N.V. Tsukanov1, S.G. Skolotnev2, T.N. Palechek2

1P.P. Shirshov Institute of Oceanology RAS, Moscow, 117997
2Geological Institute RAS, Moscow, 109017

New data on age and composition of vulcanites composing tectonic block located in interfluvial area of rivers Pervaya Nepropuskovaya and Stlanikovaya are presented in this paper. Studied formations are present in Kronotskaya paleoarc accretion prism structure; its fragment outcrops on the Kamchatsky Mys Peninsula. It is shown that vulcanites of Santonian-Maastrichtian age for the most part represent the derivatives of close parent tholeiitic melts which have undergone differentiation and generated in supra-subductional mantle wedge. At the same time there are basalts, derived from enriched tholeiitic melts; it is an evidence of small-scale chemical heterogeneity of mantle wedge. Investigated volcanic thickness represents a fragment of volcanic complex characterized by Late Cretaceous stage of Kamchatsky Mys segment (Kronotskaya paleoarc) development.

Keywords: accretion prism, Kamchatka, volcanoes, Kronotskaya paleoarc, Late Cretaceous