S. Shnyukov1, Dr. Sci. (Geol.), Assoc. Prof., Head of Department, E-mail: shnyukov@mail.univ.kiev.ua,

I. Lazareva1, Cand. Sci. (Geol.), Assoc. Prof., E-mail: lazareva@mail.univ.kiev.ua,

Yu. Nykanorova1, Postgraduate Student, Engineer, E-mail: juliyasos@ukr.net,

V. Morozenko1, Cand. Sci. (Geol.), Senior Researcher, E-mail: morozenko@mail.univ.kiev.ua


FENITIZATION HALOS IN PENCHENGA AND CHERNIGOVKA CARBONATITE MASSIFS:

SIMILARITIES AND DIFFERENCES


1Institute of Geology, Taras Schevchenko National University of Kyiv, 90 Vasylkivska Str., Kyiv, 03022 Ukraine


Mineralogical, petrographic and geochemical features of carbonatites and fenitization halos of two linear carbonatite massifs, Penchenga (Yenisei Ridge) and Chernigovka (Pre-Azov Region), have been investigated. The purpose of the research was to identify and compare regularities of mineral association changes and major and trace elements behavior during the fenitization halo evolution over different host rocks (silicate and carbonate). To achieve this goal, we carried out three principal components of the laboratory and analytical study: petrographic investigation in thin sections to determine the mineral composition as well as the textural and structural features of rocks; X-ray fluorescence analysis to identify major and trace elements; interpretation of the data obtained.

Our research produced the following results: (1) a similarity has been found in the direction of mineral association changes brought about by fenitization of different host rocks (silicate and carbonate) for both studied massifs (complete disappearance of such relict minerals as quartz, biotite and hornblende, and emergence of newly formed paragenesis: alkaline amphiboles, phlogopite, and calcite; an increase in apatite and pyrrhotite content, and the emergence of pyrochlore and titanite); (2) it has been found that in both cases, the main direction of changes in the contrast type host rocks caused by fenitization is the convergence of their mineral and chemical compositions; (3) according to their behavior during fenitization, the major and trace elements in each massif have been found to fall into three groups: lost, gained and redistributed; (4) the composition of these groups reflects a difference in the geochemical specialization of the massifs, which is also marked by the absence of nepheline rocks in the Penchenga massif in contrast to the Chernigovka massif; (5) similarities and differences in the Penchenga and Chernigovka carbonatite massifs have been revealed for the first time, and a common multiplicative geochemical zonation index has been constructed for both massifs to objectively show an increase in the level of contrast host rocks transformation. Using this index can enhance the efficiency of area selection and target evaluation.

Keywords: carbonatite massifs, fenitization, Pre-Azov Region, Ukrainian Shield, Yenisei Ridge.


References:

1. Bagdasarov Yu.A., Voronovskiy S.N., Ovchinnikova L.V., (1985). Geological position features and radiological age of the new carbonatites occurrence in the KMA Region. Reports of the USSR Academy of Sciences, 282, 2, 404-408 (In Russian).

2. Bagdasarov Yu.A., (1979). Linear-fractured carbonatite bodies – the new subformation of ultrabasic-alkaline carbonatite complexes. Reports of the USSR Academy of Sciences, 248, 2, 412-415 (In Russian).

3. Bagdasarov Yu.A., (1990). About the main geochemical features of linear type carbonatites and their formation conditions. Geochemistry, 8, 1108-1119 (In Russian).

4. Bagdasarov Yu.A., (1992). About the carbonatites multiformational and the scope of the term "carbonatite". Notes of the Russian Mineralogical Society, 2, 110-116 (In Russian)..

5. Vernikovskaya A.E., Vernikovskiy V.A., Salnikova E.B. et al., (2005). Neoproterozoic anorogenic magmatic event on the Yenisei Ridge: new geochemical and isotope-geochronological data. Reports of the Russian Academy of Sciences, 403, 5, 656-660 (In Russian).

6. Vrublevskiy V.V., Pokrovskiy B.G., Zhuravlev D.Z., Anoshin G.N., (2003). The composition and age of the Penchenga linear carbonatite complex, Yenisei Ridge. Petrology, 11, 2, 145-163 (In Russian).

