XU Sai-hua¹, REN Tao^1*, LV Chang-liang², SHI Wei-min³, WANG Cai-yan¹

(1. Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2. Guangxi Zhuang Autonomous Region Geophysical Investigation Institute, Liuzhou 545005, China;
3. Guangxi Zhuang Autonomous Region Geological Survey Institute, Nanning 530000, China)

Abstract: Cretaceous granites are widely distributed in the Southeastern Yunnan, with an area of over 500km2. Many metallic deposits, such as the world-class Gejiu Sn-Cu polymetallic deposit, Dulong Zn-In-Sn polymetallic deposit, and Nanyangtian superlarge W deposit, occurred in the peripheries of those granite bodies. Thus, the southeastern Yunnan Province has become a hot spot of domestic geoscientific researches. In this paper, we have systematically collected the geochemical, isotopic and chronological data, published by previous researchers recently, of typical Cretaceous granite bodies including the Gejiu, Bozhushan, and Laojunshan Cretaceous granite bodies in the Southeastern Yunnan. The comprehensive analysis of geologic and geochemical data shows that three large Cretaceous granite bodies in the southeastern Yunnan belong to the highly fractionated S-type granite. The systematical chronological data show that the Cretaceous magmatic movements and main metallogenic events occurred in the southeastern Yunnan with ages varying from 77 Ma to 95 Ma. The Sr and Nd isotopic values of whole rock samples and Hf isotopic values of zircon grains show that the granitic?magma was mainly derived from the partial melting of the Proterozoic metasedimentary basement of the Cathaysia Block. After a comprehensive analysis, it is preliminarily considered that the large-scale late Cretaceous acid magmatism in the Southeastern Yunnan is a response to the post-collision extensional environment after the collision of the South China Block and the Indosinian Block in Late Triassic.
Keywords: the highly fractionated S-type granite; Late Cretaceous; research progress; geochemical; the southeastern Yunnan

ACTA MINERALOGICA SINICA Vol. 39, No.2, 2019, page 149-165