Sr AND Nd ISOTOPIC COMPOSITIONS AND SOURCES OF BASALTS OF SOUTHERN PRIMORYE

Abstract

The paper presents new data on the Sr and Nd isotopic compositions in basalts of southern Primorye (43°30 –47 ° N and 134° –137 ° E). Information about this area is missing in the literature devoted to geochemical typification and sources of Cenozoic basalts of eastern Asia. Numerous K–Ar dates have recently been obtained for basalts of this region in the Laboratory of Isotopic Geochemistry and Geochronology, IGEM RAS. Taking into consideration these ages and based on geological–geochemical characteristics, we have subdivided Late Jurassic, Cretaceous, and Early Paleogene basalts into three types. The first type comprises alkaline and subalkaline varieties with high concentrations of HFSE (Ti, Zr, Nb, Hf), as well as Ba, K, Rb and LREE. They occur in faulted and thrust slabs of Triassic–Lower Cretaceous siliceous–terrigenous deposits and olistostromes.