persson, P.-O. Towards a complete magmatic barcode for the Zimbabwe craton: Baddeleyite U–Pb dating of regional dolerite dyke swarms and sill complexes. Precambrian Res. 2010, 183, 388–398. [Google Scholar] [CrossRef]
Minerals 10 00286 g001 550
Figure 1. Scheme of the geological structure of the Monchetundra massif and Monchepluton with a section along the A–B line after [13]. (1) Metadunite and metaharzburgite; (2) Paleoproterozoic Imandra-Varzuga rift structure: metabasalt, metaandesibasalt, metarhyolite, and metadacite, quartzite and a schist of varied composition; (3) microcline–plagioclase granite; (4) layered mafic intrusions of the Imandra complex; (5) Ostrovsky layered massif, from peridotite to gabbronorite; (6) Chunatundra intrusion complex of the Main Ridge: anorthosite, leucogabbro, gabbronorite, and leuconorite; (7) Monchetundra massif: leucogabbro and gabbronorite of upper zone (a), norite and orthopyroxenite of lower zone (b); (8) quartz metagabbro of massif 10 anomaly; (9) norite and metanorite of Lake Moroshkovoe massif; (10) gabbronorite and metanorite of Kirikha massif; (11) Monchepluton: Cu–Ni ore vein (a), Sopcha ore bed 330 (b), olivine norite and orthopyroxenite (c), metagabbro of Vurechuaivench foothill massif (d), gabbronorite (e), norite (f), orthopyroxenite (g), interbedding of orthopyroxenite and harzburgite (h), harzburgite (i), dunite (j); (12) diorite gneiss and quartz diorite gneiss; (13) Neoarchean Tersky-Allarechensky greenstone belt: amphibolite, biotite-amphibolite, and biotite plagioschist; (14) Paleo-Neoarchean metamorphic and ultrametamorphic units of Kola Block; (15) faults; (16) structural boreholes and their numbers.
Figure 1. Scheme of the geological structure of the Monchetundra massif and Monchepluton with a section along the A–B line after [13]. (1) Metadunite and metaharzburgite; (2) Paleoproterozoic Imandra-Varzuga rift structure: metabasalt, metaandesibasalt, metarhyolite, and metadacite, quartzite and a schist of varied composition; (3) microcline–plagioclase granite; (4) layered mafic intrusions of the Imandra complex; (5) Ostrovsky layered massif, from peridotite to gabbronorite; (6) Chunatundra intrusion complex of the Main Ridge: anorthosite, leucogabbro, gabbronorite, and leuconorite; (7) Monchetundra massif: leucogabbro and gabbronorite of upper zone (a), norite and orthopyroxenite of lower zone (b); (8) quartz metagabbro of massif 10 anomaly; (9) norite and metanorite of Lake Moroshkovoe massif; (10) gabbronorite and metanorite of Kirikha massif; (11) Monchepluton: Cu–Ni ore vein (a), Sopcha ore bed 330 (b), olivine norite and orthopyroxenite (c), metagabbro of Vurechuaivench foothill massif (d), gabbronorite (e), norite (f), orthopyroxenite (g), interbedding of orthopyroxenite and harzburgite (h), harzburgite (i), dunite (j); (12) diorite gneiss and quartz diorite gneiss; (13) Neoarchean Tersky-Allarechensky greenstone belt: amphibolite, biotite-amphibolite, and biotite plagioschist; (14) Paleo-Neoarchean metamorphic and ultrametamorphic units of Kola Block; (15) faults; (16) structural boreholes and their numbers.
Minerals 10 00286 g001
Minerals 10 00286 g002 550
Figure 2. Schematic section of borehole МТ-70 modified after [20] and pictures of thin sections of typical rocks from the Loypishnun area. Pl—plagioclase; Amp—amphibole; Opx—orthopyroxene; Cpx—clinopyroxene; Ol—olivine; Srp—serpentine; Chr—chromite; Mag—magnetite; Grt—garnet; Bt—biotite.
Figure 2. Schematic section of borehole МТ-70 modified after [20] and pictures of thin sections of typical rocks from the Loypishnun area. Pl—plagioclase; Amp—amphibole; Opx—orthopyroxene; Cpx—clinopyroxene; Ol—olivine; Srp—serpentine; Chr—chromite; Mag—magnetite; Grt—garnet; Bt—biotite.
Minerals 10 00286 g002
Minerals 10 00286 g003 550
