Abstract:
The Shamai wolframite deposit in Dong Ujimqin Banner of Inner Mongolia is located within the Erlian-Dong Ujimqin Banner arc-basin belt in the Da Hinggan Mountains-Inner Mongolia orogenic belt south of the Ergenshan fault. It is a postmagmatic high-temperature hydrothernal deposit. In this paper, wolframite Sm-Nd isotope analysis of the deposit yielded an ore formation age of 137.9±1.7Ma, whereas TIMS zircon U-Pb dating of samples from the wall rock biotite granite yielded a petrogenetic age of 139.1±0.93Ma. These isotopic ages indicate that the mineralization of Shamai wolframite deposit occurred in late Yanshanian, consis-tent with the age of the formation of the main ore deposits on the west slope of the Da Hinggan Mountains regionally. Consistent with the positive initial
εNd value of granites scattered in central Asian orogenic belt, the initial
εNd value of the wolframite is posi-tive, indicating a depleted mantle source.
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