研究塔里木大火成岩省大规模喷发持续时间的长短，对于判定其是否为地幔柱成因具有重要意义。针对目前已发表的锆石原位微区定年数据误差偏大，以及玄武岩锆石来源存在捕获自围岩的不确定性，本项目拟选择塔里木西北部柯坪地区玄武岩剖面，对剖面底部和顶部出露的中酸性凝灰岩，首先通过岩相学研究和锆石Hf同位素组成分析，对比同一剖面玄武岩的岩相学特征和全岩Hf同位素特征，确证中酸性凝灰岩与玄武岩之间的成因和源区联系，然后利用化学溶蚀-热电离质谱法（CA-TIMS），开展高精度的锆石U-Pb定年工作，从而精确制约塔里木大火成岩省的喷发时限，为明确其与地幔柱的成因联系提供重要的年代学判据。

Testing the time span of Tarim flood volcanism is very important to determine whether Tarim large igneous province is plume-origin or not. Because published age results using zircon in-situ microbeam dating methods exhibit relatively wide errors, and zircons in basalts may be captured from country rocks, this project plans to select the basaltic profile located in Keping area, northwestern Tarim as object of study. Aiming to the intermediate-silic tuffs exposed in base and top of this profile, we will analyze zircon Hf isotope compositions, compare with whole rock Hf isotope characteristics of basalts from the same profile, and combine with identification under microscope, to confirm these tuffs derived from the same magma source as basalts, then utilize CA-TIMS method (chemical-abrasion thermal ionization mass spectrometry) to carry out high-precision zircon U-Pb dating. The dating results will precisely constrain the duration of Tarim flood volcanism, and then provide important geochronological criteria for understanding the genetic relationship between Tarim LIP and mantle plume.