河流沉积物中碎屑锆石U-Pb定年与Hf同位素分析相结合可获得所研究区域地壳的形成、演化的丰富信息,细粒沉积物是对流经源区的地壳进行均匀采样的理想工具(Taylor et al.,1985、1995;Mc Lennan.,2001;Rudnick et al.,2004;Bodet et al.,2000;Luo et al.,2008;陈岳龙等,2014)。在北祁连造山带中,发源于西北端的北大河, U-Pb dating of detrital zircons in river sediments combined with Hf isotopic analysis can provide abundant information on the formation and evolution of the crust in the studied area. Fine-grained sediments are ideal tools for uniform sampling of the crust flowing through the source area Taylor et al., 1985, 1995; Mc Lennan., 2001; Rudnick et al., 2004; Bodet et al., 2000; Luo et al., 2008; Chen et al., 2014). In the North Qilian orogenic belt, originated in the northwestern tip of the North River,