Title

E. K. Ibragimova, A. V. Padkov, A. V. Molchanov, N. V. Shatova, V. V. Shatov, E. N. Lep-ekhina, A. V. Antonov, E. V. Tolmacheva, O. L. Soloviev, A. V. Terekhov, E. I. Horohorina

The results of U-Pb (SHRIMP II) isotope dating of zircons from dunite from massif Inagli (Aldan Shield) and the problem of the genesis of concentrically-oned complexes

The paper presents data on composition and U­Pb zircon age determinations (SHRIMP II) for dunite core massif Inagli and syenite its framing. Petrographic and geochemical characteristics of the rocks, the morphology of selected zircons, their isotope geochemistry, mineral and fluid inclusions were studied. Obtained intervals ages for zircons from dunite as Precambrian (2624 ± 37, 2068 ± 14 and 1955 ± 27 Ma) and Mesozoic (134 ± 2 and 122 ± 2 Ma) do not represent the crystallization time of dunite. The age of syenite and monzonite framing massif Inagli was determined as 130 ± 1 and 133 ± 1 Ma, respectively. The results, as well as literature data suggest that massif Inagli had a long evolution. Primary dunite are not genetically connected with the framing of Mesozoic rocks and just associate with them spatially. The age of dunite core is determined in a wide range from KR₂ to K₁.
Key words: concentrically­zoned massifs, dunite, U­Pb age, geochemistry.