罗布泊地区红柳沙包O、H同位素特征与环境变化研究.pdf

河北师范大学 硕士学位论文 罗布泊地区红柳沙包O、H同位素特征与环境变化研究 姓名：汪骏鸿 申请学位级别：硕士 专业：自然地理学 指导教师：赵元杰 20100330 III 摘 要 罗布泊洼地位于欧亚大陆腹地、塔里木盆地东部，是世界的极端干旱区该区南限 于阿尔金山，北限于库鲁克塔克及北山，东抵玉门关～阳关，西邻塔克拉玛干沙漠罗 布泊是塔里木盆地各大河流的归宿地， 它的环境演变是整个塔里木盆地和周边山地环境 演变的缩影 荒漠区是地球表层系统的重要组成部分，有独特的环境变化特征，全球变化科学体 系的完善需要这一地区环境变化研究的新成果 红柳沙包的存在从高分辨率计年和古环 境指示信息两方面为荒漠区古环境恢复提供了新的手段 罗布泊地区的红柳沙包主要分布在该区的南、西和西北部的河、湖沿岸及三角洲地 区在物质结构上，红柳沙包主要由红柳枝叶和风成沙互层堆积而成，红柳枝干穿插其 中大多数红柳沙包都具有清晰的沉积纹层，和树木年轮一样，它具有准确的计年和储 存环境信息的功能 本文以罗布泊地区红柳沙包为主要研究对象，采用移动平均法对红柳纤维素中的 δD 值和 δ18O 值进行预处理，并且通过相关性分析得出，δD0与 δ18O0存在显著相关 （R=0.32，p=0） 。

从而进一步分析红柳沙包稳定氢氧同位素与温度、相对湿度及降水等 气候因子之间的理论关系，探讨罗布泊地区近 160 余年来的环境演变状况主要研究内 容与结论为： （1）通过 δDma与各月平均最低气温、相对湿度的相关性分析，论证了 δD 与红柳 生长季节时的低温呈显著正相关，与生长季节的相对湿度呈显著负相关的观点 （2）δDma与 δ18Oma在红柳的生长季节都与降水呈负相关关系，体现了同位素分析 中的“雨量效应”，也可以解释为降水对红柳的生长作用较小，这与罗布泊红柳的生长 环境有关 （3）重建 3 月平均最低气温，发现罗布泊地区 3 月份最低气温总体趋势变化幅度 最多不超过 1℃，论证了温度变化这一微弱信息在植物生长过程中容易被丢失，导致与 植物稳定同位素的相关会很弱这一观点 （4）重建了 2~4 月平均相对湿度，发现 2~4 月份空气相对湿度的变化存在一定的 周期性，不过周期存在衰减现象，说明人类活动对该地区气候的影响越来越明显 （5）以 3 月平均气温的变化趋势作为冷暖期的划分依据，共划分了三个冷暖阶段： IV ①1844~1927 年，气温起伏波动小，期间有若干个偏冷或偏暖的交替；②1928~1963 年 为明显暖期，持续时间达 36 年；③1964~2006 年，总体为冷期，但在 1969~1973 年、 2002~2006 年两个时间段气温有升高现象，不过持续时间比较短。

（6）通过研究发现在较大时间尺度上，罗布泊地区在 20 世纪 60 年代中期之前是 较干燥的；20 世纪 60 年代中期以后，该地区降水开始增多，总体属于相对湿润期文 中以 7 月总降水量作为干湿期的划分依据，重建了罗布泊地区干湿期时段表 关键词：红柳沙包 δD δ18O 环境 罗布泊 V Abstract Lop Nur region is located in the hinterland of the Eurasian continent, and it is an extreme arid zone in the world. It is adjacent to Aljin Mountain in the south, and Kuruktag Mountain in the north, the Yumen Guan and Yang Guan in the east, the Taklimakan Desert in the west. Lop Nur is the accordant junction area of every river in Tarim Basin. The change of the environment in Lop Nur is a symbol for that of all the area in Tarim Basin and mountanious region around. Arid zone is an important part of the earth surface system. It has a unique characteristic of environmental change. New research for this area is needed to complete the global change science system. Tamarix Cone is a kind of biological landform and it provide a new means for the climatic factors of ancient environment reconstructiong from the two aspects both high-resolution dating and information in the carrier. Tamarix Cones in Lop Nur region are mainly distributed in the south and west and northwest, along the river, lake coastal and delta regions. Tamarix Cone is mainly deposited by the twigs and leaves of Tamarix and sand layers. Mostly, the Tamarix Cone has clear sediment layer, like tree-rings. And it has a function of exactly dating and environmental information storage. In this paper, the Tamarix Cone is the main object of study. Moving average method is used in this paper to pretreatment the data of δD values and δ18O values, and then through the correlation analysis, the result that δD0 and δ18O0 has a prominent correlation (r=0.32, p=0). Then the theoretical relationships between hydrogen isotope and air temperature, RH and precipitation are analysed, and also the oxygen isotope. The course of environment change in Lop Nur area in the last more than 160 years is sutdied. And the main process and conclusions are as follows: (1) Through the correlation analysis between δDma and the monthly mean minimum temperature, relative humidity, it is demonstrated that the relationship of δD and the minimum temperature in the season when the Tamarix is growing bloomly is positive correlation. And that is negative correlation between δD and RH. The results are all the same VI as the previous study. (2) δDma as well as δ18Oma has a negative correlationship with precipitation in Tamarix growing season, which reveals the effect of the precipitation rain fall. This is related with the surroundings where the Tamarix growing. (3) The average minimum temperature in March is reconstructed. And the change scope of the average minimum temperature in March is less than 1℃ in the last more than 160 years. That is because the information of temperature changing is easily lost in the Tamarix growing time. (4) The average RH from February to April is also reconstructed. And it reveals that the change of average RH from February to April has a certain periodity, but the periods has an attenuation phenomena, indicating human activities affecting the climate in the region is increasingly apparent. (5) Based on the changing trend of the mean temperature in March, three phases is divided as follows: 1844~1927, the temperature fluctuation is small, and there are several ① alternation between the cold and the warm periods; The period of 1828~1963 is an ② obviously warm time which lasted reach to 36 years; It can be ensured that the period of ③ 1964~2006 is totally cold time, but in the time of 1969~1973 and 2002~2006, the air temperature has a rising trend which are short durations. (6) Through the study, we found that in a longer time scale, the climate of Lop Nur region before the middle of the 1960s is relatively dry; after the middle of the 1960s, the precipitation began to increase in the 。