内蒙古维拉斯托铜锌矿床的白云母Ar/Ar年龄探讨

Laser microprobe Ar-Ar dating of biotite from the Weilasituo Cu-Zn polymetallic deposit in Inner Mongolia

采用显微激光探针法首次测定了维拉斯托铜锌矿床的白云母40Ar-39Ar年龄,结果为133.4±0.8Ma。根据白云母产出形态,认为测定的白云母与维拉斯托铜锌矿床成矿后期热液活动有关,据此确定维拉斯托矿床的成矿最晚时限为133.4±0.8Ma。区域地质背景特征显示,维拉斯托矿床在成因上受区域性造山期后岩石圈伸展作用控制,与区域性燕山晚期的岩浆作用关系密切,后者为矿床的形成可能提供了必要的热源和物源。

40Ar-39Ar fast-neutron activation dating of biotite from the Weilasituo Cu-Zn polymetallic deposit in Inner Mongolia was conducted by microprobe. The average age 133.4 ± 0.8 Ma is considered to be the time limit of the last or the late hydrothermal activity in the Weilasituo copper-zinc deposit. According to regional age relationship, the ore deposit seems to have been controlled by regional post-orogenic lithspheric thinning and strongly related to the magmatism of the late Yanshanian granite. The late regional Yanshanian granite might have provided the necessary heat and material resources for the formation of the Weilasituo deposit.