中文摘要：

安徽六安西峰寺钼矿化区地处大别造山带内，发育岩浆岩类型主要为正长岩类，可进一步分为细晶正长岩、似斑状正长岩、粗粒正长岩、正长斑岩等，辉钼矿化与后期正长斑岩脉侵入密切相关。利用LA—ICP—MS技术，对不同岩体中的锆石进行了U-Th—Pb同位素测定，得到的侵入岩206Pb／238U年龄从老至新依次为似斑状正长岩（128．2±1．7）Ma、细晶正长岩（128．1±1．5）Ma、正长斑岩（126．8±1．6）Ma、粗晶正长岩124．2±1．6Ma，均形成于早白垩世。结合前人的研究成果及区域对比，认为西峰寺钼矿化区与沙坪沟、千鹅冲等多个大型一超大型钼矿床具有相似的成矿背景和时代，具有较好的钼成矿潜力。

英文摘要：

Xifengsi of Lu＇ an is located in the Dabie orogenic belt, and the major type of intrusions is syenite, which can be further divided into aplitic syenite, porphyaceous syenite, macrocrystalline syenite and syenite porphyry, with Mo mineralization closely related to the intrusion of syenite porphyry. The authors carried out the study of geochronology about major intrusions in the Xifengsi ore district. The U-Pb ages of zircon show that, from the old to the young, there are porphyaceous syenite, aplitic syenite, syenite porphyry and macrocrystalline syenite, all formed in Early Cretaceous period. Combined with the study and the regional correlation, the authors hold that the Xifengsi Mo mineralization district has has similar background and ages to large molybdenum deposits like Shapinggou and Qian＇ echong and thus possesses a good potential of molybdenum mineralization.