Figure 3. SiO2 vs. (Na2O + K2O) plot (wt.%) after [21] for Loypishnun area rocks. 1—norites; 2—dunites; 3—pyroxenites; 4—harzburgite; 5—Amp-gabbronorite; 6—gabbro-pegmatite. Ore-bearing rocks are marked in bold. Fields of rocks according to [21].
Figure 3. SiO2 vs. (Na2O + K2O) plot (wt.%) after [21] for Loypishnun area rocks. 1—norites; 2—dunites; 3—pyroxenites; 4—harzburgite; 5—Amp-gabbronorite; 6—gabbro-pegmatite. Ore-bearing rocks are marked in bold. Fields of rocks according to [21].
Minerals 10 00286 g003
Minerals 10 00286 g004 550
Figure 4. MgO vs. major oxides plot (a–g) (wt.%) for the Loypishnun area rocks. 1—norites; 2—dunites; 3—pyroxenites; 4—harzburgite; 5—mp-gabbronorite; 6—gabbro-pegmatite; ore-bearing rocks are marked in bold.
Figure 4. MgO vs. major oxides plot (a–g) (wt.%) for the Loypishnun area rocks. 1—norites; 2—dunites; 3—pyroxenites; 4—harzburgite; 5—mp-gabbronorite; 6—gabbro-pegmatite; ore-bearing rocks are marked in bold.
Minerals 10 00286 g004
Minerals 10 00286 g005 550
Figure 5. Primitive mantle (PM)-normalized [22] trace elements and chondrite-normalized [23] REE distribution plots (a–g) for the Loypishnun area rocks. Data on average normal mid-ocean ridge basalt (N-MORB), enriched mid-ocean ridge basalt (E-MORB), oceanic island basalt (OIB), and depleted mantle (DM) shown by black lines are after [22]. Dotted lines indicate the spectra of ore-bearing rocks (PGE > 0.5 ppm).
Figure 5. Primitive mantle (PM)-normalized [22] trace elements and chondrite-normalized [23] REE distribution plots (a–g) for the Loypishnun area rocks. Data on average normal mid-ocean ridge basalt (N-MORB), enriched mid-ocean ridge basalt (E-MORB), oceanic island basalt (OIB), and depleted mantle (DM) shown by black lines are after [22]. Dotted lines indicate the spectra of ore-bearing rocks (PGE > 0.5 ppm).
Minerals 10 00286 g005
Minerals 10 00286 g006 550
Figure 6. The initial isotope Nd-Sr composition for Loypishnun area rocks. 1—norites; 2—pyroxenites; 3—amp-gabbronorite; 4—gabbro-pegmatite. Ore-host rocks are marked in bold.
Figure 6. The initial isotope Nd-Sr composition for Loypishnun area rocks. 1—norites; 2—pyroxenites; 3—amp-gabbronorite; 4—gabbro-pegmatite. Ore-host rocks are marked in bold.
Minerals 10 00286 g006
Minerals 10 00286 g007 550
Figure 7. Summarized data on petrographic, PGE, REE, and Nd-Sr for MT-70 borehole rocks. Fields indicate ore-bearing rocks with a total PGE content of >0.5 ppm.
Figure 7. Summarized data on petrographic, PGE, REE, and Nd-Sr for MT-70 borehole rocks. Fields indicate ore-bearing rocks with a total PGE content of >0.5 ppm.
Minerals 10 00286 g007
Minerals 10 00286 g008 550
Figure 8. Plot Th/Yb vs. Nb/Yb (a) [24] and (b) La/Sm vs. Nb/Th (–) for MT-70 borehole rocks. 1—norites; 2—dunites; 3—pyroxenites; 4—harzburgite; 5—Amp-gabbronorite; 6—gabbro-pegmatite. Continental crust composition according to [25]. Ore-bearing rocks are marked in bold.
Figure 8. Plot Th/Yb vs. Nb/Yb (a) [24] and (b) La/Sm vs. Nb/Th (–) for MT-70 borehole rocks. 1—norites; 2—dunites; 3—pyroxenites; 4—harzburgite; 5—Amp-gabbronorite; 6—gabbro-pegmatite. Continental crust composition according to [25]. Ore-bearing rocks are marked in bold.
Minerals 10 00286 g008
Minerals 10 00286 g009 550
Figure 9. εNd-T plot for Loypishnyn deposit rocks. 1—norites; 2—dunites; 3—pyroxenites; 4—amp-gabbronorite; 5—gabbro-pegmatite; grey field—Central-Kola Block rocks [26,27,28]. Ore-bearing rocks are marked in bold.
Figure 9. εNd-T plot for Loypishnyn deposit rocks. 1—norites; 2—dunites; 3—pyroxenites; 4—amp-gabbronorite; 5—gabbro-pegmatite; grey field—Central-Kola Block rocks [26,27,28]. Ore-bearing rocks are marked in bold.
Minerals 10 00286 g009
Minerals 10 00286 g010 550
