THE BASIC ROCKS OF MIDDLE-JURASSIC BACK-ARC DIKE BELT OF BIG CAUCASUS: GEOCHEMISTRY, THE QUESTIONS OF PETROGENETIC AND GEODYNAMICS TYPIFICATION

  • V. M. Gazeev Institute of geology of ore deposits, petrography, mineralogy and geochemistry RAS, Russia, 119017, Moscow, Staromonetny Lane, 35; ladikavkaz Scientific Center of the Russian Academy of Sciences, Russia, 362027, RNO-Alania, Vladikavkaz, Markusa Str., 22;
  • A. G. Gurbanov ag. gurbanov@iyandex. ru, Russia, 119017, Moscow, Staromonetny Lane, 35;
  • I. A. Kondrashov Institute of geology of ore deposits, petrography, mineralogy and geochemistry RAS, Russia, 119017, Moscow, Staromonetny Lane, 35
Keywords: Big Caucasus, dike belt, subductional basalts, petrography, geochemistry, geodynamic reconstruction, back-arc structure of tension

Abstract

To the north from the Main thrust of Big Caucasus the post-folding (post-aalean) dikes of basic in composition are distributed. Petrographic and geochemic investigation of these rocks have been done. The results of its analysis by RFA and ICP MS methods are given in this paper. It is shown, that initial melts are generated on melting of 3-15 % of spinel peridotite. High concentration Al2O3, a pronounced enrich by LILe, LREE, МREE and a negative anomalies of Ta, Nb, Zr, Hf are allowed to think of their as a subduction formation. Righ, in comparison with a standards of subductional basalts, content of TiO2 are characterized of this basic in composition rocks, as a generated in condition of back-arc tension, that correspond to their assumed geodynamic position.

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Published
2018-06-29
Issue
Vol 8 No 2 (2018): Geology and Geophysics of Russian South, 2018 No 2
Section
Articles