Linking the Tengchong Terrane in SW Yunnan with the Lhasa Terrane in southern Tibet through magmatic correlation

Abstract

New zircon U–Pb data, along with the data reported in the literature, reveal five phases of magmatic activity in the Tengchong Terrane since the Early Paleozoic with spatial and temporal variations summarized as Cambrian–Ordovician (500–460Ma) to the east, minor Triassic (245–206Ma) in the east and west, abundant Early Cretaceous (131–114Ma) in the east, extensive Late Cretaceous (77–65Ma) in the central region, and Paleocene–Eocene (65–49Ma) in the central and western Tengchong Terrane, in which the Cretaceous–Eocene magmatism migrated from east to west. The increased zircon εHf(t) of the Early Cretaceous granitoids from −12.3 to −1.4 at ca. 131–122Ma to −4.6 to +7.1 at ca. 122–114Ma, identified for the first time in this study, and the magmatic flare-up at ca. 53Ma in the central and western Tengchong Terrane indicate increased contributions from mantle- or juvenile crust-derived components. The spatial and temporal variations and changing magmatic compositions over time in the Tengchong Terrane closely resemble those of the Lhasa Terrane in southern Tibet. Such similarities, together with the data of stratigraphy and paleobiogeography, enable us to propose that the Tengchong Terrane in SW Yunnan is most likely linked with the Lhasa Terrane in southern Tibet, both of which experienced similar tectonomagmatic histories since the Early Paleozoic.