Chronology, geochemical characteristics and prospecting significance of the granite porphyry in Cuojie area of Middle Gangdise in Tibet
HU Lin, XU Lin, XIAO Jin, XU Gang, LUO Shaoqiang
Northwest Sichuan Geological Team, Bureau of Geology and Mineral Resources Exploration and Development of Sichuan Province, Sichuan Mianyang 621000, China
Abstract：A set of malachite-bearing granite porphyry was found in Cuojie area of the Middle Gangdise in Tibet. In order to determine the age, genesis and prospecting significance of the granite porphyry, the authors have conducted the petrographic, LA-ICP-MS zircon U-Pb chronology and geochemical characteristics of the granite porphyry. The results show that the zircons in the granite porphyry are of magmatic origin, with a weighted ave-rage age of 206Pb/238U of (13.9±0.2) Ma, and the intrusive age is Miocene. The geochemical characteristics of major elements show that the granite porphyry is characterized by high SiO2, high Al2O3, rich alkali, and rich sodium calc-alkalic characteristics. The geochemical characteristics of trace elements show that the granitic porphyry is rich in large ion lithophile elements such as U, Th, and depleted in high field strength elements such as Nb and Yb. The total amount of rare earth elements is (47.4~141.4) ×10-6, and the light rare earth elements are relatively rich with positive Eu anomaly. The granitic porphyry was formed by partial melting of the thickened lower crust, and partial separation crystallization may have occurred during the formation process, through comprehensive analysis. By comparing the geological characteristics of the granite porphyry with the typical deposits in the region, it is found that the granite porphyry in Cuojie area has similar geological characteristics and metallogenic system with the Gangdise porphyry copper deposit. And there may be a large ore-bearing porphyry buried in the deep, which briags a better prospecting prospect.
胡林, 徐琳, 肖进, 徐刚, 罗绍强. 西藏冈底斯中段错杰地区花岗斑岩年代学、地球化学特征及其找矿意义[J]. 中国地质调查, 2021, 8(5): 53-63.
HU Lin, XU Lin, XIAO Jin, XU Gang, LUO Shaoqiang. Chronology, geochemical characteristics and prospecting significance of the granite porphyry in Cuojie area of Middle Gangdise in Tibet. , 2021, 8(5): 53-63.
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2021, Vol. 8 
