Zircon U-Pb and Molybdenite Re-Os Dating of the Gangjiang Porphyry Cu-Mo Deposit in Central Gangdese and Its Geological Significance
Yang Zhen
Jiang Hua
Yang Mingguo
Mei Hongbo
Hu Guangdao
Zhang Lili
Zhang Peipei
Abstract：The Gangjiang Copper-Molybdenum deposit is a typical porphyry deposit, which locates in the Central Gangdese metallogenic belt.In order to determine the ages of magmatism and mineralization, and disentangle the complicated magmatic evolution and the relationship between magmatic process and copper-molybdenum mineralization, the author carried out a study of LA-ICP-MS zircon U-Pb ages of the monzogranite porphyry, granodiorite porphyry, and tonalite porphyrite in Gangjiang mining area.It is shown that the zircon U-Pb weighted isochron ages are 16.6±0.3Ma (MSWD=0.94, n=10), 16.1±0.2Ma (MSWD=1.07, n=12), 14.4±0.4Ma (MSWD=1.12, n=7).Meanwhile, twelve molybdenite samples separated from quartz sulfides in Gangjiang copper orebodies were used for Re-Os dating, and the model ages obtained range from 13.24±0.20Ma to 13.55±0.22Ma, with weighted average 13.4±0.1Ma (MSWD=0.65) and isochron age 13.6±1.6Ma (MSWD=1.2).On the basis of geological studies, and conbined with the results mentioned above and previous research data, it is proposed that the rock mass intrusion sequence is monzogranite porphyry→granodiorite porphyry→tonalite porphyrite→rhyolite porphyry.The porphyry occurred ranges from 16.6Ma to 14.4Ma, and the mineralization age of Gangjiang deposit is about 13.4Ma, and petrogenetic and metallogenic is a continuous process of magmatic evolution.The Re content of the molybdenite is 155.4-171.1μg/g, with an average of 162.9μg/g,suggesting that the metallogenic material originated from a source with mantle components.Gangjiang porphyry copper-molybdenum deposit was formed in post-collisional extension setting of India-Asia continental collision orogenic belt during the Miocene.
Keywords：geochemistryzircon U-Pb datingmolybdenite Re-Os datingporphyry Cu-Mo depositGangdese
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：18( 339-356 )