7. Glevasskiy E.B., Krivdik S.G., (1981). Precambrian carbonatite complex, Pre-Azov Region. Kiev, The scientific thought, 227 p. (In Russian).

8. Dunaev V.A., (2006). Geological structure and genesis features of Dubravinka massif alkaline rocks and carbonatites (KMA). News of higher educational institutions. Geology and exploration, 5, 30-33 (In Russian).

9. Zabrodin V.Yu., Malyshev A.A., (1975). The new complex of alkaline-basic rocks and carbonatites in the Yenisei Ridge. Reports of the USSR Academy of Sciences, 223, 5, 1223-1226 (In Russian).

10. Krivdik S,G., Tkachuk V.I., (1990). The petrology of Ukrainian Shield alkaline rocks. Kiev, The scientific thought, 408 p. (In Russian).

11. Lapin A.V., Ploshko V.V., Malyshev A.A., (1987). The carbonatites of the Tatarska deep-seated fault zone in the Yenisei Ridge. The geology of ore deposits, 1, 30-45 (In Russian).

12. Levin V.Ya., Ronenson B.M., Levina I.A., (1978). Carbonatites of the alkaline province of Ilmenskie-Vishnevye mountains (Ural). Reports of the USSR Academy of Sciences, 240, 4, 930-933 (In Russian).

13. Nedosekova I.L., Pribavkin S.V., (2009). Carbonatites of Ilmeno-Vishnevogorskiy complex: geochemical and genetical features, the role of the silicate-carbonate immiscibility and fluid-hydrothermal processes in formation of carbonatites. Yearbook-2008. Proceedings of IGG of Ural Branch of Russian Academy of Sciences, 156, 166-175 (In Russian).

14. Samoylov V.S., (1984). The geochemistry of carbonatites. Moscow, The science, 193 p. (In Russian).

15. Sobachenko V.N., Plyusin G.S. et al., (1986). The Rb – Sr age of near-fault alkaline metasomatic rocks and granites of the Tatarsko-Penchenginska zone (Yenisei Ridge). Reports of the Russian Academy of Sciences, 287, 5, 1220-1223 (In Russian).

16. Sobachenko V.N., Gundobin A.G., (1993). The formation type of near-fault alkaline carbonate-silicate metasomatic rocks and associated carbonatites. Geology and Geophysics, 5, 113-120 (In Russian).

17. Shnyukov S.E., (1983). Fenitization process features of Chernigovka carbonatite complex of the West Pre-Azov Region. The geological journal, 43, 4, 52-61 (In Russian).

18. Shnyukov S.E., Scherbina R.N., (1984). Desilicated rocks of the Chernigovska zone. Reports of the Ukrainian SSR Academy of Sciences, B series, 2, 28-30 (In Russian).

19. Shnyukov S.E., (1988). Apatite, zircon and sphene from fenites associated with carbonatites, and alkaline metasomatic rocks of Ukrainian Shield diaphthoresis zones as petrogenetic and geochemical indicators. Ph.D. Thesis. Lviv, Ivan Franko State University, 25 p. (In Russian).

20. Shramenko I.F., Stadnik V.A., Ocadchiy V.K., (1992). The geochemistry of Ukrainian Shield carbonatites. Kiev: The scientific thought, 214 p. (In Russian).

21. Scherbak N.P., Zagnitko V.N., Artemenko G.V., Bartnitskiy E.N., (1995). Geochronology of large geological events in Priazovskiy block of USh. Geochemistry and Ore Formation, 21, 112-129 (In Russian).

22. Carbonatites, nepheline syenites, kimberlites and related rocks in British Columbia. By Jennifer Pell, (1994). Chapter 2-3.

23. Tribe N.L., Eng P., (2011). Mineral Resource evaluation report on the Lonnie rare earth elements property. Manson Greek – Germanson landing area, Northern B.C. Vancouver, BC Canada.

24. Peter Van Straaten., (2009) Geological outline of Tanzania (carbonatites). Rocks for crops. Agrominerals of sub-Saharan Africa. Available at: http://www.uoguelph.ca/~geology/rocks_for_crops/