Zircon LA-ICP-MS dating of the magmatic breccia from the Yinachang iron-copper deposit in Wuding County of Yunnan Province and its geological significance

Central Yunnan Province is an important Proterozoic iron-copper metallogenic belt in Southwest China. Magmatic breccia, accompanied with iron-copper deposits, occurs in Proterozoic Kunyang Group. To get the zircon LA-ICP-MS U-Pb age of the magmatic breccia, the authors collected the samples of magmatic breccias that obliquely penetrate the Yinachang Formation in the Yinachang deposit of Wuding County, and selected the magmatic zircon from the cement. The core of the zircon has an average weighted 207Pb/206Pb age of 2193Ma±8Ma, which represents the age of primary zircon from the depth. The outer zones of the zircon have an average weighted 207Pb/206Pb age of 1739Ma±13Ma, representing the formation age of the magma. The metamorphic age of the breccia is 980Ma±11Ma. In combination with related data, the authors believe that the strata of the Yinachang Formation, the Upper Kunyang Group, the Dahongshan Group and the Hekou Group are contemporary products of the magmatic activity during the intraplate extension. This discovery has an important inspiration in search for IOCG type deposits around the magmatic breccia in the Proterozoic strata within the Kunyang rift of central Yunnan Province.