Geochemistry, petrogenesis, and geodynamic typification of metavolcanics of the Tunka terrane(Baikal-Hövsgöl region)
S.I. Shkol'nik*, L.Z. Reznitskii, V.G. Belichenko, I.G. Barash
Institute of the Earth's Crust, Siberian Branch of the RAS, 128 ul. Lermontova, Irkutsk, 664033 Russia
Keywords: geochemistry of metavolcanics; back-arc basin basalts; Tunka terrane
Pages: 779-788
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.
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