ESR dating of the sediments of the Last Glaciation at the source area of the Urumqi River, Tian Shan Mountains, China
ESR dating of the sediments of the Last Glaciation at the source area of the Urumqi River, Tian Shan Mountains, China
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DOI：
10.1016/s1040-6182(02)00059-9
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发表时间：
2002
影响因子：
2.2
通讯作者：
C. Yi;K. Jiao;Ke-xin Liu;Yuanqing He;Y. Ye
中科院分区：
文献类型：
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作者：
C. Yi;K. Jiao;Ke-xin Liu;Yuanqing He;Y. Ye
利用电子自旋共振（ESR）法测定了天山乌鲁木齐河源区末次冰期形成的冰川石英砂的年龄。ESR测年的基底冰碛，解释为冰下融化，直到沉积在末次冰期后期产生的终碛，是一致的年龄确定通过AMS 14 C方法。然而，上覆沉积物的年代测定，解释为冰上融出，直到与相同的冰碛，产生了不同的结果，确定使用AMS 14 C方法。冰下破碎作用可使ESR信号复位，从而使冰碛物的ESR测年成为可能。下王峰群形成于公元前2000年，其时代曾有争议。50- 70 ka，末次冰期早期。它沉积在整个主山谷，低至2300ma.s.l.，长度超过19公里。末次冰期早期和晚期之间的冰间沉积了河流桑迪砾石。
Electron spin resonance (ESR) dates were obtained from glacial quartz sands formed during the Last Glaciation at the source area of the Urumqi River, Tian Shan Mountains, northwestern China. ESR dating of a basal till, interpreted as a subglacial melt-out till deposited in an end moraine which was produced in the late stage of the Last Glaciation, is consistent with ages determined through the AMS14C method. However, dating of the overlying sediment, interpreted as supraglacial melt-out till associated with the same moraine, produced a result that differs from that determined using the AMS14C method. Subglacial comminution could reset the ESR signal, thus making ESR dating of basal till possible. The Lower Wangfeng Group, formerly of controversial age, was formed ca. 50–70ka, during the early stage of the Last Glaciation. It was deposited throughout the main valley as low as 2300ma.s.l., over a length in excess of 19km. Fluvial sandy gravel was deposited in the interstadial between the early and late stages of the Last Glaciation.