高黎贡构造带属于冈底斯地块东缘,滇西高黎贡花岗岩是冈底斯构造活动重要的岩浆记录.对高黎贡构造带的勐连花岗岩体南段的蒲川花岗岩地球化学特征进行的研究表明,蒲川花岗岩主要属于钙碱性-高钾钙碱性花岗岩,并表现出较强的过铝质特点；稀土元素配分模式曲线均表现为向右陡倾的LREE富集模式,具较弱的Eu负异常；花岗岩具后碰撞的特征,形成于主碰撞之后地壳向后碰撞-陆内转换的构造环境.LA-ICP-MS锆石U-Pb定年表明,蒲川花岗岩形成于早白垩世(128.9Ma±2.4Ma),年龄、地球化学特征与高黎贡构造带北部和中部一致,其形成可能是滇西怒江带碰撞作用的岩浆响应.%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.
展开▼
