Lalangmai tungsten-polymetallic ore district, which is located in the eastern section of East Kunlun in Qinghai Province, is a newfound skarn-type ore deposit in recent years in Chahanwusuhe area. Detailed researches on petrography, geochronology and geochemistry of the Lalangmai tonalite, which is closely related with mineralization, can provide new constraints for the Proto-Tethys tectono-magmatic evolution in East Kunlun. LA- ICP-MS zircon U-Pb dating shows that the weighted mean age of tonalite is 421.5±5.0 Ma （n = 21, MSWD = 0.34）, in the Top Silurian. Detailed lithogeochemical studies show that the tonalite belongs to weakly peraluminous low potassium （tholeiitic） to calc-alkaline series, and the genetic type of the tonalite is Ⅰ-type granite. This suite of rocks are enriched in LILE （such as Rb, Sr, K）, more mobile incompatible elements （such as U, Th） and Pb, relatively depleting in HFSE （such as Nb, Ta, P, Ti）. Rb/Sr and Nb/Ta reflect the characteristics of crust-mantle mixing magma origin. Based on a combined study of geochronology and evolutionary characteristics of regional structures, the authors consider that the tonalite emplaced in the post-collisional stage of the tectonic cycle of Proto-Tethys. Late Caledonian is an important polymetallic metallogenic epoch in East Kunlun, and we should pay sufficient attention to Late Caledonian plutons in further ore-prospecting work.
Kong Huilei Li Jinchao Jia Qunzi Guo Xianzheng Li Yazhi. Zircon U-Pb dating and geochemistry of the tonalite from Lalangmai tungsten-polymetallic ore district in East Kunlun, Qinghai Province, with implications for prospecting[J]. Chinese Journal of Geology, 2019, 54(2): 590-607.