LA-LCP-MS zircon U-Pb dating and geological implications for the Early Cretaceous volcanic rocks on the southeastern margin of the Tengchong block, western Yunnan

A succession of undated epimetamorphic sedimentary strata occurs in the Gaoligong metamorphic rock zone east of the Tengchong block, western Yunnan. The acidic volcanic rocks in these strata were identified during the 1:50 000 regional geological survey in the stratigraphic sequences of the Tuanpo section, Xuangang, Luxi, and give a zircon U-Pb age of 121.4±1.4 Ma. This age has revealed that the stratigraphic sequences cited above should be dated back to the Early Cretaceous during which the volcanic activities once took place in the study area. The Early Cretaceous felsic volcanic rocks in the study area may owe their origin to the closure of the Nujiang oceanic basin.