采用ESR方法 ,对天山乌鲁木齐河源末次冰期的冰碛石英砂进行了测年 .下望峰组冰碛层的年代与前人推测的年代不同 ,是 5 0～ 70kaBP末次冰期早阶段形成的 ,分布下限可达海拔 2 30 0m左右的红五月桥附近 .与AMS的测年结果相比 ,末次冰期晚阶段底碛的ESR年代与AMS的年代相当 ,而冰上融出碛ESR年代与AMS的年代相差较大 .认为冰下的压碎和磨蚀作用可能导致冰碛中石英砂的ESR信号归零 ,从而使底碛的ESR测年成为可能 The ESR method was used to measure the moraine quartz sand in the last glacial stage of the Urumqi Heyuan, Tianshan.The dating of the Xiaomian Formation moraine layer is different from that of the predecessors, and is formed in the early stage of the last glacial stage of 50 ~ 70kaBP. And the lower limit is up to about 2 300 m above sea level near Red May Bridge.Compared with the AMS dating, the ESR ages of the end moraine in the late stage of the last glacial ice age are equivalent to those of the AMS, The difference between the ages is large.It is believed that crushing and abrasion under ice may lead to zero ESR signal of quartz sand in moraine so as to make ESR dating of bottom moraine possible