中文摘要：

Titanite 是为因为它的相对高的 U， Th 和 Pb 的同位素的标明日期满足的 U-Pb 的一种理想的矿物质。这里，我们为用 193 nm ArF 激光脱离系统和 Agilent 7500a Q-ICP-MS titanite 标明日期的 U-Pb 开发了一种技术。titanite (BLR-1 和 OLT-1 ) 和锆石的标准(91500 并且 GJ-1 ) 被标明日期使用单个点和线光栅扫描分析方法。为了检查矩阵，效果， titanite (BLR-1 ) 和锆石(91500 ) 标准作为外部标准被分析。OLT-1 titanite 的加权的吝啬的 206Pb/238U 年龄是 1015

英文摘要：

Titanite is an ideal mineral for U-Pb isotopic dating because of its relatively high U,Th and Pb contents.Here,we developed a technique for U-Pb dating of titanite using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS.Standards of titanite （BLR-1 and OLT-1） and zircon （91500 and GJ-1） were dated using single spot and line raster scan analytical methods.To check the matrix effect,titanite （BLR-1） and zircon （91500） standards were analyzed as the external standards.The weighted mean 206 Pb/238 U ages of OLT-1 titanite are 1015±5 Ma （2,n=24） and 1017±6 Ma （2,n=24） by single spot and line raster scan analyses,respectively,using BLR-1 titanite as the external standard.These ages are consistent with its reference age of about 1014 Ma.However,using 91500 zircon as the external standard,the weighted mean 206 Pb/238 U ages are 917±4 Ma （2,n=24） and 927±5 Ma （2,n=24） for BLR-1 titanite,and 891±4 Ma （2,n=24） and 901±5 Ma （2,n=24） for OLT-1 titanite by single spot and line raster scan analyses,respectively.It is evident that these ages are ～12% younger than their reference values.Our results reveal that significant matrix effect does exist between different kinds of minerals during LA-ICPMS U-Pb age determination,whereas it is insignificant between same minerals.Therefore,same mineral must be used as the external standard for fractionation corrections during in situ LA-ICPMS U-Pb age analysis.In addition,we determined U-Pb ages for titanites from the Early Cretaceous Fangshan pluton,which indicates a rapid cooling history of this pluton.