Origin of coeval shoshonitic and calc-alkaline rocks from the metasomatized lithospheric mantle
Description
We present zircon U-Pb isotopic age (Table 1, TableS2, TableS3) and Hf isotopic composition (Table S4), clinopyroxene chemistry (Table S5, Table S6), and whole-rock elemental and Sr-Nd-Pb-Mg isotopic compositions (Table S1) of the Cenozoic Zhuopan alkaline complex in the Tethyan orogenic belt, western Yunnan. On the basis of the analytical results, we observed distinct major and trace element compositions, and slight variations in whole-rock Sr-Nd-Pb-Mg and zircon Hf isotopic compositions in coeval shoshonitic and calc-alkaline rocks, suggesting the different melting models and magma sources. This study reveals the potential composition of the lithospheric mantle beneath the southeastern Tibetan Plateau， and the regional decompression of mantle and upwelling of the asthenosphere, induced by reactivation of giant shear zones, played a critical role in the formation of the Cenozoic alkaline magmatism along the southeastern margin of the Tibetan Plateau.