Abstract: Zircon U-Pb geochronology and whole-rock geochemistry of amphibolites in Cenxi-Luchuan area, southeastern Guangxi are analyzed in this study. The results show that the amphibolites are probably formed later than the Early Palaeozoic (487-428 Ma). The Mid-Neoarchean zircons reveal that the unexposed Archean crystalline basement might be existed. The whole-rock geochemistry shows that the amphibolites are enriched in large ion lithophile elements (LILE) such as K, Rb, Ba, Sr, etc., and light rare earth elements relative to the original mantle. They are obviously depleted in high field strength elements (HFSE) such as Nb, Ta, Ti, etc., similar to the characteristics of island arc basalt (IAB). The amphibolites are formed by melting the mantle wedge of ancient subduction metasomatism, which might be in the lithospheric extension stage after collision in the Early Paleozoic.

Key words: Early Paleozoic tectonic events, amphibolites, zircon geochronology, geochemistry, petrology, Southeastern Guangxi