Abstract:Titanite(CaTiSiO5) has relatively uranium contents(1~1000 ppm) and high Pb closure temperature(650~700℃), making it an important and ideal accessory mineral for U-Pb dating. However, development of titanite U-Pb dating has been limited by matrix effect between U-Pb dating standards and titanite samples and common-lead correction by LA-ICP-MS. Taking 206Pb/238U as an example, matrix normalisation factors(FAVG) were used to evaluate the matrix effect between zircon and titanite standards for U-Pb dating in this paper. The results showed that the FAVG values of titanite reference materials were almost larger than 1.20, while the FAVG values of zircon reference materials were almost less than 1.20, which indicated the matrix effect between zircon and titanite standards could not be ignored. OLT1 and TCB titanite standard were dated by a 213 nm Nd: YAG laser ablation system coupled with an ELEMENT2 ICP-MS using BLR-1 titanite U-Pb dating standard as external reference materials. The concordia age of OLT1 was 1014.9±4.8 Ma(95% conf.,n=23,MSWD=0.32),which agreed well with the concordia age 1017.1±3.6 Ma obtained by SHRIMP and 1014.6±1.3 Ma obtained by ID-TIMS. In addition, the weighted mean 206Pb/238U、207Pb/235U、207Pb/206Pb ages of OLT1 were generally consistent with the concordia age obtained by ID-TIMS. However, the weighted mean 206Pb/238U age of OLT1 was 891.3±9.5 Ma(n=23,MSWD=5.3) obtained by 91500 zircon as external standard, which was 12% lower than the concordia age dated by ID-TIMS. Using BLR-1 as external reference material, the weighted mean 206Pb/238U age of TCB titanite was 1015.6±6.2 Ma(n=16,MSWD=0.84) after common lead corrected by 207Pb method, which was consistent with the reference age of 1018.1±1.7 Ma determined by ID-TIMS. This study showed that U-Pb ages of titanite dating by LA-ICP-MS could be well consistent with the ages obtained by ID-TIMS when using matrix-matched titanite reference material as external standard, with the precision less than 2%(2RSE).