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Olga L. Galankina
Olga L. Galankina
Senior Research Scientist, Ph.D.
Institute of Precambrian Geology and Geochronology Russian Academy of Sciences
Senior Research Scientist, Ph.D.
Institute of Precambrian Geology and Geochronology Russian Academy of Sciences
Saint Petersburg
Russia

Articles

Geology
  • Date submitted
    2023-11-08
  • Date accepted
    2024-05-02
  • Online publication date
    2024-07-26
  • Date published
    2024-07-26

Trace element composition of silicate minerals from Kunashak Meteorite (L6)

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Major (EPMA) and trace (SIMS) element geochemistry in the silicate minerals (olivine, pyroxene and plagioclase) of Kunashak equilibrated ordinary chondrite (L6) is described. No variations in the major element concentrations of the silicate minerals have been found, which is characteristic of equilibrated chondrites of petrological type VI. Low-Са pyroxene and plagioclase from the radiated olivine-pyroxene chondrule of Kunashak Meteorite contain an abundance of trace elements (Yb, Cr, Nb and Ti – pyroxene; Sr, Y, Ti and Zr – plagioclase), which is not characteristic of minerals from the porphyritic olivine and olivine-pyroxene chondrules of the meteorite. The porphyritic olivine-pyroxene chondrule of the Kunashak Meteorite has high trace element concentrations in olivine, in particular, the highest Yb concentration (0.12 ppm on the average) relative to porphyritic and radiated olivine-pyroxene chondrules (0.02 ppm). High trace element concentrations indicate rapid crystallization of a radiated chondrule in a nebula and show no traces of trace element homogenization upon thermal metamorphism. The trace element composition of silicate minerals from Kunashak Meteorite has retained the individual melting pattern of the chondrules and remained unaffected by thermal metamorphism on the parent bodies of the chondrules. Similar results, obtained in the study of Bushkhov Meteorite (L6), indicate that trace elements in olivine and low-Са pyroxene are resistant to thermal metamorphism. The persistence of the individual pattern of the chondrules enables us to use equilibrated ordinary chondrites for the study of processes at early stages in the formation of the Solar System and to better understand chondrule and planet formation mechanisms.

How to cite: Sukhanova K.G., Galankina O.L. Trace element composition of silicate minerals from Kunashak Meteorite (L6) // Journal of Mining Institute. 2024. p. EDN PYFBEB
Geology
  • Date submitted
    2022-05-02
  • Date accepted
    2022-05-25
  • Date published
    2022-07-13

Features of olivine crystallization in ordinary chondrites (Saratov meteorite): geochemistry of trace and rare earth elements

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The paper discusses the geochemistry of major (EPMA) and trace (SIMS) elements in olivine of porphyritic, nonporphyritic chondrules, and the matrix of equilibrated ordinary chondrite Saratov (L4). Olivine corresponds to forsterite and is rather heterogeneous (Fo 73-77). No differences in the content of the major elements in the olivine of the chondrule and the matrix of the meteorite were found. However, the content of major and trace elements in olivine within chondrules varies considerably; high values found in olivine from barred chondrules. Olivine from porphyritic chondrules and the matrix of the Saratov meteorite have similar concentrations of trace elements. High concentrations of refractory (Zr, Y, Al) and moderately volatile (Sr and Ba) trace elements in barred olivine chondrule indicate the chondrule melt formation due to the melting of precursor minerals and its rapid cooling in the protoplanetary disk, which is consistent with the experimental data. The olivine of the chondrules center of the Saratov meteorite differs from the olivine of the chondrules rims and meteorite matrix by the increased values of the Yb/La ratio. No relict grains and magnesian cores of olivine were found in meteorite chondrules. Individual grains in the chondrules are distinguished by their enrichment in trace elements relative to the rest of the olivine grains in the chondrule.

