【作者】 白友良；

【导师】 王金荣；

【作者基本信息】 兰州大学 ， 构造地质学， 2013， 硕士

【摘要】 罗布泊地区位于新疆东南部,是中国乃至全球的著名干旱地区之一,罗布泊地区的环境变化,是塔里木盆地及其周围山地古气候古环境变化的代表。因此,罗布泊地区的环境变化研究对全球变化研究、干旱荒漠区生态环境保护和资源开发利用等具有重要的参考价值,此外,环境变化对该地区重大工程选址、建设及建成后的长期安全性具有很大的影响,故本地区环境变化研究亦具有重要的现实意义。本文以罗布泊西北缘孔雀河北岸的LX02剖面为研究对象,在剖面沉积物光释光定年的基础上,依据晚更新世沉积物的粒度、色度、粘土矿物、碳酸盐含量、地球化学和孢粉等资料的分析和综合判别,结合统计学方法,建立了罗布泊西北缘72.4～51.Oka B.P.气候与环境变化序列,初步讨论了研究区72.4～51.Oka B.P.气候与环境变化及其对全球变化的响应。得出以下主要结论：(1)依据各环境指标随时间的波动变化将整个变化序列划分为三个阶段：72.4～66.8ka B.P.为冷干期,且冷干趋势在逐步加剧；66.8～56.1ka B.P.为暖湿期,但不乏小幅度的气候波动；56.1～51.Oka B.P.为冷干期,但冷干程度明显弱于72.4～66.8ka B.P.,且向暖湿方向发展。(2)罗布泊西北缘的气候变化具有不同于西风模式的水热配置特点,而类似于季风气候模式,即暖期湿润,冷期干旱。(3)利用主成分分析法,分别对地球化学元素指标和粒度、色度、碳酸盐指标进行了综合信息提取,并将其第一主成分(F1、F1’)在各气候阶段的平均值定义为暖湿指数。在此基础上,结合孢粉指标中B.T.P./(S.P.+H.P.)、松和栎花粉含量,与古里雅冰芯氧同位素、格陵兰冰芯氧同位素揭示的环境变化、北纬65。太阳辐射量,以及其它地区研究成果进行了对比分析,初步判断研究区72.4～51.Oka B.P.期间气候与环境变化进程受到全球变化的制约,但变化幅度的强弱和区域环境因素有关。通过高分辨率、多环境指标的综合研究,揭示了罗布泊西北缘72.4～51.OkaB.P.期间气候冷暖干湿的波动,并阐明了气候变化模式。本环境变化序列的建立,丰富了罗布泊地区晚更新世中期的气候与环境变化研究成果,为预测该区域未来数百年以至数千年可能出现的极端气候条件和突发性环境事件提供了可靠的理论依据。更多还原

【Abstract】 Lop Nur is located in the southeast of Xinjiang, China.lt is one of the driest places in the world. The environmental change in Lop Nur is the representative of the ancient climate and environment change of the mountainous region of Tarim Basin and its surroundings. Therefore, research on climate and environment change in this area is very valuable for researches on Global Change, ecological environment preservation and resources development and utilization of the drought desert area, and realistic for siting great construction projects with long-term safety evaluation during construction and after-construction.This article studied the LX02section on the north bank of Kongque River located on the northwest of the Lop Nur, based on the OSL of sediments of section, With the help of statistical methods72.4～51.0ka B.P. climate and environment change sequence on the northwest edge of the Lop Nur is established, according to the analysis and judgment of granularity, chroma, clay minerals, carbonate, geochemical elements and pollen of the sediment of the Late Pleistocene epoch, and the regional climate response to the global change is discussed. The following conclusions are developed:The whole change sequences can be classified as three stages according to each environmental index changing with time:72.4～66.8ka B.P. was a cold-arid period, and the trend became stronger with the time;66.8～56.1ka B.P. was a warm-humid period with small amplitude climatic fluctuations;56.1～51.0ka B.P. was a cold-arid period, though obviously weaker than in the period of72.4～66.8ka B.P. with a tend to another warm-humid period.The characteristics of hydrothermal allocation in the climate change in the northwest of the Lop Nur are different from those in the west westerlies, but similar with the monsoon climate mode, i.e., moist in warm period, and draught in cold period.The PCA (principal component analysis) is used for extracting the comprehensive information, such as global chemical elements index and indexes of granularity, chroma and carbonate.The average value of the first principal component (F1and F1’)in each stage is defined as warm and moisture index. Combined with B.T.P./(S.P.+H.P.) and the contents of the pine and oak pollens in sporopollen index, and compared with the change sequence of the oxygen isotopes of Guliya ice cores, as well as Greenland Highland and change sequence of radiant quantity of the sun at the northern latitude65°, it is initially determined that the climate and environment change progress in the area during the period of72.4～51.0ka B.P. had been restricted by the global change. However, the degree of change was related with the environmental factors in this region.Based on the comprehensive study of high resolution and multi environmental index, the waves of cold and warm, dry and moist and the climate change mode in the area of the northwest edge of the Lop Nur in the period of72.4～51.0kaB.P. are shown. The establishment of the environment change sequence makes the achievement of the climate and environment change study of the middle of the late Pleistocene of the Lop Nur, which provides a reliable basis for forecasting in this area the extreme climate conditions and unexpected environmental events that may occur in future hundreds and thousands of years.更多还原