【摘要】 应用ESR测年技术对采自乌鲁木齐河源区上望峰、下望峰与高望峰的冰碛物进行了测年 ,上望峰冰碛年代为 (35± 3 .5)kaBP ;下望峰冰碛 3个年代分别为 (1 71 .1± 1 7)kaBP、(1 76± 1 8)kaBP、(1 84.7± 1 8)kaBP ;高望峰冰碛年代为 (459.7± 46)kaBP .经对ESR测年结果的可靠性讨论并结合地貌地层与已有的1 4C年代、ESR年代数据得出 :上望峰冰碛沉积于MIS 2相对应的末次冰期晚期 ;下望峰冰碛系两次冰川作用沉积的 ,公路之上冰碛于MIS 4相对应的末次冰期早期沉积的 ,以下老的冰碛沉积于MIS 6相对应的冰期 ;河源区最老的冰碛高望峰冰碛形成于MIS 1 2相对应的冰期 .高望峰冰碛年代同时还表明本段天山至少于此时已经上升到与当时冰川气候相耦合的高度 ,进入了冰冻圈 ,开始发育冰川 .更多还原

【Abstract】 The tills of Shangwangfeng, Xiawangfeng and Gaowangfeng at the headwaters of the Urumqi River were deposited in the Pleistocene. Although many scholars have studied them, there are still controversies over them, especially the ages of the Xiawangfeng till so far. This restricts the further study of the Quaternary Glaciations. In the past two decades, ESR as a new dating determination technique developed rapidly, and this technique could be used to date glacial tills. The studies of the scholars in the past have shown that the Ge center in the quartz is sensitive to the sunlight and grind may bleach it. So the Ge center was chosen as ESR dating signal. Shangwangfeng, Xiawangfeng and Gaowangfeng tills were determined with this technique. The determining shows that the age of Shangwangfeng till was (35±3.5) ka BP, the age of Xiawangfeng till have three ESR values, i.e., (176±18) ka BP, (171.1±17) ka BP, and (184.7±18) ka BP, respectively, and the age of Gaowangfeng was (459.7±46) ka BP. Associated with the available 14 C and ESR ages and the law of geomorphology, the following conclusions could be drawn: The Shangwangfeng till was formed in MIS 2, maybe it included the till deposited by glacier advancing in MIS 3b. The upper part of the Xiawangfeng till was deposited in MIS 4 and the lower part of it was deposited in MIS 6. According to the distribution of it and the erosion rate of the river, it is believed that the Gaowangfeng till is the oldest at the headwaters of the rümqi River, corresponding to MIS 12. The result demonstrates that this segment of the Tianshan Mountains entered the cryosphere around this time and then glaciers began to develop.更多还原