How to cite: Sukhanova K.G., Kuznetsov A.B., Galankina O.L. Features of olivine crystallization in ordinary chondrites (Saratov meteorite): geochemistry of trace and rare earth elements // Journal of Mining Institute. 2022. Vol. 254. p. 149-157. DOI: 10.31897/PMI.2022.39
Geology
  • Date submitted
    2020-05-14
  • Date accepted
    2020-10-05
  • Date published
    2020-11-24

Fahlbands of the Keret archipelago, White Sea: the composition of rocks and minerals, ore mineralization

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This paper presents a complex mineralogical and geochemical characteristic (based on SEM-EDS, ICP-MS analysis) of the fahlband rocks of the Kiv-Guba-Kartesh occurrence within the White Sea mobile belt (WSMB ). The term “fahlband” first appeared in the silver mines of Kongsberg in the 17th century. Now fahlbands are interlayers or lenses with sulfide impregnation, located in the host, usually metamorphic rock. The level of sulfide content in the rock exceed the typical accessory values, but at the same time be insufficient for massive ores . Fahlbands are weathered in a different way than the host rocks, so they are easily distinguished in outcrops due to their rusty-brown color. The studied rocks are amphibolites, differing from each other in garnet content and silicification degree. Ore mineralization is represented mainly by pyrrhotite and pyrite, and pyrrhotite grains are often replaced along the periphery by iron oxides and hydroxides, followed by pyrite overgrowth. At the same time, the rock contains practically unaltered pyrrhotite grains of irregular shape with fine exsolution structures composed of pentlandite, and individual pyrite grains with an increased Ni content (up to 5.4 wt.%). A relatively common mineral is chalcopyrite, which forms small grains, often trapped by pyrrhotite. We have also found single submicron sobolevskite and hedleyite grains. The REE composition of the fahlband rocks suggests that they are related to Archean metabasalts of the Seryakskaya and Loukhsko-Pisemskaya structures of the WSMB, rather than with metagabbroids and metaultrabasites common in the study area.

How to cite: Salimgaraeva L.I., Skublov S.G., Berezin A.V., Galankina O.L. Fahlbands of the Keret archipelago, White Sea: the composition of rocks and minerals, ore mineralization // Journal of Mining Institute. 2020. Vol. 245. p. 513-521. DOI: 10.31897/PMI.2020.5.2
Geology
  • Date submitted
    2019-09-04
  • Date accepted
    2019-12-25
  • Date published
    2020-04-26

Composition of spherules and lower mantle minerals, isotopic and geochemical characteristics of zircon from volcaniclastic facies of the Mriya lamproite pipe

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The article presents the results of studying the rocks of the pyroclastic facies of the Mriya lamproite pipe, located on the Priazovsky block of the Ukrainian shield. In them the rock's mineral composition includes a complex of exotic mineral particles formed under extreme reduction mantle conditions: silicate spherules, particles of native metals and intermetallic alloys, oxygen-free minerals such as diamond, qusongite (WC), and osbornite (TiN). The aim of the research is to establish the genesis of volcaniclastic rocks and to develop ideas of the highly deoxidized mantle mineral association (HRMMA), as well as to conduct an isotopic and geochemical study of zircon. As a result, groups of minerals from different sources are identified in the heavy fraction: HRMMA can be attributed to the juvenile magmatic component of volcaniclastic rocks; a group of minerals and xenoliths that can be interpreted as xenogenic random material associated with mantle nodules destruction (hornblendite, olivinite and dunite xenoliths), intrusive lamproites (tremolite-hornblende) and crystalline basement rocks (zircon, hornblende, epidote, and granitic xenoliths). The studied volcaniclastic rocks can be defined as intrusive pyroclastic facies (tuffisites) formed after the lamproites intrusion. Obviously, the HRMMA components formed under extreme reducing conditions at high temperatures, which are characteristic of the transition core-mantle zone. Thus, we believe that the formation of primary metal-silicate HRMMA melts is associated with the transition zone D".

How to cite: YATSENKO I.G., SKUBLOV S.G., LEVASHOVA E.V., GALANKINA O.L., BEKESHA S.N. Composition of spherules and lower mantle minerals, isotopic and geochemical characteristics of zircon from volcaniclastic facies of the Mriya lamproite pipe // Journal of Mining Institute. 2020. Vol. 242. p. 150. DOI: 10.31897/PMI.2020.2.150