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内蒙古东乌旗沙麦钨矿位于贺根山断裂带以北的兴蒙造山系二连-东乌旗弧盆带内,为岩浆期后高温热液黑钨矿石英脉型矿床。采用黑钨矿Sm-Nd同位素分析获得黑钨矿的形成年龄为137.9±1.7Ma,采用TIMS锆石U-Pb同位素定年获得赋矿黑云母花岗岩的形成年龄为139.1±0.93Ma,据此提出,沙麦钨矿床的形成时代为燕山晚期,这与区域上大兴安岭西坡主要金属矿床的形成年龄数据相吻合。黑钨矿的初始ε_(Nd)值为正值,与中亚造山带内大量花岗岩的εNd值均为正值的特点相一致,表明其来源于亏损地幔源。
Inner Mongolia Dongwuqi Chamaite tungsten deposit is located in the Erlian-Dongwuqi arc basin of the Xingmeng orogenic belt north of the He-kanshan fault zone and is a high temperature hydrothermal wolframite vein type deposit after the magmatic period. The formation age of wolframite obtained by Sm-Nd isotope analysis of wolframite is 137.9 ± 1.7Ma, and the age of formation of biotite granite obtained by TIMS zircon U-Pb isotope dating is 139.1 ± 0.93Ma, The Shamai tungsten deposit was formed in the late Yanshanian period, which is consistent with the formation age data of the major metal deposits on the western slope of the Greater Hinggan Mountains in the area. The initial ε_ (Nd) value of wolframite is positive and consistent with the positive εNd value of a large number of granites in the Central Asian orogenic belt, indicating that it originated from a depleted mantle source.