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学科主题: 地理学::自然地理学
题名: 青藏高原腹地令戈错冰水湖泊地貌发育与环境演化研究
作者: 陈华亮
答辩日期: 2008-12-29
导师: 易朝路
专业: 自然地理学
授予单位: 中国科学院研究生院
授予地点: 北京
学位: 博士
关键词: 令戈错 ;  湖泊阶地 ;  GPS测线测量 ;  地貌 ;  西藏 ;  湖面波动 ;  全新世
索取号: S000017
部门归属: 图书馆
摘要: 青藏高原内陆湖泊是气候变化敏感的指示器,开展青藏高原湖泊的研究,对研究全球气候变化和可持续发展具有重要的意义。本论文通过青藏高原腹地令戈错湖泊地貌和沉积物的研究,恢复古湖面的升降和古气候的演化,以探明这一地区冰水湖泊地貌与环境演化的关系,明确羌塘高原内流区湖泊演化与古环境变化的规律,并为预测这一地区未来环境发展趋势提供参考依据。令戈错(东湖)位于青藏羌塘高原的东北部,普若岗日冰原以西。气候寒冷、干旱,地面盛行西风,降水集中分布于6-8月,蒸发量约是降水量的6倍。本论文采用差分GPS测量和遥感影像分析相结合的方法,精确测量了令戈错各级湖岸堤的高程;通过OSL定年技术对湖滨沉积物进行年代测定,并结合湖滨沉积物的粒度代用指标分析,重建湖泊演化的时空分布格局和环境变化历史。本论文得到以下主要结论和认识: 1、野外考察发现,在令戈错湖周围存在湖岸阶地、砂坝--泻湖类湖岸堤;湖西岸存在河流三角洲;湖东南还存在呈NW-SE向的古沙嘴,拔湖高度介于5033-5150 m。 2、上述阶地、沙嘴和湖岸堤的沉积物主要由磨圆度和分选性较好的砂或砂砾石组成。这些发育的湖岸堤、湖滨侵蚀地貌和湖滨沉积是令戈错湖存在和演化的重要证据。 3、通过OSL测年结果显示:令戈错在拔湖50-55m的湖泊阶地OSL测年结果,拔湖34-38m湖泊阶地相当的冰水河流阶地OSL测年结果,发现了令戈错湖距今6ka和2.8 ka的两次湖涨期,湖泊面积分别为371km2和244km2,分别是现在湖泊面积的4倍和2.5倍。拔湖90-100m的湖泊阶地,分布普遍,时代可能与末次冰期晚阶段相当。表明当时的冰消过程有利于冰水河流的发育,从而形成广泛出现的阶地。 4、冰水河流OSL年代为14.1kaB.P.,表明在此时期普若岗日冰川大量融化,河流与湖泊水位上涨,气候为较温暖的冰消期。 5、粒度分析表明,从冰水河流一直往湖泊,粒度特征正好与河流地貌特征和湖泊地貌特征一致。
英文摘要: Inland lakes on the Tibet Plateau are sensitive indicators for climate change, making the studies of these lakes’ variations critical to global climatic change and sustainable development discussion and strategy. This thesis uses lake geomorphology and sediment from LinggeCo to reconstruct ancient lake levels and climatic evolution and explore the relationship of glacial lake geomorphology and environmental change. Additionally, this thesis explores the causal relationship between lake change and ancient environmental change, to offer evidence for the environmental development direction. The LinggeCo (East Lake) lies in Northeast Qiantang Plateau, West of the Puruogangri ice field in the inner Tibet plateau. The climate is cold and arid with the majority of precipitation occurring between June and August. Annual evaporation is 6 times more than annual precipitation. Westerly winds prevail with the exception of July when there is a reversal. This thesis uses GPS to measure the elevation of the terrace. We confirmed the age by OSL dating methods, and used lake sediment granularity analyses to reconstruct the pattern of the space-time development and the environmental change history. All conclusions are as follows: 1. During field work we found sand –lagune terraces, and a sand spit on the west lakeshore makes for the NW-SE ancient sand spit in the southeast,at an altitude between 5033 -5150 m. 2. The land spit and lake terrace are formed by the sand and grit which have good polish and select. These well develope terraces and eroded lake features can prove the development of the Linggecuo. 3. The terraces of Linggecuo are 50-55m and 34-38m above the current lake level. We found two fluctuations at 6. ka and 2.8 ka, by OSL dating, with the areas 371km2and 244km2, and the 4 and 2.5times larger than today, respectively. It is common to find terraces at 90-100m above the lake level. This indicates that there was once a larger lake, corresponding to the late phase of last glacial stage. 4.Glacial river’s age was about 14.1ka B.P. dating by OSL,it was indicated that the Puruogangri ice field have vast meltd, the lake and river’s level rised, it’s interglacial with warm climate. 5. Grain size analyses indicate that the grain size characteristics are consistent with the lake and river features from the glacial river to the lake.
语种: 中文
内容类型: 学位论文
URI标识: http://ir.itpcas.ac.cn/handle/131C11/1233
Appears in Collections:图书馆_学位论文

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Recommended Citation:
陈华亮.青藏高原腹地令戈错冰水湖泊地貌发育与环境演化研究[博士].北京.中国科学院研究生院.2008
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