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1.
Badanina I. Yu. Belousova E. A. Malitch K. N. Sluzhenikin S. F. 《Doklady Earth Sciences》2019,489(1):1322-1325
Doklady Earth Sciences - This study presents the first results of oxygen isotope analyses (δ18O) collected on zircons from the Talnakh economic intrusion within the Noril’sk province.... 相似文献
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Malitch K. N. Lokhov D. K. Proskurnin V. F. Puchkov V. N. Badanina I. Yu. Chervyakovskaya M. A. 《Doklady Earth Sciences》2020,492(1):346-350
Doklady Earth Sciences - This study utilized SHRIMP, LA MC–ICP–MS and ID-TIMS analytical techniques and presents for the first time U–Pb age, Lu-Hf-isotope features of zircon and... 相似文献
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Economic copper, nickel, and platinum-group element (PGE) deposits are associated with the Talnakh ultramafic–mafic intrusion of the Noril’sk Province in the northwestern part of the Siberian Platform. The results of the chemical Th–U–Pb dating of monazite from the ore-bearing melanotroctolites of the Talnakh intrusion are presented. The isotope-geochemical features of monazite are compared with zircon, sulfides, and baddeleyite. 相似文献
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This study presents compositional features of platinum-group element mineralization derived from the Late Archaean placers in the eastern part of the Witwatersrand basin. The significant presence of platinum-group minerals, formed by polycomponent solid-solution series in the system Ru–Os–Ir–Pt(±Fe), was determined using an electron microprobe analysis. Compositional data indicate that the source for polycomponent solid solutions of the Ru–Os–Ir–Pt–Fe system was the Archaean mantle of the Earth, slightly differentiated with respect to platinum-group elements. 相似文献
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This contribution firstly presents particularities of mineral chemistry of platinum-group elements (PGE) mineralization from
placer deposits linked to the Bor-Uryakh massif of the Maimecha-Kotui Province, northern part of the Siberian Craton. The
chemical composition of PGE mineralization has been studied by electron microprobe analysis. At Bor-Uryakh, main platinum-group
minerals (PGM) comprise Os-Ir and Pt-Fe alloys represented by individual crystals, and polyphase PGM assemblages. The majority
(e.g., 12 out of 19) of the Os-rich nuggets are iridian osmium, with subordinate amounts of native osmium (Os) and chengdeite
(Ir3Fe). Pt-Fe alloys have a stoichiometric composition close to Pt2Fe. According to the nomen-clature by L. Cabri and C. Feather [1975] these minerals correspond to ferroan platinum. Based
on geological position and geochemical features of investigated PGE mineralization the particular rock sources have been established.
This study has demonstrated the similarity of chemical characteristics of Os-Ir and Pt-Fe alloys of the Bor-Uryakh massif
to those of PGM from the Guli massif (Maimecha-Kotui Province), platiniferous zoned-type ultramafic massifs (e.g., Kondyor,
Inagli and Chad) of the Aldan Province and Platinum belt of the Urals (Nizhny Tagil, Kytlym, etc.). 相似文献
7.
