The genetic relationship between the large Guanfang W deposit and granitic intrusions, in Yunnan Province, southwest China: Evidence from UPb and ReOs geochronology and Pb and Sr isotopic characteristics

• The intrusion of Suozuodi granite and W mineralization at the Guanfang Deposit took place simultaneously at ca. 92 Ma.
• The ore-forming materials of Guanfang deposit were derived from a crustal source, without addition mantle materials.
• Formation of Guanfang W deposit were related to collisional tectonic setting.

The recently discovered Guanfang large W deposit, in Yunnan Province, southwest China, is located in the Diandongnan thrust-nappe fold belt in the western part of the Cathaysia Block. The orebodies occur at the contacts between the Suozuodi granite and Middle Cambrian marbles. LA-ICP-MS zircon UPb dating of the ore-bearing Suozuodi granite yields a crystallization age of 91.6 ± 1.0 Ma (MSWD = 0.56). An isochron age of 91.6 ± 1.3 Ma (MSWD = 0.24) was obtained by ReOs dationg of five molybdenite samples separated from sulfide-bearing ores. Scheelite at the Guanfang deposit is characterized by broad rangs of Pb isotopic ratios (207Pb/204Pb = 15.568 to 15.735, 206Pb/204Pb = 17.912 to 18.390, 208Pb/204Pb = 38.491 to 38.730) and high initial 87 Sr/86 Sr ratios (Isr = 0.7118 to 0.7140), which consistent with the isotopic characteristics of the Suozuodi granite. Pb and Sr isotopic results indicate that the ore-forming materials were derived from a crustal source, without addition of mantle materials. The Guanfang tungsten deposit was formed in a syn-collision tectonic setting during the late stage of the Yanshanian tectonism.