HIGH-K PICRITES AND BASALTOIDS OF THE OKHOTSK MASSIF, RUSSIAN FAR EAST

Abstract

In the Okhotsk massif specified are two groups of sub-volcanic alkaline rocks (K-picrites and alkaline basaltoids) with separated areas, differing in composition, ratio of mineral phases, petrostructural characteristics. Presented and analyzed are petrogeochemical and mineralogical characteristics of potassium picrite minerals, picrobasalt and alkaline basalt minerals, alkaline picrites and basaltoids. The data for two groups indicate some differences in petrogenic oxide content as well as in REE. Nd, Sr, Pb isotopic data on potassium picrites and basaltoids show rather similar ratios, that indicating their common plutonic source, which had the mixed composition including OIB, EMI and MORB. Influence of MORB for picrites was more significant.