DOI: https://doi.org/10.24028/gzh.0203-3100.v41i4.2019.177368

«The Great» dyke of the Bug area

V. A. Entin, O. B. Gintov, S. V. Mychak, V. N. Belskyi, Yu. V. Geyko, E. B. Polyachenko, S. I. Guskov, A. V. Marchenko

Abstract


New data of geophysical, geochemical and petrologic studies of the well-known elongated 35km long linear geological structure of predictable fault-dyke nature in crystalline basement of the west part of the Bug mining area (Middle Bug area, the Ukrainian shield) have been considered.  According to the data of surface magnetic mapping of the scale 1:50 000 the structure is clearly marked in magnetic field by the linear anomaly, up to 1,5 km wide, and intensity not more than 1000 nT, but practically not pronounced in gravity field. The strike of the structure (NE 69°) is cross-secting to general latitudinal and northwestern direction of geological formations of the studied region. According to the same data, the northwestern flank of the mentioned band of magnetic maxima is accompanied by more than 40 km long clearly pronounced linear minimum corresponding to axial part of the thick inter-block Mankivska fault zone. According to geophysical features, tectonophysical dimensions, extension and direction this tectonic lineament did not have any analogues in the western part of the USh up to now. Spatial-genetic relation of the studied structure and fault zone has been ascertained. Three geochemical Au anomalies have been ascertained in the weathering crust and zone of disintegration of crystalline rocks of the studied structure by geochemical mapping. It is one third of the total number of Au geochemical anomalies revealed by this mapping within the western part of the Bug mining area. Au was observed in complex with highly contrasting anomalies of Mn, Be, P, Zr, Cr, Ni, Co. However geological nature of the studied geochemical anomaly has not been ascertained by geochemical mapping (drilling with core hydro-transportation without entrance into fresh crystalline rocks). Modern works within the northwestern exocontract of this structure a dyke of the unknown in this area crystalline rocks has been found in an exposure among granitoids of the Uman and Gaysyn complexes which could be determined according to the data of microscopic and microprobe studies, chemical analyses, magnetic and density properties (χ=(40―60)×10–3 SI units; s=2,84 g/sm3) as lamprophyres (spessartite). The studies of enclosing granitoids in contact zone with lamprophyres indicates their active dynamometamorohic and, especially, metasomatic transformation, resulted in their saturation with ferromagnetic, stipulating totally increased magnetization of these formations. Further studies of this structure are recommended both in scientific and exploration purposes.


Keywords


dyke; faults; lamprophyres; diorites; magnetic properties; Bug area; the Ukrainian shield; chemical analysis

References


Barabanov, A. P., & Tsymal, P. N. (1957). Report of the Vinnitsa Geophysical Party for 1956. Kiev: Geolfondy, 183 p. (in Russian).

Gintov, O. B., Entin, V. A., Mychak, S. V., Pavlyuk, V. N., & Zyultsle, V. V. (2016). Structural-petrophysical and tectonophysical base of geological map of crystalline basement of the central part of Golovanevsk suture zone of the Ukrainian Shield. Geofizicheskiy zhurnal, 38(3), 3―28. https://doi.org/10.24028/gzh.0203-3100.v38i3.2016.107777 (in Russian).

Dzidzinsky, A. A. (1989). Results of aeromagnetic survey of 1:25 000 and 1:50 000 scales of the territory of Ukrainian Transdniestria. Report of the Aerogeophysical Party for 1986—1989. Kiev: Geoinform, 140 p. (in Russian).

Dovgan, R. N., Entin, V. A., & Pavlyuk, V. N. (2006). Bandurovskaya paleovolcanic structure and the associated prospects for diamondiferousness. Mineralnyye resursy Ukrainy, (4), 22—28 (in Russian).

Entin, V. A., & Lukash, V. V. (1998). Report on the results of the preparation of the geophysical and geochemical basis for the GDP-200 platform cover and GGK-200 of the crystalline base of the sheet M-35-XXXVI (Gaivoron). Kiev: Geolfondy, 265 p. (in Russian).

Report of the Institute of Geophysics of the National Academy of Sciences of Ukraine on the research work «Geological structure of the Pobuzhsky mining region on the basis of modern geophysical and geological data and assessment of its prospects for mineral resources». (2018). Stage III. Kiev (in Ukrainian).

