【摘要】 白水河是祁连山东段冷龙岭南麓大通河的一条支流 ,在其谷口保存有形态较完整的冰川终碛 .终碛剖面中有将该终碛垄分成两次冰川作用的一推积垄 .此次用 ESR测年技术对采自该剖面中的冰碛物进行了测年研究 ,推积垄前部两个样品测得的 ESR年龄为 73.0 ka,5 5 .8ka;推积垄后部靠近推积垄的一个样品 ,测得 ESR年龄为 36 .7ka.所测得的 ESR年龄与终碛垄沉积的新老关系相一致 .经对 ESR测年结果的误差与其可靠性讨论并结合终碛垄沉积关系和推积垄前后的14 C年龄得出 :推积垄前部的冰碛物为末次冰期早期沉积的 ,与深海氧同位素的 4阶段相对应 ;推积垄后部的冰碛物为末次冰期晚期所沉积的 ,可与深海氧同位素的 2阶段相对应 .此结论也进一步验证以往学者所得出的结论 .说明冰碛物可以用 ESR技术进行测年 .更多还原

【Abstract】 Baishuihe River is a tributary of Datong River, located on the southern slope of Lenglongling in the eastern part of the Qilian Mountains. An integral end till remains at the entrance of the valley. There is a push moraine in the till section. Three samples were derived from this section. Two samples were collected at the front of the push moraine and another sample (near the push moraine) collected from the rear of it, ESR ages were 73.0 ka, 55 8 ka, 36 7 ka respectively. The ESR ages being consistent with the relationship of deposits. The ages before the push moraine were correlated to the deep sea oxygen isotope stage 4 within 10% deviation. Based on them, the authors could determine the till before the push moraine were formed in the early period of Last Glaciation. Comparing the ESR age of LS 5 with the results of previous 14 C, we found that the ESR age was older. Through the error correction, the authors concluded: the existing push moraine distorted the till around it, mixing the superglacial till, englacial till and subglacial till together. The authors considered: the main reason influencing the ESR age was that the englacial till and the subglacial till were not exposed completely before they deposited. Although the result of LS 5 was older than the previous 14 C, combining the ESR age and the relationship of deposit and the existing 14 C ages, the authors inferred that the rear of the push moraine was deposited in the later period of the last glaciation and was correlated to the deep sea oxygen isotope stage 2. At the same time, the conclusion once again proved the previous scholars’ conclusion. This shows the ESR technique may be applied to glacial till dating.更多还原