排序方式： 共有16条查询结果，搜索用时 62 毫秒
1.
V. M. Kotlyakov L. P. Chernova T. Ye. Khromova N. M. Zverkova 《Doklady Earth Sciences》2017,472(1):57-61
Based on complex analysis of the latest data, new conclusions have been reached about the features and causes of glacial disasters. 相似文献
2.
3.
4.
E. V. Sklyarov D. P. Gladkochub A. B. Kotov A. E. Starikova V. V. Sharygin S. D. Velikoslavinsky A. M. Larin A. M. Mazukabzov E. V. Tolmacheva E. A. Khromova 《Russian Journal of Pacific Geology》2016,10(3):155-167
Arguments in favor of magmatic or metasomatic genesis of the Katugin rare-metal ore deposit are discussed. The geological and mineralogical features of the deposit confirm its magmatic origin: (1) the shape of the ore-bearing massif and location of various types of granites (biotite, biotite–amphibole, amphibole, and amphibole–aegirine); (2) the geochemical properties of the massif rocks corresponding to A type granite (high alkali content (up to 12.3% Na2O + K2O), extremely high FeO/MgO ratio (f = 0.96–1.00), very high content of the most incoherent elements (Rb, Li, Y, Zr, Hf, Ta, Nb, Th, U, Zn, Ga, and REE) and F, and low concentrations of Ca, Mg, Al, P, Ba, and Sr); (3) Fe–F-rich rock-forming minerals; (4) no previously proposed metasomatic zoning and regular replacement of rock-forming minerals corresponding to infiltration fronts of metasomatism. The similar ages of the barren (2066 ± 6 Ma) and ore-bearing (2055 ± 7 Ma) granites along with the features of the ore mineralization speak in favor of the origin of the ore at the magmatic stage of the massif’s evolution. The nature of the ore occurrence and the relationships between the ore minerals support their crystallization from F-rich aluminosilicate melt and also under melt liquation into aluminosilicate and fluoride (and/or aluminofluoride) fractions. 相似文献
5.
6.
V. B. Savel’eva E. P. Bazarova E. A. Khromova S. V. Kanakin 《Geology of Ore Deposits》2017,59(7):561-574
The paper discusses the chemical composition and parageneses of fluorides and fluorcarbonates in rocks of the Katugin Complex, with which a unique deposit of REE–Nb–Ta ore with cryolite is associated. In mineralogy and chemical composition, the rocks correspond to biotite, biotite–amphibole, arfvedsonite, and aegirine–arfvedsonite granites, which were regarded in earlier publications as granite-like metasomatic rocks. Aegirine–arfvedsonite granite contains a cryolite–gagarinite assemblage, which reflects depletion of Ca in the mineral-forming medium and enrichment in Na and F. Arfvedsonite granite is characterized by intergrowth of yttrofluorite with fluocerite and gagarinite, which indicates a relative enrichment in Ca and low CO2 content. Biotite granite is characterized by an assemblage of fluorite with titanite, apatite, and monazite as evidence for an elevated Ca concentration along with moderate F and P contents in the system. Neighborite, coulsellite, gagarinite, fluocerite, and tveitite-(Y) appear in biotite–amphibole granite along with replacement of annite with riebeckite and development of albite after microcline. All this indicates that a moderately alkaline Na-fluoride solution with a low Ca concentration affects biotite granite. 相似文献
7.
Kotlyakov V. M. Chernova L. P. Muraviev A. Y. Khromova T. Y. 《Doklady Earth Sciences》2019,489(1):1376-1382
Doklady Earth Sciences - The results of measurements of the area of surging glaciers in 1974 and 2018 are compared to the data on their areas in 1913. A large decadal (middle-term) variability in... 相似文献
8.
9.
Savelyeva V. B. Bazarova E. P. Khromova E. A. Kanakin S. V. 《Geology of Ore Deposits》2018,60(8):643-657
The chemical composition and origin of major REE minerals of aegirine, aegirine–arfvedsonite, arfvedsonite, and annite–riebeckite–arfvedsonite granites are studied for the Katugin Ta–Nb–Zr–Y deposit with cryolite in the southwestern part of the Aldan Shield. The REE mineralization of granites includes two types: (i) disseminated grains of pyrochlore and, to a lesser extent, other Nb–Ln oxides, Ln phosphates, and Ln–F carbonates in association with zircon, ilmenite, sphalerite, and other minerals and (ii) interstitial intergrowths of Ln fluorides.
相似文献10.
I. S. Peretyazhko E. A. Savina E. A. Khromova N. S. Karmanov A. V. Ivanov 《Petrology》2018,26(2):181-211
The paper presents mineralogical and geochemical data on clinkers and paralavas and on conditions under which they were formed at the Nyalga combustion metamorphic complex, which was recently discovered in Central Mongolia. Mineral and phase assemblages of the CM rocks do not have analogues in the world. The clinkers contain pyrogenically modified mudstone relics, acid silicate glass, partly molten quartz and feldspar grains, and newly formed indialite microlites (phenocrysts) with a ferroindialite marginal zone. In the paralava melts, spinel microlites with broadly varying Fe concentrations and anorthite–bytownite were the first to crystallize, and were followed by phenocrysts of Al-clinopyroxene ± melilite and Mg–Fe olivine. The next minerals to crystallize were Ca-fayalite, kirschsteinite, pyrrhotite, minerals of the rhönite–kuratite series, K–Ba feldspars (celsian, hyalophane, and Ba-orthoclase, Fe3+-hercynite ± (native iron, wüstite, Al-magnetite, and fresnoite), nepheline ± (kalsilite), and later calcite, siderite, barite, celestine, and gypsum. The paralavas contain rare minerals of the rhönite–kuratite series, a new end-member of the rhönite subgroup Ca4Fe 8 2+ Fe 4 3+ O4 [Si8Al4O36], a tobermorite-like mineral Ca5Si5(Al,Fe)(OH)O16 · 5H2O, and high- Ba F-rich mica (K,Ba)(Mg,Fe)3(Al,Si)4O10F2. The paralavas host quenched relics of microemulsions of immiscible residual silicate melts with broadly varying Si, Al, Fe, Ca, K, Ba, and Sr concentrations, sulfide and calcitic melts, and water-rich silicate–iron ± (Mn) fluid media. The clinkers were formed less than 2 Ma ago in various parts of the Choir–Nyalga basin by melting Early Cretaceous mudstones with bulk composition varies from dacitic to andesitic. The pyrogenic transformations of the mudstones were nearly isochemical, except only for volatile components. The CM melt rocks of basaltic andesitic composition were formed via melting carbonate–silicate sediments at temperatures above 1450°C. The Ca- and Fe-enriched and silicaundersaturated paralavas crystallized near the surface at temperatures higher than 900–1100°C and oxygen fugacity \(f_{O_2 }\) between the IW and QFM buffers. In local melting domains of the carbonate–silicate sedimentary rocks and in isolations of the residual melts among the paralava matrix the fluid pressure was higher than the atmospheric one. The bulk composition, mineral and phase assemblages of CM rocks of the Nyalga complex are very diverse (dacitic, andesitic, basaltic andesitic, basaltic, and silica-undersaturated mafic) because the melts crystallized under unequilibrated conditions and were derived by the complete or partial melting of clayey and carbonate–silicate sediments during natural coal fires. 相似文献