Kisliuk, V. V., Zultsle, V., & Nikitash, L. P. (2011). Geological structure and mineral resources of the Southern Bug and Dniester watersheds. Report on the DDP-200 of the territory of sheet M-35-XXXVI (Gayvoron). Kiev: Geolfondy, 460 p. (in Ukrainian).

Mikhailov, N. D., Laptsevich, A. G., & Vladykin, N. V. (2010). Alkaline lamprophors of the Paleozoic magmatic complex of Belarus: Proc. of the 10th International Seminar «Deep Magmatism, Its Sources and Plumes», Sudak, September 14―18, 2010 (pp. 212―224). Irkutsk: Publ. house of the Institute of Geography SB RAS(in Russian).

Mychak, S. V., Murovska, G. V., Poliachenko, E. B., & Belsky, V. N. (2018). Stress-deformed state of the Earth’s crust of the Bug mining area in the section Gayvoron-Zavalye. Geofizicheskiy zhurnal, 40(2), 95—107. https://doi.org/10.24028/gzh.0203-3100.v40i2.2018.128933 (in Ukrainian).

Nechaev, S. V., Gintov, O. B., & Mychak, S. V. (2019). On a link of rare earth-rare metal and gold-ore mineralization with fault-block tectonics of the Ukrainian Shield. 2. Geofizicheskiy zhurnal, 41(2), 58—83. https://doi.org/10.24028/gzh.0203-3100.v41i2.2019.164450 (in Russian).

Pavlyuk, V. M., Bobrov, O. B., Vysotskyy, B. L., Dovhan, R. M., Zhovynskyy, E. Ya., Kostenko, M. M., Lykov, L. I., & Tsymbal, S. M. (2008). Report on the topic «Geology, petrology, geochemistry, age and ore content of mafic-ultramafic associations of the western part of the Ush». Books 1-6. State Enterprise Fund «Ukrainian Geological Company». Kyev, 683 p. (in Ukrainian).

Serzhin, V. I., & Goncharenko, K. I. (1958). Report of the Pobuzhsky Geophysical Party for 1957. Kiev: Geolfondy, 204 p. (in Russian).

Blundy, J., & Holland, T. (1990). Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer. Contributions to Mineralogy and Petrology, 104(2), 208—224. 10.1007/BF00306444.

Hammarstrom, J., & Zen, E. (1986). Aluminum in hornblende: An empirical igneous geobarometer. American Mineralogist, 71(11-12), 1297—1313.

Henry, D. J., & Guidotti, C. V. (2002) Titanium in biotite from metapelitic rocks: Temperature effects, crystal-chemical controls and petrologic applications. American Mineralogist, 87(4), 375—382.

Hollister, L. S., Grissom, G. C., Peters, E. K., Stowell, H. H., & Sisson, V. B. (1987). Confirmation of the empirical correlation of Al in hornblende with pressure of solidification of calc-alkaline plutons. American Mineralogist, 72(3-4), 231—239.

Johnson, M. C., & Rutherford, M. J. (1989). Experimental calibration of the aluminum-in-hornblende geobarometer with application to Long Valley caldera (California). Geology, 17(9), 837—841. https://doi.org/10.1130/0091-7613(1989)017<0837:ECOTAI>2.3.CO;2.

Mychak, S. V., Cherkes, S. I., Farfuliak, L. V., Poliachenko, I. B., & Murovskaya, A. V. (2018). The ratio of deformation structures and magnetic textures of rocks Pobuzhsky ore mining district: 17th International Conference on Geoinformatics ― Theoretical and Applied Aspects, 14—17 May 2018, Kiev, Ukraine. doi: 10.3997/2214-4609.201801851.

Schmidt, M. W. (1992) Amphibole composition in tonalite as a function of pressure: An experimental calibration of the AI-in-hornblende barometer. Contributions to Mineralogy and Petrology, 110(2-3), 304—310. https://doi.org/10.1007/BF00310745.

Sklyarov, E. V. (Ed.). (2001). Metamorphism and Tectonics: A Training Manual. Moscow: Intermet Engineering, 216 p. (in Russian).

Wu, C. M., Pan, Y., Wang, K., & Zhang, J. (2002). A report on a biotite-calcic hornblende geothermometer. Acta Geologica Sinica, 76(1), 126—131.




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