The Sailajiazitage volcanic and related rocks in the Tiekelik belt imply a Neoproterozoic seamount accreted to the southern Tarim Craton

The process of accretion along the margins of cratons is fundamental to continental growth. Subduction and accretion have been revealed in the northern and central parts of the Tarim Craton, however, the tectonic setting of its southern margin is still controversial, which impedes the identification of its location in the reconstruction of Rodinia Supercontinent. Here, we present our results of field observations, geochronology, geochemistry and Sr-Nd-Pb isotopes for the volcanic and related rocks of the Sailajiazitage Group in the Tiekelik belt of the southern Tarim Craton. Field outcrop exhibits that these rocks were imbricated with pillow basalt and chert. The volcanic and related rocks yield ages of 883.4 +/- 4.3 Ma (basalt), 858.6 +/- 3.6 Ma (trachyte) and 830.3 +/- 3.7 Ma (rhyolite), respectively. The basalt shows OIB character without depletion of Nb and Ta, suggesting a seamount setting. The values of sigma Nd(t) (-6.0 to 1.7) and Sr and Pb isotopes show the basalts have a source of the EMI mantle with a mixture of lower continent crust, derived from 7 to 10% partial melting of garnet peridotite. Incorporating regional sedimentary rocks, MORB and adakitic plutons, we propose that the volcanic and related rocks of the Sailajiazitage Group formed in a seamount setting during the early Neoproterozoic and were accreted to the southern Tarim Craton during the late Neoproterozoic to the late Ordovician, changing the previously assigned basement nature of the southern Tarim Craton and challenging the model of reconstruction of the southern Tarim Craton in the Rodinia Supercontinent represented by the Sailajiazitage volcanic and related rocks.