U–Pb Age and Hf–Nd–Sr Isotopic Systematics of Vein Rocks of the Volkovsky Massif,Middle Urals,Russia
E. V. Anikina K. N. Malitch E. A. Belousova I. Yu. Badanina N. G. Soloshenko I. A. Rusin A. V. Alekseev 《Geochemistry International》2018,56(3):199-210
This paper reports chemical, geochronological, and Hf–Nd–Sr isotopic-geochemical data on granite, leucogabbro, and microgabbro porphyrite vein bodies in the gabbro of the Volkovsky massif. It was proved that the vein granite and leucogabbro are genetically related to the leucogabbro–anorthosite–plagiogranite (anorthosite–granite) series of the Urals Platinum Belt. The granite was dated by U-Pb laser ablation inductively coupled plasma mass spectrometric method at 409.0 ± 2.3 Ma. The rock has 87Sr/86Sr(409 Ма) = 0.70358, high εNd(409 Ма) = 6.4–6.5, and εHf(409 Ма) ≥ 10.8. Similar values of 87Sr/86Sr(409 Ма) = 0.70370 and εNd(409 Ма) = 5.9 were obtained for the vein leucogabbro. The isotopic-geochemical data are consistent with existing concept of the formation of the leucogabbro–anorthosite–plagiogranite (anorthosite–granite) series through partial melting of the olivine gabbro. The measured 143Nd/144Nd = 0.512939 value obtained for the microgabbro porphyrite reflects their more radiogenic composition and likely a mantle source. The granite, associated leucogabbro, and microgabbro porphyrite were emplaced at the final magmatic stage in the massif evolution. This event marks the upper age boundary of the Au–Pd mineralization related to the gabbroic rocks. The vein rocks lack any signs of the mineralization. However, it is highly probable that they were sources of energy and fluid for reworking of the earlier olivine gabbro and redeposition of ore components in this rock. 相似文献
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The chemical compositions of magnetite-orthopyroxene symplectites (MOS) and rock-forming minerals—olivine (Ol), clinopyroxene (Cpx), and magnetite(Mt)—have been studied in 20 samples of olivine-bearing rocks in the Urals, including troctolite, olivine gabbro, and gabbronorite. MOS are orthopyroxene (Opx) monocrystals up to 500 μm in size containing myrmekite-like magnetite intergrowths up to 20–30 μm in width. According to the microprobe examination, the dark-colored minerals are characterized by a high Fe mole fraction F = Fe/(Fe + Mg) = 0.20–0.50, whereas F = 0.33–0.65 is typical of the bulk rock compositions. The plagioclase varies in composition from An90 to An50. No significant compositional difference has been established between the MOS and rock-forming minerals. The F opx and F Ol are closely correlated (linear trend, r = 0.97); F Ol/F Opx is ～1.2. Similarly, a positive correlation between F Opx and F Cpx is noted (linear trend, r = 0.90); F Opx/F Cpx is ～1.2. The crystallization temperature of the Ol-Opx-Cpx assemblage is roughly estimated at 700–800°C. A high positive correlation (r = 0.95) is established between the TiO2 contents in the magnetites from the MOS (Mt1) and host rock (Mt2). The Mt1/Mt2 ratio reaches ～0.8, implying that Mt1 contains somewhat less TiO2 than Mt2. Hence, the rock-forming and MOS minerals make up an equilibrium assemblage. As follows from the structural pattern, symplectites were formed as products of the reaction between olivine and oxygen in the solid state with the entire volume of the rock involved in the oxidation; i.e., the distance of the diffusion was significant. Free oxygen appeared as a product of the dissociation of the water penetrating into the hot gabbro and ultramafic rocks at the initial stage of the tectonic extension and high-temperature hydration. According to the redox state of dunite coexisting with gabbro, the oxygen fugacity is estimated at +2.7 log units of fO2 relative to the QFM buffer. The structure and products of the olivine oxidation were eventually obliterated in the course of the hydration. 相似文献
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S. Yu. Stepanov K. N. Malitch A. V. Kozlov I. Yu Badanina A. V. Antonov 《Geology of Ore Deposits》2017,59(3):244-255
The new data for the geology and mineralogy of the platinum group element (PGE) mineralization related to the chromite–platinum ore zones within the dunite of the Svetly Bor and Veresovy Bor massifs in the Middle Urals are discussed. The geological setting of the chromite–platinum ore zones, their platinum content, compositional and morphological features of the platinum group minerals (PGM) are compared to those within the Nizhny Tagil massif, the world standard of the zonal complexes in the Platinum Ural belt. The chromite–platinum orebodies are spatially related to the contacts between differently granular dunites. Majority of PGM are formed by Pt–Fe alloys that are close in terms of stoichiometry to isoferroplatinum (Pt3Fe), and associated with Os–Ir alloys, Ru–Os and Ir–Rh sulfides, and Ir–Rh thiospinels of the cuproiridsite–cuprorhodsite–ferrorhodsite solid solution. The tetraferroplatinum (PtFe)–tulameenite (PtFe0.5Cu0.5) solid solution and Pt–Cu alloys belong to the later PGM assemblage. The established features of the chromite–platinum ore zones testify to the highly probable identification of the PGE mineralization within the dunite of the Svetly Bor and Vesesovy Bor massifs and could be used in prospecting and exploration for platinum. 相似文献
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Doklady Earth Sciences - Material identity of dunite from zoned-type massifs of the Aldan shield (Kondyor, Chad and others) and dunite “cores” from the Uralian Platinum Belt (i.e., UPB)... 相似文献