Exposure　age　dating　using　in　situ(10)Be　and　Al-26　is　a　very　useful　technique　for　dating　fluvial　terraces.　This　is　especially　true　in　semiarid　regions　where　other　methods　suffer　from　a　paucity　of　suitable　dating　materials.　This　article　describes　sample　preparation　procedures　and　analytical　benchmarks　established　at　the　Xi＇an　Accelerator　Mass　Spectrometry　(AMS)　Center　for　the　study　of　in　situ(10)Be　and　Al-26.　Four　intercomparison　samples　were　analyzed　in　the　study,　using　an　improved　sample　preparation　method.　The　exposure　age　results　are　shown　to　be　in　good　agreement　with　published　data,　and　demonstrate　the　reliability　of　the　dating　method.　This　article　also　presents　new　Be-10　and　Al-26　results　from　quartz　samples　collected　from　a　series　of　fluvial　terraces　from　Guanshan　River,　along　the　Qilian　Shan,　northeastern　Tibetan　Plateau.　The　ages　of　three　fluvial　terraces　from　the　Jinfosi　site　are　shown　to　be　(56.4　+/-　5.3)　ka　for　T3,　(10.7　+/-　1.0)　ka　for　T2,　and　(7.2　+/-　1.0)　ka　for　T1.　The　dating　results　are　consistent　with　published　data　from　the　same　region　(Be-10,　C-14,　and　optically　stimulated　luminescence　dating　methods).　A　comparison　of　high-resolution　climate　records　with　age　constraints　for　the　terrace　formation　shows　a　close　relationship　between　terrace　formation　and　climate　change.