Metamorphic complexes of Sviatoy Noss peninsula region in Transbaikalia: geochemistry, age, Sm-Nd isotope data

Metamorphic complexes of Sviatoy Noss peninsula region (450 Ma) are fragments of Early Paleozoic accretion-collision system in Transbaikalia. Metamorphism degree is upper amphibolite facies (P = 6,2-7,2 kbar, T = 705-745 °C). The compositions of protoliths correspond to island arc metavolcanic or metavolcanogenic-sedimentary complexes (495-460 Ma), in which calc-alkaline and alkaline series volcanics predominate, tholeitic volcanics are less common. Sm-Nd model ages for gneisses (1626-1544 Ma) and amphibolites (867 Ma) indicate Meso- Neoproterozoic the lower age limit for the protoliths of the metamorphic complexes. Amphibole (256-245 Ma, P3-T2) and biotite (183-169 Ma, J1-2) Ar-Ar isotope ages reflect the Mesozoic history of the metamorphic complexes and correlate with the stages of the continental lithosphere extension in Transbaikalia