Sources of mesozoic polyformation magmatism in the Ketkap-Yuna Igneous Province, Aldan Upland: Isotopic data

Abstract

The KetkapYuna Igneous Province (KKYuIP) can be considered as a tectonotype of tectonomag� matic activation (TMA) zones within the Aldan Shield. The KKYuIP is represented by a series of mul� tiphase volcanicplutonic edifices of the central type stretching more than 300 km, from Kondyor Ridge (AyanMaya district of Khabarovsk Krai) to South Yakutia, as an arcshaped structure of igneous origin (Fig. 1). Rocks that are coeval and cogenetic to the KKYuIP rocks have been found in 12 areas within the Aldan Shield (2). Their origin corresponds in time to the intensive intraplate magmatism episode in the Late Mesozoic. The foundation age, degree and pattern of deformations, petrogenesis of igneous products, and duration of magmatism in the KKYuIP are the key points required for assessment of the validity of the existing geodynamical models describing evolution of the Siberian continent (5, 14, 15, etc.) and for reveal� ing the fundamental causes of origination and fading of magmatism in TMA zones.