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21.
Krivovichev S. V. Yakovenchuk V. N. Panikorovskii T. L. Savchenko E. E. Pakhomovsky Ya. A. Mikhailova Yu. A. Selivanova E. A. Kadyrova G. I. Ivanyuk G. Yu. 《Doklady Earth Sciences》2019,488(2):1200-1202
Doklady Earth Sciences - Nikmelnikovite, Ca12Fe2+Fe$$_{3}^{{3 + }}$$Al3(SiO4)6(OH)20, a new mineral from the Kovdor massif (Kola Peninsula, Russia), is described. It is the first trigonal... 相似文献
22.
G. Yu. Ivanyuk Ya. A. Pakhomovsky N. G. Konopleva V. N. Yakovenchuk Yu. P. Men’shikov Yu. A. Mikhailova 《Geology of Ore Deposits》2007,49(7):599-606
Seven spinel-group minerals in various geological settings have been revealed in the rocks of the Khibiny pluton. Hercynite, gahnite, and vuorelainenite occur only in xenoliths of hornfels after volcanic and sedimentary rocks, whereas spinel and magnesiochromite occur in alkaline ultramafic rocks of dike series. Franklinite has been discovered in a low-temperature hydrothermal vein. Ubiquitous magnetite is abundant in foyaite, foidolites, alkaline ultrabasic rocks, and pegmatite and hydrothermal veins and may even be the main mineral in some foidolite varieties. The spinel-group minerals are characterized by various chemical compositions due to the fractionation of nepheline syenites resulting in formation of the Main ring of foidolites and apatite-nepheline ore. Like most other minerals found throughout the pluton, magnetite is characterized by variation in the chemical composition along the radial line from the contact with country Proterozoic volcanic rocks to the geometric center of the pluton. Toward the center, the total Ti and Mn contents in magnetite increase from 5–15 up to 40 at %. 相似文献
23.
V. N. Yakovenchuk G. Yu. Ivanyuk Ya. A. Pakhomovsky Yu. P. Men’shikov N. G. Konopleva Yu. A. Korchak 《Geology of Ore Deposits》2008,50(8):732-745
Seven pyroxene varieties were identified in nepheline syenites and foidolites of the Khibiny pluton: enstatite, ferrosilite, diopside, hedenbergite, augite, aegirine-augite, and aegirine. Enstatite and augite are typical of alkaline and ultramafic rocks of dike series. Ferrosilite was found in country quartzitic hornfels. Diopside is a rock-forming mineral in alkaline and ultramafic rocks, alkali gabbroids, hornfels in xenoliths of volcanic and sedimentary rocks and foyaite, melteigite-urtite that assimilate them, and certain hydrothermal pegmatite veins. Hedenbergite was noted in hornfels from xenoliths of volcanic and sedimentary rocks and in a hydrothermal pegmatite vein at Mount Eveslogchorr. Aegirine-augite is the predominant pyroxene in all types of nepheline syenites, phonolites and tinguaites, foidolites, alkaline and ultramafic rocks of dike series, fenitized wall rocks surrounding the pluton, and xenoliths of Devonian volcanic and sedimentary rocks. Aegirine is an abundant primary or, more often, secondary mineral in nepheline syenites, foidolites, and hydrothermal pegmatite veins. It occurs as separate crystals, outer zones of diopside and aegirine-augite crystals, and homoaxial pseudomorphs after Na-Ca amphiboles. Microprobe analyses of 265 pyroxenes samples allowed us to distinguish ten principal trends of isomorphic replacement and corresponding typomorphic features of pyroxenes. Compositional variations in clinopyroxenes along the sampled 35-km profile from the margin of the Khibiny pluton to its center confirm the symmetric zoning of the foyaite pluton relative to semicircular faults of the Minor Arc and the Main (Central) Ring marked by Devonian volcanic and sedimentary rocks, foidolites, and related metasomatic rocks (rischorrite, albitite, and aegirinite). Changes in the composition of pyroxenes are explained mainly by the redistribution of elements between coexisting minerals of foyaites in the process of their intense differentiation under the effect of foidolite melts that have intruded into the circular fault zones. 相似文献
24.
A. V. Bazai G. Yu. Ivanyuk Ya. A. Pakhomovsky P. M. Goryainov V. N. Yakovenchuk 《Geology of Ore Deposits》2009,51(7):525-536
Eleven native minerals and intermetallic alloys were identified in rocks of the banded iron formation (BIF) in the Kola Peninsula:
copper, silver, gold, electrum, auricupride, cuproauride, tetraauricupride, bismuth, sulfur, tellurium, and graphite. Graphite
is a common mineral of sulfide-bearing BIF and gneiss. Sulfur occurs in supergene-altered sulfide-bearing BIFs together with
Fe- and Ca-sulfates. Gold of low fineness (electrum) in association with electrum, acanthite, auricupride, volynskite, hessite,
cervelleite, pavonite, petzite, and bismuth is related to the areas of hydrothermally altered skarnoids with greenalite, chamosite,
aegirine, and Na-Ca amphibole. Redeposited gold of high fineness associated with auricupride, hessite, silver, electrum, kostovite,
cuproauride, tetraauricupride, and sperrylite occurs in low-temperature zonal hydrothermal segregations hosted in aluminous
gneiss and which formed under the effect of alkalized, highly siliceous solutions at the regressive stage of BIF metamorphism. 相似文献