Figure 10. The εNd vs. ISr plot for the Monchetundra rocks. Monchetundra massif upper zone, after [4,5,8,29]; Monchepluton massif rocks, after [4,29]; Fedorovo-Pansky massif after [29]; Mt. Generalskaya after [30]; Kivakka after [31,32], Burakovskiy, Lukkulaisvaara after [31]; Finland layered intrusions after [29,33] Field of Central-Kola Block rocks, after [26,27]; Central Kola gneisses, after [28]. Ore-bearing rocks are marked in bold.
Figure 10. The εNd vs. ISr plot for the Monchetundra rocks. Monchetundra massif upper zone, after [4,5,8,29]; Monchepluton massif rocks, after [4,29]; Fedorovo-Pansky massif after [29]; Mt. Generalskaya after [30]; Kivakka after [31,32], Burakovskiy, Lukkulaisvaara after [31]; Finland layered intrusions after [29,33] Field of Central-Kola Block rocks, after [26,27]; Central Kola gneisses, after [28]. Ore-bearing rocks are marked in bold.
Minerals 10 00286 g010
Table
Table 1. The platinum group elements (PGE) content in Loypishnun area rocks, according to the MT-70 borehole section.
Table 1. The platinum group elements (PGE) content in Loypishnun area rocks, according to the MT-70 borehole section.
SamplePetrographyRu, ppmRh, ppmPd, ppmIr, ppmPt, ppmTotalPd/Pt
70/9AGN<l.d.<l.d.0.049<l.d.0.0250.071.96
70/21AGN<l.d.0.0060.150<l.d.0.0100.1715.00
70/40AGN<l.d.<l.d.0.036<l.d.0.0040.049.23
70/62AGN<l.d.0.0030.150<l.d.0.0080.1620.00
70/81AGN<l.d.0.0040.190<l.d.0.0180.2110.56
70/93AGN<l.d.<l.d.0.070<l.d.0.0020.0729.17
70/104N<l.d.<l.d.0.054<l.d.0.0340.091.59
70/127PX<l.d.<l.d.0.039<l.d.0.0180.062.17
70/127.6N<l.d.<l.d.0.031<l.d.0.0140.052.21
70/129DN0.011<l.d.0.0100.0040.0060.031.75
70/137DN0.013<l.d.0.0040.0040.0030.021.39
70/151N<l.d.0.0050.1900.0020.1000.301.90
70/157AGN<l.d.0.0020.130<l.d.0.0040.1435.14
70/165PX<l.d.<l.d.0.056<l.d.0.0370.091.51
70/170N<l.d.0.0030.110<l.d.0.0440.162.50
70/172PX<l.d.0.0030.053<l.d.0.0240.082.21
70/177N0.0050.0421.3500.0080.4001.803.38
70/189PX0.0050.0290.9700.0070.6001.611.62
70/194PX0.0030.0210.5900.0050.1700.793.47
70/196N<l.d.0.0040.160<l.d.0.0330.204.85
70/200HB0.0060.0050.1000.0020.0470.162.13
70/204PX0.0120.0050.0860.0050.0550.161.56
70/214N<l.d.0.0060.180<l.d.0.0480.233.75
70/219DN0.008<l.d.0.007<l.d.0.0080.020.86
70/225PX0.0030.0160.5700.0040.3000.891.90
70/245N0.0050.0280.8000.0070.4701.311.70
70/259N0.0030.0250.7900.0050.4301.251.84
70/264GP<l.d.0.0270.5200.0040.2900.841.79
70/275GP0.0030.0480.3900.0030.1700.612.29
70/281N<l.d.0.6600.1600.0080.0790.912.03
70/303N<l.d.<l.d.0.094<l.d.0.0150.116.27
70/319N0.0030.0050.3700.0020.2300.611.61
70/324DN0.0080.0050.0340.0030.0100.063.58
Detection limits (l.d.) for all elements are 0.002 ppm. AGN—Amp-gabbronorites; N—norites; DN—dunites; PX—pyroxenites; HB—harzburgite; and GP—gabbro-pegmatites.
Table
Table 2. The isotope Nd-Sr composition of Loypishnun area rocks.
Table 2. The isotope Nd-Sr composition of Loypishnun area rocks.
SamplePetrographyRb, ppmSr, ppm87Rb/86Sr87Sr/86Sr±2σ abs.ISr(2500)Sm, ppmNd, ppm147Sm/144Nd143Nd/144Nd±2σ abs.εNd(2500)
70/21Amp-Gabbronorite1.08251.910.01210.702970.000190.702530.481.660.17310.5123340.0000171.60
70/104Norite0.6533.870.05410.706290.000220.70433------
70/151Norite6.98132.610.14860.709070.000160.703701.727.860.13190.5114640.000004-2.16
70/157Amp-Gabbronorite9.29264.000.09930.708530.000150.70494------
70/177Ore-Norite24.72187.740.37150.717690.000180.704260.813.580.13610.5113510.000011−5.72
70/189Ore-Pyroxenite5.4549.220.31230.716270.000280.704980.271.100.14890.5119870.0000162.61
70/214Norite4.5177.120.16500.707450.000140.701490.271.020.16160.5118530.000019−4.13
70/225Ore-Pyroxenite5.82142.040.11570.707910.000160.703730.311.350.13780.5117160.0000290.88
70/259Ore-Norite9.09156.300.16410.709900.000210.703970.993.650.16460.5117970.000010−6.20
70/275Gabbro-pegmatite63.94407.300.44290.719080.000150.703401.909.060.12710.5109010.000080−11.64
70/325Dunite0.463.250.40560.706980.00022-0.060.220.15340.5119700.0000500.81

