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本文就雅鲁藏布江大拐弯入口打林村冰碛物阶地砾石的宇宙成因核素(10Be)暴露年龄和观景台冰砾阜堆积物中的14C年代学展开研究。研究结果表明，海拔3150米的打林村阶地砾石暴露年龄在9.0KaB.P.左右，海拔约3200米左右的观景台冰砾阜的14C年龄为24Ka 左右(Z05G01 号样品) 和17.6Ka左右(Z05G02号样品)。分别代表24KaB.P.时发生一次冰进事件和打林村阶地面的形成时间。结合野外地貌调查以及DEM 地形地貌分析表明，则隆弄冰川在24kaB.P.左右(末次盛冰期)发生一次大规模冰进并阻江，冰碛物堆积在雅鲁藏布江宜淀—龙白之间的河谷中。阻江造成宜淀上游回水成湖，并在宜淀以上雅鲁藏布江河谷中发育湖相沉积。巨厚的冰水湖相沉积层说明当时雅鲁藏布江下切幅度已经达到与现今相似的深度。堰塞湖水以冰下河或从冰碛坝顶漫流的方式排泄。宜淀发育的一套海拔3010-3100米湖相沉积中发现冰川坠石就是这次事件的一个重要证据，该套湖相沉积中部的14C年龄为19,610±2260a。直到9.0KaB.P.时，则隆弄冰川又一次跃动堵江，形成打林村阶地。最近60年来有记录的则隆弄冰川3次跃动指示了近年青藏高原的3次气温突变事件。导致河水下切巨大冰碛坝，湖面下降和此后多次冰川跃动的可能原因是：1，随着气温回暖，冰川融化，雅鲁藏布江水量增大；2，该地区在距今1.5万年以来，构造在快速抬升，导致漫顶通过冰碛坝的水流溯源侵蚀作用加快。构造的间歇性抬升也造成多级阶地密集分布在大拐弯入口地区。则隆弄冰川的冰进或跃动对气候环境和构造有良好的指示意义。初步研究结论修正了前人认为则隆弄冰川跃动堵江与林芝、米林等地湖相沉积之间存在直接因果关系的理解，造成该地湖相沉积物的原因可能与鲁霞、丹娘、德阳等地的泥石流阻江事件有关。

Our study focus on the 10Be exposure ages of boulders at the Dalin terraces and AMS 14C age of Guanjingtai lacustrine strata. The results of the boulders exposure ages is about 8.7-9.0 ka B.P. which are at the top of Dalin terraces (3150m asl.), 24KaB.P. and 17.6KaB.P. of 14C age of Guanjingtai lacustrine strata samples (3200m asl.). There are the ages of a glacier development event at 24KaB.P.（Last Glacial Maximum）and the terrace surface age at Dalin. After our field work for geomorphology and DEM analysis, these Chronological data implicate that Zelongnong glacier developed at 24 ka B.P., had been dammed out Tsangpo River from Yidian to Longbai. An ice lake at the upstream of Yidian is caused by the moraine dam. Lake sediments develop in Yidian upstream of Tsangpo River valley. Thick ice lake sediments to explain Tsangpo River incision down the depth was similar to the current day. The water on the ice dammed lake drainaged by the channels beneath or overflowing form the top of moraine dam. A lake sediment including a 14C age date 19,610 ± 2260 at the middle is found at Yidian about 3010-3100m. Glacier dropstones included in the sediment is an important evidence for this event. Until 9.0KaB.P., Zelongnong glacier got another major jump down and damming, formed Dalin terrace. Lately, Water level of dammed lake decreased and incised moraine dam, which are cause by two reasons. Firstly, 9.0KaB.P. is a warm stage after the LGM, glaciers thaw and water level increases in Tspongo River. Secondly, traceability erosion is enhanced by active tectonics after 15Ka B.P. at Namche Barwa area. We find multiple stage terraces distributing at the gorge of Tsangpo River by tectonic uplift and river incision. In the last 60 years, Zelongnong glacier has at least three times of activities indicating 3 times climatic warmth events in Tibetan Plateau. All in all, Zelongnong glacier development has relationship among environment and tectonic uplifting. According to the study above, the relationship between Zelongnong glacier and Linzhi-Milin lake sediments was known again. Linzhi-Milin lake sediments might have relationship with glacial disaster events between Luxia, Danniang and Deyang regions.

引言………………………………………………………………………….……….. 1
第一章 青藏高原大拐弯地区的研究现状及存在问题…………………...……….. 6
第一节 雅鲁藏布江大拐弯入口地区地质概况……………………...…………6
第二节 雅鲁藏布江大拐弯入口地区地貌概况………………………..……….8
第三节 雅鲁藏布江大拐弯入口地区气候概况……………………….………14
第四节 青藏高原第四纪环境及藏东南环境概况………………………....….15
第五节 区内地质灾害概况及其与则隆弄冰川下移事件关系的研究…….…18
第六节 青藏高原及周边地区冰碛物宇宙成因核素年代研究现状………….21
第七节 存在问题……………………………………………………………….23
第二章 野外地貌考察…………………………………………………………...….24
第一节 打林村冰碛物堰塞体……………………………………………….…24
第二节 宜淀湖相沉积物…………………………………………………….…26
第三节 观景台堆积………………………………………………………..…...27
第四节 沉积平台的DEM与实测剖面分析…………………………………..28
第三章 宇宙成因核素定年方法……………………………………………...…….31
第一节 宇宙射线与原地宇宙成因核素生成机制………………………...…..31
第二节 宇宙成因核素的生成速率…………………………………………….34
第三节 宇宙成因核素的模式年龄………………………………….................37
第四节 核素分析应用策略…………………………………………………….39
第五节 宇宙成因核素测年的范围和精度…………………………………….43
第四章 样品的野外采集和实验室处理……………………………………………46
第一节 宇宙成因核素样品的野外采集…………………………………..……46
第二节 宇宙成因核素样品实验室制备…………………………………..……47
第三节 观景台堆积物的14C样品野外采样与实验室处理………………….54
第五章 冰碛物年龄及其意义讨论……………………………………………..…..56
第一节 打林村阶地冰碛物暴露年龄………………………………………..…56
第二节 观景台堆积中的14C年龄…………………………………………..…56
第三节 冰川(则隆弄)作用的古地貌恢复……………………….…………..…57
第四节 冰川(则隆弄)下移历史与气候变化的讨论……………………….…..61
第六章 结 论…………………………………..…………………………………..63
参考文献…………………………………………………………………………..…64
发表文章目录………………………………………………………………….…….69
致 谢………………………………………………………………………..………70
附件：
1打林阶地样品测试原始数据（10Be/9Be）………………………...…………… 72
2中国科学院广州地球化学研究所14C年龄测试报告单………………………....73