LA-ICP-MS zircon U-Pb dating of southern Menglian granite in Tengchong area of western Yunnan Province and its tectonic implications

Gaoligong tectonic belt is located in eastern Gandise block, and Gaoligong granites in western Yunnan constitute an important magmatic record of Gandise tectonic movement. Research on the geochemical characteristics of Puchuan granites in southern Menglian granites of Gaoligong tectonic belt suggests that these granites with strong peraluminous character can be assigned to high-K calc-alkaline granites. REE distribution patterns show steeply right oblique feature and enrichment of LREE, with weak negative Eu anomaly. Puchuan granites, with post-collision characteristics, were formed in a tectonic environment of transition from major collision to post-collision and inland. LA-ICP-MS U-Pb dating of zircons indicates that Puchuan granites were emplaced during the Early Cretaceous period (128.9±2.4Ma). Geochemical and chronological data of these granites are consistent to those of granites in northern and central Gaoligong tectonic belts. The formation of Puchuan granites might have been a magmatic response to collision of Nujiang tectonic belt in western Yunnan.