Share and Cite

MDPI and ACS Style

Kunakkuzin, E.; Borisenko, E.; Nerovich, L.; Serov, P.; Bayanova, T.; Elizarov, D. The Origin and Evolution of Ore-Bearing Rocks in the Loypishnun Deposit (Monchetundra Massif, NE Fennoscandian Shield): Isotope Nd-Sr and REE Geochemical Data. Minerals 2020, 10, 286. https://doi.org/10.3390/min10030286

AMA Style

Kunakkuzin E, Borisenko E, Nerovich L, Serov P, Bayanova T, Elizarov D. The Origin and Evolution of Ore-Bearing Rocks in the Loypishnun Deposit (Monchetundra Massif, NE Fennoscandian Shield): Isotope Nd-Sr and REE Geochemical Data. Minerals. 2020; 10(3):286. https://doi.org/10.3390/min10030286

Chicago/Turabian Style

Kunakkuzin, Evgeniy, Elena Borisenko, Luydmila Nerovich, Pavel Serov, Tamara Bayanova, and Dmitry Elizarov. 2020. "The Origin and Evolution of Ore-Bearing Rocks in the Loypishnun Deposit (Monchetundra Massif, NE Fennoscandian Shield): Isotope Nd-Sr and REE Geochemical Data" Minerals 10, no. 3: 286. https://doi.org/10.3390/min10030286

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop