Geochemistry, petrogenesis, and geodynamic typification of metavolcanics of the Tunka terrane (<i>Baikal–Hövsgöl region</i>)

Abstract

Abstract The geochemical composition of metavolcanics (metabasalts and metaandesites) of the Tunka terrane is considered. They are differently enriched in incompatible elements relative to N-MORB. The geochemical features of the basalts (LILE and LREE enrichment, Zr and Hf negative anomalies) point to the suprasubductional nature of synsedimentary volcanism; at the same time, the rocks lack negative Nb, Ta, and Ti anomalies. Comparison of the Tunka metavolcanics with those of modern geodynamic settings shows their analogy to back-arc basin basalts.