由于缺乏磁铁矿(U-Th)/He标样，同时鉴于矿物铀钍含量低，He扩散机理不明，无法进行α粒子丢失校正等问题导致该矿物的(U-Th)/He年代学研究和应用严重不足。本项目拟选取热液活动时限清晰的西藏知不拉（~17Ma）和浦桑果（~15Ma）矽卡岩型热液矿床开展磁铁矿(U-Th)/He年代学方法研究。结合矿物地球化学研究，通过升级改造传统Alphachron氦测量仪和摸索高效萃取低铀钍含量样品的离子交换法来建立一套完善可靠的磁铁矿(U-Th)/He测年实验流程和数据分析方法。通过矽卡岩型矿床中不同粒径单颗粒磁铁矿阶段升温实验来探讨He的扩散机制及与温度，粒径之间的关系，为解释不同成因磁铁矿的(U-Th)/He年龄提供实验依据。该方法可用于约束富磁铁矿地质体时代，如蛇纹岩，基性火成岩和岩浆热液矿床，具有广泛的应用前景。

Due to the lack of magnetite (U-Th)/He standard samples, as well as the low content of uranium and thorium in the mineral, the unclear mechanism of He diffusion, and the inability to conduct correction for the loss of alpha particles, the study and application of (U-Th)/He chronology of the mineral is seriously insufficient. This project intends to select the Zhibula (~17Ma) and Pusangguo (~15Ma) skarn type hydrothermal deposits in Tibet with clear hydrothermal activity time limit to carry out the study of magnetite (U-Th)/He chronology. Combined with mineral geochemistry research, a complete and reliable magnetite (U-Th)/He dating procedure and data analysis method will be established by upgrading the traditional Alphachron helium measuring instrument and exploring the ion exchange method for high-efficiency extraction of samples with low uranium and thorium content. This project will also investigate the diffusion mechanism of He and the relationship between temperature and particle size by means of the phase heating experiment of single-grain magnetite with different particle sizes in skarn type deposits, and provides experimental basis for explaining the (U-Th)/He age of magnetite with different origin. The magnetite (U-Th)/He chronology can be used to constrain magnetite rich geological age, such as serpentinite, basic igneous rock and magmatic hydrothermal deposit, and has a wide application prospect.